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