1 /*
2  * jdapimin.c
3  *
4  * Copyright (C) 1994-1998, Thomas G. Lane.
5  * Modified 2009-2013 by Guido Vollbeding.
6  * This file is part of the Independent JPEG Group's software.
7  * For conditions of distribution and use, see the accompanying README file.
8  *
9  * This file contains application interface code for the decompression half
10  * of the JPEG library.  These are the "minimum" API routines that may be
11  * needed in either the normal full-decompression case or the
12  * transcoding-only case.
13  *
14  * Most of the routines intended to be called directly by an application
15  * are in this file or in jdapistd.c.  But also see jcomapi.c for routines
16  * shared by compression and decompression, and jdtrans.c for the transcoding
17  * case.
18  */
19 
20 #define JPEG_INTERNALS
21 #include "jinclude.h"
22 #include "jpeglib.h"
23 
24 
25 /*
26  * Initialization of a JPEG decompression object.
27  * The error manager must already be set up (in case memory manager fails).
28  */
29 
30 GLOBAL(void)
jpeg_CreateDecompress(j_decompress_ptr cinfo,int version,size_t structsize)31 jpeg_CreateDecompress (j_decompress_ptr cinfo, int version, size_t structsize)
32 {
33   int i;
34 
35   /* Guard against version mismatches between library and caller. */
36   cinfo->mem = NULL;		/* so jpeg_destroy knows mem mgr not called */
37   if (version != JPEG_LIB_VERSION)
38     ERREXIT2(cinfo, JERR_BAD_LIB_VERSION, JPEG_LIB_VERSION, version);
39   if (structsize != SIZEOF(struct jpeg_decompress_struct))
40     ERREXIT2(cinfo, JERR_BAD_STRUCT_SIZE,
41 	     (int) SIZEOF(struct jpeg_decompress_struct), (int) structsize);
42 
43   /* For debugging purposes, we zero the whole master structure.
44    * But the application has already set the err pointer, and may have set
45    * client_data, so we have to save and restore those fields.
46    * Note: if application hasn't set client_data, tools like Purify may
47    * complain here.
48    */
49   {
50     struct jpeg_error_mgr * err = cinfo->err;
51     void * client_data = cinfo->client_data; /* ignore Purify complaint here */
52     MEMZERO(cinfo, SIZEOF(struct jpeg_decompress_struct));
53     cinfo->err = err;
54     cinfo->client_data = client_data;
55   }
56   cinfo->is_decompressor = TRUE;
57 
58   /* Initialize a memory manager instance for this object */
59   jinit_memory_mgr((j_common_ptr) cinfo);
60 
61   /* Zero out pointers to permanent structures. */
62   cinfo->progress = NULL;
63   cinfo->src = NULL;
64 
65   for (i = 0; i < NUM_QUANT_TBLS; i++)
66     cinfo->quant_tbl_ptrs[i] = NULL;
67 
68   for (i = 0; i < NUM_HUFF_TBLS; i++) {
69     cinfo->dc_huff_tbl_ptrs[i] = NULL;
70     cinfo->ac_huff_tbl_ptrs[i] = NULL;
71   }
72 
73   /* Initialize marker processor so application can override methods
74    * for COM, APPn markers before calling jpeg_read_header.
75    */
76   cinfo->marker_list = NULL;
77   jinit_marker_reader(cinfo);
78 
79   /* And initialize the overall input controller. */
80   jinit_input_controller(cinfo);
81 
82   /* OK, I'm ready */
83   cinfo->global_state = DSTATE_START;
84 }
85 
86 
87 /*
88  * Destruction of a JPEG decompression object
89  */
90 
91 GLOBAL(void)
jpeg_destroy_decompress(j_decompress_ptr cinfo)92 jpeg_destroy_decompress (j_decompress_ptr cinfo)
93 {
94   jpeg_destroy((j_common_ptr) cinfo); /* use common routine */
95 }
96 
97 
98 /*
99  * Abort processing of a JPEG decompression operation,
100  * but don't destroy the object itself.
101  */
102 
103 GLOBAL(void)
jpeg_abort_decompress(j_decompress_ptr cinfo)104 jpeg_abort_decompress (j_decompress_ptr cinfo)
105 {
106   jpeg_abort((j_common_ptr) cinfo); /* use common routine */
107 }
108 
109 
110 /*
111  * Set default decompression parameters.
