| Line | Branch | Exec | Source |
|---|---|---|---|
| 1 | /* | ||
| 2 | * Copyright (c) 2016 Umair Khan <omerjerk@gmail.com> | ||
| 3 | * | ||
| 4 | * This file is part of FFmpeg. | ||
| 5 | * | ||
| 6 | * FFmpeg is free software; you can redistribute it and/or | ||
| 7 | * modify it under the terms of the GNU Lesser General Public | ||
| 8 | * License as published by the Free Software Foundation; either | ||
| 9 | * version 2.1 of the License, or (at your option) any later version. | ||
| 10 | * | ||
| 11 | * FFmpeg is distributed in the hope that it will be useful, | ||
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | ||
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | ||
| 14 | * Lesser General Public License for more details. | ||
| 15 | * | ||
| 16 | * You should have received a copy of the GNU Lesser General Public | ||
| 17 | * License along with FFmpeg; if not, write to the Free Software | ||
| 18 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | ||
| 19 | */ | ||
| 20 | |||
| 21 | #include "mlz.h" | ||
| 22 | |||
| 23 | ✗ | av_cold int ff_mlz_init_dict(void *context, MLZ *mlz) | |
| 24 | { | ||
| 25 | ✗ | mlz->dict = av_mallocz(TABLE_SIZE * sizeof(*mlz->dict)); | |
| 26 | ✗ | if (!mlz->dict) | |
| 27 | ✗ | return AVERROR(ENOMEM); | |
| 28 | |||
| 29 | ✗ | mlz->flush_code = FLUSH_CODE; | |
| 30 | ✗ | mlz->current_dic_index_max = DIC_INDEX_INIT; | |
| 31 | ✗ | mlz->dic_code_bit = CODE_BIT_INIT; | |
| 32 | ✗ | mlz->bump_code = (DIC_INDEX_INIT - 1); | |
| 33 | ✗ | mlz->next_code = FIRST_CODE; | |
| 34 | ✗ | mlz->freeze_flag = 0; | |
| 35 | ✗ | mlz->context = context; | |
| 36 | |||
| 37 | ✗ | return 0; | |
| 38 | } | ||
| 39 | |||
| 40 | ✗ | av_cold void ff_mlz_flush_dict(MLZ *mlz) { | |
| 41 | ✗ | MLZDict *dict = mlz->dict; | |
| 42 | int i; | ||
| 43 | ✗ | for ( i = 0; i < TABLE_SIZE; i++ ) { | |
| 44 | ✗ | dict[i].string_code = CODE_UNSET; | |
| 45 | ✗ | dict[i].parent_code = CODE_UNSET; | |
| 46 | ✗ | dict[i].match_len = 0; | |
| 47 | } | ||
| 48 | ✗ | mlz->current_dic_index_max = DIC_INDEX_INIT; | |
| 49 | ✗ | mlz->dic_code_bit = CODE_BIT_INIT; // DicCodeBitInit; | |
| 50 | ✗ | mlz->bump_code = mlz->current_dic_index_max - 1; | |
| 51 | ✗ | mlz->next_code = FIRST_CODE; | |
| 52 | ✗ | mlz->freeze_flag = 0; | |
| 53 | ✗ | } | |
| 54 | |||
| 55 | ✗ | static void set_new_entry_dict(MLZDict* dict, int string_code, int parent_code, int char_code) { | |
| 56 | ✗ | dict[string_code].parent_code = parent_code; | |
| 57 | ✗ | dict[string_code].string_code = string_code; | |
| 58 | ✗ | dict[string_code].char_code = char_code; | |
| 59 | ✗ | if (parent_code < FIRST_CODE) { | |
| 60 | ✗ | dict[string_code].match_len = 2; | |
| 61 | } else { | ||
| 62 | ✗ | dict[string_code].match_len = (dict[parent_code].match_len) + 1; | |
| 63 | } | ||
| 64 | ✗ | } | |
| 65 | |||
