int CHuffmanEncode(struct CHuffman *ch)
{
bit_file_t bfpOut;
int i;
unsigned char c;
bfpOut.buf = ch->outBuf;
bfpOut.bufLen = ch->outLen;
bfpOut.mode = BF_WRITE;
BitFileInit(&bfpOut);
/* read characters from file and write them to encoded file */
for (i = 0; i < ch->inLen; i++) {
c = ch->inBuf[i];
/* write encoded symbols */
if (BitFilePutBits(&bfpOut,
BitArrayGetBits(ch->canonicalList[c].code),
ch->canonicalList[c].codeLen) == EOF)
{
fprintf(stderr, "buffer full writing\n");
exit(1);
}
}
/* now write EOF */
if (BitFilePutBits(&bfpOut,
BitArrayGetBits(ch->canonicalList[EOF_CHAR].code),
ch->canonicalList[EOF_CHAR].codeLen) == EOF)
{
fprintf(stderr, "buffer full writing\n");
exit(1);
}
/* clean up */
BitFileClose(&bfpOut);
ch->outIndex = bfpOut.bufPos;
return 0;
}
/****************************************************************************
* Function : HuffmanEncodeFile
* Description: This routine genrates a huffman tree optimized for a file
* and writes out an encoded version of that file.
* Parameters : inFile - Open file pointer for file to encode (must be
* rewindable).
* outFile - Open file pointer for file receiving encoded data
* Effects : File is Huffman encoded
* Returned : 0 for success, -1 for failure. errno will be set in the
* event of a failure. Either way, inFile and outFile will
* be left open.
****************************************************************************/
int HuffmanEncodeFile(FILE *inFile, FILE *outFile)
{
huffman_node_t *huffmanTree; /* root of huffman tree */
code_list_t codeList[NUM_CHARS]; /* table for quick encode */
bit_file_t *bOutFile;
int c;
/* validate input and output files */
if ((NULL == inFile) || (NULL == outFile))
{
errno = ENOENT;
return -1;
}
bOutFile = MakeBitFile(outFile, BF_WRITE);
if (NULL == bOutFile)
{
perror("Making Output File a BitFile");
return -1;
}
/* build tree */
if ((huffmanTree = GenerateTreeFromFile(inFile)) == NULL)
{
outFile = BitFileToFILE(bOutFile);
return -1;
}
/* build a list of codes for each symbol */
/* initialize code list */
for (c = 0; c < NUM_CHARS; c++)
{
codeList[c].code = NULL;
codeList[c].codeLen = 0;
}
if (0 != MakeCodeList(huffmanTree, codeList))
{
outFile = BitFileToFILE(bOutFile);
return -1;
}
/* write out encoded file */
/* write header for rebuilding of tree */
WriteHeader(huffmanTree, bOutFile);
/* read characters from file and write them to encoded file */
rewind(inFile); /* start another pass on the input file */
while((c = fgetc(inFile)) != EOF)
{
BitFilePutBits(bOutFile,
BitArrayGetBits(codeList[c].code),
codeList[c].codeLen);
}
/* now write EOF */
BitFilePutBits(bOutFile,
BitArrayGetBits(codeList[EOF_CHAR].code),
codeList[EOF_CHAR].codeLen);
/* free the code list */
for (c = 0; c < NUM_CHARS; c++)
{
if (codeList[c].code != NULL)
{
BitArrayDestroy(codeList[c].code);
}
}
/* clean up */
outFile = BitFileToFILE(bOutFile); /* make file normal again */
FreeHuffmanTree(huffmanTree); /* free allocated memory */
return 0;
}
