diff options
Diffstat (limited to 'common/quic.c')
| -rw-r--r-- | common/quic.c | 25 |
1 files changed, 24 insertions, 1 deletions
diff --git a/common/quic.c b/common/quic.c index 3e7c802..c9c3624 100644 --- a/common/quic.c +++ b/common/quic.c @@ -75,6 +75,9 @@ typedef struct QuicFamily { unsigned int notGRsuffixlen[MAXNUMCODES]; /* indexed by code number, contains suffix length of the not-GR codeword */ + unsigned int golomb_code_len[256][MAXNUMCODES]; + unsigned int golomb_code[256][MAXNUMCODES]; + /* array for translating distribution U to L for depths up to 8 bpp, initialized by decorelateinit() */ BYTE xlatU2L[256]; @@ -360,9 +363,22 @@ static void corelate_init(QuicFamily *family, int bpc) } } +static void golomb_coding_slow(QuicFamily *family, const BYTE n, const unsigned int l, + unsigned int * const codeword, + unsigned int * const codewordlen) +{ + if (n < family->nGRcodewords[l]) { + (*codeword) = bitat[l] | (n & bppmask[l]); + (*codewordlen) = (n >> l) + l + 1; + } else { + (*codeword) = n - family->nGRcodewords[l]; + (*codewordlen) = family->notGRcwlen[l]; + } +} + static void family_init(QuicFamily *family, int bpc, int limit) { - int l; + int l, b; for (l = 0; l < bpc; l++) { /* fill arrays indexed by code number */ int altprefixlen, altcodewords; @@ -378,6 +394,13 @@ static void family_init(QuicFamily *family, int bpc, int limit) family->notGRcwlen[l] = altprefixlen + ceil_log_2(altcodewords); family->notGRprefixmask[l] = bppmask[32 - altprefixlen]; /* needed for decoding only */ family->notGRsuffixlen[l] = ceil_log_2(altcodewords); /* needed for decoding only */ + + for (b = 0; b < 256; b++) { + unsigned int code, len; + golomb_coding_slow(family, b, l, &code, &len); + family->golomb_code[b][l] = code; + family->golomb_code_len[b][l] = len; + } } decorelate_init(family, bpc); |