| /* ------------------------------------------------------------------ |
| * Copyright (C) 1998-2009 PacketVideo |
| * |
| * 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. |
| * ------------------------------------------------------------------- |
| */ |
| /* |
| |
| Pathname: getbits.h |
| |
| ------------------------------------------------------------------------------ |
| REVISION HISTORY |
| |
| Description: Update comments for the structure |
| |
| Description: Move structur to another file |
| |
| Who: Date: MM/DD/YYYY |
| Description: |
| |
| |
| ------------------------------------------------------------------------------ |
| INCLUDE DESCRIPTION |
| |
| Header file for the function getbits(). |
| |
| ------------------------------------------------------------------------------ |
| */ |
| |
| /*---------------------------------------------------------------------------- |
| ; CONTINUE ONLY IF NOT ALREADY DEFINED |
| ----------------------------------------------------------------------------*/ |
| #ifndef GETBITS_H |
| #define GETBITS_H |
| |
| #ifdef __cplusplus |
| extern "C" |
| { |
| #endif |
| |
| /*---------------------------------------------------------------------------- |
| ; INCLUDES |
| ----------------------------------------------------------------------------*/ |
| #include "pv_audio_type_defs.h" |
| #include "ibstream.h" |
| |
| /*---------------------------------------------------------------------------- |
| ; MACROS |
| ; Define module specific macros here |
| ----------------------------------------------------------------------------*/ |
| |
| /*---------------------------------------------------------------------------- |
| ; DEFINES |
| ; Include all pre-processor statements here. |
| ----------------------------------------------------------------------------*/ |
| |
| /*---------------------------------------------------------------------------- |
| ; EXTERNAL VARIABLES REFERENCES |
| ; Declare variables used in this module but defined elsewhere |
| ----------------------------------------------------------------------------*/ |
| |
| /*---------------------------------------------------------------------------- |
| ; SIMPLE TYPEDEF'S |
| ----------------------------------------------------------------------------*/ |
| |
| /*---------------------------------------------------------------------------- |
| ; ENUMERATED TYPEDEF'S |
| ----------------------------------------------------------------------------*/ |
| |
| /*---------------------------------------------------------------------------- |
| ; STRUCTURES TYPEDEF'S |
| ----------------------------------------------------------------------------*/ |
| |
| /*---------------------------------------------------------------------------- |
| ; GLOBAL FUNCTION DEFINITIONS |
| ; Function Prototype declaration |
| ----------------------------------------------------------------------------*/ |
| |
| #define INBUF_ARRAY_INDEX_SHIFT (3) |
| #define INBUF_BIT_WIDTH (1<<(INBUF_ARRAY_INDEX_SHIFT)) |
| #define INBUF_BIT_MODULO_MASK ((INBUF_BIT_WIDTH)-1) |
| |
| #define MAX_GETBITS (25) |
| |
| #define CHECK_INPUT_BUFFER_LIMITS 1 |
| |
| __inline UInt32 getbits( |
| const UInt neededBits, |
| BITS *pInputStream) |
| { |
| UInt32 returnValue = 0; |
| UInt offset; |
| UInt bitIndex; |
| UChar *pElem; /* Needs to be same type as pInput->pBuffer */ |
| |
| offset = (pInputStream->usedBits) >> INBUF_ARRAY_INDEX_SHIFT; |
| |
| pElem = pInputStream->pBuffer + offset; |
| |
| #if CHECK_INPUT_BUFFER_LIMITS |
| |
| offset = pInputStream->inputBufferCurrentLength - offset; |
| /* check if access to input buffer does not go beyond boundaries */ |
| if (offset > 3) |
| { |
| returnValue = (((UInt32) * (pElem)) << 24) | |
| (((UInt32) * (pElem + 1)) << 16) | |
| (((UInt32) * (pElem + 2)) << 8) | |
| ((UInt32) * (pElem + 3)); |
| } |
| else /* then access only available bytes */ |
| { |
| /* Access to the bitstream beyond frame boundaries are not allowed, |
| * Here, only what was available before the end of the frame will |
| * be processed. Non-accessible bytes will be filled in with zeros. |
| * Zero values guarantees that the data structures are filled in with values |
| * that eventually will signal an error (like invalid parameters) or that allow |
| * completion of the parsing routine. |
| * Overrun is detected on file pvmp4audiodecodeframe.cpp. |
| */ |
| switch (offset) |
| { |
| case 3: |
| returnValue = (((UInt32) * (pElem + 2)) << 8); |
| case 2: |
| returnValue |= (((UInt32) * (pElem + 1)) << 16); |
| case 1: |
| returnValue |= (((UInt32) * (pElem)) << 24); |
| default: |
| break; |
| } |
| } |
| |
| |
| #else |
| |
| returnValue = (((UInt32) * (pElem)) << 24) | |
| (((UInt32) * (pElem + 1)) << 16) | |
| (((UInt32) * (pElem + 2)) << 8) | |
| ((UInt32) * (pElem + 3)); |
| #endif |
| |
| /* Remove extra high bits by shifting up */ |
| bitIndex = (UInt)((pInputStream->usedBits) & INBUF_BIT_MODULO_MASK); |
| |
| /* This line is faster way to mask off the high bits. */ |
| returnValue = returnValue << (bitIndex); |
