| /* |
| zip_source_seek.c -- seek to offset |
| Copyright (C) 2014-2021 Dieter Baron and Thomas Klausner |
| |
| This file is part of libzip, a library to manipulate ZIP archives. |
| The authors can be contacted at <libzip@nih.at> |
| |
| Redistribution and use in source and binary forms, with or without |
| modification, are permitted provided that the following conditions |
| are met: |
| 1. Redistributions of source code must retain the above copyright |
| notice, this list of conditions and the following disclaimer. |
| 2. Redistributions in binary form must reproduce the above copyright |
| notice, this list of conditions and the following disclaimer in |
| the documentation and/or other materials provided with the |
| distribution. |
| 3. The names of the authors may not be used to endorse or promote |
| products derived from this software without specific prior |
| written permission. |
| |
| THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS |
| OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
| WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY |
| DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE |
| GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER |
| IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR |
| OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN |
| IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| |
| #include "zipint.h" |
| |
| |
| ZIP_EXTERN int |
| zip_source_seek(zip_source_t *src, zip_int64_t offset, int whence) { |
| zip_source_args_seek_t args; |
| |
| if (src->source_closed) { |
| return -1; |
| } |
| if (!ZIP_SOURCE_IS_OPEN_READING(src) || (whence != SEEK_SET && whence != SEEK_CUR && whence != SEEK_END)) { |
| zip_error_set(&src->error, ZIP_ER_INVAL, 0); |
| return -1; |
| } |
| |
| args.offset = offset; |
| args.whence = whence; |
| |
| if (_zip_source_call(src, &args, sizeof(args), ZIP_SOURCE_SEEK) < 0) { |
| return -1; |
| } |
| |
| src->eof = 0; |
| return 0; |
| } |
| |
| |
| zip_int64_t |
| zip_source_seek_compute_offset(zip_uint64_t offset, zip_uint64_t length, void *data, zip_uint64_t data_length, zip_error_t *error) { |
| zip_int64_t new_offset; |
| zip_source_args_seek_t *args = ZIP_SOURCE_GET_ARGS(zip_source_args_seek_t, data, data_length, error); |
| |
| if (args == NULL) { |
| return -1; |
| } |
| |
| switch (args->whence) { |
| case SEEK_CUR: |
| new_offset = (zip_int64_t)offset + args->offset; |
| break; |
| |
| case SEEK_END: |
| new_offset = (zip_int64_t)length + args->offset; |
| break; |
| |
| case SEEK_SET: |
| new_offset = args->offset; |
| break; |
| |
| default: |
| zip_error_set(error, ZIP_ER_INVAL, 0); |
| return -1; |
| } |
| |
| if (new_offset < 0 || (zip_uint64_t)new_offset > length) { |
| zip_error_set(error, ZIP_ER_INVAL, 0); |
| return -1; |
| } |
| |
| return new_offset; |
| } |