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1 /* |
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2 zip_source_seek.c -- seek to offset |
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3 Copyright (C) 2014 Dieter Baron and Thomas Klausner |
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4 |
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5 This file is part of libzip, a library to manipulate ZIP archives. |
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6 The authors can be contacted at <libzip@nih.at> |
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7 |
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8 Redistribution and use in source and binary forms, with or without |
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9 modification, are permitted provided that the following conditions |
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10 are met: |
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11 1. Redistributions of source code must retain the above copyright |
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12 notice, this list of conditions and the following disclaimer. |
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13 2. Redistributions in binary form must reproduce the above copyright |
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14 notice, this list of conditions and the following disclaimer in |
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15 the documentation and/or other materials provided with the |
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16 distribution. |
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17 3. The names of the authors may not be used to endorse or promote |
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18 products derived from this software without specific prior |
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19 written permission. |
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20 |
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21 THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS |
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22 OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
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23 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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24 ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY |
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25 DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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26 DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE |
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27 GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
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28 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER |
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29 IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR |
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30 OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN |
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31 IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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32 */ |
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33 |
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34 |
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35 #include "zipint.h" |
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36 |
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37 |
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38 ZIP_EXTERN int |
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39 zip_source_seek(zip_source_t *src, zip_int64_t offset, int whence) |
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40 { |
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41 zip_source_args_seek_t args; |
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42 |
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43 if (src->source_closed) { |
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44 return -1; |
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45 } |
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46 if (!ZIP_SOURCE_IS_OPEN_READING(src) || (whence != SEEK_SET && whence != SEEK_CUR && whence != SEEK_END)) { |
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47 zip_error_set(&src->error, ZIP_ER_INVAL, 0); |
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48 return -1; |
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49 } |
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50 |
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51 args.offset = offset; |
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52 args.whence = whence; |
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53 |
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54 return (_zip_source_call(src, &args, sizeof(args), ZIP_SOURCE_SEEK) < 0 ? -1 : 0); |
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55 } |
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56 |
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57 |
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58 zip_int64_t |
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59 zip_source_seek_compute_offset(zip_uint64_t offset, zip_uint64_t length, void *data, zip_uint64_t data_length, zip_error_t *error) |
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60 { |
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61 zip_int64_t new_offset; |
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62 zip_source_args_seek_t *args = ZIP_SOURCE_GET_ARGS(zip_source_args_seek_t, data, data_length, error); |
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63 |
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64 if (args == NULL) { |
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65 return -1; |
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66 } |
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67 |
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68 switch (args->whence) { |
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69 case SEEK_CUR: |
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70 new_offset = (zip_int64_t)offset + args->offset; |
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71 break; |
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72 |
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73 case SEEK_END: |
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74 new_offset = (zip_int64_t)length + args->offset; |
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75 break; |
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76 |
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77 case SEEK_SET: |
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78 new_offset = args->offset; |
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79 break; |
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80 |
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81 default: |
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82 zip_error_set(error, ZIP_ER_INVAL, 0); |
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83 return -1; |
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84 } |
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85 |
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86 if (new_offset < 0 || (zip_uint64_t)new_offset > length) { |
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87 zip_error_set(error, ZIP_ER_INVAL, 0); |
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88 return -1; |
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89 } |
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90 |
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91 return new_offset; |
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92 } |
