| /****************************************************************************** |
| * |
| * Copyright (C) 2014 The Android Open Source Project |
| * Copyright 2003 - 2004 Open Interface North America, Inc. All rights |
| * reserved. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at: |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| * |
| ******************************************************************************/ |
| |
| /******************************************************************************* |
| $Revision: #1 $ |
| ******************************************************************************/ |
| |
| /** |
| @file |
| Functions for manipulating input bitstreams. |
| |
| @ingroup codec_internal |
| */ |
| |
| /** |
| @addtogroup codec_internal |
| @{ |
| */ |
| |
| #include "oi_assert.h" |
| #include "oi_bitstream.h" |
| #include "oi_stddefs.h" |
| |
| PRIVATE void OI_BITSTREAM_ReadInit(OI_BITSTREAM* bs, const OI_BYTE* buffer) { |
| bs->value = |
| ((int32_t)buffer[0] << 16) | ((int32_t)buffer[1] << 8) | (buffer[2]); |
| bs->ptr.r = buffer + 3; |
| bs->bitPtr = 8; |
| } |
| |
| PRIVATE uint32_t OI_BITSTREAM_ReadUINT(OI_BITSTREAM* bs, OI_UINT bits) { |
| uint32_t result; |
| |
| OI_BITSTREAM_READUINT(result, bits, bs->ptr.r, bs->value, bs->bitPtr); |
| |
| return result; |
| } |
| |
| PRIVATE uint8_t OI_BITSTREAM_ReadUINT4Aligned(OI_BITSTREAM* bs) { |
| uint32_t result; |
| |
| OI_ASSERT(bs->bitPtr < 16); |
| OI_ASSERT(bs->bitPtr % 4 == 0); |
| |
| if (bs->bitPtr == 8) { |
| result = bs->value << 8; |
| bs->bitPtr = 12; |
| } else { |
| result = bs->value << 12; |
| bs->value = (bs->value << 8) | *bs->ptr.r++; |
| bs->bitPtr = 8; |
| } |
| result >>= 28; |
| OI_ASSERT(result < (1u << 4)); |
| return (uint8_t)result; |
| } |
| |
| PRIVATE uint8_t OI_BITSTREAM_ReadUINT8Aligned(OI_BITSTREAM* bs) { |
| uint32_t result; |
| OI_ASSERT(bs->bitPtr == 8); |
| |
| result = bs->value >> 16; |
| bs->value = (bs->value << 8) | *bs->ptr.r++; |
| |
| return (uint8_t)result; |
| } |
| |
| /** |
| @} |
| */ |