| |
| /* Move the field down. */ |
| returnValue = returnValue >> (32 - neededBits); |
| |
| pInputStream->usedBits += neededBits; |
| |
| return (returnValue); |
| |
| } |
| |
| |
| |
| __inline UInt get1bits( |
| BITS *pInputStream) |
| { |
| UInt returnValue; |
| UInt offset; |
| UInt bitIndex; |
| UChar *pElem; /* Needs to be same type as pInput->pBuffer */ |
| |
| offset = (pInputStream->usedBits) >> INBUF_ARRAY_INDEX_SHIFT; |
| |
| pElem = pInputStream->pBuffer + offset; |
| |
| #if CHECK_INPUT_BUFFER_LIMITS |
| returnValue = (offset < pInputStream->inputBufferCurrentLength) ? ((UInt) * (pElem)) : 0; |
| #else |
| returnValue = ((UInt32) * (pElem)); |
| #endif |
| |
| |
| /* Remove extra high bits by shifting up */ |
| bitIndex = (UInt)((pInputStream->usedBits++) & INBUF_BIT_MODULO_MASK); |
| |
| /* This line is faster way to mask off the high bits. */ |
| returnValue = 0xFF & (returnValue << (bitIndex)); |
| |
| /* Move the field down. */ |
| |
| return ((UInt)(returnValue >> 7)); |
| |
| } |
| |
| |
| |
| __inline UInt get9_n_lessbits( |
| const UInt neededBits, |
| BITS *pInputStream) |
| |
| { |
| UInt returnValue; |
| UInt offset; |
| UInt bitIndex; |
| UChar *pElem; /* Needs to be same type as pInput->pBuffer */ |
| |
| offset = (pInputStream->usedBits) >> INBUF_ARRAY_INDEX_SHIFT; |
| |
| pElem = pInputStream->pBuffer + offset; |
| |
| #if CHECK_INPUT_BUFFER_LIMITS |
| |
| |
| offset = pInputStream->inputBufferCurrentLength - offset; |
| /* check if access to input buffer does not go beyond boundaries */ |
| if (offset > 1) |
| { |
| returnValue = (((UInt32) * (pElem)) << 8) | |
| ((UInt32) * (pElem + 1)); |
| } |
| else /* then access only available bytes */ |
| { |
| /* Access to the bitstream beyond frame boundaries are not allowed, |
| * Here, only what was available before the end of the frame will |
| * be processed. Non-accessible bytes will be filled in with zeros. |
| * Zero values guarantees that the data structures are filled in with values |
| * that eventually will signal an error (like invalid parameters) or that allow |
| * completion of the parsing routine. |
| * Overrun is detected on file pvmp4audiodecodeframe.cpp |
| */ |
| switch (offset) |
| { |
| case 1: |
| returnValue = (((UInt32) * (pElem)) << 8); |
| break; |
| default: |
| returnValue = 0; |
| break; |
| } |
| } |
| |
| |
| #else |
| returnValue = (((UInt32) * (pElem)) << 8) | |
| ((UInt32) * (pElem + 1)) ; |
| #endif |
| |
| /* Remove extra high bits by shifting up */ |
| bitIndex = (UInt)((pInputStream->usedBits) & INBUF_BIT_MODULO_MASK); |
| |
| pInputStream->usedBits += neededBits; |
| |
| /* This line is faster way to mask off the high bits. */ |
| returnValue = 0xFFFF & (returnValue << (bitIndex)); |
| |
| /* Move the field down. */ |
| |
| return (UInt)(returnValue >> (16 - neededBits)); |
| |
| } |
| |
| __inline UInt32 get17_n_lessbits( |
| const UInt neededBits, |
| BITS *pInputStream) |
| { |
| UInt32 returnValue; |
| UInt offset; |
| UInt bitIndex; |
| UChar *pElem; /* Needs to be same type as pInput->pBuffer */ |
| |
| offset = (pInputStream->usedBits) >> INBUF_ARRAY_INDEX_SHIFT; |
| |
| pElem = pInputStream->pBuffer + offset; |
| |
| #if CHECK_INPUT_BUFFER_LIMITS |
| |
| offset = pInputStream->inputBufferCurrentLength - offset; |
| /* check if access to input buffer does not go beyond boundaries */ |
| |
| if (offset > 2) |
| { |
| returnValue = (((UInt32) * (pElem)) << 16) | |
| (((UInt32) * (pElem + 1)) << 8) | |
| ((UInt32) * (pElem + 2)); |
| } |
| else /* then access only available bytes */ |
| { |
| /* Access to the bitstream beyond frame boundaries are not allowed, |
| * Here, only what was available before the end of the frame will |
| * be processed. Non-accessible bytes will be filled in with zeros. |
| * Zero values guarantees that the data structures are filled in with values |
| * that eventually will signal an error (like invalid parameters) or that allow |
| * completion of the parsing routine. |
| * Overrun is detected on file pvmp4audiodecodeframe.cpp |
| */ |
| returnValue = 0; |
| switch (offset) |
| { |
| case 2: |
| returnValue = (((UInt32) * (pElem + 1)) << 8); |
| case 1: |
| returnValue |= (((UInt32) * (pElem)) << 16); |
| default: |
| break; |
| } |
| } |
| |
| #else |
| |
| returnValue = (((UInt32) * (pElem)) << 16) | |
| (((UInt32) * (pElem + 1)) << 8) | |
| ((UInt32) * (pElem + 2)); |
| #endif |
| |
| /* Remove extra high bits by shifting up */ |
| bitIndex = (UInt)((pInputStream->usedBits) & INBUF_BIT_MODULO_MASK); |
| |
| /* This line is faster way to mask off the high bits. */ |
| returnValue = 0xFFFFFF & (returnValue << (bitIndex)); |
| |
| /* Move the field down. */ |
| returnValue = returnValue >> (24 - neededBits); |
| |
| pInputStream->usedBits += neededBits; |
| |
| return (returnValue); |
| |
| } |
| |
| #ifdef __cplusplus |
| } |
| #endif |
| |
| /*---------------------------------------------------------------------------- |
| ; END |
| ----------------------------------------------------------------------------*/ |
| #endif /* GETBITS_H*/ |
| |
| |
