1 /*
2 zip_source_crc.c -- pass-through source that calculates CRC32 and size
3 Copyright (C) 2009 Dieter Baron and Thomas Klausner
4
5 This file is part of libzip, a library to manipulate ZIP archives.
6 The authors can be contacted at <libzip@nih.at>
7
8 Redistribution and use in source and binary forms, with or without
9 modification, are permitted provided that the following conditions
10 are met:
11 1. Redistributions of source code must retain the above copyright
12 notice, this list of conditions and the following disclaimer.
13 2. Redistributions in binary form must reproduce the above copyright
14 notice, this list of conditions and the following disclaimer in
15 the documentation and/or other materials provided with the
16 distribution.
17 3. The names of the authors may not be used to endorse or promote
18 products derived from this software without specific prior
19 written permission.
20
21 THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS
22 OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
23 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
25 DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
27 GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
28 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
29 IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
30 OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
31 IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 */
33
34
35
36 #include <stdlib.h>
37 #include <string.h>
38
39 #include "zipint.h"
40
41 struct crc {
42 int eof;
43 int validate;
44 int e[2];
45 zip_uint64_t size;
46 zip_uint32_t crc;
47 };
48
49 static zip_int64_t crc_read(struct zip_source *, void *, void *
50 , zip_uint64_t, enum zip_source_cmd);
51
52
53
54 ZIP_EXTERN(struct zip_source *)
zip_source_crc(struct zip * za,struct zip_source * src,int validate)55 zip_source_crc(struct zip *za, struct zip_source *src, int validate)
56 {
57 struct crc *ctx;
58
59 if (src == NULL) {
60 _zip_error_set(&za->error, ZIP_ER_INVAL, 0);
61 return NULL;
62 }
63
64 if ((ctx=(struct crc *)malloc(sizeof(*ctx))) == NULL) {
65 _zip_error_set(&za->error, ZIP_ER_MEMORY, 0);
66 return NULL;
67 }
68
69 ctx->validate = validate;
70
71 return zip_source_layered(za, src, crc_read, ctx);
72 }
73
74
75
76 static zip_int64_t
crc_read(struct zip_source * src,void * _ctx,void * data,zip_uint64_t len,enum zip_source_cmd cmd)77 crc_read(struct zip_source *src, void *_ctx, void *data,
78 zip_uint64_t len, enum zip_source_cmd cmd)
79 {
80 struct crc *ctx;
81 zip_int64_t n;
82
83 ctx = (struct crc *)_ctx;
84
85 switch (cmd) {
86 case ZIP_SOURCE_OPEN:
87 ctx->eof = 0;
88 ctx->crc = crc32(0, NULL, 0);
89 ctx->size = 0;
90
91 return 0;
92
93 case ZIP_SOURCE_READ:
94 if (ctx->eof || len == 0)
95 return 0;
96
97 if ((n=zip_source_read(src, data, len)) < 0)
98 return ZIP_SOURCE_ERR_LOWER;
99
100 if (n == 0) {
101 ctx->eof = 1;
102 if (ctx->validate) {
103 struct zip_stat st;
104
105 if (zip_source_stat(src, &st) < 0)
106 return ZIP_SOURCE_ERR_LOWER;
107
108 if ((st.valid & ZIP_STAT_CRC) && st.crc != ctx->crc) {
109 ctx->e[0] = ZIP_ER_CRC;
110 ctx->e[1] = 0;
111
112 return -1;
113 }
114 if ((st.valid & ZIP_STAT_SIZE) && st.size != ctx->size) {
115 ctx->e[0] = ZIP_ER_INCONS;
116 ctx->e[1] = 0;
117
118 return -1;
119 }
120 }
121 }
122 else {
123 ctx->size += n;
124 ctx->crc = crc32(ctx->crc, data, n);
125 }
126 return n;
127
128 case ZIP_SOURCE_CLOSE:
129 return 0;
130
131 case ZIP_SOURCE_STAT:
132 {
133 struct zip_stat *st;
134
135 st = (struct zip_stat *)data;
136
137 if (ctx->eof) {
138 /* XXX: Set comp_size, comp_method, encryption_method?
139 After all, this only works for uncompressed data. */
140 st->size = ctx->size;
141 st->crc = ctx->crc;
142 st->valid |= ZIP_STAT_SIZE|ZIP_STAT_CRC;
143 }
144 }
145 return 0;
146
147 case ZIP_SOURCE_ERROR:
148 memcpy(data, ctx->e, sizeof(ctx->e));
149 return 0;
150
151 case ZIP_SOURCE_FREE:
152 free(ctx);
153 return 0;
154
155 default:
156 return -1;
157 }
158
159 }
160
