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bb547203bf
In order to eliminate the WebRTC Subtree mirror in Chromium, WebRTC is moving the content of the src/webrtc directory up to the src/ directory. NOPRESUBMIT=true NOTREECHECKS=true NOTRY=true TBR=tommi@webrtc.org Bug: chromium:611808 Change-Id: Iac59c5b51b950f174119565bac87955a7994bc38 Reviewed-on: https://webrtc-review.googlesource.com/1560 Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org> Reviewed-by: Henrik Kjellander <kjellander@webrtc.org> Cr-Commit-Position: refs/heads/master@{#19845}
122 lines
3.7 KiB
C
122 lines
3.7 KiB
C
/*
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* Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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/*
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* arith_routins.c
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*
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* This C file contains a function for finalizing the bitstream
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* after arithmetic coding.
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*
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*/
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#include "arith_routins.h"
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/****************************************************************************
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* WebRtcIsacfix_EncTerminate(...)
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*
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* Final call to the arithmetic coder for an encoder call. This function
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* terminates and return byte stream.
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*
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* Input:
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* - streamData : in-/output struct containing bitstream
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*
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* Return value : number of bytes in the stream
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*/
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int16_t WebRtcIsacfix_EncTerminate(Bitstr_enc *streamData)
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{
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uint16_t *streamPtr;
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uint16_t negCarry;
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/* point to the right place in the stream buffer */
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streamPtr = streamData->stream + streamData->stream_index;
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/* find minimum length (determined by current interval width) */
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if ( streamData->W_upper > 0x01FFFFFF )
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{
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streamData->streamval += 0x01000000;
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/* if result is less than the added value we must take care of the carry */
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if (streamData->streamval < 0x01000000)
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{
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/* propagate carry */
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if (streamData->full == 0) {
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/* Add value to current value */
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negCarry = *streamPtr;
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negCarry += 0x0100;
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*streamPtr = negCarry;
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/* if value is too big, propagate carry to next byte, and so on */
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while (!(negCarry))
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{
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negCarry = *--streamPtr;
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negCarry++;
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*streamPtr = negCarry;
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}
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} else {
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/* propagate carry by adding one to the previous byte in the
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* stream if that byte is 0xFFFF we need to propagate the carry
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* furhter back in the stream */
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while ( !(++(*--streamPtr)) );
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}
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/* put pointer back to the old value */
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streamPtr = streamData->stream + streamData->stream_index;
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}
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/* write remaining data to bitstream, if "full == 0" first byte has data */
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if (streamData->full == 0) {
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*streamPtr++ += (uint16_t)(streamData->streamval >> 24);
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streamData->full = 1;
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} else {
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*streamPtr = (uint16_t)((streamData->streamval >> 24) << 8);
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streamData->full = 0;
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}
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}
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else
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{
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streamData->streamval += 0x00010000;
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/* if result is less than the added value we must take care of the carry */
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if (streamData->streamval < 0x00010000)
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{
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/* propagate carry */
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if (streamData->full == 0) {
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/* Add value to current value */
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negCarry = *streamPtr;
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negCarry += 0x0100;
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*streamPtr = negCarry;
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/* if value to big, propagate carry to next byte, and so on */
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while (!(negCarry))
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{
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negCarry = *--streamPtr;
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negCarry++;
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*streamPtr = negCarry;
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}
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} else {
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/* Add carry to previous byte */
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while ( !(++(*--streamPtr)) );
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}
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/* put pointer back to the old value */
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streamPtr = streamData->stream + streamData->stream_index;
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}
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/* write remaining data (2 bytes) to bitstream */
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if (streamData->full) {
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*streamPtr++ = (uint16_t)(streamData->streamval >> 16);
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} else {
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*streamPtr++ |= (uint16_t)(streamData->streamval >> 24);
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*streamPtr = (uint16_t)(streamData->streamval >> 8) & 0xFF00;
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}
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}
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/* calculate stream length in bytes */
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return (((streamPtr - streamData->stream)<<1) + !(streamData->full));
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}
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