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comparison zip.c @ 1692:5dacaef602a7 segacd

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Merge from default
author Michael Pavone <pavone@retrodev.com>
date Sat, 05 Jan 2019 00:58:08 -0800
parents 137dbd05ceab
children 0111c8344477
comparison
equal deleted inserted replaced
1504:95b3a1a8b26c 1692:5dacaef602a7
1 #include <stdio.h>
2 #include <stdlib.h>
3 #include <stddef.h>
4 #include <string.h>
5 #include "util.h"
6 #include "zip.h"
7 #ifndef DISABLE_ZLIB
8 #include "zlib/zlib.h"
9 #endif
10
11 static const char cdfd_magic[4] = {'P', 'K', 1, 2};
12 static const char eocd_magic[4] = {'P', 'K', 5, 6};
13 #define MIN_EOCD_SIZE 22
14 #define MIN_CDFD_SIZE 46
15 #define ZIP_MAX_EOCD_OFFSET (64*1024+MIN_EOCD_SIZE)
16
17 enum {
18 ZIP_STORE = 0,
19 ZIP_DEFLATE = 8
20 };
21
22 zip_file *zip_open(const char *filename)
23 {
24 FILE *f = fopen(filename, "rb");
25 if (!f) {
26 return NULL;
27 }
28 long fsize = file_size(f);
29 if (fsize < MIN_EOCD_SIZE) {
30 //too small to be a zip file
31 goto fail;
32 }
33
34 long max_offset = fsize > ZIP_MAX_EOCD_OFFSET ? ZIP_MAX_EOCD_OFFSET : fsize;
35 fseek(f, -max_offset, SEEK_END);
36 uint8_t *buf = malloc(max_offset);
37 if (max_offset != fread(buf, 1, max_offset, f)) {
38 goto fail;
39 }
40
41 long current_offset;
42 uint32_t cd_start, cd_size;
43 uint16_t cd_count;
44 for (current_offset = max_offset - MIN_EOCD_SIZE; current_offset >= 0; current_offset--)
45 {
46 if (memcmp(eocd_magic, buf + current_offset, sizeof(eocd_magic))) {
47 continue;
48 }
49 uint16_t comment_size = buf[current_offset + 20] | buf[current_offset + 21] << 8;
50 if (comment_size != (max_offset - current_offset - MIN_EOCD_SIZE)) {
51 continue;
52 }
53 cd_start = buf[current_offset + 16] | buf[current_offset + 17] << 8
54 | buf[current_offset + 18] << 16 | buf[current_offset + 19] << 24;
55 if (cd_start > (fsize - (max_offset - current_offset))) {
56 continue;
57 }
58 cd_size = buf[current_offset + 12] | buf[current_offset + 13] << 8
59 | buf[current_offset + 14] << 16 | buf[current_offset + 15] << 24;
60 if ((cd_start + cd_size) > (fsize - (max_offset - current_offset))) {
61 continue;
62 }
63 cd_count = buf[current_offset + 10] | buf[current_offset + 11] << 8;
64 break;
65 }
66 free(buf);
67 if (current_offset < 0) {
68 //failed to find EOCD
69 goto fail;
70 }
71 buf = malloc(cd_size);
72 fseek(f, cd_start, SEEK_SET);
73 if (cd_size != fread(buf, 1, cd_size, f)) {
74 goto fail_free;
75 }
76 zip_entry *entries = calloc(cd_count, sizeof(zip_entry));
77 uint32_t cd_max_last = cd_size - MIN_CDFD_SIZE;
78 zip_entry *cur_entry = entries;
79 for (uint32_t off = 0; cd_count && off <= cd_max_last; cur_entry++, cd_count--)
80 {
81 if (memcmp(buf + off, cdfd_magic, sizeof(cdfd_magic))) {
82 goto fail_entries;
83 }
84 uint32_t name_length = buf[off + 28] | buf[off + 29] << 8;
85 uint32_t extra_length = buf[off + 30] | buf[off + 31] << 8;
86 //TODO: verify name length doesn't go past end of CD
87
88 cur_entry->name = malloc(name_length + 1);
