1*760c2415Smrg /* zlib.d: modified from zlib.h by Walter Bright */
2*760c2415Smrg /* updated from 1.2.1 to 1.2.3 by Thomas Kuehne */
3*760c2415Smrg /* updated from 1.2.3 to 1.2.8 by Dmitry Atamanov */
4*760c2415Smrg /* updated from 1.2.8 to 1.2.11 by Iain Buclaw */
5*760c2415Smrg
6*760c2415Smrg module etc.c.zlib;
7*760c2415Smrg
8*760c2415Smrg import core.stdc.config;
9*760c2415Smrg
10*760c2415Smrg /* zlib.h -- interface of the 'zlib' general purpose compression library
11*760c2415Smrg version 1.2.11, January 15th, 2017
12*760c2415Smrg
13*760c2415Smrg Copyright (C) 1995-2017 Jean-loup Gailly and Mark Adler
14*760c2415Smrg
15*760c2415Smrg This software is provided 'as-is', without any express or implied
16*760c2415Smrg warranty. In no event will the authors be held liable for any damages
17*760c2415Smrg arising from the use of this software.
18*760c2415Smrg
19*760c2415Smrg Permission is granted to anyone to use this software for any purpose,
20*760c2415Smrg including commercial applications, and to alter it and redistribute it
21*760c2415Smrg freely, subject to the following restrictions:
22*760c2415Smrg
23*760c2415Smrg 1. The origin of this software must not be misrepresented; you must not
24*760c2415Smrg claim that you wrote the original software. If you use this software
25*760c2415Smrg in a product, an acknowledgment in the product documentation would be
26*760c2415Smrg appreciated but is not required.
27*760c2415Smrg 2. Altered source versions must be plainly marked as such, and must not be
28*760c2415Smrg misrepresented as being the original software.
29*760c2415Smrg 3. This notice may not be removed or altered from any source distribution.
30*760c2415Smrg
31*760c2415Smrg Jean-loup Gailly Mark Adler
32*760c2415Smrg jloup@gzip.org madler@alumni.caltech.edu
33*760c2415Smrg
34*760c2415Smrg
35*760c2415Smrg The data format used by the zlib library is described by RFCs (Request for
36*760c2415Smrg Comments) 1950 to 1952 in the files http://tools.ietf.org/html/rfc1950
37*760c2415Smrg (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format).
38*760c2415Smrg */
39*760c2415Smrg
40*760c2415Smrg nothrow:
41*760c2415Smrg extern (C):
42*760c2415Smrg
43*760c2415Smrg const char[] ZLIB_VERSION = "1.2.11";
44*760c2415Smrg const ZLIB_VERNUM = 0x12b0;
45*760c2415Smrg
46*760c2415Smrg /*
47*760c2415Smrg The 'zlib' compression library provides in-memory compression and
48*760c2415Smrg decompression functions, including integrity checks of the uncompressed data.
49*760c2415Smrg This version of the library supports only one compression method (deflation)
50*760c2415Smrg but other algorithms will be added later and will have the same stream
51*760c2415Smrg interface.
52*760c2415Smrg
53*760c2415Smrg Compression can be done in a single step if the buffers are large enough,
54*760c2415Smrg or can be done by repeated calls of the compression function. In the latter
55*760c2415Smrg case, the application must provide more input and/or consume the output
56*760c2415Smrg (providing more output space) before each call.
57*760c2415Smrg
58*760c2415Smrg The compressed data format used by default by the in-memory functions is
59*760c2415Smrg the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped
60*760c2415Smrg around a deflate stream, which is itself documented in RFC 1951.
61*760c2415Smrg
62*760c2415Smrg The library also supports reading and writing files in gzip (.gz) format
63*760c2415Smrg with an interface similar to that of stdio using the functions that start
64*760c2415Smrg with "gz". The gzip format is different from the zlib format. gzip is a
65*760c2415Smrg gzip wrapper, documented in RFC 1952, wrapped around a deflate stream.
66*760c2415Smrg
67*760c2415Smrg This library can optionally read and write gzip and raw deflate streams in
68*760c2415Smrg memory as well.
69*760c2415Smrg
70*760c2415Smrg The zlib format was designed to be compact and fast for use in memory
71*760c2415Smrg and on communications channels. The gzip format was designed for single-
72*760c2415Smrg file compression on file systems, has a larger header than zlib to maintain
73*760c2415Smrg directory information, and uses a different, slower check method than zlib.
74*760c2415Smrg
75*760c2415Smrg The library does not install any signal handler. The decoder checks
76*760c2415Smrg the consistency of the compressed data, so the library should never crash
77*760c2415Smrg even in the case of corrupted input.
78*760c2415Smrg */
79*760c2415Smrg
80*760c2415Smrg alias alloc_func = void* function (void* opaque, uint items, uint size);
81*760c2415Smrg alias free_func = void function (void* opaque, void* address);
82*760c2415Smrg
83*760c2415Smrg struct z_stream
84*760c2415Smrg {
85*760c2415Smrg const(ubyte)* next_in; /* next input byte */
86*760c2415Smrg uint avail_in; /* number of bytes available at next_in */
87*760c2415Smrg c_ulong total_in; /* total nb of input bytes read so far */
88*760c2415Smrg
89*760c2415Smrg ubyte* next_out; /* next output byte will go here */
90*760c2415Smrg uint avail_out; /* remaining free space at next_out */
91*760c2415Smrg c_ulong total_out; /* total nb of bytes output so far */
92*760c2415Smrg
93*760c2415Smrg const(char)* msg; /* last error message, NULL if no error */
94*760c2415Smrg void* state; /* not visible by applications */
95*760c2415Smrg
96*760c2415Smrg alloc_func zalloc; /* used to allocate the internal state */
97*760c2415Smrg free_func zfree; /* used to free the internal state */
98*760c2415Smrg void* opaque; /* private data object passed to zalloc and zfree */
99*760c2415Smrg
100*760c2415Smrg int data_type; /* best guess about the data type: binary or text
101*760c2415Smrg for deflate, or the decoding state for inflate */
102*760c2415Smrg c_ulong adler; /* Adler-32 or CRC-32 value of the uncompressed data */
103*760c2415Smrg c_ulong reserved; /* reserved for future use */
104*760c2415Smrg }
105*760c2415Smrg
106*760c2415Smrg alias z_streamp = z_stream*;
107*760c2415Smrg
108*760c2415Smrg /*
109*760c2415Smrg gzip header information passed to and from zlib routines. See RFC 1952
110*760c2415Smrg for more details on the meanings of these fields.
111*760c2415Smrg */
112*760c2415Smrg struct gz_header
113*760c2415Smrg {
114*760c2415Smrg int text; /* true if compressed data believed to be text */
115*760c2415Smrg c_ulong time; /* modification time */
116*760c2415Smrg int xflags; /* extra flags (not used when writing a gzip file) */
117*760c2415Smrg int os; /* operating system */
118*760c2415Smrg byte *extra; /* pointer to extra field or Z_NULL if none */
119*760c2415Smrg uint extra_len; /* extra field length (valid if extra != Z_NULL) */
120*760c2415Smrg uint extra_max; /* space at extra (only when reading header) */
121*760c2415Smrg byte* name; /* pointer to zero-terminated file name or Z_NULL */
122*760c2415Smrg uint name_max; /* space at name (only when reading header) */
123*760c2415Smrg byte* comment; /* pointer to zero-terminated comment or Z_NULL */
124*760c2415Smrg uint comm_max; /* space at comment (only when reading header) */
125*760c2415Smrg int hcrc; /* true if there was or will be a header crc */
126*760c2415Smrg int done; /* true when done reading gzip header (not used
127*760c2415Smrg when writing a gzip file) */
128*760c2415Smrg }
129*760c2415Smrg
130*760c2415Smrg alias gz_headerp = gz_header*;
131*760c2415Smrg
132*760c2415Smrg /*
133*760c2415Smrg The application must update next_in and avail_in when avail_in has dropped
134*760c2415Smrg to zero. It must update next_out and avail_out when avail_out has dropped
135*760c2415Smrg to zero. The application must initialize zalloc, zfree and opaque before
136*760c2415Smrg calling the init function. All other fields are set by the compression
137*760c2415Smrg library and must not be updated by the application.
138*760c2415Smrg
139*760c2415Smrg The opaque value provided by the application will be passed as the first
140*760c2415Smrg parameter for calls of zalloc and zfree. This can be useful for custom
141*760c2415Smrg memory management. The compression library attaches no meaning to the
142*760c2415Smrg opaque value.
143*760c2415Smrg
144*760c2415Smrg zalloc must return Z_NULL if there is not enough memory for the object.
145*760c2415Smrg If zlib is used in a multi-threaded application, zalloc and zfree must be
146*760c2415Smrg thread safe. In that case, zlib is thread-safe. When zalloc and zfree are
147*760c2415Smrg Z_NULL on entry to the initialization function, they are set to internal
148*760c2415Smrg routines that use the standard library functions malloc() and free().
149*760c2415Smrg
150*760c2415Smrg On 16-bit systems, the functions zalloc and zfree must be able to allocate
151*760c2415Smrg exactly 65536 bytes, but will not be required to allocate more than this if
152*760c2415Smrg the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, pointers
153*760c2415Smrg returned by zalloc for objects of exactly 65536 bytes *must* have their
154*760c2415Smrg offset normalized to zero. The default allocation function provided by this
155*760c2415Smrg library ensures this (see zutil.c). To reduce memory requirements and avoid
156*760c2415Smrg any allocation of 64K objects, at the expense of compression ratio, compile
157*760c2415Smrg the library with -DMAX_WBITS=14 (see zconf.h).
158*760c2415Smrg
159*760c2415Smrg The fields total_in and total_out can be used for statistics or progress
160*760c2415Smrg reports. After compression, total_in holds the total size of the
161*760c2415Smrg uncompressed data and may be saved for use by the decompressor (particularly
162*760c2415Smrg if the decompressor wants to decompress everything in a single step).
163*760c2415Smrg */
164*760c2415Smrg
165*760c2415Smrg /* constants */
166*760c2415Smrg
167*760c2415Smrg enum
168*760c2415Smrg {
169*760c2415Smrg Z_NO_FLUSH = 0,
170*760c2415Smrg Z_PARTIAL_FLUSH = 1, /* will be removed, use Z_SYNC_FLUSH instead */
171*760c2415Smrg Z_SYNC_FLUSH = 2,
172*760c2415Smrg Z_FULL_FLUSH = 3,
173*760c2415Smrg Z_FINISH = 4,
174*760c2415Smrg Z_BLOCK = 5,
175*760c2415Smrg Z_TREES = 6,
176*760c2415Smrg }
177*760c2415Smrg /* Allowed flush values; see deflate() and inflate() below for details */
178*760c2415Smrg
179*760c2415Smrg enum
180*760c2415Smrg {
181*760c2415Smrg Z_OK = 0,
182*760c2415Smrg Z_STREAM_END = 1,
183*760c2415Smrg Z_NEED_DICT = 2,
184*760c2415Smrg Z_ERRNO = -1,
185*760c2415Smrg Z_STREAM_ERROR = -2,
186*760c2415Smrg Z_DATA_ERROR = -3,
187*760c2415Smrg Z_MEM_ERROR = -4,
188*760c2415Smrg Z_BUF_ERROR = -5,
189*760c2415Smrg Z_VERSION_ERROR = -6,
190*760c2415Smrg }
191*760c2415Smrg /* Return codes for the compression/decompression functions. Negative
192*760c2415Smrg * values are errors, positive values are used for special but normal events.
193*760c2415Smrg */
194*760c2415Smrg
195*760c2415Smrg enum
196*760c2415Smrg {
197*760c2415Smrg Z_NO_COMPRESSION = 0,
198*760c2415Smrg Z_BEST_SPEED = 1,
199*760c2415Smrg Z_BEST_COMPRESSION = 9,
200*760c2415Smrg Z_DEFAULT_COMPRESSION = -1,
201*760c2415Smrg }
202*760c2415Smrg /* compression levels */
203*760c2415Smrg
204*760c2415Smrg enum
205*760c2415Smrg {
206*760c2415Smrg Z_FILTERED = 1,
207*760c2415Smrg Z_HUFFMAN_ONLY = 2,
208*760c2415Smrg Z_RLE = 3,
209*760c2415Smrg Z_FIXED = 4,
210*760c2415Smrg Z_DEFAULT_STRATEGY = 0,
211*760c2415Smrg }
212*760c2415Smrg /* compression strategy; see deflateInit2() below for details */
213*760c2415Smrg
214*760c2415Smrg enum
215*760c2415Smrg {
216*760c2415Smrg Z_BINARY = 0,
217*760c2415Smrg Z_TEXT = 1,
218*760c2415Smrg Z_UNKNOWN = 2,
219*760c2415Smrg
220*760c2415Smrg Z_ASCII = Z_TEXT
221*760c2415Smrg }
222*760c2415Smrg /* Possible values of the data_type field for deflate() */
223*760c2415Smrg
224*760c2415Smrg enum
225*760c2415Smrg {
226*760c2415Smrg Z_DEFLATED = 8,
227*760c2415Smrg }
228*760c2415Smrg /* The deflate compression method (the only one supported in this version) */
229*760c2415Smrg
230*760c2415Smrg const int Z_NULL = 0; /* for initializing zalloc, zfree, opaque */
231*760c2415Smrg
232*760c2415Smrg /* basic functions */
233*760c2415Smrg
234*760c2415Smrg const(char)* zlibVersion();
235*760c2415Smrg /* The application can compare zlibVersion and ZLIB_VERSION for consistency.
236*760c2415Smrg If the first character differs, the library code actually used is not
237*760c2415Smrg compatible with the zlib.h header file used by the application. This check
238*760c2415Smrg is automatically made by deflateInit and inflateInit.
