| 408 | } |
| 409 | |
| 410 | Mp3Info Mp3::parseMp3Info(fl::span<const fl::u8> data, fl::string* error_message) { |
| 411 | Mp3Info info; |
| 412 | |
| 413 | // Validate input data |
| 414 | if (data.empty()) { |
| 415 | if (error_message) { |
| 416 | *error_message = "Empty MP3 data"; |
| 417 | } |
| 418 | return info; // returns invalid info |
| 419 | } |
| 420 | |
| 421 | // Minimum size check - need at least an MP3 frame header (4 bytes) + some data |
| 422 | if (data.size() < 128) { |
| 423 | if (error_message) { |
| 424 | *error_message = "MP3 data too small"; |
| 425 | } |
| 426 | return info; |
| 427 | } |
| 428 | |
| 429 | // Look for MP3 sync word (11 bits set: 0xFFE or 0xFFF) |
| 430 | bool foundSync = false; |
| 431 | fl::size syncOffset = 0; |
| 432 | |
| 433 | for (fl::size i = 0; i <= data.size() - 4; i++) { |
| 434 | if (data[i] == 0xFF && (data[i + 1] & 0xE0) == 0xE0) { |
| 435 | foundSync = true; |
| 436 | syncOffset = i; |
| 437 | break; |
| 438 | } |
| 439 | } |
| 440 | |
| 441 | if (!foundSync) { |
| 442 | if (error_message) { |
| 443 | *error_message = "Invalid MP3 stream - no sync word found"; |
| 444 | } |
| 445 | return info; |
| 446 | } |
| 447 | |
| 448 | // Use the decoder to parse the first frame |
| 449 | third_party::Mp3HelixDecoder decoder; |
| 450 | if (!decoder.init()) { |
| 451 | if (error_message) { |
| 452 | *error_message = "Failed to initialize MP3 decoder"; |
| 453 | } |
| 454 | return info; |
| 455 | } |
| 456 | |
| 457 | const fl::u8* inptr = data.data() + syncOffset; |
| 458 | fl::size bytes_left = data.size() - syncOffset; |
| 459 | |
| 460 | // Try to decode first frame to get metadata |
| 461 | int offset = decoder.findSyncWord(inptr, bytes_left); |
| 462 | if (offset >= 0) { |
| 463 | inptr += offset; |
| 464 | bytes_left -= offset; |
| 465 | |
| 466 | int result = decoder.decodeFrame(&inptr, &bytes_left); |
| 467 | if (result == 0) { |
nothing calls this directly
no test coverage detected