89 memcpy(cur_entry->name, buf + off + MIN_CDFD_SIZE, name_length);
90 cur_entry->name[name_length] = 0;
91
92 cur_entry->compressed_size = buf[off + 20] | buf[off + 21] << 8
93 | buf[off + 22] << 16 | buf[off + 23] << 24;
94 cur_entry->size = buf[off + 24] | buf[off + 25] << 8
95 | buf[off + 26] << 16 | buf[off + 27] << 24;
96
97 cur_entry->local_header_off = buf[off + 42] | buf[off + 43] << 8
98 | buf[off + 44] << 16 | buf[off + 45] << 24;
99
100 cur_entry->compression_method = buf[off + 10] | buf[off + 11] << 8;
101
102 off += name_length + extra_length + MIN_CDFD_SIZE;
103 }
104
105 zip_file *z = malloc(sizeof(zip_file));
106 z->entries = entries;
107 z->file = f;
108 z->num_entries = cur_entry - entries;
109 return z;
110
111 fail_entries:
112 for (cur_entry--; cur_entry >= entries; cur_entry--)
113 {
114 free(cur_entry->name);
115 }
116 free(entries);
117 fail_free:
118 free(buf);
119 fail:
120 fclose(f);
121 return NULL;
122 }
123
124 uint8_t *zip_read(zip_file *f, uint32_t index, size_t *out_size)
125 {
126
127 fseek(f->file, f->entries[index].local_header_off + 26, SEEK_SET);
128 uint8_t tmp[4];
129 if (sizeof(tmp) != fread(tmp, 1, sizeof(tmp), f->file)) {
130 return NULL;
131 }
132 uint32_t local_variable = (tmp[0] | tmp[1] << 8) + (tmp[2] | tmp[3] << 8);
133 fseek(f->file, f->entries[index].local_header_off + local_variable + 30, SEEK_SET);
134
135 size_t int_size;
136 if (!out_size) {
137 out_size = &int_size;
138 int_size = f->entries[index].size;
139 }
140
141 uint8_t *buf = malloc(*out_size);
142 if (*out_size > f->entries[index].size) {
143 *out_size = f->entries[index].size;
144 }
145 switch(f->entries[index].compression_method)
146 {
147 case ZIP_STORE:
148 if (*out_size != fread(buf, 1, *out_size, f->file)) {
149 free(buf);
150 return NULL;
151 }
152 break;
153 #ifndef DISABLE_ZLIB
154 case ZIP_DEFLATE: {
155 //note in unzip.c in zlib/contrib suggests a dummy byte is needed, so we allocate an extra byte here
156 uint8_t *src_buf = malloc(f->entries[index].compressed_size + 1);
157 if (f->entries[index].compressed_size != fread(src_buf, 1, f->entries[index].compressed_size, f->file)) {
158 free(src_buf);
159 return NULL;
160 }
161 uLongf destLen = *out_size;
162 z_stream stream;
163 memset(&stream, 0, sizeof(stream));
164 stream.avail_in = f->entries[index].compressed_size + 1;
165 stream.next_in = src_buf;
166 stream.next_out = buf;
167 stream.avail_out = *out_size;
168 if (Z_OK == inflateInit2(&stream, -15)) {
169 int result = inflate(&stream, Z_FINISH);
170 *out_size = stream.total_out;
171 free(src_buf);
172 inflateEnd(&stream);
173 if (result != Z_OK && result != Z_STREAM_END && result != Z_BUF_ERROR) {
174 free(buf);
175 return NULL;
176 }
177 }
178 break;
179 }
180 #endif
181 default:
182 free(buf);
183 return NULL;
184 }
185
186 return buf;
187 }
188
189 void zip_close(zip_file *f)
190 {
191 fclose(f->file);
192 for (uint32_t i = 0; i < f->num_entries; i++)
193 {
194 free(f->entries[i].name);
195 }
196 free(f->entries);
197 free(f);
198 }
199
200