239*760c2415Smrg */
240*760c2415Smrg
deflateInit(z_streamp strm,int level)241*760c2415Smrg int deflateInit(z_streamp strm, int level)
242*760c2415Smrg {
243*760c2415Smrg return deflateInit_(strm, level, ZLIB_VERSION.ptr, z_stream.sizeof);
244*760c2415Smrg }
245*760c2415Smrg /*
246*760c2415Smrg Initializes the internal stream state for compression. The fields
247*760c2415Smrg zalloc, zfree and opaque must be initialized before by the caller. If
248*760c2415Smrg zalloc and zfree are set to Z_NULL, deflateInit updates them to use default
249*760c2415Smrg allocation functions.
250*760c2415Smrg
251*760c2415Smrg The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
252*760c2415Smrg 1 gives best speed, 9 gives best compression, 0 gives no compression at all
253*760c2415Smrg (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION
254*760c2415Smrg requests a default compromise between speed and compression (currently
255*760c2415Smrg equivalent to level 6).
256*760c2415Smrg
257*760c2415Smrg deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
258*760c2415Smrg memory, Z_STREAM_ERROR if level is not a valid compression level, or
259*760c2415Smrg Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
260*760c2415Smrg with the version assumed by the caller (ZLIB_VERSION). msg is set to null
261*760c2415Smrg if there is no error message. deflateInit does not perform any compression:
262*760c2415Smrg this will be done by deflate().
263*760c2415Smrg */
264*760c2415Smrg
265*760c2415Smrg
266*760c2415Smrg int deflate(z_streamp strm, int flush);
267*760c2415Smrg /*
268*760c2415Smrg deflate compresses as much data as possible, and stops when the input
269*760c2415Smrg buffer becomes empty or the output buffer becomes full. It may introduce
270*760c2415Smrg some output latency (reading input without producing any output) except when
271*760c2415Smrg forced to flush.
272*760c2415Smrg
273*760c2415Smrg The detailed semantics are as follows. deflate performs one or both of the
274*760c2415Smrg following actions:
275*760c2415Smrg
276*760c2415Smrg - Compress more input starting at next_in and update next_in and avail_in
277*760c2415Smrg accordingly. If not all input can be processed (because there is not
278*760c2415Smrg enough room in the output buffer), next_in and avail_in are updated and
279*760c2415Smrg processing will resume at this point for the next call of deflate().
280*760c2415Smrg
281*760c2415Smrg - Generate more output starting at next_out and update next_out and avail_out
282*760c2415Smrg accordingly. This action is forced if the parameter flush is non zero.
283*760c2415Smrg Forcing flush frequently degrades the compression ratio, so this parameter
284*760c2415Smrg should be set only when necessary. Some output may be provided even if
285*760c2415Smrg flush is zero.
286*760c2415Smrg
287*760c2415Smrg Before the call of deflate(), the application should ensure that at least
288*760c2415Smrg one of the actions is possible, by providing more input and/or consuming more
289*760c2415Smrg output, and updating avail_in or avail_out accordingly; avail_out should
290*760c2415Smrg never be zero before the call. The application can consume the compressed
291*760c2415Smrg output when it wants, for example when the output buffer is full (avail_out
292*760c2415Smrg == 0), or after each call of deflate(). If deflate returns Z_OK and with
293*760c2415Smrg zero avail_out, it must be called again after making room in the output
294*760c2415Smrg buffer because there might be more output pending. See deflatePending(),
295*760c2415Smrg which can be used if desired to determine whether or not there is more ouput
296*760c2415Smrg in that case.
297*760c2415Smrg
298*760c2415Smrg Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to
299*760c2415Smrg decide how much data to accumulate before producing output, in order to
300*760c2415Smrg maximize compression.
301*760c2415Smrg
302*760c2415Smrg If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
303*760c2415Smrg flushed to the output buffer and the output is aligned on a byte boundary, so
304*760c2415Smrg that the decompressor can get all input data available so far. (In
305*760c2415Smrg particular avail_in is zero after the call if enough output space has been
306*760c2415Smrg provided before the call.) Flushing may degrade compression for some
307*760c2415Smrg compression algorithms and so it should be used only when necessary. This
308*760c2415Smrg completes the current deflate block and follows it with an empty stored block
309*760c2415Smrg that is three bits plus filler bits to the next byte, followed by four bytes
310*760c2415Smrg (00 00 ff ff).
311*760c2415Smrg
312*760c2415Smrg If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the
313*760c2415Smrg output buffer, but the output is not aligned to a byte boundary. All of the
314*760c2415Smrg input data so far will be available to the decompressor, as for Z_SYNC_FLUSH.
315*760c2415Smrg This completes the current deflate block and follows it with an empty fixed
316*760c2415Smrg codes block that is 10 bits long. This assures that enough bytes are output
317*760c2415Smrg in order for the decompressor to finish the block before the empty fixed
318*760c2415Smrg codes block.
319*760c2415Smrg
320*760c2415Smrg If flush is set to Z_BLOCK, a deflate block is completed and emitted, as
321*760c2415Smrg for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to
322*760c2415Smrg seven bits of the current block are held to be written as the next byte after
323*760c2415Smrg the next deflate block is completed. In this case, the decompressor may not
324*760c2415Smrg be provided enough bits at this point in order to complete decompression of
325*760c2415Smrg the data provided so far to the compressor. It may need to wait for the next
326*760c2415Smrg block to be emitted. This is for advanced applications that need to control
327*760c2415Smrg the emission of deflate blocks.
328*760c2415Smrg
329*760c2415Smrg If flush is set to Z_FULL_FLUSH, all output is flushed as with
330*760c2415Smrg Z_SYNC_FLUSH, and the compression state is reset so that decompression can
331*760c2415Smrg restart from this point if previous compressed data has been damaged or if
332*760c2415Smrg random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
333*760c2415Smrg compression.
334*760c2415Smrg
335*760c2415Smrg If deflate returns with avail_out == 0, this function must be called again
336*760c2415Smrg with the same value of the flush parameter and more output space (updated
337*760c2415Smrg avail_out), until the flush is complete (deflate returns with non-zero
338*760c2415Smrg avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that
339*760c2415Smrg avail_out is greater than six to avoid repeated flush markers due to
340*760c2415Smrg avail_out == 0 on return.
341*760c2415Smrg
342*760c2415Smrg If the parameter flush is set to Z_FINISH, pending input is processed,
343*760c2415Smrg pending output is flushed and deflate returns with Z_STREAM_END if there was
344*760c2415Smrg enough output space. If deflate returns with Z_OK or Z_BUF_ERROR, this
345*760c2415Smrg function must be called again with Z_FINISH and more output space (updated
346*760c2415Smrg avail_out) but no more input data, until it returns with Z_STREAM_END or an
347*760c2415Smrg error. After deflate has returned Z_STREAM_END, the only possible operations
348*760c2415Smrg on the stream are deflateReset or deflateEnd.
349*760c2415Smrg
350*760c2415Smrg Z_FINISH can be used in the first deflate call after deflateInit if all the
351*760c2415Smrg compression is to be done in a single step. In order to complete in one
352*760c2415Smrg call, avail_out must be at least the value returned by deflateBound (see
353*760c2415Smrg below). Then deflate is guaranteed to return Z_STREAM_END. If not enough
354*760c2415Smrg output space is provided, deflate will not return Z_STREAM_END, and it must
355*760c2415Smrg be called again as described above.
356*760c2415Smrg
357*760c2415Smrg deflate() sets strm->adler to the Adler-32 checksum of all input read
358*760c2415Smrg so far (that is, total_in bytes). If a gzip stream is being generated, then
359*760c2415Smrg strm->adler will be the CRC-32 checksum of the input read so far. (See
360*760c2415Smrg deflateInit2 below.)
361*760c2415Smrg
362*760c2415Smrg deflate() may update strm->data_type if it can make a good guess about
363*760c2415Smrg the input data type (Z_BINARY or Z_TEXT). If in doubt, the data is
364*760c2415Smrg considered binary. This field is only for information purposes and does not
365*760c2415Smrg affect the compression algorithm in any manner.
366*760c2415Smrg
367*760c2415Smrg deflate() returns Z_OK if some progress has been made (more input
368*760c2415Smrg processed or more output produced), Z_STREAM_END if all input has been
369*760c2415Smrg consumed and all output has been produced (only when flush is set to
370*760c2415Smrg Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
371*760c2415Smrg if next_in or next_out was Z_NULL or the state was inadvertently written over
372*760c2415Smrg by the application), or Z_BUF_ERROR if no progress is possible (for example
373*760c2415Smrg avail_in or avail_out was zero). Note that Z_BUF_ERROR is not fatal, and
374*760c2415Smrg deflate() can be called again with more input and more output space to
375*760c2415Smrg continue compressing.
376*760c2415Smrg */
377*760c2415Smrg
378*760c2415Smrg
379*760c2415Smrg int deflateEnd(z_streamp strm);
380*760c2415Smrg /*
381*760c2415Smrg All dynamically allocated data structures for this stream are freed.
382*760c2415Smrg This function discards any unprocessed input and does not flush any pending
383*760c2415Smrg output.
384*760c2415Smrg
385*760c2415Smrg deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
386*760c2415Smrg stream state was inconsistent, Z_DATA_ERROR if the stream was freed
387*760c2415Smrg prematurely (some input or output was discarded). In the error case, msg
388*760c2415Smrg may be set but then points to a static string (which must not be
389*760c2415Smrg deallocated).
390*760c2415Smrg */
391*760c2415Smrg
392*760c2415Smrg
inflateInit(z_streamp strm)393*760c2415Smrg int inflateInit(z_streamp strm)
394*760c2415Smrg {
395*760c2415Smrg return inflateInit_(strm, ZLIB_VERSION.ptr, z_stream.sizeof);
396*760c2415Smrg }
397*760c2415Smrg /*
398*760c2415Smrg Initializes the internal stream state for decompression. The fields
399*760c2415Smrg next_in, avail_in, zalloc, zfree and opaque must be initialized before by
400*760c2415Smrg the caller. In the current version of inflate, the provided input is not
401*760c2415Smrg read or consumed. The allocation of a sliding window will be deferred to
402*760c2415Smrg the first call of inflate (if the decompression does not complete on the
403*760c2415Smrg first call). If zalloc and zfree are set to Z_NULL, inflateInit updates
404*760c2415Smrg them to use default allocation functions.
405*760c2415Smrg
406*760c2415Smrg inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
407*760c2415Smrg memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
408*760c2415Smrg version assumed by the caller, or Z_STREAM_ERROR if the parameters are
409*760c2415Smrg invalid, such as a null pointer to the structure. msg is set to null if
410*760c2415Smrg there is no error message. inflateInit does not perform any decompression.
411*760c2415Smrg Actual decompression will be done by inflate(). So next_in, and avail_in,
412*760c2415Smrg next_out, and avail_out are unused and unchanged. The current
413*760c2415Smrg implementation of inflateInit() does not process any header information --
414*760c2415Smrg that is deferred until inflate() is called.
415*760c2415Smrg */
416*760c2415Smrg
417*760c2415Smrg
418*760c2415Smrg int inflate(z_streamp strm, int flush);
419*760c2415Smrg /*
420*760c2415Smrg inflate decompresses as much data as possible, and stops when the input
421*760c2415Smrg buffer becomes empty or the output buffer becomes full. It may introduce
422*760c2415Smrg some output latency (reading input without producing any output) except when
423*760c2415Smrg forced to flush.
424*760c2415Smrg
425*760c2415Smrg The detailed semantics are as follows. inflate performs one or both of the
426*760c2415Smrg following actions:
427*760c2415Smrg
428*760c2415Smrg - Decompress more input starting at next_in and update next_in and avail_in
429*760c2415Smrg accordingly. If not all input can be processed (because there is not
430*760c2415Smrg enough room in the output buffer), then next_in and avail_in are updated
431*760c2415Smrg accordingly, and processing will resume at this point for the next call of
432*760c2415Smrg inflate().
433*760c2415Smrg
434*760c2415Smrg - Generate more output starting at next_out and update next_out and avail_out
435*760c2415Smrg accordingly. inflate() provides as much output as possible, until there is
436*760c2415Smrg no more input data or no more space in the output buffer (see below about
437*760c2415Smrg the flush parameter).
438*760c2415Smrg
439*760c2415Smrg Before the call of inflate(), the application should ensure that at least
440*760c2415Smrg one of the actions is possible, by providing more input and/or consuming more
441*760c2415Smrg output, and updating the next_* and avail_* values accordingly. If the
442*760c2415Smrg caller of inflate() does not provide both available input and available
443*760c2415Smrg output space, it is possible that there will be no progress made. The
444*760c2415Smrg application can consume the uncompressed output when it wants, for example
445*760c2415Smrg when the output buffer is full (avail_out == 0), or after each call of
446*760c2415Smrg inflate(). If inflate returns Z_OK and with zero avail_out, it must be
447*760c2415Smrg called again after making room in the output buffer because there might be
448*760c2415Smrg more output pending.
449*760c2415Smrg
450*760c2415Smrg The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH,
451*760c2415Smrg Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much
452*760c2415Smrg output as possible to the output buffer. Z_BLOCK requests that inflate()
453*760c2415Smrg stop if and when it gets to the next deflate block boundary. When decoding
454*760c2415Smrg the zlib or gzip format, this will cause inflate() to return immediately
455*760c2415Smrg after the header and before the first block. When doing a raw inflate,
456*760c2415Smrg inflate() will go ahead and process the first block, and will return when it
457*760c2415Smrg gets to the end of that block, or when it runs out of data.
458*760c2415Smrg
459*760c2415Smrg The Z_BLOCK option assists in appending to or combining deflate streams.
