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author | Matthias P. Braendli <matthias.braendli@mpb.li> | 2016-02-15 02:44:20 +0100 |
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committer | Matthias P. Braendli <matthias.braendli@mpb.li> | 2016-02-15 02:44:20 +0100 |
commit | 22f1fce330059ef8a383cf327a023d6a9da5ad3e (patch) | |
tree | 6893f158dcaaaa1b9f1317923c32a841ba31f768 /libtoolame-dab/crc.c | |
parent | 891bb2592944aa2be2d81e1583e73e632e70537f (diff) | |
download | ODR-AudioEnc-22f1fce330059ef8a383cf327a023d6a9da5ad3e.tar.gz ODR-AudioEnc-22f1fce330059ef8a383cf327a023d6a9da5ad3e.tar.bz2 ODR-AudioEnc-22f1fce330059ef8a383cf327a023d6a9da5ad3e.zip |
Include toolame-dab as library
Diffstat (limited to 'libtoolame-dab/crc.c')
-rw-r--r-- | libtoolame-dab/crc.c | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/libtoolame-dab/crc.c b/libtoolame-dab/crc.c new file mode 100644 index 0000000..b83ac03 --- /dev/null +++ b/libtoolame-dab/crc.c @@ -0,0 +1,113 @@ +#include <stdio.h> +#include <string.h> +#include "common.h" +#include "crc.h" + +/***************************************************************************** +* +* CRC error protection package +* +*****************************************************************************/ + +void CRC_calc (frame_info * frame, unsigned int bit_alloc[2][SBLIMIT], + unsigned int scfsi[2][SBLIMIT], unsigned int *crc) +{ + int i, k; + frame_header *header = frame->header; + int nch = frame->nch; + int sblimit = frame->sblimit; + int jsbound = frame->jsbound; + al_table *alloc = frame->alloc; + + *crc = 0xffff; /* changed from '0' 92-08-11 shn */ + update_CRC (header->bitrate_index, 4, crc); + update_CRC (header->sampling_frequency, 2, crc); + update_CRC (header->padding, 1, crc); + update_CRC (header->extension, 1, crc); + update_CRC (header->mode, 2, crc); + update_CRC (header->mode_ext, 2, crc); + update_CRC (header->copyright, 1, crc); + update_CRC (header->original, 1, crc); + update_CRC (header->emphasis, 2, crc); + + for (i = 0; i < sblimit; i++) + for (k = 0; k < ((i < jsbound) ? nch : 1); k++) + update_CRC (bit_alloc[k][i], (*alloc)[i][0].bits, crc); + + for (i = 0; i < sblimit; i++) + for (k = 0; k < nch; k++) + if (bit_alloc[k][i]) + update_CRC (scfsi[k][i], 2, crc); +} + +void update_CRC (unsigned int data, unsigned int length, unsigned int *crc) +{ + unsigned int masking, carry; + + masking = 1 << length; + + while ((masking >>= 1)) { + carry = *crc & 0x8000; + *crc <<= 1; + if (!carry ^ !(data & masking)) + *crc ^= CRC16_POLYNOMIAL; + } + *crc &= 0xffff; +} + +void +CRC_calcDAB (frame_info * frame, + unsigned int bit_alloc[2][SBLIMIT], + unsigned int scfsi[2][SBLIMIT], + unsigned int scalar[2][3][SBLIMIT], unsigned int *crc, + int packed) +{ + int i, j, k; + int nch = frame->nch; + int nb_scalar; + int f[5] = { 0, 4, 8, 16, 30 }; + int first, last; + + first = f[packed]; + last = f[packed + 1]; + if (last > frame->sblimit) + last = frame->sblimit; + + nb_scalar = 0; + *crc = 0x0; + for (i = first; i < last; i++) + for (k = 0; k < nch; k++) + if (bit_alloc[k][i]) /* above jsbound, bit_alloc[0][i] == ba[1][i] */ + switch (scfsi[k][i]) { + case 0: + for (j = 0; j < 3; j++) { + nb_scalar++; + update_CRCDAB (scalar[k][j][i] >> 3, 3, crc); + } + break; + case 1: + case 3: + nb_scalar += 2; + update_CRCDAB (scalar[k][0][i] >> 3, 3, crc); + update_CRCDAB (scalar[k][2][i] >> 3, 3, crc); + break; + case 2: + nb_scalar++; + update_CRCDAB (scalar[k][0][i] >> 3, 3, crc); + } +} + +void update_CRCDAB (unsigned int data, unsigned int length, unsigned int *crc) +{ + unsigned int masking, carry; + + masking = 1 << length; + + while ((masking >>= 1)) { + carry = *crc & 0x80; + *crc <<= 1; + if (!carry ^ !(data & masking)) + *crc ^= CRC8_POLYNOMIAL; + } + *crc &= 0xff; +} |