112  */
113 
114 LOCAL(void)
default_decompress_parms(j_decompress_ptr cinfo)115 default_decompress_parms (j_decompress_ptr cinfo)
116 {
117   int cid0, cid1, cid2;
118 
119   /* Guess the input colorspace, and set output colorspace accordingly. */
120   /* Note application may override our guesses. */
121   switch (cinfo->num_components) {
122   case 1:
123     cinfo->jpeg_color_space = JCS_GRAYSCALE;
124     cinfo->out_color_space = JCS_GRAYSCALE;
125     break;
126 
127   case 3:
128     cid0 = cinfo->comp_info[0].component_id;
129     cid1 = cinfo->comp_info[1].component_id;
130     cid2 = cinfo->comp_info[2].component_id;
131 
132     /* First try to guess from the component IDs */
133     if      (cid0 == 0x01 && cid1 == 0x02 && cid2 == 0x03)
134       cinfo->jpeg_color_space = JCS_YCbCr;
135     else if (cid0 == 0x01 && cid1 == 0x22 && cid2 == 0x23)
136       cinfo->jpeg_color_space = JCS_BG_YCC;
137     else if (cid0 == 0x52 && cid1 == 0x47 && cid2 == 0x42)
138       cinfo->jpeg_color_space = JCS_RGB;	/* ASCII 'R', 'G', 'B' */
139     else if (cid0 == 0x72 && cid1 == 0x67 && cid2 == 0x62)
140       cinfo->jpeg_color_space = JCS_BG_RGB;	/* ASCII 'r', 'g', 'b' */
141     else if (cinfo->saw_JFIF_marker)
142       cinfo->jpeg_color_space = JCS_YCbCr;	/* assume it's YCbCr */
143     else if (cinfo->saw_Adobe_marker) {
144       switch (cinfo->Adobe_transform) {
145       case 0:
146 	cinfo->jpeg_color_space = JCS_RGB;
147 	break;
148       case 1:
149 	cinfo->jpeg_color_space = JCS_YCbCr;
150 	break;
151       default:
152 	WARNMS1(cinfo, JWRN_ADOBE_XFORM, cinfo->Adobe_transform);
153 	cinfo->jpeg_color_space = JCS_YCbCr;	/* assume it's YCbCr */
154 	break;
155       }
156     } else {
157       TRACEMS3(cinfo, 1, JTRC_UNKNOWN_IDS, cid0, cid1, cid2);
158       cinfo->jpeg_color_space = JCS_YCbCr;	/* assume it's YCbCr */
159     }
160     /* Always guess RGB is proper output colorspace. */
161     cinfo->out_color_space = JCS_RGB;
162     break;
163 
164   case 4:
165     if (cinfo->saw_Adobe_marker) {
166       switch (cinfo->Adobe_transform) {
167       case 0:
168 	cinfo->jpeg_color_space = JCS_CMYK;
169 	break;
170       case 2:
171 	cinfo->jpeg_color_space = JCS_YCCK;
172 	break;
173       default:
174 	WARNMS1(cinfo, JWRN_ADOBE_XFORM, cinfo->Adobe_transform);
175 	cinfo->jpeg_color_space = JCS_YCCK;	/* assume it's YCCK */
176 	break;
177       }
178     } else {
179       /* No special markers, assume straight CMYK. */
180       cinfo->jpeg_color_space = JCS_CMYK;
181     }
182     cinfo->out_color_space = JCS_CMYK;
183     break;
184 
185   default:
186     cinfo->jpeg_color_space = JCS_UNKNOWN;
187     cinfo->out_color_space = JCS_UNKNOWN;
188     break;
189   }
190 
191   /* Set defaults for other decompression parameters. */
192   cinfo->scale_num = cinfo->block_size;		/* 1:1 scaling */
193   cinfo->scale_denom = cinfo->block_size;
194   cinfo->output_gamma = 1.0;
195   cinfo->buffered_image = FALSE;
196   cinfo->raw_data_out = FALSE;
197   cinfo->dct_method = JDCT_DEFAULT;
198   cinfo->do_fancy_upsampling = TRUE;
199   cinfo->do_block_smoothing = TRUE;
200   cinfo->quantize_colors = FALSE;
201   /* We set these in case application only sets quantize_colors. */
202   cinfo->dither_mode = JDITHER_FS;
203 #ifdef QUANT_2PASS_SUPPORTED
204   cinfo->two_pass_quantize = TRUE;
205 #else
206   cinfo->two_pass_quantize = FALSE;
207 #endif
208   cinfo->desired_number_of_colors = 256;
209   cinfo->colormap = NULL;
210   /* Initialize for no mode change in buffered-image mode. */
211   cinfo->enable_1pass_quant = FALSE;
212   cinfo->enable_external_quant = FALSE;
213   cinfo->enable_2pass_quant = FALSE;
214 }
215 
216 
217 /*
218  * Decompression startup: read start of JPEG datastream to see what's there.