460*760c2415Smrg To assist in this, on return inflate() always sets strm->data_type to the
461*760c2415Smrg number of unused bits in the last byte taken from strm->next_in, plus 64 if
462*760c2415Smrg inflate() is currently decoding the last block in the deflate stream, plus
463*760c2415Smrg 128 if inflate() returned immediately after decoding an end-of-block code or
464*760c2415Smrg decoding the complete header up to just before the first byte of the deflate
465*760c2415Smrg stream. The end-of-block will not be indicated until all of the uncompressed
466*760c2415Smrg data from that block has been written to strm->next_out. The number of
467*760c2415Smrg unused bits may in general be greater than seven, except when bit 7 of
468*760c2415Smrg data_type is set, in which case the number of unused bits will be less than
469*760c2415Smrg eight. data_type is set as noted here every time inflate() returns for all
470*760c2415Smrg flush options, and so can be used to determine the amount of currently
471*760c2415Smrg consumed input in bits.
472*760c2415Smrg
473*760c2415Smrg The Z_TREES option behaves as Z_BLOCK does, but it also returns when the
474*760c2415Smrg end of each deflate block header is reached, before any actual data in that
475*760c2415Smrg block is decoded. This allows the caller to determine the length of the
476*760c2415Smrg deflate block header for later use in random access within a deflate block.
477*760c2415Smrg 256 is added to the value of strm->data_type when inflate() returns
478*760c2415Smrg immediately after reaching the end of the deflate block header.
479*760c2415Smrg
480*760c2415Smrg inflate() should normally be called until it returns Z_STREAM_END or an
481*760c2415Smrg error. However if all decompression is to be performed in a single step (a
482*760c2415Smrg single call of inflate), the parameter flush should be set to Z_FINISH. In
483*760c2415Smrg this case all pending input is processed and all pending output is flushed;
484*760c2415Smrg avail_out must be large enough to hold all of the uncompressed data for the
485*760c2415Smrg operation to complete. (The size of the uncompressed data may have been
486*760c2415Smrg saved by the compressor for this purpose.) The use of Z_FINISH is not
487*760c2415Smrg required to perform an inflation in one step. However it may be used to
488*760c2415Smrg inform inflate that a faster approach can be used for the single inflate()
489*760c2415Smrg call. Z_FINISH also informs inflate to not maintain a sliding window if the
490*760c2415Smrg stream completes, which reduces inflate's memory footprint. If the stream
491*760c2415Smrg does not complete, either because not all of the stream is provided or not
492*760c2415Smrg enough output space is provided, then a sliding window will be allocated and
493*760c2415Smrg inflate() can be called again to continue the operation as if Z_NO_FLUSH had
494*760c2415Smrg been used.
495*760c2415Smrg
496*760c2415Smrg In this implementation, inflate() always flushes as much output as
497*760c2415Smrg possible to the output buffer, and always uses the faster approach on the
498*760c2415Smrg first call. So the effects of the flush parameter in this implementation are
499*760c2415Smrg on the return value of inflate() as noted below, when inflate() returns early
500*760c2415Smrg when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of
501*760c2415Smrg memory for a sliding window when Z_FINISH is used.
502*760c2415Smrg
503*760c2415Smrg If a preset dictionary is needed after this call (see inflateSetDictionary
504*760c2415Smrg below), inflate sets strm->adler to the Adler-32 checksum of the dictionary
505*760c2415Smrg chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
506*760c2415Smrg strm->adler to the Adler-32 checksum of all output produced so far (that is,
507*760c2415Smrg total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
508*760c2415Smrg below. At the end of the stream, inflate() checks that its computed Adler-32
509*760c2415Smrg checksum is equal to that saved by the compressor and returns Z_STREAM_END
510*760c2415Smrg only if the checksum is correct.
511*760c2415Smrg
512*760c2415Smrg inflate() can decompress and check either zlib-wrapped or gzip-wrapped
513*760c2415Smrg deflate data. The header type is detected automatically, if requested when
514*760c2415Smrg initializing with inflateInit2(). Any information contained in the gzip
515*760c2415Smrg header is not retained unless inflateGetHeader() is used. When processing
516*760c2415Smrg gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output
517*760c2415Smrg produced so far. The CRC-32 is checked against the gzip trailer, as is the
518*760c2415Smrg uncompressed length, modulo 2^32.
519*760c2415Smrg
520*760c2415Smrg inflate() returns Z_OK if some progress has been made (more input processed
521*760c2415Smrg or more output produced), Z_STREAM_END if the end of the compressed data has
522*760c2415Smrg been reached and all uncompressed output has been produced, Z_NEED_DICT if a
523*760c2415Smrg preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
524*760c2415Smrg corrupted (input stream not conforming to the zlib format or incorrect check
525*760c2415Smrg value, in which case strm->msg points to a string with a more specific
526*760c2415Smrg error), Z_STREAM_ERROR if the stream structure was inconsistent (for example
527*760c2415Smrg next_in or next_out was Z_NULL, or the state was inadvertently written over
528*760c2415Smrg by the application), Z_MEM_ERROR if there was not enough memory, Z_BUF_ERROR
529*760c2415Smrg if no progress was possible or if there was not enough room in the output
530*760c2415Smrg buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and
531*760c2415Smrg inflate() can be called again with more input and more output space to
532*760c2415Smrg continue decompressing. If Z_DATA_ERROR is returned, the application may
533*760c2415Smrg then call inflateSync() to look for a good compression block if a partial
534*760c2415Smrg recovery of the data is to be attempted.
535*760c2415Smrg */
536*760c2415Smrg
537*760c2415Smrg
538*760c2415Smrg int inflateEnd(z_streamp strm);
539*760c2415Smrg /*
540*760c2415Smrg All dynamically allocated data structures for this stream are freed.
541*760c2415Smrg This function discards any unprocessed input and does not flush any pending
542*760c2415Smrg output.
543*760c2415Smrg
544*760c2415Smrg inflateEnd returns Z_OK if success, or Z_STREAM_ERROR if the stream state
545*760c2415Smrg was inconsistent.
546*760c2415Smrg */
547*760c2415Smrg
548*760c2415Smrg /* Advanced functions */
549*760c2415Smrg
550*760c2415Smrg /*
551*760c2415Smrg The following functions are needed only in some special applications.
552*760c2415Smrg */
553*760c2415Smrg
deflateInit2(z_streamp strm,int level,int method,int windowBits,int memLevel,int strategy)554*760c2415Smrg int deflateInit2(z_streamp strm,
555*760c2415Smrg int level,
556*760c2415Smrg int method,
557*760c2415Smrg int windowBits,
558*760c2415Smrg int memLevel,
559*760c2415Smrg int strategy)
560*760c2415Smrg {
561*760c2415Smrg return deflateInit2_(strm, level, method, windowBits, memLevel,
562*760c2415Smrg strategy, ZLIB_VERSION.ptr, z_stream.sizeof);
563*760c2415Smrg }
564*760c2415Smrg /*
565*760c2415Smrg This is another version of deflateInit with more compression options. The
566*760c2415Smrg fields next_in, zalloc, zfree and opaque must be initialized before by the
567*760c2415Smrg caller.
568*760c2415Smrg
569*760c2415Smrg The method parameter is the compression method. It must be Z_DEFLATED in
570*760c2415Smrg this version of the library.
571*760c2415Smrg
572*760c2415Smrg The windowBits parameter is the base two logarithm of the window size
573*760c2415Smrg (the size of the history buffer). It should be in the range 8 .. 15 for this
574*760c2415Smrg version of the library. Larger values of this parameter result in better
575*760c2415Smrg compression at the expense of memory usage. The default value is 15 if
576*760c2415Smrg deflateInit is used instead.
577*760c2415Smrg
578*760c2415Smrg For the current implementation of deflate(), a windowBits value of 8 (a
579*760c2415Smrg window size of 256 bytes) is not supported. As a result, a request for 8
580*760c2415Smrg will result in 9 (a 512-byte window). In that case, providing 8 to
581*760c2415Smrg inflateInit2() will result in an error when the zlib header with 9 is
582*760c2415Smrg checked against the initialization of inflate(). The remedy is to not use 8
583*760c2415Smrg with deflateInit2() with this initialization, or at least in that case use 9
584*760c2415Smrg with inflateInit2().
585*760c2415Smrg
586*760c2415Smrg windowBits can also be -8..-15 for raw deflate. In this case, -windowBits
587*760c2415Smrg determines the window size. deflate() will then generate raw deflate data
588*760c2415Smrg with no zlib header or trailer, and will not compute a check value.
589*760c2415Smrg
590*760c2415Smrg windowBits can also be greater than 15 for optional gzip encoding. Add
591*760c2415Smrg 16 to windowBits to write a simple gzip header and trailer around the
592*760c2415Smrg compressed data instead of a zlib wrapper. The gzip header will have no
593*760c2415Smrg file name, no extra data, no comment, no modification time (set to zero), no
594*760c2415Smrg header crc, and the operating system will be set to the appropriate value,
595*760c2415Smrg if the operating system was determined at compile time. If a gzip stream is
596*760c2415Smrg being written, strm->adler is a CRC-32 instead of an Adler-32.
597*760c2415Smrg
598*760c2415Smrg For raw deflate or gzip encoding, a request for a 256-byte window is
599*760c2415Smrg rejected as invalid, since only the zlib header provides a means of
600*760c2415Smrg transmitting the window size to the decompressor.
601*760c2415Smrg
602*760c2415Smrg The memLevel parameter specifies how much memory should be allocated
603*760c2415Smrg for the internal compression state. memLevel=1 uses minimum memory but is
604*760c2415Smrg slow and reduces compression ratio; memLevel=9 uses maximum memory for
605*760c2415Smrg optimal speed. The default value is 8. See zconf.h for total memory usage
606*760c2415Smrg as a function of windowBits and memLevel.
607*760c2415Smrg
608*760c2415Smrg The strategy parameter is used to tune the compression algorithm. Use the
609*760c2415Smrg value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
610*760c2415Smrg filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no
611*760c2415Smrg string match), or Z_RLE to limit match distances to one (run-length
612*760c2415Smrg encoding). Filtered data consists mostly of small values with a somewhat
613*760c2415Smrg random distribution. In this case, the compression algorithm is tuned to
614*760c2415Smrg compress them better. The effect of Z_FILTERED is to force more Huffman
615*760c2415Smrg coding and less string matching; it is somewhat intermediate between
616*760c2415Smrg Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as
617*760c2415Smrg fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The
618*760c2415Smrg strategy parameter only affects the compression ratio but not the
619*760c2415Smrg correctness of the compressed output even if it is not set appropriately.
620*760c2415Smrg Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler
621*760c2415Smrg decoder for special applications.
622*760c2415Smrg
623*760c2415Smrg deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
624*760c2415Smrg memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid
625*760c2415Smrg method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is
626*760c2415Smrg incompatible with the version assumed by the caller (ZLIB_VERSION). msg is
627*760c2415Smrg set to null if there is no error message. deflateInit2 does not perform any
628*760c2415Smrg compression: this will be done by deflate().
629*760c2415Smrg */
630*760c2415Smrg
631*760c2415Smrg int deflateSetDictionary(z_streamp strm, const(ubyte)* dictionary, uint dictLength);
632*760c2415Smrg /*
633*760c2415Smrg Initializes the compression dictionary from the given byte sequence
634*760c2415Smrg without producing any compressed output. When using the zlib format, this
635*760c2415Smrg function must be called immediately after deflateInit, deflateInit2 or
636*760c2415Smrg deflateReset, and before any call of deflate. When doing raw deflate, this
637*760c2415Smrg function must be called either before any call of deflate, or immediately
638*760c2415Smrg after the completion of a deflate block, i.e. after all input has been
639*760c2415Smrg consumed and all output has been delivered when using any of the flush
640*760c2415Smrg options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The
641*760c2415Smrg compressor and decompressor must use exactly the same dictionary (see
642*760c2415Smrg inflateSetDictionary).
643*760c2415Smrg
644*760c2415Smrg The dictionary should consist of strings (byte sequences) that are likely
645*760c2415Smrg to be encountered later in the data to be compressed, with the most commonly
646*760c2415Smrg used strings preferably put towards the end of the dictionary. Using a
647*760c2415Smrg dictionary is most useful when the data to be compressed is short and can be
648*760c2415Smrg predicted with good accuracy; the data can then be compressed better than
649*760c2415Smrg with the default empty dictionary.
650*760c2415Smrg
651*760c2415Smrg Depending on the size of the compression data structures selected by
652*760c2415Smrg deflateInit or deflateInit2, a part of the dictionary may in effect be
653*760c2415Smrg discarded, for example if the dictionary is larger than the window size
654*760c2415Smrg provided in deflateInit or deflateInit2. Thus the strings most likely to be
655*760c2415Smrg useful should be put at the end of the dictionary, not at the front. In
656*760c2415Smrg addition, the current implementation of deflate will use at most the window
657*760c2415Smrg size minus 262 bytes of the provided dictionary.
658*760c2415Smrg
659*760c2415Smrg Upon return of this function, strm->adler is set to the Adler-32 value
660*760c2415Smrg of the dictionary; the decompressor may later use this value to determine
661*760c2415Smrg which dictionary has been used by the compressor. (The Adler-32 value
662*760c2415Smrg applies to the whole dictionary even if only a subset of the dictionary is
663*760c2415Smrg actually used by the compressor.) If a raw deflate was requested, then the
664*760c2415Smrg Adler-32 value is not computed and strm->adler is not set.
665*760c2415Smrg
666*760c2415Smrg deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
667*760c2415Smrg parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
668*760c2415Smrg inconsistent (for example if deflate has already been called for this stream
669*760c2415Smrg or if not at a block boundary for raw deflate). deflateSetDictionary does
670*760c2415Smrg not perform any compression: this will be done by deflate().
671*760c2415Smrg */
672*760c2415Smrg
673*760c2415Smrg int deflateGetDictionary(z_streamp strm, ubyte *dictionary, uint dictLength);
674*760c2415Smrg /*
675*760c2415Smrg Returns the sliding dictionary being maintained by deflate. dictLength is
676*760c2415Smrg set to the number of bytes in the dictionary, and that many bytes are copied
677*760c2415Smrg to dictionary. dictionary must have enough space, where 32768 bytes is
678*760c2415Smrg always enough. If deflateGetDictionary() is called with dictionary equal to
679*760c2415Smrg Z_NULL, then only the dictionary length is returned, and nothing is copied.
