📄 libmng_read.c
字号:
/* ************************************************************************** */
/* * For conditions of distribution and use, * */
/* * see copyright notice in libmng.h * */
/* ************************************************************************** */
/* * * */
/* * project : libmng * */
/* * file : libmng_read.c copyright (c) 2000-2004 G.Juyn * */
/* * version : 1.0.8 * */
/* * * */
/* * purpose : Read logic (implementation) * */
/* * * */
/* * author : G.Juyn * */
/* * * */
/* * comment : implementation of the high-level read logic * */
/* * * */
/* * changes : 0.5.1 - 05/08/2000 - G.Juyn * */
/* * - changed strict-ANSI stuff * */
/* * 0.5.1 - 05/11/2000 - G.Juyn * */
/* * - added callback error-reporting support * */
/* * 0.5.1 - 05/12/2000 - G.Juyn * */
/* * - changed trace to macro for callback error-reporting * */
/* * * */
/* * 0.5.2 - 05/19/2000 - G.Juyn * */
/* * - cleaned up some code regarding mixed support * */
/* * 0.5.2 - 05/20/2000 - G.Juyn * */
/* * - added support for JNG * */
/* * 0.5.2 - 05/31/2000 - G.Juyn * */
/* * - fixed up punctuation (contribution by Tim Rowley) * */
/* * * */
/* * 0.5.3 - 06/16/2000 - G.Juyn * */
/* * - changed progressive-display processing * */
/* * * */
/* * 0.9.1 - 07/08/2000 - G.Juyn * */
/* * - changed read-processing for improved I/O-suspension * */
/* * 0.9.1 - 07/14/2000 - G.Juyn * */
/* * - changed EOF processing behavior * */
/* * 0.9.1 - 07/14/2000 - G.Juyn * */
/* * - changed default readbuffer size from 1024 to 4200 * */
/* * * */
/* * 0.9.2 - 07/27/2000 - G.Juyn * */
/* * - B110320 - fixed GCC warning about mix-sized pointer math * */
/* * 0.9.2 - 07/31/2000 - G.Juyn * */
/* * - B110546 - fixed for improperly returning UNEXPECTEDEOF * */
/* * 0.9.2 - 08/04/2000 - G.Juyn * */
/* * - B111096 - fixed large-buffer read-suspension * */
/* * 0.9.2 - 08/05/2000 - G.Juyn * */
/* * - changed file-prefixes * */
/* * * */
/* * 0.9.3 - 08/26/2000 - G.Juyn * */
/* * - added MAGN chunk * */
/* * 0.9.3 - 10/11/2000 - G.Juyn * */
/* * - removed test-MaGN * */
/* * 0.9.3 - 10/16/2000 - G.Juyn * */
/* * - added support for JDAA * */
/* * * */
/* * 0.9.5 - 01/23/2001 - G.Juyn * */
/* * - fixed timing-problem with switching framing_modes * */
/* * * */
/* * 1.0.4 - 06/22/2002 - G.Juyn * */
/* * - B495443 - incorrect suspend check in read_databuffer * */
/* * * */
/* * 1.0.5 - 07/04/2002 - G.Juyn * */
/* * - added errorcode for extreme chunk-sizes * */
/* * 1.0.5 - 07/08/2002 - G.Juyn * */
/* * - B578572 - removed eMNGma hack (thanks Dimitri!) * */
/* * 1.0.5 - 07/16/2002 - G.Juyn * */
/* * - B581625 - large chunks fail with suspension reads * */
/* * 1.0.5 - 08/19/2002 - G.Juyn * */
/* * - B597134 - libmng pollutes the linker namespace * */
/* * - added HLAPI function to copy chunks * */
/* * 1.0.5 - 09/16/2002 - G.Juyn * */
/* * - added event handling for dynamic MNG * */
/* * * */
/* * 1.0.6 - 05/25/2003 - G.R-P * */
/* * - added MNG_SKIPCHUNK_cHNK footprint optimizations * */
/* * 1.0.6 - 07/07/2003 - G.R-P * */
/* * - added MNG_NO_DELTA_PNG reduction * */
/* * - skip additional code when MNG_INCLUDE_JNG is not enabled * */
/* * 1.0.6 - 07/29/2003 - G.R-P * */
/* * - added conditionals around PAST chunk support * */
/* * 1.0.6 - 08/17/2003 - G.R-P * */
/* * - added conditionals around non-VLC chunk support * */
/* * * */
/* * 1.0.7 - 03/10/2004 - G.R-P * */
/* * - added conditionals around openstream/closestream * */
/* * * */
/* * 1.0.8 - 04/08/2004 - G.Juyn * */
/* * - added CRC existence & checking flags * */
/* * 1.0.8 - 04/11/2004 - G.Juyn * */
/* * - added data-push mechanisms for specialized decoders * */
/* * 1.0.8 - 07/06/2004 - G.R-P * */
/* * - defend against using undefined closestream function * */
/* * 1.0.8 - 07/28/2004 - G.R-P * */
/* * - added check for extreme chunk-lengths * */
/* * * */
/* ************************************************************************** */
#include "libmng.h"
#include "libmng_data.h"
#include "libmng_error.h"
#include "libmng_trace.h"
#ifdef __BORLANDC__
#pragma hdrstop
#endif
#include "libmng_memory.h"
#include "libmng_objects.h"
#include "libmng_object_prc.h"
#include "libmng_chunks.h"
