2 zip_source_crc.c -- pass-through source that calculates CRC32 and size
3 Copyright (C) 2009-2021 Dieter Baron and Thomas Klausner
5 This file is part of libzip, a library to manipulate ZIP archives.
6 The authors can be contacted at <info@libzip.org>
8 Redistribution and use in source and binary forms, with or without
9 modification, are permitted provided that the following conditions
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
17 3. The names of the authors may not be used to endorse or promote
18 products derived from this software without specific prior
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.
42 int validate; /* whether to check CRC on EOF and return error on mismatch */
43 int crc_complete; /* whether CRC was computed for complete file */
46 zip_uint64_t position; /* current reading position */
47 zip_uint64_t crc_position; /* how far we've computed the CRC */
51 static zip_int64_t crc_read(zip_source_t *, void *, void *, zip_uint64_t, zip_source_cmd_t);
55 zip_source_crc_create(zip_source_t *src, int validate, zip_error_t *error) {
56 struct crc_context *ctx;
59 zip_error_set(error, ZIP_ER_INVAL, 0);
63 if ((ctx = (struct crc_context *)malloc(sizeof(*ctx))) == NULL) {
64 zip_error_set(error, ZIP_ER_MEMORY, 0);
68 zip_error_init(&ctx->error);
69 ctx->validate = validate;
70 ctx->crc_complete = 0;
71 ctx->crc_position = 0;
72 ctx->crc = (zip_uint32_t)crc32(0, NULL, 0);
75 return zip_source_layered_create(src, crc_read, ctx, error);
80 crc_read(zip_source_t *src, void *_ctx, void *data, zip_uint64_t len, zip_source_cmd_t cmd) {
81 struct crc_context *ctx;
84 ctx = (struct crc_context *)_ctx;
92 if ((n = zip_source_read(src, data, len)) < 0) {
93 _zip_error_set_from_source(&ctx->error, src);
98 if (ctx->crc_position == ctx->position) {
99 ctx->crc_complete = 1;
100 ctx->size = ctx->position;
105 if (zip_source_stat(src, &st) < 0) {
106 _zip_error_set_from_source(&ctx->error, src);
110 if ((st.valid & ZIP_STAT_CRC) && st.crc != ctx->crc) {
111 zip_error_set(&ctx->error, ZIP_ER_CRC, 0);
114 if ((st.valid & ZIP_STAT_SIZE) && st.size != ctx->size) {
115 /* We don't have the index here, but the caller should know which file they are reading from. */
116 zip_error_set(&ctx->error, ZIP_ER_INCONS, MAKE_DETAIL_WITH_INDEX(ZIP_ER_DETAIL_INVALID_FILE_LENGTH, MAX_DETAIL_INDEX));
122 else if (!ctx->crc_complete && ctx->position <= ctx->crc_position) {
125 for (i = ctx->crc_position - ctx->position; i < (zip_uint64_t)n; i += nn) {
126 nn = ZIP_MIN(UINT_MAX, (zip_uint64_t)n - i);
128 ctx->crc = (zip_uint32_t)crc32(ctx->crc, (const Bytef *)data + i, (uInt)nn);
129 ctx->crc_position += nn;
132 ctx->position += (zip_uint64_t)n;
135 case ZIP_SOURCE_CLOSE:
138 case ZIP_SOURCE_STAT: {
141 st = (zip_stat_t *)data;
143 if (ctx->crc_complete) {
144 /* TODO: Set comp_size, comp_method, encryption_method?
145 After all, this only works for uncompressed data. */
146 st->size = ctx->size;
148 st->comp_size = ctx->size;
149 st->comp_method = ZIP_CM_STORE;
150 st->encryption_method = ZIP_EM_NONE;
151 st->valid |= ZIP_STAT_SIZE | ZIP_STAT_CRC | ZIP_STAT_COMP_SIZE | ZIP_STAT_COMP_METHOD | ZIP_STAT_ENCRYPTION_METHOD;
156 case ZIP_SOURCE_ERROR:
157 return zip_error_to_data(&ctx->error, data, len);
159 case ZIP_SOURCE_FREE:
163 case ZIP_SOURCE_SUPPORTS: {
164 zip_int64_t mask = zip_source_supports(src);
167 _zip_error_set_from_source(&ctx->error, src);
171 return mask & ~zip_source_make_command_bitmap(ZIP_SOURCE_BEGIN_WRITE, ZIP_SOURCE_COMMIT_WRITE, ZIP_SOURCE_ROLLBACK_WRITE, ZIP_SOURCE_SEEK_WRITE, ZIP_SOURCE_TELL_WRITE, ZIP_SOURCE_REMOVE, ZIP_SOURCE_GET_FILE_ATTRIBUTES, -1);
174 case ZIP_SOURCE_SEEK: {
175 zip_int64_t new_position;
176 zip_source_args_seek_t *args = ZIP_SOURCE_GET_ARGS(zip_source_args_seek_t, data, len, &ctx->error);
181 if (zip_source_seek(src, args->offset, args->whence) < 0 || (new_position = zip_source_tell(src)) < 0) {
182 _zip_error_set_from_source(&ctx->error, src);
186 ctx->position = (zip_uint64_t)new_position;
191 case ZIP_SOURCE_TELL:
192 return (zip_int64_t)ctx->position;
195 zip_error_set(&ctx->error, ZIP_ER_OPNOTSUPP, 0);