nulib2/nufxlib-0/Compress.c

364 lines
12 KiB
C

/*
* NuFX archive manipulation library
* Copyright (C) 2000 by Andy McFadden, All Rights Reserved.
* This is free software; you can redistribute it and/or modify it under the
* terms of the GNU Library General Public License, see the file COPYING.LIB.
*
* Compress data into an archive.
*/
#include "NufxLibPriv.h"
/* for ShrinkIt-mimic mode, don't compress files under 512 bytes */
#define kNuSHKLZWThreshold 512
/*
* "Compress" an uncompressed thread.
*/
static NuError
Nu_CompressUncompressed(NuArchive* pArchive, NuStraw* pStraw,
FILE* fp, ulong srcLen, ulong* pDstLen, ushort *pCrc)
{
NuError err = kNuErrNone;
/*uchar* buffer = nil;*/
ulong count, getsize;
Assert(pArchive != nil);
Assert(pStraw != nil);
Assert(fp != nil);
Assert(srcLen > 0);
*pDstLen = srcLen; /* get this over with */
/* doesn't have to be same size as funnel, but it's not a bad idea */
/*buffer = Nu_Malloc(pArchive, kNuFunnelBufSize);*/
/*BailAlloc(buffer);*/
err = Nu_AllocCompressionBufferIFN(pArchive);
BailError(err);
if (pCrc != nil)
*pCrc = kNuInitialThreadCRC;
count = srcLen;
while (count) {
getsize = (count > kNuGenCompBufSize) ? kNuGenCompBufSize : count;
err = Nu_StrawRead(pArchive, pStraw, pArchive->compBuf, getsize);
BailError(err);
if (pCrc != nil)
*pCrc = Nu_CalcCRC16(*pCrc, pArchive->compBuf, getsize);
err = Nu_FWrite(fp, pArchive->compBuf, getsize);
BailError(err);
count -= getsize;
}
bail:
/*Nu_Free(pArchive, buffer);*/
return err;
}
/*
* Compress from a data source to an archive.
*
* All archive-specified fields in "pThread" will be filled in, as will
* "actualThreadEOF". The "nuThreadIdx" and "fileOffset" fields will
* not be modified.
*
* If "sourceFormat" is uncompressed:
* "targetFormat" will be used to compress the data
* the data source length will be placed into pThread->thThreadEOF
* the compressed size will be placed into pThread->thCompThreadEOF
*
* If "sourceFormat" is compressed:
* the data will be copied without compression (targetFormat is ignored)
* the data source "otherLen" value will be placed into pThread->thThreadEOF
* the data source length will be placed into pThread->thCompThreadEOF
*
* The actual format used will be placed in pThread->thThreadFormat, and
* the CRC of the uncompressed data will be placed in pThread->thThreadCRC.
* The remaining fields of "pThread", thThreadClass and thThreadKind, will
* be set based on the fields in "pDataSource".
*
* The output file will be positioned after the last byte of the output.
* (For a pre-sized buffer, this may not be the desired result.)
*/
NuError
Nu_CompressToArchive(NuArchive* pArchive, NuDataSource* pDataSource,
NuThreadID threadID, NuThreadFormat sourceFormat,
NuThreadFormat targetFormat, NuProgressData* pProgressData, FILE* dstFp,
NuThread* pThread)
{
NuError err;
long origOffset;
NuStraw* pStraw = nil;
NuDataSink* pDataSink = nil;
ulong srcLen, dstLen;
ushort threadCrc;
Assert(pArchive != nil);
Assert(pDataSource != nil);
/* okay if pProgressData is nil */
Assert(dstFp != nil);
Assert(pThread != nil);
/* remember file offset, so we can back up if compression fails */
err = Nu_FTell(dstFp, &origOffset);
BailError(err);
Assert(origOffset == pThread->fileOffset); /* can get rid of ftell? */
/* fill in some thread fields */
threadCrc = kNuInitialThreadCRC;
pThread->thThreadClass = NuThreadIDGetClass(threadID);
pThread->thThreadKind = NuThreadIDGetKind(threadID);
pThread->actualThreadEOF = (ulong)-1;
/* nuThreadIdx and fileOffset should already be set */
/*
* Get the input length. For "buffer" and "fp" sources, this is just
* a value passed in. For "file" sources, this is the length of the
* file on disk. The file should already have been opened successfully
* by the caller.
*
* If the input file is zero bytes long, "store" it uncompressed and
* bail immediately.