680*760c2415Smrg Similary, if dictLength is Z_NULL, then it is not set.
681*760c2415Smrg
682*760c2415Smrg deflateGetDictionary() may return a length less than the window size, even
683*760c2415Smrg when more than the window size in input has been provided. It may return up
684*760c2415Smrg to 258 bytes less in that case, due to how zlib's implementation of deflate
685*760c2415Smrg manages the sliding window and lookahead for matches, where matches can be
686*760c2415Smrg up to 258 bytes long. If the application needs the last window-size bytes of
687*760c2415Smrg input, then that would need to be saved by the application outside of zlib.
688*760c2415Smrg
689*760c2415Smrg deflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the
690*760c2415Smrg stream state is inconsistent.
691*760c2415Smrg */
692*760c2415Smrg
693*760c2415Smrg int deflateCopy(z_streamp dest, z_streamp source);
694*760c2415Smrg /*
695*760c2415Smrg Sets the destination stream as a complete copy of the source stream.
696*760c2415Smrg
697*760c2415Smrg This function can be useful when several compression strategies will be
698*760c2415Smrg tried, for example when there are several ways of pre-processing the input
699*760c2415Smrg data with a filter. The streams that will be discarded should then be freed
700*760c2415Smrg by calling deflateEnd. Note that deflateCopy duplicates the internal
701*760c2415Smrg compression state which can be quite large, so this strategy is slow and can
702*760c2415Smrg consume lots of memory.
703*760c2415Smrg
704*760c2415Smrg deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
705*760c2415Smrg enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
706*760c2415Smrg (such as zalloc being Z_NULL). msg is left unchanged in both source and
707*760c2415Smrg destination.
708*760c2415Smrg */
709*760c2415Smrg
710*760c2415Smrg int deflateReset(z_streamp strm);
711*760c2415Smrg /*
712*760c2415Smrg This function is equivalent to deflateEnd followed by deflateInit, but
713*760c2415Smrg does not free and reallocate the internal compression state. The stream
714*760c2415Smrg will leave the compression level and any other attributes that may have been
715*760c2415Smrg set unchanged.
716*760c2415Smrg
717*760c2415Smrg deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
718*760c2415Smrg stream state was inconsistent (such as zalloc or state being Z_NULL).
719*760c2415Smrg */
720*760c2415Smrg
721*760c2415Smrg int deflateParams(z_streamp strm, int level, int strategy);
722*760c2415Smrg /*
723*760c2415Smrg Dynamically update the compression level and compression strategy. The
724*760c2415Smrg interpretation of level and strategy is as in deflateInit2(). This can be
725*760c2415Smrg used to switch between compression and straight copy of the input data, or
726*760c2415Smrg to switch to a different kind of input data requiring a different strategy.
727*760c2415Smrg If the compression approach (which is a function of the level) or the
728*760c2415Smrg strategy is changed, and if any input has been consumed in a previous
729*760c2415Smrg deflate() call, then the input available so far is compressed with the old
730*760c2415Smrg level and strategy using deflate(strm, Z_BLOCK). There are three approaches
731*760c2415Smrg for the compression levels 0, 1 .. 3, and 4 .. 9 respectively. The new level
732*760c2415Smrg and strategy will take effect at the next call of deflate().
733*760c2415Smrg
734*760c2415Smrg If a deflate(strm, Z_BLOCK) is performed by deflateParams(), and it does
735*760c2415Smrg not have enough output space to complete, then the parameter change will not
736*760c2415Smrg take effect. In this case, deflateParams() can be called again with the
737*760c2415Smrg same parameters and more output space to try again.
738*760c2415Smrg
739*760c2415Smrg In order to assure a change in the parameters on the first try, the
740*760c2415Smrg deflate stream should be flushed using deflate() with Z_BLOCK or other flush
741*760c2415Smrg request until strm.avail_out is not zero, before calling deflateParams().
742*760c2415Smrg Then no more input data should be provided before the deflateParams() call.
743*760c2415Smrg If this is done, the old level and strategy will be applied to the data
744*760c2415Smrg compressed before deflateParams(), and the new level and strategy will be
745*760c2415Smrg applied to the the data compressed after deflateParams().
746*760c2415Smrg
747*760c2415Smrg deflateParams returns Z_OK on success, Z_STREAM_ERROR if the source stream
748*760c2415Smrg state was inconsistent or if a parameter was invalid, or Z_BUF_ERROR if
749*760c2415Smrg there was not enough output space to complete the compression of the
750*760c2415Smrg available input data before a change in the strategy or approach. Note that
751*760c2415Smrg in the case of a Z_BUF_ERROR, the parameters are not changed. A return
752*760c2415Smrg value of Z_BUF_ERROR is not fatal, in which case deflateParams() can be
753*760c2415Smrg retried with more output space.
754*760c2415Smrg */
755*760c2415Smrg
756*760c2415Smrg int deflateTune(z_streamp strm, int good_length, int max_lazy, int nice_length,
757*760c2415Smrg int max_chain);
758*760c2415Smrg /*
759*760c2415Smrg Fine tune deflate's internal compression parameters. This should only be
760*760c2415Smrg used by someone who understands the algorithm used by zlib's deflate for
761*760c2415Smrg searching for the best matching string, and even then only by the most
762*760c2415Smrg fanatic optimizer trying to squeeze out the last compressed bit for their
763*760c2415Smrg specific input data. Read the deflate.c source code for the meaning of the
764*760c2415Smrg max_lazy, good_length, nice_length, and max_chain parameters.
765*760c2415Smrg
766*760c2415Smrg deflateTune() can be called after deflateInit() or deflateInit2(), and
767*760c2415Smrg returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.
768*760c2415Smrg */
769*760c2415Smrg
770*760c2415Smrg size_t deflateBound(z_streamp strm, size_t sourceLen);
771*760c2415Smrg /*
772*760c2415Smrg deflateBound() returns an upper bound on the compressed size after
773*760c2415Smrg deflation of sourceLen bytes. It must be called after deflateInit() or
774*760c2415Smrg deflateInit2(), and after deflateSetHeader(), if used. This would be used
775*760c2415Smrg to allocate an output buffer for deflation in a single pass, and so would be
776*760c2415Smrg called before deflate(). If that first deflate() call is provided the
777*760c2415Smrg sourceLen input bytes, an output buffer allocated to the size returned by
778*760c2415Smrg deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed
779*760c2415Smrg to return Z_STREAM_END. Note that it is possible for the compressed size to
780*760c2415Smrg be larger than the value returned by deflateBound() if flush options other
781*760c2415Smrg than Z_FINISH or Z_NO_FLUSH are used.
782*760c2415Smrg */
783*760c2415Smrg
784*760c2415Smrg int deflatePending(z_streamp strm, uint* pending, int* bits);
785*760c2415Smrg /*
786*760c2415Smrg deflatePending() returns the number of bytes and bits of output that have
787*760c2415Smrg been generated, but not yet provided in the available output. The bytes not
788*760c2415Smrg provided would be due to the available output space having being consumed.
789*760c2415Smrg The number of bits of output not provided are between 0 and 7, where they
790*760c2415Smrg await more bits to join them in order to fill out a full byte. If pending
791*760c2415Smrg or bits are Z_NULL, then those values are not set.
792*760c2415Smrg
793*760c2415Smrg deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source
794*760c2415Smrg stream state was inconsistent.
795*760c2415Smrg */
796*760c2415Smrg
797*760c2415Smrg int deflatePrime(z_streamp strm, int bits, int value);
798*760c2415Smrg /*
799*760c2415Smrg deflatePrime() inserts bits in the deflate output stream. The intent
800*760c2415Smrg is that this function is used to start off the deflate output with the bits
801*760c2415Smrg leftover from a previous deflate stream when appending to it. As such, this
802*760c2415Smrg function can only be used for raw deflate, and must be used before the first
803*760c2415Smrg deflate() call after a deflateInit2() or deflateReset(). bits must be less
804*760c2415Smrg than or equal to 16, and that many of the least significant bits of value
805*760c2415Smrg will be inserted in the output.
806*760c2415Smrg
807*760c2415Smrg deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough
808*760c2415Smrg room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the
809*760c2415Smrg source stream state was inconsistent.
810*760c2415Smrg */
811*760c2415Smrg
812*760c2415Smrg int deflateSetHeader(z_streamp strm, gz_headerp head);
813*760c2415Smrg /*
814*760c2415Smrg deflateSetHeader() provides gzip header information for when a gzip
815*760c2415Smrg stream is requested by deflateInit2(). deflateSetHeader() may be called
816*760c2415Smrg after deflateInit2() or deflateReset() and before the first call of
817*760c2415Smrg deflate(). The text, time, os, extra field, name, and comment information
818*760c2415Smrg in the provided gz_header structure are written to the gzip header (xflag is
819*760c2415Smrg ignored -- the extra flags are set according to the compression level). The
820*760c2415Smrg caller must assure that, if not Z_NULL, name and comment are terminated with
821*760c2415Smrg a zero byte, and that if extra is not Z_NULL, that extra_len bytes are
822*760c2415Smrg available there. If hcrc is true, a gzip header crc is included. Note that
823*760c2415Smrg the current versions of the command-line version of gzip (up through version
824*760c2415Smrg 1.3.x) do not support header crc's, and will report that it is a "multi-part
825*760c2415Smrg gzip file" and give up.
826*760c2415Smrg
827*760c2415Smrg If deflateSetHeader is not used, the default gzip header has text false,
828*760c2415Smrg the time set to zero, and os set to 255, with no extra, name, or comment
829*760c2415Smrg fields. The gzip header is returned to the default state by deflateReset().
830*760c2415Smrg
831*760c2415Smrg deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
832*760c2415Smrg stream state was inconsistent.
833*760c2415Smrg */
834*760c2415Smrg
inflateInit2(z_streamp strm,int windowBits)835*760c2415Smrg int inflateInit2(z_streamp strm, int windowBits)
836*760c2415Smrg {
837*760c2415Smrg return inflateInit2_(strm, windowBits, ZLIB_VERSION.ptr, z_stream.sizeof);
838*760c2415Smrg }
839*760c2415Smrg /*
840*760c2415Smrg This is another version of inflateInit with an extra parameter. The
841*760c2415Smrg fields next_in, avail_in, zalloc, zfree and opaque must be initialized
842*760c2415Smrg before by the caller.
843*760c2415Smrg
844*760c2415Smrg The windowBits parameter is the base two logarithm of the maximum window
845*760c2415Smrg size (the size of the history buffer). It should be in the range 8 .. 15 for
846*760c2415Smrg this version of the library. The default value is 15 if inflateInit is used
847*760c2415Smrg instead. windowBits must be greater than or equal to the windowBits value
848*760c2415Smrg provided to deflateInit2() while compressing, or it must be equal to 15 if
849*760c2415Smrg deflateInit2() was not used. If a compressed stream with a larger window
850*760c2415Smrg size is given as input, inflate() will return with the error code
851*760c2415Smrg Z_DATA_ERROR instead of trying to allocate a larger window.
852*760c2415Smrg
853*760c2415Smrg windowBits can also be zero to request that inflate use the window size in
854*760c2415Smrg the zlib header of the compressed stream.
855*760c2415Smrg
856*760c2415Smrg windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
857*760c2415Smrg determines the window size. inflate() will then process raw deflate data,
858*760c2415Smrg not looking for a zlib or gzip header, not generating a check value, and not
859*760c2415Smrg looking for any check values for comparison at the end of the stream. This
860*760c2415Smrg is for use with other formats that use the deflate compressed data format
861*760c2415Smrg such as zip. Those formats provide their own check values. If a custom
862*760c2415Smrg format is developed using the raw deflate format for compressed data, it is
863*760c2415Smrg recommended that a check value such as an Adler-32 or a CRC-32 be applied to
864*760c2415Smrg the uncompressed data as is done in the zlib, gzip, and zip formats. For
865*760c2415Smrg most applications, the zlib format should be used as is. Note that comments
866*760c2415Smrg above on the use in deflateInit2() applies to the magnitude of windowBits.
867*760c2415Smrg
868*760c2415Smrg windowBits can also be greater than 15 for optional gzip decoding. Add
869*760c2415Smrg 32 to windowBits to enable zlib and gzip decoding with automatic header
870*760c2415Smrg detection, or add 16 to decode only the gzip format (the zlib format will
871*760c2415Smrg return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a
872*760c2415Smrg CRC-32 instead of an Adler-32. Unlike the gunzip utility and gzread() (see
873*760c2415Smrg below), inflate() will not automatically decode concatenated gzip streams.
874*760c2415Smrg inflate() will return Z_STREAM_END at the end of the gzip stream. The state
875*760c2415Smrg would need to be reset to continue decoding a subsequent gzip stream.
876*760c2415Smrg
877*760c2415Smrg inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
878*760c2415Smrg memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
879*760c2415Smrg version assumed by the caller, or Z_STREAM_ERROR if the parameters are
880*760c2415Smrg invalid, such as a null pointer to the structure. msg is set to null if
881*760c2415Smrg there is no error message. inflateInit2 does not perform any decompression
882*760c2415Smrg apart from possibly reading the zlib header if present: actual decompression
883*760c2415Smrg will be done by inflate(). (So next_in and avail_in may be modified, but
884*760c2415Smrg next_out and avail_out are unused and unchanged.) The current implementation
885*760c2415Smrg of inflateInit2() does not process any header information -- that is
886*760c2415Smrg deferred until inflate() is called.
