diff options
Diffstat (limited to 'src/framing.c')
| -rw-r--r-- | src/framing.c | 130 |
1 files changed, 43 insertions, 87 deletions
diff --git a/src/framing.c b/src/framing.c index 5e09f2d..d127ec4 100644 --- a/src/framing.c +++ b/src/framing.c @@ -5,7 +5,7 @@ * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE * * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING. * * * - * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2010 * + * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2018 * * by the Xiph.Org Foundation http://www.xiph.org/ * * * ******************************************************************** @@ -102,90 +102,31 @@ int ogg_page_packets(const ogg_page *og){ #if 0 /* helper to initialize lookup for direct-table CRC (illustrative; we - use the static init below) */ - -static ogg_uint32_t _ogg_crc_entry(unsigned long index){ - int i; - unsigned long r; - - r = index << 24; - for (i=0; i<8; i++) - if (r & 0x80000000UL) - r = (r << 1) ^ 0x04c11db7; /* The same as the ethernet generator - polynomial, although we use an - unreflected alg and an init/final - of 0, not 0xffffffff */ - else - r<<=1; - return (r & 0xffffffffUL); + use the static init in crctable.h) */ + +static void _ogg_crc_init(){ + int i, j; + ogg_uint32_t polynomial, crc; + polynomial = 0x04c11db7; /* The same as the ethernet generator + polynomial, although we use an + unreflected alg and an init/final + of 0, not 0xffffffff */ + for (i = 0; i <= 0xFF; i++){ + crc = i << 24; + + for (j = 0; j < 8; j++) + crc = (crc << 1) ^ (crc & (1 << 31) ? polynomial : 0); + + crc_lookup[0][i] = crc; + } + + for (i = 0; i <= 0xFF; i++) + for (j = 1; j < 8; j++) + crc_lookup[j][i] = crc_lookup[0][(crc_lookup[j - 1][i] >> 24) & 0xFF] ^ (crc_lookup[j - 1][i] << 8); } #endif -static const ogg_uint32_t crc_lookup[256]={ - 0x00000000,0x04c11db7,0x09823b6e,0x0d4326d9, - 0x130476dc,0x17c56b6b,0x1a864db2,0x1e475005, - 0x2608edb8,0x22c9f00f,0x2f8ad6d6,0x2b4bcb61, - 0x350c9b64,0x31cd86d3,0x3c8ea00a,0x384fbdbd, - 0x4c11db70,0x48d0c6c7,0x4593e01e,0x4152fda9, - 0x5f15adac,0x5bd4b01b,0x569796c2,0x52568b75, - 0x6a1936c8,0x6ed82b7f,0x639b0da6,0x675a1011, - 0x791d4014,0x7ddc5da3,0x709f7b7a,0x745e66cd, - 0x9823b6e0,0x9ce2ab57,0x91a18d8e,0x95609039, - 0x8b27c03c,0x8fe6dd8b,0x82a5fb52,0x8664e6e5, - 0xbe2b5b58,0xbaea46ef,0xb7a96036,0xb3687d81, - 0xad2f2d84,0xa9ee3033,0xa4ad16ea,0xa06c0b5d, - 0xd4326d90,0xd0f37027,0xddb056fe,0xd9714b49, - 0xc7361b4c,0xc3f706fb,0xceb42022,0xca753d95, - 0xf23a8028,0xf6fb9d9f,0xfbb8bb46,0xff79a6f1, - 0xe13ef6f4,0xe5ffeb43,0xe8bccd9a,0xec7dd02d, - 0x34867077,0x30476dc0,0x3d044b19,0x39c556ae, - 0x278206ab,0x23431b1c,0x2e003dc5,0x2ac12072, - 0x128e9dcf,0x164f8078,0x1b0ca6a1,0x1fcdbb16, - 0x018aeb13,0x054bf6a4,0x0808d07d,0x0cc9cdca, - 0x7897ab07,0x7c56b6b0,0x71159069,0x75d48dde, - 0x6b93dddb,0x6f52c06c,0x6211e6b5,0x66d0fb02, - 0x5e9f46bf,0x5a5e5b08,0x571d7dd1,0x53dc6066, - 0x4d9b3063,0x495a2dd4,0x44190b0d,0x40d816ba, - 0xaca5c697,0xa864db20,0xa527fdf9,0xa1e6e04e, - 0xbfa1b04b,0xbb60adfc,0xb6238b25,0xb2e29692, - 0x8aad2b2f,0x8e6c3698,0x832f1041,0x87ee0df6, - 0x99a95df3,0x9d684044,0x902b669d,0x94ea7b2a, - 