omxicjp_decodehuffmanspecinit_u8.c

The OpenMAX DL (Development Layer) APIs contain a comprehensive set of audio, video, signal processi

/**
 *
 * 
 * File Name:  omxICJP_DecodeHuffmanSpecInit_U8.c
 * OpenMAX DL: v1.0.2
 * Revision:   10586
 * Date:       Wednesday, March 5, 2008
 * 
 * (c) Copyright 2007-2008 ARM Limited. All Rights Reserved.
 * 
 * 
 *
 * Brief        : Huffman table initialization function.
 *
 */

#include "omxtypes.h"
#include "armOMX.h"
#include "omxIC.h"

#include "armCOMM.h"
#include "armIC.h"

/**
 * Function:  omxICJP_DecodeHuffmanSpecInit_U8   (5.1.3.5.2)
 *
 * Description:
 * Initializes the DC or AC Huffman decoder table specification. 
 *
 * Input Arguments:
 *   
 *   pHuffBits - Pointer to the array of HUFFBITS, which contains the number 
 *            of Huffman codes for size 1-16 
 *   pHuffValue - Pointer to the array of HUFFVAL, which contains the symbol 
 *            values to be associated with the Huffman codes ordering by size 
 *
 * Output Arguments:
 *   
 *   pHuffTable - pointer to a OMXICJPHuffmanDecodeSpec data structure; must 
 *            be aligned on a 4 byte boundary. 
 *
 * Return Value:
 *    
 *    OMX_Sts_NoErr - no error 
 *    OMX_Sts_BadArgErr - Bad arguments. Returned for any of the following 
 *              conditions: 
 *    -    a pointer was NULL 
 *
 */

OMXResult omxICJP_DecodeHuffmanSpecInit_U8(
    const OMX_U8 *pHuffBits,
    const OMX_U8 *pHuffValue,
    OMXICJPHuffmanDecodeSpec *pHuffTable
)
{
    armICJP_DecHuffmanSpec *pHuffSpec_ref = (armICJP_DecHuffmanSpec *) pHuffTable;
    ARM_VLC32 *pHuffStruct = pHuffSpec_ref->pHuffStruct;
    OMX_INT i;
    OMX_U8 value, codesPerBitLength;
    OMX_U16 code;
    OMX_INT maxValue;
    
    armRetArgErrIf(!pHuffBits,  OMX_Sts_BadArgErr);
    armRetArgErrIf(!pHuffValue, OMX_Sts_BadArgErr);
    armRetArgErrIf(!pHuffTable, OMX_Sts_BadArgErr);

    for(i = 0; i < ARM_ICJP_HUFFTABLE_SIZE; i++) 
    {
        pHuffStruct[i].codeLen = 0;
        pHuffStruct[i].codeWord = 1;
    }
    
    code = 0;
    maxValue = -1;
    for(i = 1; i <= 16; i++) 
    {
        codesPerBitLength = *pHuffBits++;
        for(; codesPerBitLength > 0; codesPerBitLength--) 
        {
            value = *pHuffValue++;
            if(value > maxValue) maxValue = value;
            /* check this as otherwise it means 2 codes have same value
             * codeLen was initialized to 0 and it gets changed when 
             * some code gets that value
             */
            armAssert(pHuffStruct[value].codeLen == 0);
            pHuffStruct[value].codeLen = i;
            pHuffStruct[value].codeWord = code;
            code++;
        }
        code <<= 1;
    }

    /* mark end of search by encountering a {0, 0} (codeLen, codeWord) pair */
    pHuffStruct[maxValue + 1].codeWord = 0;

    return OMX_Sts_NoErr;
}

/* End of file */