219  * Need only initialize JPEG object and supply a data source before calling.
220  *
221  * This routine will read as far as the first SOS marker (ie, actual start of
222  * compressed data), and will save all tables and parameters in the JPEG
223  * object.  It will also initialize the decompression parameters to default
224  * values, and finally return JPEG_HEADER_OK.  On return, the application may
225  * adjust the decompression parameters and then call jpeg_start_decompress.
226  * (Or, if the application only wanted to determine the image parameters,
227  * the data need not be decompressed.  In that case, call jpeg_abort or
228  * jpeg_destroy to release any temporary space.)
229  * If an abbreviated (tables only) datastream is presented, the routine will
230  * return JPEG_HEADER_TABLES_ONLY upon reaching EOI.  The application may then
231  * re-use the JPEG object to read the abbreviated image datastream(s).
232  * It is unnecessary (but OK) to call jpeg_abort in this case.
233  * The JPEG_SUSPENDED return code only occurs if the data source module
234  * requests suspension of the decompressor.  In this case the application
235  * should load more source data and then re-call jpeg_read_header to resume
236  * processing.
237  * If a non-suspending data source is used and require_image is TRUE, then the
238  * return code need not be inspected since only JPEG_HEADER_OK is possible.
239  *
240  * This routine is now just a front end to jpeg_consume_input, with some
241  * extra error checking.
242  */
243 
244 GLOBAL(int)
jpeg_read_header(j_decompress_ptr cinfo,boolean require_image)245 jpeg_read_header (j_decompress_ptr cinfo, boolean require_image)
246 {
247   int retcode;
248 
249   if (cinfo->global_state != DSTATE_START &&
250       cinfo->global_state != DSTATE_INHEADER)
251     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
252 
253   retcode = jpeg_consume_input(cinfo);
254 
255   switch (retcode) {
256   case JPEG_REACHED_SOS:
257     retcode = JPEG_HEADER_OK;
258     break;
259   case JPEG_REACHED_EOI:
260     if (require_image)		/* Complain if application wanted an image */
261       ERREXIT(cinfo, JERR_NO_IMAGE);
262     /* Reset to start state; it would be safer to require the application to
263      * call jpeg_abort, but we can't change it now for compatibility reasons.
264      * A side effect is to free any temporary memory (there shouldn't be any).
265      */
266     jpeg_abort((j_common_ptr) cinfo); /* sets state = DSTATE_START */
267     retcode = JPEG_HEADER_TABLES_ONLY;
268     break;
269   case JPEG_SUSPENDED:
270     /* no work */
271     break;
272   }
273 
274   return retcode;
275 }
276 
277 
278 /*
279  * Consume data in advance of what the decompressor requires.
280  * This can be called at any time once the decompressor object has
281  * been created and a data source has been set up.
282  *
283  * This routine is essentially a state machine that handles a couple
284  * of critical state-transition actions, namely initial setup and
285  * transition from header scanning to ready-for-start_decompress.
286  * All the actual input is done via the input controller's consume_input
287  * method.