#include "libmng_chunk_prc.h"
#include "libmng_chunk_io.h"
#include "libmng_display.h"
#include "libmng_read.h"
#if defined(__BORLANDC__) && defined(MNG_STRICT_ANSI)
#pragma option -A /* force ANSI-C */
#endif
/* ************************************************************************** */
#ifdef MNG_INCLUDE_READ_PROCS
/* ************************************************************************** */
mng_retcode mng_process_eof (mng_datap pData)
{
if (!pData->bEOF) /* haven't closed the stream yet ? */
{
pData->bEOF = MNG_TRUE; /* now we do! */
#ifndef MNG_NO_OPEN_CLOSE_STREAM
if (pData->fClosestream && !pData->fClosestream ((mng_handle)pData))
{
MNG_ERROR (pData, MNG_APPIOERROR)
}
#endif
}
return MNG_NOERROR;
}
/* ************************************************************************** */
mng_retcode mng_release_pushdata (mng_datap pData)
{
mng_pushdatap pFirst = pData->pFirstpushdata;
mng_pushdatap pNext = pFirst->pNext;
#ifdef MNG_SUPPORT_TRACE
MNG_TRACE (pData, MNG_FN_RELEASE_PUSHDATA, MNG_LC_START)
#endif
pData->pFirstpushdata = pNext; /* next becomes the first */
if (!pNext) /* no next? => no last! */
pData->pLastpushdata = MNG_NULL;
/* buffer owned and release callback defined? */
if ((pFirst->bOwned) && (pData->fReleasedata))
pData->fReleasedata ((mng_handle)pData, pFirst->pData, pFirst->iLength);
else /* otherwise use internal free mechanism */
MNG_FREEX (pData, pFirst->pData, pFirst->iLength)
/* and free it */
MNG_FREEX (pData, pFirst, sizeof(mng_pushdata))
#ifdef MNG_SUPPORT_TRACE
MNG_TRACE (pData, MNG_FN_RELEASE_PUSHDATA, MNG_LC_END)
#endif
return MNG_NOERROR;
}
/* ************************************************************************** */
mng_retcode mng_release_pushchunk (mng_datap pData)
{
mng_pushdatap pFirst = pData->pFirstpushchunk;
mng_pushdatap pNext = pFirst->pNext;
#ifdef MNG_SUPPORT_TRACE
MNG_TRACE (pData, MNG_FN_RELEASE_PUSHCHUNK, MNG_LC_START)
#endif
pData->pFirstpushchunk = pNext; /* next becomes the first */
if (!pNext) /* no next? => no last! */
pData->pLastpushchunk = MNG_NULL;
/* buffer owned and release callback defined? */
if ((pFirst->bOwned) && (pData->fReleasedata))
pData->fReleasedata ((mng_handle)pData, pFirst->pData, pFirst->iLength);
else /* otherwise use internal free mechanism */
MNG_FREEX (pData, pFirst->pData, pFirst->iLength)
/* and free it */
MNG_FREEX (pData, pFirst, sizeof(mng_pushdata))
#ifdef MNG_SUPPORT_TRACE
MNG_TRACE (pData, MNG_FN_RELEASE_PUSHCHUNK, MNG_LC_END)
#endif
return MNG_NOERROR;
}
/* ************************************************************************** */
MNG_LOCAL mng_retcode read_data (mng_datap pData,
mng_uint8p pBuf,
mng_uint32 iSize,
mng_uint32 * iRead)
{
mng_retcode iRetcode;
mng_uint32 iTempsize = iSize;
mng_uint8p pTempbuf = pBuf;
mng_pushdatap pPush = pData->pFirstpushdata;
mng_uint32 iPushsize = 0;
*iRead = 0; /* nothing yet */
#ifdef MNG_SUPPORT_TRACE
MNG_TRACE (pData, MNG_FN_READ_DATA, MNG_LC_START)
#endif
while (pPush) /* calculate size of pushed data */
{
iPushsize += pPush->iRemaining;
pPush = pPush->pNext;
}
if (iTempsize <= iPushsize) /* got enough push data? */
{
while (iTempsize)
{
pPush = pData->pFirstpushdata;
/* enough data remaining in this buffer? */
if (pPush->iRemaining <= iTempsize)
{ /* no: then copy what we've got */
MNG_COPY (pTempbuf, pPush->pDatanext, pPush->iRemaining)
/* move pointers & lengths */
pTempbuf += pPush->iRemaining;
*iRead += pPush->iRemaining;
iTempsize -= pPush->iRemaining;
/* release the depleted buffer */
iRetcode = mng_release_pushdata (pData);
if (iRetcode)
return iRetcode;
}
else
{ /* copy the needed bytes */
MNG_COPY (pTempbuf, pPush->pDatanext, iTempsize)
/* move pointers & lengths */
pPush->iRemaining -= iTempsize;
pPush->pDatanext += iTempsize;
pTempbuf += iTempsize;
*iRead += iTempsize;
iTempsize = 0; /* all done!!! */
}
}
}
else
{
mng_uint32 iTempread = 0;
/* get it from the app then */
if (!pData->fReaddata (((mng_handle)pData), pTempbuf, iTempsize, &iTempread))
MNG_ERROR (pData, MNG_APPIOERROR);
*iRead += iTempread;
}
#ifdef MNG_SUPPORT_TRACE
MNG_TRACE (pData, MNG_FN_READ_DATA, MNG_LC_END)
#endif
return MNG_NOERROR;
}
⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -