1 /*
2 Copyright 2013 Google Inc. All Rights Reserved.
3
4 Licensed under the Apache License, Version 2.0 (the "License");
5 you may not use this file except in compliance with the License.
6 You may obtain a copy of the License at
7
8 http://www.apache.org/licenses/LICENSE-2.0
9
10 Unless required by applicable law or agreed to in writing, software
11 distributed under the License is distributed on an "AS IS" BASIS,
12 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 See the License for the specific language governing permissions and
14 limitations under the License.
15
16 Author: lode.vandevenne@gmail.com (Lode Vandevenne)
17 Author: jyrki.alakuijala@gmail.com (Jyrki Alakuijala)
18 */
19
20 #include "gzip_container.h"
21 #include "util.h"
22
23 #include <stdio.h>
24
25 #include "deflate.h"
26
27 /* CRC polynomial: 0xedb88320 */
28 static const unsigned long crc32_table[256] = {
29 0u, 1996959894u, 3993919788u, 2567524794u, 124634137u, 1886057615u,
30 3915621685u, 2657392035u, 249268274u, 2044508324u, 3772115230u, 2547177864u,
31 162941995u, 2125561021u, 3887607047u, 2428444049u, 498536548u, 1789927666u,
32 4089016648u, 2227061214u, 450548861u, 1843258603u, 4107580753u, 2211677639u,
33 325883990u, 1684777152u, 4251122042u, 2321926636u, 335633487u, 1661365465u,
34 4195302755u, 2366115317u, 997073096u, 1281953886u, 3579855332u, 2724688242u,
35 1006888145u, 1258607687u, 3524101629u, 2768942443u, 901097722u, 1119000684u,
36 3686517206u, 2898065728u, 853044451u, 1172266101u, 3705015759u, 2882616665u,
37 651767980u, 1373503546u, 3369554304u, 3218104598u, 565507253u, 1454621731u,
38 3485111705u, 3099436303u, 671266974u, 1594198024u, 3322730930u, 2970347812u,
39 795835527u, 1483230225u, 3244367275u, 3060149565u, 1994146192u, 31158534u,
40 2563907772u, 4023717930u, 1907459465u, 112637215u, 2680153253u, 3904427059u,
41 2013776290u, 251722036u, 2517215374u, 3775830040u, 2137656763u, 141376813u,
42 2439277719u, 3865271297u, 1802195444u, 476864866u, 2238001368u, 4066508878u,
43 1812370925u, 453092731u, 2181625025u, 4111451223u, 1706088902u, 314042704u,
44 2344532202u, 4240017532u, 1658658271u, 366619977u, 2362670323u, 4224994405u,
45 1303535960u, 984961486u, 2747007092u, 3569037538u, 1256170817u, 1037604311u,
46 2765210733u, 3554079995u, 1131014506u, 879679996u, 2909243462u, 3663771856u,
47 1141124467u, 855842277u, 2852801631u, 3708648649u, 1342533948u, 654459306u,
48 3188396048u, 3373015174u, 1466479909u, 544179635u, 3110523913u, 3462522015u,
49 1591671054u, 702138776u, 2966460450u, 3352799412u, 1504918807u, 783551873u,
50 3082640443u, 3233442989u, 3988292384u, 2596254646u, 62317068u, 1957810842u,
51 3939845945u, 2647816111u, 81470997u, 1943803523u, 3814918930u, 2489596804u,
52 225274430u, 2053790376u, 3826175755u, 2466906013u, 167816743u, 2097651377u,
53 4027552580u, 2265490386u, 503444072u, 1762050814u, 4150417245u, 2154129355u,
54 426522225u, 1852507879u, 4275313526u, 2312317920u, 282753626u, 1742555852u,
55 4189708143u, 2394877945u, 397917763u, 1622183637u, 3604390888u, 2714866558u,
56 953729732u, 1340076626u, 3518719985u, 2797360999u, 1068828381u, 1219638859u,
57 3624741850u, 2936675148u, 906185462u, 1090812512u, 3747672003u, 2825379669u,
58 829329135u, 1181335161u, 3412177804u, 3160834842u, 628085408u, 1382605366u,
59 3423369109u, 3138078467u, 570562233u, 1426400815u, 3317316542u, 2998733608u,
60 733239954u, 1555261956u, 3268935591u, 3050360625u, 752459403u, 1541320221u,
61 2607071920u, 3965973030u, 1969922972u, 40735498u, 2617837225u, 3943577151u,
62 1913087877u, 83908371u, 2512341634u, 3803740692u, 2075208622u, 213261112u,
63 2463272603u, 3855990285u, 2094854071u, 198958881u, 2262029012u, 4057260610u,
64 1759359992u, 534414190u, 2176718541u, 4139329115u, 1873836001u, 414664567u,
65 2282248934u, 4279200368u, 1711684554u, 285281116u, 2405801727u, 4167216745u,
66 1634467795u, 376229701u, 2685067896u, 3608007406u, 1308918612u, 956543938u,
67 2808555105u, 3495958263u, 1231636301u, 1047427035u, 2932959818u, 3654703836u,
68 1088359270u, 936918000u, 2847714899u, 3736837829u, 1202900863u, 817233897u,
69 3183342108u, 3401237130u, 1404277552u, 615818150u, 3134207493u, 3453421203u,
70 1423857449u, 601450431u, 3009837614u, 3294710456u, 1567103746u, 711928724u,
71 3020668471u, 3272380065u, 1510334235u, 755167117u
72 };
73
74 /* Returns the CRC32 */
CRC(const unsigned char * data,size_t size)75 static unsigned long CRC(const unsigned char* data, size_t size) {
76 unsigned long result = 0xffffffffu;
77 for (; size > 0; size--) {
78 result = crc32_table[(result ^ *(data++)) & 0xff] ^ (result >> 8);
79 }
80 return result ^ 0xffffffffu;
81 }
82
83 /* Compresses the data according to the gzip specification, RFC 1952. */
ZopfliGzipCompress(const ZopfliOptions * options,const unsigned char * in,size_t insize,unsigned char ** out,size_t * outsize)84 void ZopfliGzipCompress(const ZopfliOptions* options,
85 const unsigned char* in, size_t insize,
86 unsigned char** out, size_t* outsize) {
87 unsigned long crcvalue = CRC(in, insize);
88 unsigned char bp = 0;
89
90 ZOPFLI_APPEND_DATA(31, out, outsize); /* ID1 */
91 ZOPFLI_APPEND_DATA(139, out, outsize); /* ID2 */
92 ZOPFLI_APPEND_DATA(8, out, outsize); /* CM */
93 ZOPFLI_APPEND_DATA(0, out, outsize); /* FLG */
94 /* MTIME */
95 ZOPFLI_APPEND_DATA(0, out, outsize);
96 ZOPFLI_APPEND_DATA(0, out, outsize);
97 ZOPFLI_APPEND_DATA(0, out, outsize);
98 ZOPFLI_APPEND_DATA(0, out, outsize);
99
100 ZOPFLI_APPEND_DATA(2, out, outsize); /* XFL, 2 indicates best compression. */
101 ZOPFLI_APPEND_DATA(3, out, outsize); /* OS follows Unix conventions. */
102
103 ZopfliDeflate(options, 2 /* Dynamic block */, 1,
104 in, insize, &bp, out, outsize);
105
106 /* CRC */
107 ZOPFLI_APPEND_DATA(crcvalue % 256, out, outsize);
108 ZOPFLI_APPEND_DATA((crcvalue >> 8) % 256, out, outsize);
109 ZOPFLI_APPEND_DATA((crcvalue >> 16) % 256, out, outsize);
110 ZOPFLI_APPEND_DATA((crcvalue >> 24) % 256, out, outsize);
111
112 /* ISIZE */
113 ZOPFLI_APPEND_DATA(insize % 256, out, outsize);
114 ZOPFLI_APPEND_DATA((insize >> 8) % 256, out, outsize);
115 ZOPFLI_APPEND_DATA((insize >> 16) % 256, out, outsize);
116 ZOPFLI_APPEND_DATA((insize >> 24) % 256, out, outsize);
117
118 if (options->verbose) {
119 fprintf(stderr,
120 "Original Size: %d, Gzip: %d, Compression: %f%% Removed\n",
121 (int)insize, (int)*outsize,
122 100.0 * (double)(insize - *outsize) / (double)insize);
123 }
124 }
125