887*760c2415Smrg */
888*760c2415Smrg
889*760c2415Smrg int inflateSetDictionary(z_streamp strm, const(ubyte)* dictionary, uint dictLength);
890*760c2415Smrg /*
891*760c2415Smrg Initializes the decompression dictionary from the given uncompressed byte
892*760c2415Smrg sequence. This function must be called immediately after a call of inflate,
893*760c2415Smrg if that call returned Z_NEED_DICT. The dictionary chosen by the compressor
894*760c2415Smrg can be determined from the Adler-32 value returned by that call of inflate.
895*760c2415Smrg The compressor and decompressor must use exactly the same dictionary (see
896*760c2415Smrg deflateSetDictionary). For raw inflate, this function can be called at any
897*760c2415Smrg time to set the dictionary. If the provided dictionary is smaller than the
898*760c2415Smrg window and there is already data in the window, then the provided dictionary
899*760c2415Smrg will amend what's there. The application must insure that the dictionary
900*760c2415Smrg that was used for compression is provided.
901*760c2415Smrg
902*760c2415Smrg inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
903*760c2415Smrg parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is
904*760c2415Smrg inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
905*760c2415Smrg expected one (incorrect Adler-32 value). inflateSetDictionary does not
906*760c2415Smrg perform any decompression: this will be done by subsequent calls of
907*760c2415Smrg inflate().
908*760c2415Smrg */
909*760c2415Smrg
910*760c2415Smrg int inflateGetDictionary(z_streamp strm, ubyte* dictionary, uint* dictLength);
911*760c2415Smrg /*
912*760c2415Smrg Returns the sliding dictionary being maintained by inflate. dictLength is
913*760c2415Smrg set to the number of bytes in the dictionary, and that many bytes are copied
914*760c2415Smrg to dictionary. dictionary must have enough space, where 32768 bytes is
915*760c2415Smrg always enough. If inflateGetDictionary() is called with dictionary equal to
916*760c2415Smrg Z_NULL, then only the dictionary length is returned, and nothing is copied.
917*760c2415Smrg Similary, if dictLength is Z_NULL, then it is not set.
918*760c2415Smrg
919*760c2415Smrg inflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the
920*760c2415Smrg stream state is inconsistent.
921*760c2415Smrg */
922*760c2415Smrg
923*760c2415Smrg int inflateSync(z_streamp strm);
924*760c2415Smrg /*
925*760c2415Smrg Skips invalid compressed data until a possible full flush point (see above
926*760c2415Smrg for the description of deflate with Z_FULL_FLUSH) can be found, or until all
927*760c2415Smrg available input is skipped. No output is provided.
928*760c2415Smrg
929*760c2415Smrg inflateSync searches for a 00 00 FF FF pattern in the compressed data.
930*760c2415Smrg All full flush points have this pattern, but not all occurrences of this
931*760c2415Smrg pattern are full flush points.
932*760c2415Smrg
933*760c2415Smrg inflateSync returns Z_OK if a possible full flush point has been found,
934*760c2415Smrg Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point
935*760c2415Smrg has been found, or Z_STREAM_ERROR if the stream structure was inconsistent.
936*760c2415Smrg In the success case, the application may save the current current value of
937*760c2415Smrg total_in which indicates where valid compressed data was found. In the
938*760c2415Smrg error case, the application may repeatedly call inflateSync, providing more
939*760c2415Smrg input each time, until success or end of the input data.
940*760c2415Smrg */
941*760c2415Smrg
942*760c2415Smrg int inflateCopy(z_streamp dest, z_streamp source);
943*760c2415Smrg /*
944*760c2415Smrg Sets the destination stream as a complete copy of the source stream.
945*760c2415Smrg
946*760c2415Smrg This function can be useful when randomly accessing a large stream. The
947*760c2415Smrg first pass through the stream can periodically record the inflate state,
948*760c2415Smrg allowing restarting inflate at those points when randomly accessing the
949*760c2415Smrg stream.
950*760c2415Smrg
951*760c2415Smrg inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
952*760c2415Smrg enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
953*760c2415Smrg (such as zalloc being Z_NULL). msg is left unchanged in both source and
954*760c2415Smrg destination.
955*760c2415Smrg */
956*760c2415Smrg
957*760c2415Smrg int inflateReset(z_streamp strm);
958*760c2415Smrg /*
959*760c2415Smrg This function is equivalent to inflateEnd followed by inflateInit,
960*760c2415Smrg but does not free and reallocate the internal decompression state. The
961*760c2415Smrg stream will keep attributes that may have been set by inflateInit2.
962*760c2415Smrg
963*760c2415Smrg inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
964*760c2415Smrg stream state was inconsistent (such as zalloc or state being Z_NULL).
965*760c2415Smrg */
966*760c2415Smrg
967*760c2415Smrg int inflateReset2(z_streamp strm, int windowBits);
968*760c2415Smrg /*
969*760c2415Smrg This function is the same as inflateReset, but it also permits changing
970*760c2415Smrg the wrap and window size requests. The windowBits parameter is interpreted
971*760c2415Smrg the same as it is for inflateInit2. If the window size is changed, then the
972*760c2415Smrg memory allocated for the window is freed, and the window will be reallocated
973*760c2415Smrg by inflate() if needed.
974*760c2415Smrg
975*760c2415Smrg inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source
976*760c2415Smrg stream state was inconsistent (such as zalloc or state being Z_NULL), or if
977*760c2415Smrg the windowBits parameter is invalid.
978*760c2415Smrg */
979*760c2415Smrg
980*760c2415Smrg int inflatePrime(z_streamp strm, int bits, int value);
981*760c2415Smrg /*
982*760c2415Smrg This function inserts bits in the inflate input stream. The intent is
983*760c2415Smrg that this function is used to start inflating at a bit position in the
984*760c2415Smrg middle of a byte. The provided bits will be used before any bytes are used
985*760c2415Smrg from next_in. This function should only be used with raw inflate, and
986*760c2415Smrg should be used before the first inflate() call after inflateInit2() or
987*760c2415Smrg inflateReset(). bits must be less than or equal to 16, and that many of the
988*760c2415Smrg least significant bits of value will be inserted in the input.
989*760c2415Smrg
990*760c2415Smrg If bits is negative, then the input stream bit buffer is emptied. Then
991*760c2415Smrg inflatePrime() can be called again to put bits in the buffer. This is used
992*760c2415Smrg to clear out bits leftover after feeding inflate a block description prior
993*760c2415Smrg to feeding inflate codes.
994*760c2415Smrg
995*760c2415Smrg inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
996*760c2415Smrg stream state was inconsistent.
997*760c2415Smrg */
998*760c2415Smrg
999*760c2415Smrg c_long inflateMark(z_streamp strm);
1000*760c2415Smrg /*
1001*760c2415Smrg This function returns two values, one in the lower 16 bits of the return
1002*760c2415Smrg value, and the other in the remaining upper bits, obtained by shifting the
1003*760c2415Smrg return value down 16 bits. If the upper value is -1 and the lower value is
1004*760c2415Smrg zero, then inflate() is currently decoding information outside of a block.
1005*760c2415Smrg If the upper value is -1 and the lower value is non-zero, then inflate is in
1006*760c2415Smrg the middle of a stored block, with the lower value equaling the number of
1007*760c2415Smrg bytes from the input remaining to copy. If the upper value is not -1, then
1008*760c2415Smrg it is the number of bits back from the current bit position in the input of
1009*760c2415Smrg the code (literal or length/distance pair) currently being processed. In
1010*760c2415Smrg that case the lower value is the number of bytes already emitted for that
1011*760c2415Smrg code.
1012*760c2415Smrg
1013*760c2415Smrg A code is being processed if inflate is waiting for more input to complete
1014*760c2415Smrg decoding of the code, or if it has completed decoding but is waiting for
1015*760c2415Smrg more output space to write the literal or match data.
1016*760c2415Smrg
1017*760c2415Smrg inflateMark() is used to mark locations in the input data for random
1018*760c2415Smrg access, which may be at bit positions, and to note those cases where the
1019*760c2415Smrg output of a code may span boundaries of random access blocks. The current
1020*760c2415Smrg location in the input stream can be determined from avail_in and data_type
1021*760c2415Smrg as noted in the description for the Z_BLOCK flush parameter for inflate.
1022*760c2415Smrg
1023*760c2415Smrg inflateMark returns the value noted above, or -65536 if the provided
1024*760c2415Smrg source stream state was inconsistent.
1025*760c2415Smrg */
1026*760c2415Smrg
1027*760c2415Smrg int inflateGetHeader(z_streamp strm, gz_headerp head);
1028*760c2415Smrg /*
1029*760c2415Smrg inflateGetHeader() requests that gzip header information be stored in the
1030*760c2415Smrg provided gz_header structure. inflateGetHeader() may be called after
1031*760c2415Smrg inflateInit2() or inflateReset(), and before the first call of inflate().
1032*760c2415Smrg As inflate() processes the gzip stream, head->done is zero until the header
1033*760c2415Smrg is completed, at which time head->done is set to one. If a zlib stream is
1034*760c2415Smrg being decoded, then head->done is set to -1 to indicate that there will be
1035*760c2415Smrg no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be
1036*760c2415Smrg used to force inflate() to return immediately after header processing is
1037*760c2415Smrg complete and before any actual data is decompressed.
1038*760c2415Smrg
1039*760c2415Smrg The text, time, xflags, and os fields are filled in with the gzip header
1040*760c2415Smrg contents. hcrc is set to true if there is a header CRC. (The header CRC
1041*760c2415Smrg was valid if done is set to one.) If extra is not Z_NULL, then extra_max
1042*760c2415Smrg contains the maximum number of bytes to write to extra. Once done is true,
1043*760c2415Smrg extra_len contains the actual extra field length, and extra contains the
1044*760c2415Smrg extra field, or that field truncated if extra_max is less than extra_len.
1045*760c2415Smrg If name is not Z_NULL, then up to name_max characters are written there,
1046*760c2415Smrg terminated with a zero unless the length is greater than name_max. If
1047*760c2415Smrg comment is not Z_NULL, then up to comm_max characters are written there,
1048*760c2415Smrg terminated with a zero unless the length is greater than comm_max. When any
1049*760c2415Smrg of extra, name, or comment are not Z_NULL and the respective field is not
1050*760c2415Smrg present in the header, then that field is set to Z_NULL to signal its
1051*760c2415Smrg absence. This allows the use of deflateSetHeader() with the returned
1052*760c2415Smrg structure to duplicate the header. However if those fields are set to
1053*760c2415Smrg allocated memory, then the application will need to save those pointers
1054*760c2415Smrg elsewhere so that they can be eventually freed.
1055*760c2415Smrg
1056*760c2415Smrg If inflateGetHeader is not used, then the header information is simply
1057*760c2415Smrg discarded. The header is always checked for validity, including the header
1058*760c2415Smrg CRC if present. inflateReset() will reset the process to discard the header
1059*760c2415Smrg information. The application would need to call inflateGetHeader() again to
1060*760c2415Smrg retrieve the header from the next gzip stream.
1061*760c2415Smrg
1062*760c2415Smrg inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
1063*760c2415Smrg stream state was inconsistent.
1064*760c2415Smrg */
1065*760c2415Smrg
1066*760c2415Smrg
inflateBackInit(z_stream * strm,int windowBits,ubyte * window)1067*760c2415Smrg int inflateBackInit(z_stream* strm, int windowBits, ubyte* window)
1068*760c2415Smrg {
1069*760c2415Smrg return inflateBackInit_(strm, windowBits, window, ZLIB_VERSION.ptr, z_stream.sizeof);
1070*760c2415Smrg }
1071*760c2415Smrg /*
1072*760c2415Smrg Initialize the internal stream state for decompression using inflateBack()
1073*760c2415Smrg calls. The fields zalloc, zfree and opaque in strm must be initialized
1074*760c2415Smrg before the call. If zalloc and zfree are Z_NULL, then the default library-
1075*760c2415Smrg derived memory allocation routines are used. windowBits is the base two
1076*760c2415Smrg logarithm of the window size, in the range 8 .. 15. window is a caller
1077*760c2415Smrg supplied buffer of that size. Except for special applications where it is
1078*760c2415Smrg assured that deflate was used with small window sizes, windowBits must be 15
1079*760c2415Smrg and a 32K byte window must be supplied to be able to decompress general
1080*760c2415Smrg deflate streams.
1081*760c2415Smrg
1082*760c2415Smrg See inflateBack() for the usage of these routines.
1083*760c2415Smrg
1084*760c2415Smrg inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of
1085*760c2415Smrg the parameters are invalid, Z_MEM_ERROR if the internal state could not be
1086*760c2415Smrg allocated, or Z_VERSION_ERROR if the version of the library does not match
1087*760c2415Smrg the version of the header file.
1088*760c2415Smrg */
1089*760c2415Smrg
1090*760c2415Smrg alias in_func = uint function(void*, ubyte**);
1091*760c2415Smrg alias out_func = int function(void*, ubyte*, uint);
1092*760c2415Smrg
1093*760c2415Smrg int inflateBack(z_stream* strm,
1094*760c2415Smrg in_func f_in,
1095*760c2415Smrg void* in_desc,
1096*760c2415Smrg out_func f_out,
1097*760c2415Smrg void* out_desc);
1098*760c2415Smrg /*
1099*760c2415Smrg inflateBack() does a raw inflate with a single call using a call-back
1100*760c2415Smrg interface for input and output. This is potentially more efficient than
1101*760c2415Smrg inflate() for file i/o applications, in that it avoids copying between the
1102*760c2415Smrg output and the sliding window by simply making the window itself the output
1103*760c2415Smrg buffer. inflate() can be faster on modern CPUs when used with large
1104*760c2415Smrg buffers. inflateBack() trusts the application to not change the output
1105*760c2415Smrg buffer passed by the output function, at least until inflateBack() returns.
1106*760c2415Smrg
1107*760c2415Smrg inflateBackInit() must be called first to allocate the internal state
1108*760c2415Smrg and to initialize the state with the user-provided window buffer.
1109*760c2415Smrg inflateBack() may then be used multiple times to inflate a complete, raw
1110*760c2415Smrg deflate stream with each call. inflateBackEnd() is then called to free the
1111*760c2415Smrg allocated state.
