| File: | root/firefox-clang/third_party/sipcc/sdp_base64.c |
| Warning: | line 206, column 2 Value stored to 'line_count' is never read |
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| 1 | /* This Source Code Form is subject to the terms of the Mozilla Public |
| 2 | * License, v. 2.0. If a copy of the MPL was not distributed with this |
| 3 | * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| 4 | |
| 5 | #include "sdp_base64.h" |
| 6 | |
| 7 | /* |
| 8 | * Local definitions for Base64 to Raw table entries. |
| 9 | */ |
| 10 | #define INVALID_CHAR0xFF 0xFF /* Character not in supported Base64 set */ |
| 11 | #define WHITE_SPACE0xFE 0xFE /* Space, tab, newline, etc character */ |
| 12 | #define PADDING0xFD 0xFD /* The character '=' */ |
| 13 | |
| 14 | #define PAD_CHAR'=' '=' /* The character '=' */ |
| 15 | |
| 16 | /* Maximum length of a base64 encoded line */ |
| 17 | #define MAX_BASE64_LINE_LENGTH76 76 |
| 18 | |
| 19 | /* |
| 20 | * base64_result_table |
| 21 | * String table for translating base64 error codes into human |
| 22 | * understanable strings. |
| 23 | */ |
| 24 | char *base64_result_table[BASE64_RESULT_MAX] = |
| 25 | { |
| 26 | "Base64 successful", |
| 27 | "Base64 Buffer Overrun", |
| 28 | "Base64 Bad Data", |
| 29 | "Base64 Bad Padding", |
| 30 | "Base64 Bad Block Size" |
| 31 | }; |
| 32 | |
| 33 | /* |
| 34 | * base64_to_raw_table |
| 35 | * Heart of the Base64 decoding algorithm. Lookup table to convert |
| 36 | * the Base64 characters into their specified representative values. |
| 37 | * Invalid characters are marked with 0xFF, white space characters |
| 38 | * are marked with 0xFE, and the special pading character is marked |
| 39 | * with 0xFD. |
| 40 | */ |
| 41 | unsigned char base64_to_raw_table[128] = |
| 42 | { |
| 43 | 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFE, /* 0-9 */ |
| 44 | 0xFE, 0xFF, 0xFF, 0xFE, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, /* 10-19 */ |
| 45 | 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, /* 20-29 */ |
| 46 | 0xFF, 0xFF, 0xFE, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, /* 30-39 */ |
| 47 | 0xFF, 0xFF, 0xFF, 62, 0xFF, 0xFF, 0xFF, 63, 52, 53, /* 40-49 */ |
| 48 | 54, 55, 56, 57, 58, 59, 60, 61, 0xFF, 0xFF, /* 50-59 */ |
| 49 | 0xFF, 0xFD, 0xFF, 0xFF, 0xFF, 0, 1, 2, 3, 4, /* 60-69 */ |
| 50 | 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, /* 70-79 */ |
| 51 | 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, /* 80-89 */ |
| 52 | 25, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 26, 27, 28, /* 90-99 */ |
| 53 | 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, /* 100-109 */ |
| 54 | 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, /* 110-119 */ |
| 55 | 49, 50, 51, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF /* 120-127 */ |
| 56 | }; |
| 57 | |
| 58 | unsigned char raw_to_base64_table[64] = |
| 59 | { |
| 60 | 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', /* 0-9 */ |
| 61 | 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', /* 10-19 */ |
| 62 | 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', /* 20-29 */ |
| 63 | 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', /* 30-39 */ |
| 64 | 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', /* 40-49 */ |
| 65 | 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', /* 50-59 */ |
| 66 | '8', '9', '+', '/' /* 60-63 */ |
| 67 | }; |
| 68 | |
| 69 | /* |
| 70 | * base64_encode_size_bytes |
| 71 | * |
| 72 | * DESCRIPTION |
| 73 | * Estimates the size of buffer required for holding the result of |
| 74 | * encoding data of size raw_size_bytes. |
| 75 | * |
| 76 | * PARAMETERS |