*
* (Our desire to store uncompressible data without compression clashes
* with a passing interest in doing CRLF conversions on input data. We
* want to know the length ahead of time, which potentially makes the
* compression code simpler, but prevents us from doing the conversion
* unless we pre-flight the conversion with a separate pass through the
* input file. Of course, it's still possible for the application to
* convert the file into a temp file and add from there, so all is
* not lost.)
*/
srcLen = Nu_DataSourceGetDataLen(pDataSource);
/*DBUG(("+++ input file length is %lu\n", srcLen));*/
/*
* Create a "Straw" to slurp the input through and track progress.
*/
err = Nu_StrawNew(pArchive, pDataSource, pProgressData, &pStraw);
BailError(err);
if (!srcLen) {
/* empty file! */
pThread->thThreadFormat = kNuThreadFormatUncompressed;
pThread->thThreadCRC = threadCrc;
pThread->thThreadEOF = 0;
pThread->thCompThreadEOF = 0;
pThread->actualThreadEOF = 0;
goto done; /* send final progress message */
}
if (sourceFormat == kNuThreadFormatUncompressed) {
/*
* Compress the input.
*/
/* GSHK doesn't compress anything under 512 bytes */
if (pArchive->valMimicSHK && srcLen < kNuSHKLZWThreshold)
targetFormat = kNuThreadFormatUncompressed;
if (pProgressData != nil) {
if (targetFormat != kNuThreadFormatUncompressed)
Nu_StrawSetProgressState(pStraw, kNuProgressCompressing);
else
Nu_StrawSetProgressState(pStraw, kNuProgressStoring);
}
err = Nu_ProgressDataCompressPrep(pArchive, pStraw, targetFormat,
srcLen);
BailError(err);
switch (targetFormat) {
case kNuThreadFormatUncompressed:
err = Nu_CompressUncompressed(pArchive, pStraw, dstFp, srcLen,
&dstLen, &threadCrc);
break;
case kNuThreadFormatLZW1:
err = Nu_CompressLZW1(pArchive, pStraw, dstFp, srcLen, &dstLen,
&threadCrc);
break;
case kNuThreadFormatLZW2:
err = Nu_CompressLZW2(pArchive, pStraw, dstFp, srcLen, &dstLen,
&threadCrc);
break;
default:
Assert(0);
err = kNuErrInternal;
goto bail;
}
BailError(err);
pThread->thThreadCRC = threadCrc; /* CRC of uncompressed data */
if (dstLen < srcLen ||
(dstLen == srcLen && targetFormat == kNuThreadFormatUncompressed))
{
/* got smaller, or we didn't try to compress it; keep it */
pThread->thThreadEOF = srcLen;
pThread->thCompThreadEOF = dstLen;
pThread->thThreadFormat = targetFormat;
} else {
/* got bigger, store it uncompressed */
err = Nu_FSeek(dstFp, origOffset, SEEK_SET);
BailError(err);
err = Nu_StrawRewind(pArchive, pStraw);
BailError(err);
if (pProgressData != nil)
Nu_StrawSetProgressState(pStraw, kNuProgressStoring);
err = Nu_ProgressDataCompressPrep(pArchive, pStraw,
kNuThreadFormatUncompressed, srcLen);
BailError(err);
DBUG(("--- compression (%d) failed (%ld vs %ld), storing\n",
targetFormat, dstLen, srcLen));
err = Nu_CompressUncompressed(pArchive, pStraw, dstFp, srcLen,
&dstLen, &threadCrc);
BailError(err);
/* [didn't need to recompute CRC, but I was being paranoid] */
Assert(threadCrc == pThread->thThreadCRC);
pThread->thThreadEOF = srcLen;
pThread->thCompThreadEOF = dstLen;
pThread->thThreadFormat = kNuThreadFormatUncompressed;
}
} else {
/*
* Copy the already-compressed input.
