ref: b9745c60a1bf2a3876e411d38c67a0980d70e3a3
dir: /sys/src/cmd/aux/antiword/asc85enc.c/
/* * 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 */