1112*760c2415Smrg
1113*760c2415Smrg A raw deflate stream is one with no zlib or gzip header or trailer.
1114*760c2415Smrg This routine would normally be used in a utility that reads zip or gzip
1115*760c2415Smrg files and writes out uncompressed files. The utility would decode the
1116*760c2415Smrg header and process the trailer on its own, hence this routine expects only
1117*760c2415Smrg the raw deflate stream to decompress. This is different from the default
1118*760c2415Smrg behavior of inflate(), which expects a zlib header and trailer around the
1119*760c2415Smrg deflate stream.
1120*760c2415Smrg
1121*760c2415Smrg inflateBack() uses two subroutines supplied by the caller that are then
1122*760c2415Smrg called by inflateBack() for input and output. inflateBack() calls those
1123*760c2415Smrg routines until it reads a complete deflate stream and writes out all of the
1124*760c2415Smrg uncompressed data, or until it encounters an error. The function's
1125*760c2415Smrg parameters and return types are defined above in the in_func and out_func
1126*760c2415Smrg typedefs. inflateBack() will call in(in_desc, &buf) which should return the
1127*760c2415Smrg number of bytes of provided input, and a pointer to that input in buf. If
1128*760c2415Smrg there is no input available, in() must return zero -- buf is ignored in that
1129*760c2415Smrg case -- and inflateBack() will return a buffer error. inflateBack() will
1130*760c2415Smrg call out(out_desc, buf, len) to write the uncompressed data buf[0 .. len-1].
1131*760c2415Smrg out() should return zero on success, or non-zero on failure. If out()
1132*760c2415Smrg returns non-zero, inflateBack() will return with an error. Neither in() nor
1133*760c2415Smrg out() are permitted to change the contents of the window provided to
1134*760c2415Smrg inflateBackInit(), which is also the buffer that out() uses to write from.
1135*760c2415Smrg The length written by out() will be at most the window size. Any non-zero
1136*760c2415Smrg amount of input may be provided by in().
1137*760c2415Smrg
1138*760c2415Smrg For convenience, inflateBack() can be provided input on the first call by
1139*760c2415Smrg setting strm->next_in and strm->avail_in. If that input is exhausted, then
1140*760c2415Smrg in() will be called. Therefore strm->next_in must be initialized before
1141*760c2415Smrg calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called
1142*760c2415Smrg immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in
1143*760c2415Smrg must also be initialized, and then if strm->avail_in is not zero, input will
1144*760c2415Smrg initially be taken from strm->next_in[0 .. strm->avail_in - 1].
1145*760c2415Smrg
1146*760c2415Smrg The in_desc and out_desc parameters of inflateBack() is passed as the
1147*760c2415Smrg first parameter of in() and out() respectively when they are called. These
1148*760c2415Smrg descriptors can be optionally used to pass any information that the caller-
1149*760c2415Smrg supplied in() and out() functions need to do their job.
1150*760c2415Smrg
1151*760c2415Smrg On return, inflateBack() will set strm->next_in and strm->avail_in to
1152*760c2415Smrg pass back any unused input that was provided by the last in() call. The
1153*760c2415Smrg return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR
1154*760c2415Smrg if in() or out() returned an error, Z_DATA_ERROR if there was a format error
1155*760c2415Smrg in the deflate stream (in which case strm->msg is set to indicate the nature
1156*760c2415Smrg of the error), or Z_STREAM_ERROR if the stream was not properly initialized.
1157*760c2415Smrg In the case of Z_BUF_ERROR, an input or output error can be distinguished
1158*760c2415Smrg using strm->next_in which will be Z_NULL only if in() returned an error. If
1159*760c2415Smrg strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning
1160*760c2415Smrg non-zero. (in() will always be called before out(), so strm->next_in is
1161*760c2415Smrg assured to be defined if out() returns non-zero.) Note that inflateBack()
1162*760c2415Smrg cannot return Z_OK.
1163*760c2415Smrg */
1164*760c2415Smrg
1165*760c2415Smrg int inflateBackEnd(z_stream* strm);
1166*760c2415Smrg /*
1167*760c2415Smrg All memory allocated by inflateBackInit() is freed.
1168*760c2415Smrg
1169*760c2415Smrg inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream
1170*760c2415Smrg state was inconsistent.
1171*760c2415Smrg */
1172*760c2415Smrg
1173*760c2415Smrg uint zlibCompileFlags();
1174*760c2415Smrg /* Return flags indicating compile-time options.
1175*760c2415Smrg
1176*760c2415Smrg Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:
1177*760c2415Smrg 1.0: size of uInt
1178*760c2415Smrg 3.2: size of uLong
1179*760c2415Smrg 5.4: size of voidpf (pointer)
1180*760c2415Smrg 7.6: size of z_off_t
1181*760c2415Smrg
1182*760c2415Smrg Compiler, assembler, and debug options:
1183*760c2415Smrg 8: ZLIB_DEBUG
1184*760c2415Smrg 9: ASMV or ASMINF -- use ASM code
1185*760c2415Smrg 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention
1186*760c2415Smrg 11: 0 (reserved)
1187*760c2415Smrg
1188*760c2415Smrg One-time table building (smaller code, but not thread-safe if true):
1189*760c2415Smrg 12: BUILDFIXED -- build static block decoding tables when needed
1190*760c2415Smrg 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed
1191*760c2415Smrg 14,15: 0 (reserved)
1192*760c2415Smrg
1193*760c2415Smrg Library content (indicates missing functionality):
1194*760c2415Smrg 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking
1195*760c2415Smrg deflate code when not needed)
1196*760c2415Smrg 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect
1197*760c2415Smrg and decode gzip streams (to avoid linking crc code)
1198*760c2415Smrg 18-19: 0 (reserved)
1199*760c2415Smrg
1200*760c2415Smrg Operation variations (changes in library functionality):
1201*760c2415Smrg 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate
1202*760c2415Smrg 21: FASTEST -- deflate algorithm with only one, lowest compression level
1203*760c2415Smrg 22,23: 0 (reserved)
1204*760c2415Smrg
1205*760c2415Smrg The sprintf variant used by gzprintf (zero is best):
1206*760c2415Smrg 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format
1207*760c2415Smrg 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!
1208*760c2415Smrg 26: 0 = returns value, 1 = void -- 1 means inferred string length returned
1209*760c2415Smrg
1210*760c2415Smrg Remainder:
1211*760c2415Smrg 27-31: 0 (reserved)
1212*760c2415Smrg */
1213*760c2415Smrg
1214*760c2415Smrg /* utility functions */
1215*760c2415Smrg
1216*760c2415Smrg /*
1217*760c2415Smrg The following utility functions are implemented on top of the basic
1218*760c2415Smrg stream-oriented functions. To simplify the interface, some default options
1219*760c2415Smrg are assumed (compression level and memory usage, standard memory allocation
1220*760c2415Smrg functions). The source code of these utility functions can be modified if
1221*760c2415Smrg you need special options.
1222*760c2415Smrg */
1223*760c2415Smrg
1224*760c2415Smrg int compress(ubyte* dest,
1225*760c2415Smrg size_t* destLen,
1226*760c2415Smrg const(ubyte)* source,
1227*760c2415Smrg size_t sourceLen);
1228*760c2415Smrg /*
1229*760c2415Smrg Compresses the source buffer into the destination buffer. sourceLen is
1230*760c2415Smrg the byte length of the source buffer. Upon entry, destLen is the total size
1231*760c2415Smrg of the destination buffer, which must be at least the value returned by
1232*760c2415Smrg compressBound(sourceLen). Upon exit, destLen is the actual size of the
1233*760c2415Smrg compressed data. compress() is equivalent to compress2() with a level
1234*760c2415Smrg parameter of Z_DEFAULT_COMPRESSION.
1235*760c2415Smrg
1236*760c2415Smrg compress returns Z_OK if success, Z_MEM_ERROR if there was not
1237*760c2415Smrg enough memory, Z_BUF_ERROR if there was not enough room in the output
1238*760c2415Smrg buffer.
1239*760c2415Smrg */
1240*760c2415Smrg
1241*760c2415Smrg int compress2(ubyte* dest,
1242*760c2415Smrg size_t* destLen,
1243*760c2415Smrg const(ubyte)* source,
1244*760c2415Smrg size_t sourceLen,
1245*760c2415Smrg int level);
1246*760c2415Smrg /*
1247*760c2415Smrg Compresses the source buffer into the destination buffer. The level
1248*760c2415Smrg parameter has the same meaning as in deflateInit. sourceLen is the byte
1249*760c2415Smrg length of the source buffer. Upon entry, destLen is the total size of the
1250*760c2415Smrg destination buffer, which must be at least the value returned by
1251*760c2415Smrg compressBound(sourceLen). Upon exit, destLen is the actual size of the
1252*760c2415Smrg compressed data.
1253*760c2415Smrg
1254*760c2415Smrg compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
1255*760c2415Smrg memory, Z_BUF_ERROR if there was not enough room in the output buffer,
1256*760c2415Smrg Z_STREAM_ERROR if the level parameter is invalid.
1257*760c2415Smrg */
1258*760c2415Smrg
1259*760c2415Smrg size_t compressBound(size_t sourceLen);
1260*760c2415Smrg /*
1261*760c2415Smrg compressBound() returns an upper bound on the compressed size after
1262*760c2415Smrg compress() or compress2() on sourceLen bytes. It would be used before a
1263*760c2415Smrg compress() or compress2() call to allocate the destination buffer.
1264*760c2415Smrg */
1265*760c2415Smrg
1266*760c2415Smrg int uncompress(ubyte* dest,
1267*760c2415Smrg size_t* destLen,
1268*760c2415Smrg const(ubyte)* source,
1269*760c2415Smrg size_t sourceLen);
1270*760c2415Smrg /*
1271*760c2415Smrg Decompresses the source buffer into the destination buffer. sourceLen is
1272*760c2415Smrg the byte length of the source buffer. Upon entry, destLen is the total size
1273*760c2415Smrg of the destination buffer, which must be large enough to hold the entire
1274*760c2415Smrg uncompressed data. (The size of the uncompressed data must have been saved
1275*760c2415Smrg previously by the compressor and transmitted to the decompressor by some
1276*760c2415Smrg mechanism outside the scope of this compression library.) Upon exit, destLen
1277*760c2415Smrg is the actual size of the uncompressed data.
1278*760c2415Smrg
1279*760c2415Smrg uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
1280*760c2415Smrg enough memory, Z_BUF_ERROR if there was not enough room in the output
1281*760c2415Smrg buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. In
1282*760c2415Smrg the case where there is not enough room, uncompress() will fill the output
1283*760c2415Smrg buffer with the uncompressed data up to that point.
1284*760c2415Smrg */
1285*760c2415Smrg
1286*760c2415Smrg int uncompress2(ubyte* dest,
1287*760c2415Smrg size_t* destLen,
1288*760c2415Smrg const(ubyte)* source,
1289*760c2415Smrg size_t* sourceLen);
1290*760c2415Smrg /*
1291*760c2415Smrg Same as uncompress, except that sourceLen is a pointer, where the
1292*760c2415Smrg length of the source is *sourceLen. On return, *sourceLen is the number of
1293*760c2415Smrg source bytes consumed.
1294*760c2415Smrg */
1295*760c2415Smrg
1296*760c2415Smrg /* gzip file access functions */
1297*760c2415Smrg
1298*760c2415Smrg /*
1299*760c2415Smrg This library supports reading and writing files in gzip (.gz) format with
1300*760c2415Smrg an interface similar to that of stdio, using the functions that start with
1301*760c2415Smrg "gz". The gzip format is different from the zlib format. gzip is a gzip
1302*760c2415Smrg wrapper, documented in RFC 1952, wrapped around a deflate stream.
1303*760c2415Smrg */
1304*760c2415Smrg
1305*760c2415Smrg alias gzFile = void*;
1306*760c2415Smrg alias z_off_t = int; // file offset
1307*760c2415Smrg alias z_size_t = size_t;
1308*760c2415Smrg
1309*760c2415Smrg gzFile gzopen(const(char)* path, const(char)* mode);
1310*760c2415Smrg /*
1311*760c2415Smrg Opens a gzip (.gz) file for reading or writing. The mode parameter is as
1312*760c2415Smrg in fopen ("rb" or "wb") but can also include a compression level ("wb9") or
1313*760c2415Smrg a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only
1314*760c2415Smrg compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F'
1315*760c2415Smrg for fixed code compression as in "wb9F". (See the description of
1316*760c2415Smrg deflateInit2 for more information about the strategy parameter.) 'T' will
1317*760c2415Smrg request transparent writing or appending with no compression and not using
1318*760c2415Smrg the gzip format.
1319*760c2415Smrg
1320*760c2415Smrg "a" can be used instead of "w" to request that the gzip stream that will
1321*760c2415Smrg be written be appended to the file. "+" will result in an error, since
1322*760c2415Smrg reading and writing to the same gzip file is not supported. The addition of
1323*760c2415Smrg "x" when writing will create the file exclusively, which fails if the file
1324*760c2415Smrg already exists. On systems that support it, the addition of "e" when
1325*760c2415Smrg reading or writing will set the flag to close the file on an execve() call.
1326*760c2415Smrg
1327*760c2415Smrg These functions, as well as gzip, will read and decode a sequence of gzip
1328*760c2415Smrg streams in a file. The append function of gzopen() can be used to create
1329*760c2415Smrg such a file. (Also see gzflush() for another way to do this.) When
1330*760c2415Smrg appending, gzopen does not test whether the file begins with a gzip stream,
1331*760c2415Smrg nor does it look for the end of the gzip streams to begin appending. gzopen
1332*760c2415Smrg will simply append a gzip stream to the existing file.