*/
if (pProgressData != nil)
Nu_StrawSetProgressState(pStraw, kNuProgressCopying);
err = Nu_ProgressDataCompressPrep(pArchive, pStraw,
kNuThreadFormatUncompressed, srcLen);
BailError(err);
err = Nu_CompressUncompressed(pArchive, pStraw, dstFp, srcLen,
&dstLen, nil);
BailError(err);
pThread->thThreadEOF = Nu_DataSourceGetOtherLen(pDataSource);
pThread->thCompThreadEOF = srcLen;
pThread->thThreadFormat = sourceFormat;
pThread->thThreadCRC = Nu_DataSourceGetRawCrc(pDataSource);
}
pThread->actualThreadEOF = pThread->thThreadEOF;
done:
DBUG(("+++ srcLen=%ld, dstLen=%ld, actual=%ld\n",
srcLen, dstLen, pThread->actualThreadEOF));
/* make sure we send a final "success" progress message at 100% */
if (pProgressData != nil) {
(void) Nu_StrawSetProgressState(pStraw, kNuProgressDone);
err = Nu_StrawSendProgressUpdate(pArchive, pStraw);
BailError(err);
}
bail:
(void) Nu_StrawFree(pArchive, pStraw);
(void) Nu_DataSinkFree(pDataSink);
return err;
}
/*
* Copy pre-sized data into the archive at the current offset.
*
* All archive-specified fields in "pThread" will be filled in, as will
* "actualThreadEOF". The "nuThreadIdx" and "fileOffset" fields will
* not be modified.
*
* Pre-sized data is always uncompressed, and doesn't have a CRC. This
* will copy the data, and then continue writing zeros to fill out the rest
* of the pre-sized buffer.
*/
NuError
Nu_CopyPresizedToArchive(NuArchive* pArchive, NuDataSource* pDataSource,
NuThreadID threadID, FILE* dstFp, NuThread* pThread, char** ppSavedCopy)
{
NuError err = kNuErrNone;
NuStraw* pStraw = nil;
/*uchar* buffer = nil;*/
ulong srcLen, bufferLen;
ulong count, getsize;
srcLen = Nu_DataSourceGetDataLen(pDataSource);
bufferLen = Nu_DataSourceGetOtherLen(pDataSource);
if (bufferLen < srcLen) {
/* hey, this won't fit! */
DBUG(("--- can't fit %lu into buffer of %lu!\n", srcLen, bufferLen));
err = kNuErrPreSizeOverflow;
goto bail;
}
DBUG(("+++ copying %lu into buffer of %lu\n", srcLen, bufferLen));
pThread->thThreadClass = NuThreadIDGetClass(threadID);
pThread->thThreadFormat = kNuThreadFormatUncompressed;
pThread->thThreadKind = NuThreadIDGetKind(threadID);
pThread->thThreadCRC = 0; /* no CRC on pre-sized stuff */
pThread->thThreadEOF = srcLen;
pThread->thCompThreadEOF = bufferLen;
pThread->actualThreadEOF = bufferLen;
/* nuThreadIdx and fileOffset should already be set */
/*
* Prepare to copy the data through a buffer. The "straw" thing
* is a convenient way to deal with the dataSource, even though we
* don't have a progress updater.
*/
err = Nu_StrawNew(pArchive, pDataSource, nil, &pStraw);
BailError(err);
count = srcLen;
/*buffer = Nu_Malloc(pArchive, kNuFunnelBufSize);*/
/*BailAlloc(buffer);*/
err = Nu_AllocCompressionBufferIFN(pArchive);
BailError(err);
while (count) {
getsize = (count > kNuGenCompBufSize) ? kNuGenCompBufSize : count;
err = Nu_StrawRead(pArchive, pStraw, pArchive->compBuf, getsize);
BailError(err);
err = Nu_FWrite(dstFp, pArchive->compBuf, getsize);
BailError(err);
if (ppSavedCopy != nil && *ppSavedCopy == nil) {
/*
* Grab a copy of the filename for our own use. This assumes
* that the filename fits in kNuGenCompBufSize, which is a
* pretty safe thing to assume.
*/
Assert(threadID == kNuThreadIDFilename);
Assert(count == getsize);
*ppSavedCopy = Nu_Malloc(pArchive, getsize+1);
BailAlloc(*ppSavedCopy);
memcpy(*ppSavedCopy, pArchive->compBuf, getsize);
(*ppSavedCopy)[getsize] = '\0'; /* make sure it's terminated */
}
count -= getsize;
}
/*
* Pad out the rest of the buffer. Could probably do this more
* efficiently through the buffer we've allocated, but these regions
* tend to be either 32 or 200 bytes.
*/
count = bufferLen - srcLen;
while (count--)
Nu_WriteOne(pArchive, dstFp, 0);
bail:
(void) Nu_StrawFree(pArchive, pStraw);
/*Nu_Free(pArchive, buffer);*/
return err;
}