| 66 | ✗ | static int decode_string(MLZ* mlz, unsigned char *buff, int string_code, int *first_char_code, unsigned long bufsize) { | |
| 67 | ✗ | MLZDict* dict = mlz->dict; | |
| 68 | unsigned long count, offset; | ||
| 69 | int current_code, parent_code, tmp_code; | ||
| 70 | |||
| 71 | ✗ | count = 0; | |
| 72 | ✗ | current_code = string_code; | |
| 73 | ✗ | *first_char_code = CODE_UNSET; | |
| 74 | |||
| 75 | ✗ | while (count < bufsize) { | |
| 76 | ✗ | switch (current_code) { | |
| 77 | ✗ | case CODE_UNSET: | |
| 78 | ✗ | return count; | |
| 79 | break; | ||
| 80 | ✗ | default: | |
| 81 | ✗ | if (current_code < FIRST_CODE) { | |
| 82 | ✗ | *first_char_code = current_code; | |
| 83 | ✗ | buff[0] = current_code; | |
| 84 | ✗ | count++; | |
| 85 | ✗ | return count; | |
| 86 | } else { | ||
| 87 | ✗ | offset = dict[current_code].match_len - 1; | |
| 88 | ✗ | tmp_code = dict[current_code].char_code; | |
| 89 | ✗ | if (offset >= bufsize) { | |
| 90 | ✗ | av_log(mlz->context, AV_LOG_ERROR, "MLZ offset error.\n"); | |
| 91 | ✗ | return count; | |
| 92 | } | ||
| 93 | ✗ | buff[offset] = tmp_code; | |
| 94 | ✗ | count++; | |
| 95 | } | ||
| 96 | ✗ | current_code = dict[current_code].parent_code; | |
| 97 | ✗ | if ((current_code < 0) || (current_code > (DIC_INDEX_MAX - 1))) { | |
| 98 | ✗ | av_log(mlz->context, AV_LOG_ERROR, "MLZ dic index error.\n"); | |
| 99 | ✗ | return count; | |
| 100 | } | ||
| 101 | ✗ | if (current_code > FIRST_CODE) { | |
| 102 | ✗ | parent_code = dict[current_code].parent_code; | |
| 103 | ✗ | offset = (dict[current_code].match_len) - 1; | |
| 104 | ✗ | if (parent_code < 0 || parent_code > DIC_INDEX_MAX-1) { | |
| 105 | ✗ | av_log(mlz->context, AV_LOG_ERROR, "MLZ dic index error.\n"); | |
| 106 | ✗ | return count; | |
| 107 | } | ||
| 108 | ✗ | if (( offset > (DIC_INDEX_MAX - 1))) { | |
| 109 | ✗ | av_log(mlz->context, AV_LOG_ERROR, "MLZ dic offset error.\n"); | |
| 110 | ✗ | return count; | |
| 111 | } | ||
| 112 | } | ||
| 113 | ✗ | break; | |
| 114 | } | ||
| 115 | } | ||
| 116 | ✗ | return count; | |
| 117 | } | ||
| 118 | |||
| 119 | ✗ | static int input_code(GetBitContext* gb, int len) { | |
| 120 | ✗ | int tmp_code = 0; | |
| 121 | int i; | ||
| 122 | ✗ | for (i = 0; i < len; ++i) { | |
| 123 | ✗ | tmp_code |= get_bits1(gb) << i; | |
| 124 | } | ||
| 125 | ✗ | return tmp_code; | |
| 126 | } | ||
| 127 | |||
| 128 | ✗ | int ff_mlz_decompression(MLZ* mlz, GetBitContext* gb, int size, unsigned char *buff) { | |
| 129 | ✗ | MLZDict *dict = mlz->dict; | |
| 130 | unsigned long output_chars; | ||
| 131 | int string_code, last_string_code, char_code; | ||
| 132 | |||
| 133 | ✗ | string_code = 0; | |
| 134 | ✗ | char_code = -1; | |
| 135 | ✗ | last_string_code = -1; | |
| 136 | ✗ | output_chars = 0; | |
| 137 | |||
| 138 | ✗ | while (output_chars < size) { | |
| 139 | ✗ | string_code = input_code(gb, mlz->dic_code_bit); | |
| 140 | ✗ | switch (string_code) { | |