0xe0b41de7,0xe4750050,0xe9362689,0xedf73b3e, - 0xf3b06b3b,0xf771768c,0xfa325055,0xfef34de2, - 0xc6bcf05f,0xc27dede8,0xcf3ecb31,0xcbffd686, - 0xd5b88683,0xd1799b34,0xdc3abded,0xd8fba05a, - 0x690ce0ee,0x6dcdfd59,0x608edb80,0x644fc637, - 0x7a089632,0x7ec98b85,0x738aad5c,0x774bb0eb, - 0x4f040d56,0x4bc510e1,0x46863638,0x42472b8f, - 0x5c007b8a,0x58c1663d,0x558240e4,0x51435d53, - 0x251d3b9e,0x21dc2629,0x2c9f00f0,0x285e1d47, - 0x36194d42,0x32d850f5,0x3f9b762c,0x3b5a6b9b, - 0x0315d626,0x07d4cb91,0x0a97ed48,0x0e56f0ff, - 0x1011a0fa,0x14d0bd4d,0x19939b94,0x1d528623, - 0xf12f560e,0xf5ee4bb9,0xf8ad6d60,0xfc6c70d7, - 0xe22b20d2,0xe6ea3d65,0xeba91bbc,0xef68060b, - 0xd727bbb6,0xd3e6a601,0xdea580d8,0xda649d6f, - 0xc423cd6a,0xc0e2d0dd,0xcda1f604,0xc960ebb3, - 0xbd3e8d7e,0xb9ff90c9,0xb4bcb610,0xb07daba7, - 0xae3afba2,0xaafbe615,0xa7b8c0cc,0xa379dd7b, - 0x9b3660c6,0x9ff77d71,0x92b45ba8,0x9675461f, - 0x8832161a,0x8cf30bad,0x81b02d74,0x857130c3, - 0x5d8a9099,0x594b8d2e,0x5408abf7,0x50c9b640, - 0x4e8ee645,0x4a4ffbf2,0x470cdd2b,0x43cdc09c, - 0x7b827d21,0x7f436096,0x7200464f,0x76c15bf8, - 0x68860bfd,0x6c47164a,0x61043093,0x65c52d24, - 0x119b4be9,0x155a565e,0x18197087,0x1cd86d30, - 0x029f3d35,0x065e2082,0x0b1d065b,0x0fdc1bec, - 0x3793a651,0x3352bbe6,0x3e119d3f,0x3ad08088, - 0x2497d08d,0x2056cd3a,0x2d15ebe3,0x29d4f654, - 0xc5a92679,0xc1683bce,0xcc2b1d17,0xc8ea00a0, - 0xd6ad50a5,0xd26c4d12,0xdf2f6bcb,0xdbee767c, - 0xe3a1cbc1,0xe760d676,0xea23f0af,0xeee2ed18, - 0xf0a5bd1d,0xf464a0aa,0xf9278673,0xfde69bc4, - 0x89b8fd09,0x8d79e0be,0x803ac667,0x84fbdbd0, - 0x9abc8bd5,0x9e7d9662,0x933eb0bb,0x97ffad0c, - 0xafb010b1,0xab710d06,0xa6322bdf,0xa2f33668, - 0xbcb4666d,0xb8757bda,0xb5365d03,0xb1f740b4}; +#include "crctable.h" /* init the encode/decode logical stream state */ @@ -293,10 +234,27 @@ static int _os_lacing_expand(ogg_stream_state *os,long needed){ /* Direct table CRC; note that this will be faster in the future if we perform the checksum simultaneously with other copies */ +static ogg_uint32_t _os_update_crc(ogg_uint32_t crc, unsigned char *buffer, int size){ + while (size>=8){ + crc^=buffer[0]<<24|buffer[1]<<16|buffer[2]<<8|buffer[3]; + + crc=crc_lookup[7][ crc>>24 ]^crc_lookup[6][(crc>>16)&0xFF]^ + crc_lookup[5][(crc>> 8)&0xFF]^crc_lookup[4][ crc &0xFF]^ + crc_lookup[3][buffer[4] ]^crc_lookup[2][buffer[5] ]^ + crc_lookup[1][buffer[6] ]^crc_lookup[0][buffer[7] ]; + + buffer+=8; + size-=8; + } + + while (size--) + crc=(crc<<8)^crc_lookup[0][((crc >> 24)&0xff)^*buffer++]; + return crc; +} + void ogg_page_checksum_set(ogg_page *og){ if(og){ ogg_uint32_t crc_reg=0; - int i; /* safety; needed for API behavior, but not framing code */ og->header[22]=0; @@ -304,10 +262,8 @@ void ogg_page_checksum_set(ogg_page *og){ og->header[24]=0; og->header[25]=0; - for(i=0;i<og->header_len;i++) - crc_reg=(crc_reg<<8)^crc_lookup[((crc_reg >> 24)&0xff)^og->header[i]]; - for(i=0;i<og->body_len;i++) - crc_reg=(crc_reg<<8)^crc_lookup[((crc_reg >> 24)&0xff)^og->body[i]]; + crc_reg=_os_update_crc(crc_reg,og->header,og->header_len); + crc_reg=_os_update_crc(crc_reg,og->body,og->body_len); og->header[22]=(unsigned char)(crc_reg&0xff); og->header[23]=(unsigned char)((crc_reg>>8)&0xff); |