288  */
289 
290 GLOBAL(int)
jpeg_consume_input(j_decompress_ptr cinfo)291 jpeg_consume_input (j_decompress_ptr cinfo)
292 {
293   int retcode = JPEG_SUSPENDED;
294 
295   /* NB: every possible DSTATE value should be listed in this switch */
296   switch (cinfo->global_state) {
297   case DSTATE_START:
298     /* Start-of-datastream actions: reset appropriate modules */
299     (*cinfo->inputctl->reset_input_controller) (cinfo);
300     /* Initialize application's data source module */
301     (*cinfo->src->init_source) (cinfo);
302     cinfo->global_state = DSTATE_INHEADER;
303     /*FALLTHROUGH*/
304   case DSTATE_INHEADER:
305     retcode = (*cinfo->inputctl->consume_input) (cinfo);
306     if (retcode == JPEG_REACHED_SOS) { /* Found SOS, prepare to decompress */
307       /* Set up default parameters based on header data */
308       default_decompress_parms(cinfo);
309       /* Set global state: ready for start_decompress */
310       cinfo->global_state = DSTATE_READY;
311     }
312     break;
313   case DSTATE_READY:
314     /* Can't advance past first SOS until start_decompress is called */
315     retcode = JPEG_REACHED_SOS;
316     break;
317   case DSTATE_PRELOAD:
318   case DSTATE_PRESCAN:
319   case DSTATE_SCANNING:
320   case DSTATE_RAW_OK:
321   case DSTATE_BUFIMAGE:
322   case DSTATE_BUFPOST:
323   case DSTATE_STOPPING:
324     retcode = (*cinfo->inputctl->consume_input) (cinfo);
325     break;
326   default:
327     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
328   }
329   return retcode;
330 }
331 
332 
333 /*
334  * Have we finished reading the input file?
335  */
336 
337 GLOBAL(boolean)
jpeg_input_complete(j_decompress_ptr cinfo)338 jpeg_input_complete (j_decompress_ptr cinfo)
339 {
340   /* Check for valid jpeg object */
341   if (cinfo->global_state < DSTATE_START ||
342       cinfo->global_state > DSTATE_STOPPING)
343     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
344   return cinfo->inputctl->eoi_reached;
345 }
346 
347 
348 /*
349  * Is there more than one scan?
350  */
351 
352 GLOBAL(boolean)
jpeg_has_multiple_scans(j_decompress_ptr cinfo)353 jpeg_has_multiple_scans (j_decompress_ptr cinfo)
354 {
355   /* Only valid after jpeg_read_header completes */
356   if (cinfo->global_state < DSTATE_READY ||
357       cinfo->global_state > DSTATE_STOPPING)
358     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
359   return cinfo->inputctl->has_multiple_scans;
360 }
361 
362 
363 /*
364  * Finish JPEG decompression.
365  *
366  * This will normally just verify the file trailer and release temp storage.
367  *
368  * Returns FALSE if suspended.  The return value need be inspected only if
369  * a suspending data source is used.
370  */
371 
372 GLOBAL(boolean)
jpeg_finish_decompress(j_decompress_ptr cinfo)373 jpeg_finish_decompress (j_decompress_ptr cinfo)
374 {
375   if ((cinfo->global_state == DSTATE_SCANNING ||
376        cinfo->global_state == DSTATE_RAW_OK) && ! cinfo->buffered_image) {
377     /* Terminate final pass of non-buffered mode */
378     if (cinfo->output_scanline < cinfo->output_height)
379       ERREXIT(cinfo, JERR_TOO_LITTLE_DATA);
380     (*cinfo->master->finish_output_pass) (cinfo);
381     cinfo->global_state = DSTATE_STOPPING;
382   } else if (cinfo->global_state == DSTATE_BUFIMAGE) {
383     /* Finishing after a buffered-image operation */
384     cinfo->global_state = DSTATE_STOPPING;
385   } else if (cinfo->global_state != DSTATE_STOPPING) {
386     /* STOPPING = repeat call after a suspension, anything else is error */
387     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
388   }
389   /* Read until EOI */
390   while (! cinfo->inputctl->eoi_reached) {
391     if ((*cinfo->inputctl->consume_input) (cinfo) == JPEG_SUSPENDED)
392       return FALSE;		/* Suspend, come back later */
393   }
394   /* Do final cleanup */
395   (*cinfo->src->term_source) (cinfo);
396   /* We can use jpeg_abort to release memory and reset global_state */
397   jpeg_abort((j_common_ptr) cinfo);
398   return TRUE;
399 }
400