98 lines
3.0 KiB
C
98 lines
3.0 KiB
C
/******************************************************************************
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* *
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* Copyright (C) 2018 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*****************************************************************************
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* Originally developed and contributed by Ittiam Systems Pvt. Ltd, Bangalore
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*/
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#include "ixheaacd_type_def.h"
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#include "ixheaacd_bitbuffer.h"
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#include "ixheaacd_sbr_crc.h"
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#include "ixheaacd_sbr_const.h"
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static VOID ixheaacd_calc_chk_sum(WORD16* crc_state, WORD32 stream_data,
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WORD32 num_bits) {
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WORD32 i;
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WORD32 data_bit_mask = (1 << (num_bits - 1));
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WORD16 crc10 = SBR_CRC_POLY;
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WORD16 crc_mask = (1 << 9);
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WORD16 crc_state_local = *crc_state;
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for (i = 0; i < num_bits; i++) {
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WORD32 bit0, bit1;
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bit0 = ((crc_state_local & crc_mask) ? 1 : 0);
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bit1 = ((data_bit_mask & stream_data) ? 1 : 0);
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bit0 ^= bit1;
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crc_state_local = (WORD16)((WORD32)(crc_state_local & 0x0000FFFF) << 1);
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if (bit0) {
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crc_state_local ^= crc10;
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}
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data_bit_mask = (data_bit_mask >> 1);
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}
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*crc_state = crc_state_local;
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return;
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}
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static PLATFORM_INLINE WORD32 ixheaacd_sbr_crc(ia_bit_buf_struct* it_bit_buff,
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WORD32 num_crc_bits) {
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WORD32 i;
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WORD32 num_full_bytes, rem_bits;
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WORD32 byte_value;
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WORD16 crc_state = 0;
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num_full_bytes = (num_crc_bits >> 3);
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rem_bits = (num_crc_bits & 0x7);
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for (i = 0; i < num_full_bytes; i++) {
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byte_value = ixheaacd_read_bits_buf(it_bit_buff, 8);
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ixheaacd_calc_chk_sum(&crc_state, byte_value, 8);
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}
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byte_value = ixheaacd_read_bits_buf(it_bit_buff, rem_bits);
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ixheaacd_calc_chk_sum(&crc_state, byte_value, rem_bits);
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return (crc_state & 0x03FF);
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}
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FLAG ixheaacd_sbr_crccheck(ia_bit_buf_struct* it_bit_buff,
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WORD32 crc_bits_len) {
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struct ia_bit_buf_struct it_bit_buff_local = {0};
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WORD32 num_crc_bits;
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WORD32 calc_crc_sum;
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WORD32 bits_available;
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WORD32 crc_check_sum;
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crc_check_sum = ixheaacd_read_bits_buf(it_bit_buff, SBR_CYC_REDCY_CHK_BITS);
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it_bit_buff_local = *it_bit_buff;
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bits_available = it_bit_buff->cnt_bits;
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if (bits_available <= 0) {
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return 0;
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}
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num_crc_bits =
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(crc_bits_len > bits_available) ? bits_available : crc_bits_len;
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calc_crc_sum = ixheaacd_sbr_crc(&it_bit_buff_local, num_crc_bits);
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if (calc_crc_sum != crc_check_sum) {
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return 0;
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}
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return 1;
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}
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