/*
* asc85enc.c
* Copyright (C) 2000-2003 A.J. van Os; Released under GPL
*
* Description:
* Functions to for ASCII 85 encoding
*
*====================================================================
* This part of the software is based on:
* asc85ec.c - ASCII85 and Hex encoding for PostScript Level 2 and PDF
* Copyright (C) 1994-99 Thomas Merz (
[email protected])
*====================================================================
* The credit should go to him, but all the bugs are mine.
*/
#include <stdio.h>
#include "antiword.h"
static const ULONG aulPower85[5] = {
1UL, 85UL, 85UL * 85, 85UL * 85 * 85, 85UL * 85 * 85 * 85,
};
static int iOutBytes = 0; /* Number of characters in an output line */
static char cCharPrev = '\0';
/*
* Two percent characters at the start of a line will cause trouble
* with some post-processing software. In order to avoid this, we
* simply insert a line break if we encounter two percent characters
* at the start of the line. Of course, this rather simplistic
* algorithm may lead to a large line count in pathological cases,
* but the chance for hitting such a case is very small, and even
* so it's only a cosmetic flaw and not a functional restriction.
*/
/*
* vOutputByte - output one byte
*/
static void
vOutputByte(ULONG ulChar, FILE *pOutFile)
{
if (iOutBytes == 1 && cCharPrev == '%' && ulChar == (ULONG)'%') {
if (putc('\n', pOutFile) != EOF) {
iOutBytes = 0;
}
}
if (putc((int)ulChar, pOutFile) == EOF) {
return;
}
iOutBytes++;
if (iOutBytes > 63) {
if (putc('\n', pOutFile) != EOF) {
iOutBytes = 0;
}
}
cCharPrev = (char)ulChar;
} /* end of vOutputByte */
/*
* vASCII85EncodeByte - ASCII 85 encode a byte
*/
void
vASCII85EncodeByte(FILE *pOutFile, int iByte)
{
static ULONG ulBuffer[4] = { 0, 0, 0, 0 };
static int iInBuffer = 0;
ULONG ulValue, ulTmp;
int iIndex;
fail(pOutFile == NULL);
fail(iInBuffer < 0);
fail(iInBuffer > 3);
if (iByte == EOF) {
/* End Of File, time to clean up */
if (iInBuffer > 0 && iInBuffer < 4) {
/* Encode the remaining bytes */
ulValue = 0;
for (iIndex = iInBuffer - 1; iIndex >= 0; iIndex--) {
ulValue |=
ulBuffer[iIndex] << (8 * (3 - iIndex));
}
for (iIndex = 4; iIndex >= 4 - iInBuffer; iIndex--) {
ulTmp = ulValue / aulPower85[iIndex];
vOutputByte(ulTmp + '!', pOutFile);
ulValue -= ulTmp * aulPower85[iIndex];
}
}
/* Add the End Of Data marker */
(void)putc('~', pOutFile);
(void)putc('>', pOutFile);
(void)putc('\n', pOutFile);
/* Reset the control variables */
iInBuffer = 0;
iOutBytes = 0;
cCharPrev = '\0';
return;
}
ulBuffer[iInBuffer] = (ULONG)iByte & 0xff;
iInBuffer++;
if (iInBuffer >= 4) {
ulValue = (ulBuffer[0] << 24) | (ulBuffer[1] << 16) |
(ulBuffer[2] << 8) | ulBuffer[3];
if (ulValue == 0) {
vOutputByte((ULONG)'z', pOutFile); /* Shortcut for 0 */
} else {
for (iIndex = 4; iIndex >= 0; iIndex--) {
ulTmp = ulValue / aulPower85[iIndex];
vOutputByte(ulTmp + '!', pOutFile);
ulValue -= ulTmp * aulPower85[iIndex];
}
}
/* Reset the buffer */
iInBuffer = 0;
}
} /* end of vASCII85EncodeByte */
/*
* vASCII85EncodeArray - ASCII 85 encode a byte array
*/
void
vASCII85EncodeArray(FILE *pInFile, FILE *pOutFile, size_t tLength)
{
size_t tCount;
int iByte;
fail(pInFile == NULL);
fail(pOutFile == NULL);
DBG_DEC(tLength);
for (tCount = 0; tCount < tLength; tCount++) {
iByte = iNextByte(pInFile);
if (iByte == EOF) {
break;
}
vASCII85EncodeByte(pOutFile, iByte);
}
} /* end of vASCII85EncodeArray */
/*
* vASCII85EncodeFile - ASCII 85 encode part of a file
*/
void
vASCII85EncodeFile(FILE *pInFile, FILE *pOutFile, size_t tLength)
{
fail(pInFile == NULL);
fail(pOutFile == NULL);
fail(tLength == 0);
vASCII85EncodeArray(pInFile, pOutFile, tLength);
vASCII85EncodeByte(pOutFile, EOF);
} /* end of vASCII85EncodeFile */