| 77 | * raw_size_bytes = Estimated size of the un-encoded data in bytes. |
| 78 | * |
| 79 | * RETURN VALUE |
| 80 | * The size of destination buffer to use for encoding in bytes. |
| 81 | */ |
| 82 | int base64_est_encode_size_bytes (int raw_size_bytes) |
| 83 | { |
| 84 | int length; |
| 85 | |
| 86 | /* |
| 87 | * Find the number of bytes needed to represent the data |
| 88 | * using a 4/3 expansion ratio. That result must be |
| 89 | * rounded to the next higher multiple of four to account |
| 90 | * for padding. Then add in a term to account for any '\n's |
| 91 | * added. |
| 92 | */ |
| 93 | length = ((((raw_size_bytes * 4 + 2)/ 3) + 3) & ~(0x3)) + |
| 94 | raw_size_bytes / MAX_BASE64_LINE_LENGTH76; |
| 95 | |
| 96 | return length; |
| 97 | } |
| 98 | |
| 99 | /* |
| 100 | * base64_decode_size_bytes |
| 101 | * |
| 102 | * DESCRIPTION |
| 103 | * Estimates the size of buffer required for holding the result of |
| 104 | * decoding data of size base64_size_bytes. |
| 105 | * |
| 106 | * PARAMETERS |
| 107 | * base64_size_bytes = Estimated size of the Base64 data in bytes. |
| 108 | * |
| 109 | * RETURN VALUE |
| 110 | * The size of destination buffer to use for decoding in bytes. |
| 111 | */ |
| 112 | int base64_est_decode_size_bytes (int base64_size_bytes) |
| 113 | { |
| 114 | int length; |
| 115 | |
| 116 | length = (base64_size_bytes * 3 + 3) / 4; |
| 117 | return length; |
| 118 | } |
| 119 | |
| 120 | /* |
| 121 | * base64_encode |
| 122 | * |
| 123 | * DESCRIPTION |
| 124 | * Encode data pointed to by src into the buffer pointer to by dest |
| 125 | * using the Base64 algorithm. |
| 126 | * |
| 127 | * NOTE: No trailing '\n' character will be added. |
| 128 | * |
| 129 | * NOTE: As per specification, '\n' will be placed every 76 chars. |
| 130 | * |
| 131 | * PARAMETERS |
| 132 | * src = Pointer to the raw data to base64 encode. |
| 133 | * src_bytes = The number of bytes in the src buffer to encode. |
| 134 | * dest = Pointer to the destination buffer where the converted data |
| 135 | * will reside when complete. |
| 136 | * dest_bytes = Initially holds the size of the destination buffer |
| 137 | * but at completion holds the number of bytes converted. |
| 138 | * |
| 139 | * RETURN VALUE |
| 140 | * base64_success if the buffer was successfully converted, the |
| 141 | * appropriate error code otherwise. |
| 142 | * |
| 143 | * The dest parameter holds the converted data. |
| 144 | * |
| 145 | * The dest_bytes parameter holds the actual number of bytes converted. |
| 146 | */ |
| 147 | base64_result_t base64_encode(unsigned char *src, int src_bytes, unsigned char *dest, int *dest_bytes) |
| 148 | { |
| 149 | int i, j=0; |
| 150 | int line_count = 0; |
| 151 | unsigned char index; /* index into base64 lookup table */ |
| 152 | int smax = src_bytes-2; /* only do full multiples of 3 */ |
| 153 | int dmax = *dest_bytes; /* destination maximum */ |
| 154 | |
| 155 | *dest_bytes = 0; |
| 156 | |
| 157 | /* Do full groups. Base64 must be done in blocks of 3 src bytes */ |
| 158 | for (i=0; i<smax; i+=3) { |
| 159 | /* Check to see if newline should be injected */ |
| 160 | if (line_count>=MAX_BASE64_LINE_LENGTH76) { |
| 161 | if (j<dmax){ |
| 162 | dest[j++] = '\n'; |
| 163 | } else { |
| 164 | return BASE64_BUFFER_OVERRUN; |
| 165 | } |
| 166 | line_count = 0; |
| 167 | } |
| 168 | |
| 169 | line_count += 4; |
| 170 | |
| 171 | if ((j+3) < dmax) { |
| 172 | |
| 173 | /* Find mapping of upper 6 bits */ |
| 174 | index = (src[i] >> 2) & 0x3F; |
| 175 | dest[j++] = raw_to_base64_table[index]; |
| 176 | |
| 177 | /* bottom 2 bits of first word, high 4 bits of second word */ |
| 178 | index = ((src[i] << 4) & 0x30) | ((src[i+1] >> 4) & 0x0F); |
| 179 | dest[j++] = raw_to_base64_table[index]; |
| 180 | |
| 181 | /* bottom 4 bits of second word, high 2 bits of third word */ |
| 182 | index = ((src[i+1] << 2) & 0x3C) | ((src[i+2] >> 6) & 0x03); |
| 183 | dest[j++] = raw_to_base64_table[index]; |
| 184 | |
| 185 | /* bottom 6 bits of third word */ |
| 186 | index = src[i+2] & 0x3F; |
| 187 | dest[j++] = raw_to_base64_table[index]; |
| 188 | } else { |
| 189 | return BASE64_BUFFER_OVERRUN; |
| 190 | } |
| 191 | } |
| 192 | |
| 193 | /* Check to see if any more work must be done */ |
| 194 | if (i<src_bytes) { |
| 195 | |
| 196 | /* Check to see if a newline should be output */ |
| 197 | if (line_count>=MAX_BASE64_LINE_LENGTH76) { |
| 198 | if (j<dmax){ |
| 199 | dest[j++] = '\n'; |
| 200 | } else { |
| 201 | return BASE64_BUFFER_OVERRUN; |
| 202 | } |
| 203 | line_count = 0; |
| 204 | } |
| 205 | |
| 206 | line_count += 4; |
Value stored to 'line_count' is never read | |
| 207 | |
| 208 | /* Must fill another quantum */ |
| 209 | if (j+4>dmax) { |
| 210 | /* No room left in output buffer! */ |
| 211 | return BASE64_BUFFER_OVERRUN; |
| 212 | } |
| 213 | |
| 214 | /* Find mapping of upper 6 bits */ |
| 215 | index = (src[i] >> 2) & 0x3F; |
| 216 | dest[j++] = raw_to_base64_table[index]; |
| 217 | |
| 218 | /* check for another stragler */ |
| 219 | if ((i+1)<src_bytes) { |
| 220 | /* bottom 2 bits of first word, high 4 bits of second word */ |
| 221 | index = ((src[i] << 4) & 0x30) | ((src[i+1] >> 4) & 0x0F); |
| 222 | dest[j++] = raw_to_base64_table[index]; |
| 223 | |
| 224 | /* bottom 4 bits of second word */ |
| 225 | index = (src[i+1] << 2) & 0x3C; |
| 226 | dest[j++] = raw_to_base64_table[index]; |
| 227 | dest[j++] = PAD_CHAR'='; |
| 228 | } else { |
| 229 | /* bottom 2 bits of first word */ |
| 230 | index = (src[i] << 4) & 0x30; |
| 231 | dest[j++] = raw_to_base64_table[index]; |
| 232 | dest[j++] = PAD_CHAR'='; |
| 233 | dest[j++] = PAD_CHAR'='; |
| 234 | } |
| 235 | } |
| 236 | |
| 237 | *dest_bytes = j; |
| 238 | |
| 239 | return BASE64_SUCCESS; |
| 240 | } |
| 241 | |
| 242 | unsigned char base64_decode_get_raw(unsigned char index) |
| 243 | { |
| 244 | /* only have 128 values, MSB must not be set! */ |
| 245 | if (index >= 128) { |
| 246 | return INVALID_CHAR0xFF; |
| 247 | } |
| 248 | return base64_to_raw_table[index]; |
| 249 | } |
| 250 | |
| 251 | /* |
| 252 | * base64_decode |
| 253 | * |
| 254 | * DESCRIPTION |
| 255 | * Decode data pointed to by src into the buffer pointer to by dest |
| 256 | * using the Base64 algorithm. |
| 257 | * |
| 258 | * PARAMETERS |
| 259 | * src = Pointer to the Base64 data to decode. |
| 260 | * src_bytes = The number of bytes in the src buffer to decode. |
| 261 | * dest = Pointer to the destination buffer where the converted data |
| 262 | * will reside when complete. |
| 263 | * dest_bytes = Initially holds the size of the destination buffer |
| 264 | * but at completion holds the number of bytes converted. |
| 265 | * |
| 266 | * RETURN VALUE |
| 267 | * base64_success if the buffer was successfully converted, the |
| 268 | * appropriate error code otherwise. |
| 269 | * |
| 270 | * The dest parameter holds the converted data. |
| 271 | * |
| 272 | * The dest_bytes parameter holds the actual number of bytes converted. |
| 273 | */ |
| 274 | base64_result_t base64_decode(unsigned char *src, int src_bytes, unsigned char *dest, int *dest_bytes) |
| 275 | { |
| 276 | int i, j = 0; |
| 277 | int sindex = 0; /* Current NON-whitespace source |
| 278 | * index */ |
| 279 | int pad_count=0; /* Number of padding characters |
| 280 | * encountered */ |
| 281 | int dest_size_bytes = *dest_bytes; /* Save size of destination buffer */ |
| 282 | unsigned char cindex; /* The current Base64 character to |
| 283 | * process */ |
| 284 | unsigned char val; /* The value of the current Base64 |
| 285 | * character */ |
| 286 | |
| 287 | *dest_bytes = 0; |
| 288 | |
| 289 | for (i=0; i<src_bytes; i++) { |
| 290 | cindex = src[i]; |
| 291 | |
| 292 | val = base64_decode_get_raw(cindex); |
| 293 | if (val == INVALID_CHAR0xFF) { |
| 294 | /* Invalid base64 character */ |
| 295 | return BASE64_BAD_DATA; |
| 296 | } |
| 297 | |
| 298 | if (val == WHITE_SPACE0xFE) { |
| 299 | /* Ignore white space */ |
| 300 | continue; |
| 301 | } |
| 302 | |
| 303 | if (val == PADDING0xFD) { |
| 304 | /* we must be at the end-finish up */ |
| 305 | pad_count++; |
| 306 | if (++i<src_bytes) { |
| 307 | /* can have up to 2 pad chars */ |
| 308 | if (base64_decode_get_raw(src[i]) != PADDING0xFD) { |
| 309 | return BASE64_BAD_PADDING; |
| 310 | } |
| 311 | |
| 312 | if (++i<src_bytes) { |
| 313 | /* should not have any more padding! */ |
| 314 | return BASE64_BAD_PADDING; |
| 315 | } |
| 316 | |
| 317 | pad_count++; |
| 318 | } |
| 319 | |
| 320 | /* DONE! */ |
| 321 | break; |
| 322 | } |
| 323 | |
| 324 | /* Determine which portion of the 3 bytes this data will fill */ |
| 325 | switch (sindex & 0x3) { |
| 326 | case 0: |
| 327 | /* Fill upper 6 bits */ |
| 328 | if (j<dest_size_bytes) { |
| 329 | dest[j] = val << 2; |
| 330 | } else { |
| 331 | return BASE64_BUFFER_OVERRUN; |
| 332 | } |
| 333 | break; |
| 334 | case 1: |
| 335 | /* Fill Bottom 2 bits */ |
| 336 | dest[j++] |= val >> 4; |
| 337 | |
| 338 | if (j<dest_size_bytes) { |
| 339 | /* Fill Top 4 bits */ |
| 340 | dest[j] = (val << 4) & 0xF0; |
| 341 | } else { |
| 342 | /* |
| 343 | * Check to see if there is any more data present. |
| 344 | * Next base64 character MUST be a pad character and |
| 345 | * the rest of this data MUST be zero. |
| 346 | * |
| 347 | * If this is not the end of data then a buffer overrun |
| 348 | * has occurred |
| 349 | */ |
| 350 | if ((val & 0x0F) || |
| 351 | (i+1>=src_bytes) || |
| 352 | (base64_decode_get_raw(src[i+1]) != PADDING0xFD)) { |
| 353 | return BASE64_BUFFER_OVERRUN; |
| 354 | } |
| 355 | } |
| 356 | break; |
| 357 | case 2: |
| 358 | /* Fill Bottom 4 bits */ |
| 359 | dest[j++] |= val >> 2; |
| 360 | |
| 361 | if (j<dest_size_bytes) { |
| 362 | /* Fill Top 2 bits */ |
| 363 | dest[j] = (val << 6) & 0xC0; |
| 364 | } else { |
| 365 | /* |
| 366 | * Check to see if there is any more data present. |
| 367 | * Next base64 character MUST be a pad character and |
| 368 | * the rest of this data MUST be zero. |
| 369 | * |
| 370 | * If this is not the end of data then a buffer overrun |
| 371 | * has occurred |
| 372 | */ |
| 373 | if ((val & 0x03) || |
| 374 | (i+1>=src_bytes) || |
| 375 | (base64_decode_get_raw(src[i+1]) != PADDING0xFD)) { |
| 376 | return BASE64_BUFFER_OVERRUN; |
| 377 | } |
| 378 | } |
| 379 | break; |
| 380 | case 3: |
| 381 | /* |
| 382 | * No need to check for overrun here since the |
| 383 | * previous case was already checked. If another |
| 384 | * group is present then case 0 will check again. |
| 385 | */ |
| 386 | |
| 387 | /* Fill Bottom 6 bits */ |
| 388 | dest[j++] |= val; |
| 389 | break; |
| 390 | } |
| 391 | sindex++; |
| 392 | } |
| 393 | |
| 394 | /* Check length for multiple of 3 bytes */ |
| 395 | if (((j + pad_count)% 3) != 0) { |
| 396 | return BASE64_BAD_BLOCK_SIZE; |
| 397 | } |
| 398 | |
| 399 | /* Save off the number of bytes converted */ |
| 400 | *dest_bytes = j; |
| 401 | |
| 402 | return BASE64_SUCCESS; |
| 403 | } |