yading@10: /* yading@10: * MLP codec common code yading@10: * Copyright (c) 2007-2008 Ian Caulfield yading@10: * yading@10: * This file is part of FFmpeg. yading@10: * yading@10: * FFmpeg is free software; you can redistribute it and/or yading@10: * modify it under the terms of the GNU Lesser General Public yading@10: * License as published by the Free Software Foundation; either yading@10: * version 2.1 of the License, or (at your option) any later version. yading@10: * yading@10: * FFmpeg is distributed in the hope that it will be useful, yading@10: * but WITHOUT ANY WARRANTY; without even the implied warranty of yading@10: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU yading@10: * Lesser General Public License for more details. yading@10: * yading@10: * You should have received a copy of the GNU Lesser General Public yading@10: * License along with FFmpeg; if not, write to the Free Software yading@10: * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA yading@10: */ yading@10: yading@10: #include yading@10: yading@10: #include "libavutil/crc.h" yading@10: #include "libavutil/intreadwrite.h" yading@10: #include "mlp.h" yading@10: yading@10: const uint8_t ff_mlp_huffman_tables[3][18][2] = { yading@10: { /* Huffman table 0, -7 - +10 */ yading@10: {0x01, 9}, {0x01, 8}, {0x01, 7}, {0x01, 6}, {0x01, 5}, {0x01, 4}, {0x01, 3}, yading@10: {0x04, 3}, {0x05, 3}, {0x06, 3}, {0x07, 3}, yading@10: {0x03, 3}, {0x05, 4}, {0x09, 5}, {0x11, 6}, {0x21, 7}, {0x41, 8}, {0x81, 9}, yading@10: }, { /* Huffman table 1, -7 - +8 */ yading@10: {0x01, 9}, {0x01, 8}, {0x01, 7}, {0x01, 6}, {0x01, 5}, {0x01, 4}, {0x01, 3}, yading@10: {0x02, 2}, {0x03, 2}, yading@10: {0x03, 3}, {0x05, 4}, {0x09, 5}, {0x11, 6}, {0x21, 7}, {0x41, 8}, {0x81, 9}, yading@10: }, { /* Huffman table 2, -7 - +7 */ yading@10: {0x01, 9}, {0x01, 8}, {0x01, 7}, {0x01, 6}, {0x01, 5}, {0x01, 4}, {0x01, 3}, yading@10: {0x01, 1}, yading@10: {0x03, 3}, {0x05, 4}, {0x09, 5}, {0x11, 6}, {0x21, 7}, {0x41, 8}, {0x81, 9}, yading@10: } yading@10: }; yading@10: yading@10: static int crc_init = 0; yading@10: #if CONFIG_SMALL yading@10: #define CRC_TABLE_SIZE 257 yading@10: #else yading@10: #define CRC_TABLE_SIZE 1024 yading@10: #endif yading@10: static AVCRC crc_63[CRC_TABLE_SIZE]; yading@10: static AVCRC crc_1D[CRC_TABLE_SIZE]; yading@10: static AVCRC crc_2D[CRC_TABLE_SIZE]; yading@10: yading@10: av_cold void ff_mlp_init_crc(void) yading@10: { yading@10: if (!crc_init) { yading@10: av_crc_init(crc_63, 0, 8, 0x63, sizeof(crc_63)); yading@10: av_crc_init(crc_1D, 0, 8, 0x1D, sizeof(crc_1D)); yading@10: av_crc_init(crc_2D, 0, 16, 0x002D, sizeof(crc_2D)); yading@10: crc_init = 1; yading@10: } yading@10: } yading@10: yading@10: uint16_t ff_mlp_checksum16(const uint8_t *buf, unsigned int buf_size) yading@10: { yading@10: uint16_t crc; yading@10: yading@10: crc = av_crc(crc_2D, 0, buf, buf_size - 2); yading@10: crc ^= AV_RL16(buf + buf_size - 2); yading@10: return crc; yading@10: } yading@10: yading@10: uint8_t ff_mlp_checksum8(const uint8_t *buf, unsigned int buf_size) yading@10: { yading@10: uint8_t checksum = av_crc(crc_63, 0x3c, buf, buf_size - 1); // crc_63[0xa2] == 0x3c yading@10: checksum ^= buf[buf_size-1]; yading@10: return checksum; yading@10: } yading@10: yading@10: uint8_t ff_mlp_restart_checksum(const uint8_t *buf, unsigned int bit_size) yading@10: { yading@10: int i; yading@10: int num_bytes = (bit_size + 2) / 8; yading@10: yading@10: int crc = crc_1D[buf[0] & 0x3f]; yading@10: crc = av_crc(crc_1D, crc, buf + 1, num_bytes - 2); yading@10: crc ^= buf[num_bytes - 1]; yading@10: yading@10: for (i = 0; i < ((bit_size + 2) & 7); i++) { yading@10: crc <<= 1; yading@10: if (crc & 0x100) yading@10: crc ^= 0x11D; yading@10: crc ^= (buf[num_bytes] >> (7 - i)) & 1; yading@10: } yading@10: yading@10: return crc; yading@10: } yading@10: yading@10: uint8_t ff_mlp_calculate_parity(const uint8_t *buf, unsigned int buf_size) yading@10: { yading@10: uint32_t scratch = 0; yading@10: const uint8_t *buf_end = buf + buf_size; yading@10: yading@10: for (; ((intptr_t) buf & 3) && buf < buf_end; buf++) yading@10: scratch ^= *buf; yading@10: for (; buf < buf_end - 3; buf += 4) yading@10: scratch ^= *((const uint32_t*)buf); yading@10: yading@10: scratch = xor_32_to_8(scratch); yading@10: yading@10: for (; buf < buf_end; buf++) yading@10: scratch ^= *buf; yading@10: yading@10: return scratch; yading@10: }