1333*760c2415Smrg
1334*760c2415Smrg gzopen can be used to read a file which is not in gzip format; in this
1335*760c2415Smrg case gzread will directly read from the file without decompression. When
1336*760c2415Smrg reading, this will be detected automatically by looking for the magic two-
1337*760c2415Smrg byte gzip header.
1338*760c2415Smrg
1339*760c2415Smrg gzopen returns NULL if the file could not be opened, if there was
1340*760c2415Smrg insufficient memory to allocate the gzFile state, or if an invalid mode was
1341*760c2415Smrg specified (an 'r', 'w', or 'a' was not provided, or '+' was provided).
1342*760c2415Smrg errno can be checked to determine if the reason gzopen failed was that the
1343*760c2415Smrg file could not be opened.
1344*760c2415Smrg */
1345*760c2415Smrg
1346*760c2415Smrg gzFile gzdopen(int fd, const(char)* mode);
1347*760c2415Smrg /*
1348*760c2415Smrg gzdopen associates a gzFile with the file descriptor fd. File descriptors
1349*760c2415Smrg are obtained from calls like open, dup, creat, pipe or fileno (if the file
1350*760c2415Smrg has been previously opened with fopen). The mode parameter is as in gzopen.
1351*760c2415Smrg
1352*760c2415Smrg The next call of gzclose on the returned gzFile will also close the file
1353*760c2415Smrg descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor
1354*760c2415Smrg fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd,
1355*760c2415Smrg mode);. The duplicated descriptor should be saved to avoid a leak, since
1356*760c2415Smrg gzdopen does not close fd if it fails. If you are using fileno() to get the
1357*760c2415Smrg file descriptor from a FILE *, then you will have to use dup() to avoid
1358*760c2415Smrg double-close()ing the file descriptor. Both gzclose() and fclose() will
1359*760c2415Smrg close the associated file descriptor, so they need to have different file
1360*760c2415Smrg descriptors.
1361*760c2415Smrg
1362*760c2415Smrg gzdopen returns NULL if there was insufficient memory to allocate the
1363*760c2415Smrg gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not
1364*760c2415Smrg provided, or '+' was provided), or if fd is -1. The file descriptor is not
1365*760c2415Smrg used until the next gz* read, write, seek, or close operation, so gzdopen
1366*760c2415Smrg will not detect if fd is invalid (unless fd is -1).
1367*760c2415Smrg */
1368*760c2415Smrg
1369*760c2415Smrg int gzbuffer(gzFile file, uint size);
1370*760c2415Smrg /*
1371*760c2415Smrg Set the internal buffer size used by this library's functions. The
1372*760c2415Smrg default buffer size is 8192 bytes. This function must be called after
1373*760c2415Smrg gzopen() or gzdopen(), and before any other calls that read or write the
1374*760c2415Smrg file. The buffer memory allocation is always deferred to the first read or
1375*760c2415Smrg write. Three times that size in buffer space is allocated. A larger buffer
1376*760c2415Smrg size of, for example, 64K or 128K bytes will noticeably increase the speed
1377*760c2415Smrg of decompression (reading).
1378*760c2415Smrg
1379*760c2415Smrg The new buffer size also affects the maximum length for gzprintf().
1380*760c2415Smrg
1381*760c2415Smrg gzbuffer() returns 0 on success, or -1 on failure, such as being called
1382*760c2415Smrg too late.
1383*760c2415Smrg */
1384*760c2415Smrg
1385*760c2415Smrg int gzsetparams(gzFile file, int level, int strategy);
1386*760c2415Smrg /*
1387*760c2415Smrg Dynamically update the compression level or strategy. See the description
1388*760c2415Smrg of deflateInit2 for the meaning of these parameters. Previously provided
1389*760c2415Smrg data is flushed before the parameter change.
1390*760c2415Smrg
1391*760c2415Smrg gzsetparams returns Z_OK if success, Z_STREAM_ERROR if the file was not
1392*760c2415Smrg opened for writing, Z_ERRNO if there is an error writing the flushed data,
1393*760c2415Smrg or Z_MEM_ERROR if there is a memory allocation error.
1394*760c2415Smrg */
1395*760c2415Smrg
1396*760c2415Smrg int gzread(gzFile file, void* buf, uint len);
1397*760c2415Smrg /*
1398*760c2415Smrg Reads the given number of uncompressed bytes from the compressed file. If
1399*760c2415Smrg the input file is not in gzip format, gzread copies the given number of
1400*760c2415Smrg bytes into the buffer directly from the file.
1401*760c2415Smrg
1402*760c2415Smrg After reaching the end of a gzip stream in the input, gzread will continue
1403*760c2415Smrg to read, looking for another gzip stream. Any number of gzip streams may be
1404*760c2415Smrg concatenated in the input file, and will all be decompressed by gzread().
1405*760c2415Smrg If something other than a gzip stream is encountered after a gzip stream,
1406*760c2415Smrg that remaining trailing garbage is ignored (and no error is returned).
1407*760c2415Smrg
1408*760c2415Smrg gzread can be used to read a gzip file that is being concurrently written.
1409*760c2415Smrg Upon reaching the end of the input, gzread will return with the available
1410*760c2415Smrg data. If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then
1411*760c2415Smrg gzclearerr can be used to clear the end of file indicator in order to permit
1412*760c2415Smrg gzread to be tried again. Z_OK indicates that a gzip stream was completed
1413*760c2415Smrg on the last gzread. Z_BUF_ERROR indicates that the input file ended in the
1414*760c2415Smrg middle of a gzip stream. Note that gzread does not return -1 in the event
1415*760c2415Smrg of an incomplete gzip stream. This error is deferred until gzclose(), which
1416*760c2415Smrg will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip
1417*760c2415Smrg stream. Alternatively, gzerror can be used before gzclose to detect this
1418*760c2415Smrg case.
1419*760c2415Smrg
1420*760c2415Smrg gzread returns the number of uncompressed bytes actually read, less than
1421*760c2415Smrg len for end of file, or -1 for error. If len is too large to fit in an int,
1422*760c2415Smrg then nothing is read, -1 is returned, and the error state is set to
1423*760c2415Smrg Z_STREAM_ERROR.
1424*760c2415Smrg */
1425*760c2415Smrg
1426*760c2415Smrg z_size_t gzfread(void* buf, z_size_t size, z_size_t nitems, gzFile file);
1427*760c2415Smrg /*
1428*760c2415Smrg Read up to nitems items of size size from file to buf, otherwise operating
1429*760c2415Smrg as gzread() does. This duplicates the interface of stdio's fread(), with
1430*760c2415Smrg size_t request and return types. If the library defines size_t, then
1431*760c2415Smrg z_size_t is identical to size_t. If not, then z_size_t is an unsigned
1432*760c2415Smrg integer type that can contain a pointer.
1433*760c2415Smrg
1434*760c2415Smrg gzfread() returns the number of full items read of size size, or zero if
1435*760c2415Smrg the end of the file was reached and a full item could not be read, or if
1436*760c2415Smrg there was an error. gzerror() must be consulted if zero is returned in
1437*760c2415Smrg order to determine if there was an error. If the multiplication of size and
1438*760c2415Smrg nitems overflows, i.e. the product does not fit in a z_size_t, then nothing
1439*760c2415Smrg is read, zero is returned, and the error state is set to Z_STREAM_ERROR.
1440*760c2415Smrg
1441*760c2415Smrg In the event that the end of file is reached and only a partial item is
1442*760c2415Smrg available at the end, i.e. the remaining uncompressed data length is not a
1443*760c2415Smrg multiple of size, then the final partial item is nevetheless read into buf
1444*760c2415Smrg and the end-of-file flag is set. The length of the partial item read is not
1445*760c2415Smrg provided, but could be inferred from the result of gztell(). This behavior
1446*760c2415Smrg is the same as the behavior of fread() implementations in common libraries,
1447*760c2415Smrg but it prevents the direct use of gzfread() to read a concurrently written
1448*760c2415Smrg file, reseting and retrying on end-of-file, when size is not 1.
1449*760c2415Smrg */
1450*760c2415Smrg
1451*760c2415Smrg int gzwrite(gzFile file, void* buf, uint len);
1452*760c2415Smrg /*
1453*760c2415Smrg Writes the given number of uncompressed bytes into the compressed file.
1454*760c2415Smrg gzwrite returns the number of uncompressed bytes written or 0 in case of
1455*760c2415Smrg error.
1456*760c2415Smrg */
1457*760c2415Smrg
1458*760c2415Smrg z_size_t gzfwrite(void* buf, z_size_t size, z_size_t nitems, gzFile file);
1459*760c2415Smrg /*
1460*760c2415Smrg gzfwrite() writes nitems items of size size from buf to file, duplicating
1461*760c2415Smrg the interface of stdio's fwrite(), with size_t request and return types. If
1462*760c2415Smrg the library defines size_t, then z_size_t is identical to size_t. If not,
1463*760c2415Smrg then z_size_t is an unsigned integer type that can contain a pointer.
1464*760c2415Smrg
1465*760c2415Smrg gzfwrite() returns the number of full items written of size size, or zero
1466*760c2415Smrg if there was an error. If the multiplication of size and nitems overflows,
1467*760c2415Smrg i.e. the product does not fit in a z_size_t, then nothing is written, zero
1468*760c2415Smrg is returned, and the error state is set to Z_STREAM_ERROR.
1469*760c2415Smrg */
1470*760c2415Smrg
1471*760c2415Smrg int gzprintf(gzFile file, const(char)* format, ...);
1472*760c2415Smrg /*
1473*760c2415Smrg Converts, formats, and writes the arguments to the compressed file under
1474*760c2415Smrg control of the format string, as in fprintf. gzprintf returns the number of
1475*760c2415Smrg uncompressed bytes actually written, or a negative zlib error code in case
1476*760c2415Smrg of error. The number of uncompressed bytes written is limited to 8191, or
1477*760c2415Smrg one less than the buffer size given to gzbuffer(). The caller should assure
1478*760c2415Smrg that this limit is not exceeded. If it is exceeded, then gzprintf() will
1479*760c2415Smrg return an error (0) with nothing written. In this case, there may also be a
1480*760c2415Smrg buffer overflow with unpredictable consequences, which is possible only if
1481*760c2415Smrg zlib was compiled with the insecure functions sprintf() or vsprintf()
1482*760c2415Smrg because the secure snprintf() or vsnprintf() functions were not available.
1483*760c2415Smrg This can be determined using zlibCompileFlags().
1484*760c2415Smrg */
1485*760c2415Smrg
1486*760c2415Smrg int gzputs(gzFile file, const(char)* s);
1487*760c2415Smrg /*
1488*760c2415Smrg Writes the given null-terminated string to the compressed file, excluding
1489*760c2415Smrg the terminating null character.
1490*760c2415Smrg
1491*760c2415Smrg gzputs returns the number of characters written, or -1 in case of error.
1492*760c2415Smrg */
1493*760c2415Smrg
1494*760c2415Smrg const(char)* gzgets(gzFile file, const(char)* buf, int len);
1495*760c2415Smrg /*
1496*760c2415Smrg Reads bytes from the compressed file until len-1 characters are read, or a
1497*760c2415Smrg newline character is read and transferred to buf, or an end-of-file
1498*760c2415Smrg condition is encountered. If any characters are read or if len == 1, the
1499*760c2415Smrg string is terminated with a null character. If no characters are read due
1500*760c2415Smrg to an end-of-file or len < 1, then the buffer is left untouched.
1501*760c2415Smrg
1502*760c2415Smrg gzgets returns buf which is a null-terminated string, or it returns NULL
1503*760c2415Smrg for end-of-file or in case of error. If there was an error, the contents at
1504*760c2415Smrg buf are indeterminate.
1505*760c2415Smrg */
1506*760c2415Smrg
1507*760c2415Smrg int gzputc(gzFile file, int c);
1508*760c2415Smrg /*
1509*760c2415Smrg Writes c, converted to an unsigned char, into the compressed file. gzputc
1510*760c2415Smrg returns the value that was written, or -1 in case of error.
1511*760c2415Smrg */
1512*760c2415Smrg
1513*760c2415Smrg int gzgetc(gzFile file);
1514*760c2415Smrg /*
1515*760c2415Smrg Reads one byte from the compressed file. gzgetc returns this byte or -1
1516*760c2415Smrg in case of end of file or error. This is implemented as a macro for speed.
1517*760c2415Smrg As such, it does not do all of the checking the other functions do. I.e.
1518*760c2415Smrg it does not check to see if file is NULL, nor whether the structure file
1519*760c2415Smrg points to has been clobbered or not.
1520*760c2415Smrg */
1521*760c2415Smrg
1522*760c2415Smrg int gzungetc(int c, gzFile file);
1523*760c2415Smrg /*
1524*760c2415Smrg Push one character back onto the stream to be read as the first character
1525*760c2415Smrg on the next read. At least one character of push-back is allowed.
1526*760c2415Smrg gzungetc() returns the character pushed, or -1 on failure. gzungetc() will
1527*760c2415Smrg fail if c is -1, and may fail if a character has been pushed but not read
1528*760c2415Smrg yet. If gzungetc is used immediately after gzopen or gzdopen, at least the
1529*760c2415Smrg output buffer size of pushed characters is allowed. (See gzbuffer above.)
1530*760c2415Smrg The pushed character will be discarded if the stream is repositioned with
1531*760c2415Smrg gzseek() or gzrewind().
1532*760c2415Smrg */
1533*760c2415Smrg
1534*760c2415Smrg int gzflush(gzFile file, int flush);
1535*760c2415Smrg /*
1536*760c2415Smrg Flushes all pending output into the compressed file. The parameter flush
1537*760c2415Smrg is as in the deflate() function. The return value is the zlib error number
1538*760c2415Smrg (see function gzerror below). gzflush is only permitted when writing.
1539*760c2415Smrg
1540*760c2415Smrg If the flush parameter is Z_FINISH, the remaining data is written and the
1541*760c2415Smrg gzip stream is completed in the output. If gzwrite() is called again, a new
1542*760c2415Smrg gzip stream will be started in the output. gzread() is able to read such
1543*760c2415Smrg concatenated gzip streams.