| 141 | ✗ | case FLUSH_CODE: | |
| 142 | case MAX_CODE: | ||
| 143 | ✗ | ff_mlz_flush_dict(mlz); | |
| 144 | ✗ | char_code = -1; | |
| 145 | ✗ | last_string_code = -1; | |
| 146 | ✗ | break; | |
| 147 | ✗ | case FREEZE_CODE: | |
| 148 | ✗ | mlz->freeze_flag = 1; | |
| 149 | ✗ | break; | |
| 150 | ✗ | default: | |
| 151 | ✗ | if (string_code > mlz->current_dic_index_max) { | |
| 152 | ✗ | av_log(mlz->context, AV_LOG_ERROR, "String code %d exceeds maximum value of %d.\n", string_code, mlz->current_dic_index_max); | |
| 153 | ✗ | return output_chars; | |
| 154 | } | ||
| 155 | ✗ | if (string_code == (int) mlz->bump_code) { | |
| 156 | ✗ | ++mlz->dic_code_bit; | |
| 157 | ✗ | mlz->current_dic_index_max *= 2; | |
| 158 | ✗ | mlz->bump_code = mlz->current_dic_index_max - 1; | |
| 159 | } else { | ||
| 160 | ✗ | if (string_code >= mlz->next_code) { | |
| 161 | ✗ | int ret = decode_string(mlz, &buff[output_chars], last_string_code, &char_code, size - output_chars); | |
| 162 | ✗ | if (ret < 0 || ret > size - output_chars) { | |
| 163 | ✗ | av_log(mlz->context, AV_LOG_ERROR, "output chars overflow\n"); | |
| 164 | ✗ | return output_chars; | |
| 165 | } | ||
| 166 | ✗ | output_chars += ret; | |
| 167 | ✗ | ret = decode_string(mlz, &buff[output_chars], char_code, &char_code, size - output_chars); | |
| 168 | ✗ | if (ret < 0 || ret > size - output_chars) { | |
| 169 | ✗ | av_log(mlz->context, AV_LOG_ERROR, "output chars overflow\n"); | |
| 170 | ✗ | return output_chars; | |
| 171 | } | ||
| 172 | ✗ | output_chars += ret; | |
| 173 | ✗ | set_new_entry_dict(dict, mlz->next_code, last_string_code, char_code); | |
| 174 | ✗ | if (mlz->next_code >= TABLE_SIZE - 1) { | |
| 175 | ✗ | av_log(mlz->context, AV_LOG_ERROR, "Too many MLZ codes\n"); | |
| 176 | ✗ | return output_chars; | |
| 177 | } | ||
| 178 | ✗ | mlz->next_code++; | |
| 179 | } else { | ||
| 180 | ✗ | int ret = decode_string(mlz, &buff[output_chars], string_code, &char_code, size - output_chars); | |
| 181 | ✗ | if (ret < 0 || ret > size - output_chars) { | |
| 182 | ✗ | av_log(mlz->context, AV_LOG_ERROR, "output chars overflow\n"); | |
| 183 | ✗ | return output_chars; | |
| 184 | } | ||
| 185 | ✗ | output_chars += ret; | |
| 186 | ✗ | if (output_chars <= size && !mlz->freeze_flag) { | |
| 187 | ✗ | if (last_string_code != -1) { | |
| 188 | ✗ | set_new_entry_dict(dict, mlz->next_code, last_string_code, char_code); | |
| 189 | ✗ | if (mlz->next_code >= TABLE_SIZE - 1) { | |
| 190 | ✗ | av_log(mlz->context, AV_LOG_ERROR, "Too many MLZ codes\n"); | |
| 191 | ✗ | return output_chars; | |
| 192 | } | ||
| 193 | ✗ | mlz->next_code++; | |
| 194 | } | ||
| 195 | } else { | ||
| 196 | break; | ||
| 197 | } | ||
| 198 | } | ||
| 199 | ✗ | last_string_code = string_code; | |
| 200 | } | ||
| 201 | ✗ | break; | |
| 202 | } | ||
| 203 | } | ||
| 204 | ✗ | return output_chars; | |
| 205 | } | ||
| 206 |