/* ------------------------------------------------------------------ * 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*/