1544*760c2415Smrg
1545*760c2415Smrg gzflush should be called only when strictly necessary because it will
1546*760c2415Smrg degrade compression if called too often.
1547*760c2415Smrg */
1548*760c2415Smrg
1549*760c2415Smrg z_off_t gzseek(gzFile file, z_off_t offset, int whence);
1550*760c2415Smrg /*
1551*760c2415Smrg Sets the starting position for the next gzread or gzwrite on the given
1552*760c2415Smrg compressed file. The offset represents a number of bytes in the
1553*760c2415Smrg uncompressed data stream. The whence parameter is defined as in lseek(2);
1554*760c2415Smrg the value SEEK_END is not supported.
1555*760c2415Smrg
1556*760c2415Smrg If the file is opened for reading, this function is emulated but can be
1557*760c2415Smrg extremely slow. If the file is opened for writing, only forward seeks are
1558*760c2415Smrg supported; gzseek then compresses a sequence of zeroes up to the new
1559*760c2415Smrg starting position.
1560*760c2415Smrg
1561*760c2415Smrg gzseek returns the resulting offset location as measured in bytes from
1562*760c2415Smrg the beginning of the uncompressed stream, or -1 in case of error, in
1563*760c2415Smrg particular if the file is opened for writing and the new starting position
1564*760c2415Smrg would be before the current position.
1565*760c2415Smrg */
1566*760c2415Smrg
1567*760c2415Smrg int gzrewind(gzFile file);
1568*760c2415Smrg /*
1569*760c2415Smrg Rewinds the given file. This function is supported only for reading.
1570*760c2415Smrg
1571*760c2415Smrg gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
1572*760c2415Smrg */
1573*760c2415Smrg
1574*760c2415Smrg z_off_t gztell(gzFile file);
1575*760c2415Smrg /*
1576*760c2415Smrg Returns the starting position for the next gzread or gzwrite on the given
1577*760c2415Smrg compressed file. This position represents a number of bytes in the
1578*760c2415Smrg uncompressed data stream, and is zero when starting, even if appending or
1579*760c2415Smrg reading a gzip stream from the middle of a file using gzdopen().
1580*760c2415Smrg
1581*760c2415Smrg gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
1582*760c2415Smrg */
1583*760c2415Smrg
1584*760c2415Smrg z_off_t gzoffset(gzFile file);
1585*760c2415Smrg /*
1586*760c2415Smrg Returns the current offset in the file being read or written. This offset
1587*760c2415Smrg includes the count of bytes that precede the gzip stream, for example when
1588*760c2415Smrg appending or when using gzdopen() for reading. When reading, the offset
1589*760c2415Smrg does not include as yet unused buffered input. This information can be used
1590*760c2415Smrg for a progress indicator. On error, gzoffset() returns -1.
1591*760c2415Smrg */
1592*760c2415Smrg
1593*760c2415Smrg int gzeof(gzFile file);
1594*760c2415Smrg /*
1595*760c2415Smrg Returns true (1) if the end-of-file indicator has been set while reading,
1596*760c2415Smrg false (0) otherwise. Note that the end-of-file indicator is set only if the
1597*760c2415Smrg read tried to go past the end of the input, but came up short. Therefore,
1598*760c2415Smrg just like feof(), gzeof() may return false even if there is no more data to
1599*760c2415Smrg read, in the event that the last read request was for the exact number of
1600*760c2415Smrg bytes remaining in the input file. This will happen if the input file size
1601*760c2415Smrg is an exact multiple of the buffer size.
1602*760c2415Smrg
1603*760c2415Smrg If gzeof() returns true, then the read functions will return no more data,
1604*760c2415Smrg unless the end-of-file indicator is reset by gzclearerr() and the input file
1605*760c2415Smrg has grown since the previous end of file was detected.
1606*760c2415Smrg */
1607*760c2415Smrg
1608*760c2415Smrg int gzdirect(gzFile file);
1609*760c2415Smrg /*
1610*760c2415Smrg Returns true (1) if file is being copied directly while reading, or false
1611*760c2415Smrg (0) if file is a gzip stream being decompressed.
1612*760c2415Smrg
1613*760c2415Smrg If the input file is empty, gzdirect() will return true, since the input
1614*760c2415Smrg does not contain a gzip stream.
1615*760c2415Smrg
1616*760c2415Smrg If gzdirect() is used immediately after gzopen() or gzdopen() it will
1617*760c2415Smrg cause buffers to be allocated to allow reading the file to determine if it
1618*760c2415Smrg is a gzip file. Therefore if gzbuffer() is used, it should be called before
1619*760c2415Smrg gzdirect().
1620*760c2415Smrg
1621*760c2415Smrg When writing, gzdirect() returns true (1) if transparent writing was
1622*760c2415Smrg requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note:
1623*760c2415Smrg gzdirect() is not needed when writing. Transparent writing must be
1624*760c2415Smrg explicitly requested, so the application already knows the answer. When
1625*760c2415Smrg linking statically, using gzdirect() will include all of the zlib code for
1626*760c2415Smrg gzip file reading and decompression, which may not be desired.)
1627*760c2415Smrg */
1628*760c2415Smrg
1629*760c2415Smrg int gzclose(gzFile file);
1630*760c2415Smrg /*
1631*760c2415Smrg Flushes all pending output if necessary, closes the compressed file and
1632*760c2415Smrg deallocates the (de)compression state. Note that once file is closed, you
1633*760c2415Smrg cannot call gzerror with file, since its structures have been deallocated.
1634*760c2415Smrg gzclose must not be called more than once on the same file, just as free
1635*760c2415Smrg must not be called more than once on the same allocation.
1636*760c2415Smrg
1637*760c2415Smrg gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a
1638*760c2415Smrg file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the
1639*760c2415Smrg last read ended in the middle of a gzip stream, or Z_OK on success.
1640*760c2415Smrg */
1641*760c2415Smrg
1642*760c2415Smrg int gzclose_r(gzFile file);
1643*760c2415Smrg int gzclose_w(gzFile file);
1644*760c2415Smrg /*
1645*760c2415Smrg Same as gzclose(), but gzclose_r() is only for use when reading, and
1646*760c2415Smrg gzclose_w() is only for use when writing or appending. The advantage to
1647*760c2415Smrg using these instead of gzclose() is that they avoid linking in zlib
1648*760c2415Smrg compression or decompression code that is not used when only reading or only
1649*760c2415Smrg writing respectively. If gzclose() is used, then both compression and
1650*760c2415Smrg decompression code will be included the application when linking to a static
1651*760c2415Smrg zlib library.
1652*760c2415Smrg */
1653*760c2415Smrg
1654*760c2415Smrg const(char)* gzerror(gzFile file, int* errnum);
1655*760c2415Smrg /*
1656*760c2415Smrg Returns the error message for the last error which occurred on the given
1657*760c2415Smrg compressed file. errnum is set to zlib error number. If an error occurred
1658*760c2415Smrg in the file system and not in the compression library, errnum is set to
1659*760c2415Smrg Z_ERRNO and the application may consult errno to get the exact error code.
1660*760c2415Smrg
1661*760c2415Smrg The application must not modify the returned string. Future calls to
1662*760c2415Smrg this function may invalidate the previously returned string. If file is
1663*760c2415Smrg closed, then the string previously returned by gzerror will no longer be
1664*760c2415Smrg available.
1665*760c2415Smrg
1666*760c2415Smrg gzerror() should be used to distinguish errors from end-of-file for those
1667*760c2415Smrg functions above that do not distinguish those cases in their return values.
1668*760c2415Smrg */
1669*760c2415Smrg
1670*760c2415Smrg void gzclearerr(gzFile file);
1671*760c2415Smrg /*
1672*760c2415Smrg Clears the error and end-of-file flags for file. This is analogous to the
1673*760c2415Smrg clearerr() function in stdio. This is useful for continuing to read a gzip
1674*760c2415Smrg file that is being written concurrently.
1675*760c2415Smrg */
1676*760c2415Smrg
1677*760c2415Smrg /* checksum functions */
1678*760c2415Smrg
1679*760c2415Smrg /*
1680*760c2415Smrg These functions are not related to compression but are exported
1681*760c2415Smrg anyway because they might be useful in applications using the compression
1682*760c2415Smrg library.
1683*760c2415Smrg */
1684*760c2415Smrg
1685*760c2415Smrg uint adler32(uint adler, const(ubyte)* buf, uint len);
1686*760c2415Smrg /*
1687*760c2415Smrg Update a running Adler-32 checksum with the bytes buf[0 .. len-1] and
1688*760c2415Smrg return the updated checksum. If buf is Z_NULL, this function returns the
1689*760c2415Smrg required initial value for the checksum.
1690*760c2415Smrg
1691*760c2415Smrg An Adler-32 checksum is almost as reliable as a CRC-32 but can be computed
1692*760c2415Smrg much faster.
1693*760c2415Smrg
1694*760c2415Smrg Usage example:
1695*760c2415Smrg
1696*760c2415Smrg uLong adler = adler32(0L, Z_NULL, 0);
1697*760c2415Smrg
1698*760c2415Smrg while (read_buffer(buffer, length) != EOF)
1699*760c2415Smrg adler = adler32(adler, buffer, length);
1700*760c2415Smrg
1701*760c2415Smrg if (adler != original_adler) error();
1702*760c2415Smrg */
1703*760c2415Smrg
1704*760c2415Smrg uint adler32_z (uint adler, const(ubyte)* buf, z_size_t len);
1705*760c2415Smrg /*
1706*760c2415Smrg Same as adler32(), but with a size_t length.
1707*760c2415Smrg */
1708*760c2415Smrg
1709*760c2415Smrg uint adler32_combine(uint adler1, uint adler2, z_off_t len2);
1710*760c2415Smrg /*
1711*760c2415Smrg Combine two Adler-32 checksums into one. For two sequences of bytes, seq1
1712*760c2415Smrg and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for
1713*760c2415Smrg each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of
1714*760c2415Smrg seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. Note
1715*760c2415Smrg that the z_off_t type (like off_t) is a signed integer. If len2 is
1716*760c2415Smrg negative, the result has no meaning or utility.
1717*760c2415Smrg */
1718*760c2415Smrg
1719*760c2415Smrg uint crc32(uint crc, const(ubyte)* buf, uint len);
1720*760c2415Smrg /*
1721*760c2415Smrg Update a running CRC-32 with the bytes buf[0 .. len-1] and return the
1722*760c2415Smrg updated CRC-32. If buf is Z_NULL, this function returns the required
1723*760c2415Smrg initial value for the crc. Pre- and post-conditioning (one's complement) is
1724*760c2415Smrg performed within this function so it shouldn't be done by the application.
1725*760c2415Smrg
1726*760c2415Smrg Usage example:
1727*760c2415Smrg
1728*760c2415Smrg uLong crc = crc32(0L, Z_NULL, 0);
1729*760c2415Smrg
1730*760c2415Smrg while (read_buffer(buffer, length) != EOF)
1731*760c2415Smrg crc = crc32(crc, buffer, length);
1732*760c2415Smrg
1733*760c2415Smrg if (crc != original_crc) error();
1734*760c2415Smrg */
1735*760c2415Smrg
1736*760c2415Smrg uint crc32_z(uint adler, const(ubyte)* buf, z_size_t len);
1737*760c2415Smrg /*
1738*760c2415Smrg Same as crc32(), but with a size_t length.
1739*760c2415Smrg */
1740*760c2415Smrg
1741*760c2415Smrg uint crc32_combine(uint crc1, uint crc2, z_off_t len2);
1742*760c2415Smrg
1743*760c2415Smrg /*
1744*760c2415Smrg Combine two CRC-32 check values into one. For two sequences of bytes,
1745*760c2415Smrg seq1 and seq2 with lengths len1 and len2, CRC-32 check values were
1746*760c2415Smrg calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32
1747*760c2415Smrg check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and
1748*760c2415Smrg len2.
1749*760c2415Smrg */
1750*760c2415Smrg
1751*760c2415Smrg
1752*760c2415Smrg /* various hacks, don't look :) */
1753*760c2415Smrg
1754*760c2415Smrg /* deflateInit and inflateInit are macros to allow checking the zlib version
1755*760c2415Smrg * and the compiler's view of z_stream:
1756*760c2415Smrg */
1757*760c2415Smrg int deflateInit_(z_streamp strm,
1758*760c2415Smrg int level,
1759*760c2415Smrg const(char)* versionx,
1760*760c2415Smrg int stream_size);
1761*760c2415Smrg
1762*760c2415Smrg int inflateInit_(z_streamp strm,
1763*760c2415Smrg const(char)* versionx,
1764*760c2415Smrg int stream_size);
1765*760c2415Smrg
1766*760c2415Smrg int deflateInit2_(z_streamp strm,
1767*760c2415Smrg int level,
1768*760c2415Smrg int method,
1769*760c2415Smrg int windowBits,
1770*760c2415Smrg int memLevel,
1771*760c2415Smrg int strategy,
1772*760c2415Smrg const(char)* versionx,
1773*760c2415Smrg int stream_size);
1774*760c2415Smrg
1775*760c2415Smrg int inflateBackInit_(z_stream* strm,
1776*760c2415Smrg int windowBits,
1777*760c2415Smrg ubyte* window,
1778*760c2415Smrg const(char)* z_version,
1779*760c2415Smrg int stream_size);
1780*760c2415Smrg
1781*760c2415Smrg int inflateInit2_(z_streamp strm,
1782*760c2415Smrg int windowBits,
1783*760c2415Smrg const(char)* versionx,
1784*760c2415Smrg int stream_size);
1785*760c2415Smrg
1786*760c2415Smrg const(char)* zError(int err);
1787*760c2415Smrg int inflateSyncPoint(z_streamp z);
1788*760c2415Smrg const(uint)* get_crc_table();
1789