/* ************************************************************************** */ /* * For conditions of distribution and use, * */ /* * see copyright notice in libmng.h * */ /* ************************************************************************** */ /* * * */ /* * project : libmng * */ /* * file : libmng_read.c copyright (c) 2000 G.Juyn * */ /* * version : 1.0.4 * */ /* * * */ /* * purpose : Read logic (implementation) * */ /* * * */ /* * author : G.Juyn * */ /* * web : http://www.3-t.com * */ /* * email : mailto:info@3-t.com * */ /* * * */ /* * 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 * */ /* * * */ /* ************************************************************************** */ #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 process_eof (mng_datap pData) { if (!pData->bEOF) /* haven't closed the stream yet ? */ { pData->bEOF = MNG_TRUE; /* now we do! */ if (!pData->fClosestream ((mng_handle)pData)) MNG_ERROR (pData, MNG_APPIOERROR) } return MNG_NOERROR; } /* ************************************************************************** */ mng_retcode read_databuffer (mng_datap pData, mng_uint8p pBuf, mng_uint32 iSize, mng_uint32 * iRead) { #ifdef MNG_SUPPORT_TRACE MNG_TRACE (pData, MNG_FN_READ_DATABUFFER, MNG_LC_START) #endif if (pData->bSuspensionmode) { mng_uint8p pTemp; mng_uint32 iTemp; *iRead = 0; /* let's be negative about the outcome */ if (!pData->pSuspendbuf) /* need to create a suspension buffer ? */ { pData->iSuspendbufsize = MNG_SUSPENDBUFFERSIZE; /* so, create it */ MNG_ALLOC (pData, pData->pSuspendbuf, pData->iSuspendbufsize) pData->iSuspendbufleft = 0; /* make sure to fill it first time */ pData->pSuspendbufnext = pData->pSuspendbuf; } /* more than our buffer can hold ? */ if (iSize > pData->iSuspendbufsize) { mng_uint32 iRemain; if (!pData->pReadbufnext) /* first time ? */ { if (pData->iSuspendbufleft) /* do we have some data left ? */ { /* then copy it */ MNG_COPY (pBuf, pData->pSuspendbufnext, pData->iSuspendbufleft) /* fixup variables */ pData->pReadbufnext = pBuf + pData->iSuspendbufleft; pData->pSuspendbufnext = pData->pSuspendbuf; pData->iSuspendbufleft = 0; } else { pData->pReadbufnext = pBuf; } } /* calculate how much to get */ iRemain = iSize - (mng_uint32)(pData->pReadbufnext - pBuf); /* let's go get it */ if (!pData->fReaddata (((mng_handle)pData), pData->pReadbufnext, iRemain, &iTemp)) MNG_ERROR (pData, MNG_APPIOERROR); /* first read after suspension return 0 means EOF */ if ((pData->iSuspendpoint) && (iTemp == 0)) { /* that makes it final */ mng_retcode iRetcode = process_eof (pData); if (iRetcode) /* on error bail out */ return iRetcode; /* indicate the source is depleted */ *iRead = iSize - iRemain + iTemp; } else { if (iTemp < iRemain) /* suspension required ? */ { pData->pReadbufnext = pData->pReadbufnext + iTemp; pData->bSuspended = MNG_TRUE; } else { *iRead = iSize; /* got it all now ! */ } } } else { /* need to read some more ? */ while ((!pData->bSuspended) && (!pData->bEOF) && (iSize > pData->iSuspendbufleft)) { /* not enough space left in buffer ? */ if (pData->iSuspendbufsize - pData->iSuspendbufleft - (mng_uint32)(pData->pSuspendbufnext - pData->pSuspendbuf) < MNG_SUSPENDREQUESTSIZE) { if (pData->iSuspendbufleft) /* then lets shift (if there's anything left) */ MNG_COPY (pData->pSuspendbuf, pData->pSuspendbufnext, pData->iSuspendbufleft) /* adjust running pointer */ pData->pSuspendbufnext = pData->pSuspendbuf; } /* still not enough room ? */ if (pData->iSuspendbufsize - pData->iSuspendbufleft < MNG_SUSPENDREQUESTSIZE) MNG_ERROR (pData, MNG_INTERNALERROR) /* now read some more data */ pTemp = pData->pSuspendbufnext + pData->iSuspendbufleft; if (!pData->fReaddata (((mng_handle)pData), pTemp, MNG_SUSPENDREQUESTSIZE, &iTemp)) MNG_ERROR (pData, MNG_APPIOERROR); /* adjust fill-counter */ pData->iSuspendbufleft += iTemp; /* first read after suspension returning 0 means EOF */ if ((pData->iSuspendpoint) && (iTemp == 0)) { /* that makes it final */ mng_retcode iRetcode = process_eof (pData); if (iRetcode) /* on error bail out */ return iRetcode; if (pData->iSuspendbufleft) /* return the leftover scraps */ MNG_COPY (pBuf, pData->pSuspendbufnext, pData->iSuspendbufleft) /* and indicate so */ *iRead = pData->iSuspendbufleft; pData->pSuspendbufnext = pData->pSuspendbuf; pData->iSuspendbufleft = 0; } else { /* suspension required ? */ if ((iSize > pData->iSuspendbufleft) && (iTemp < MNG_SUSPENDREQUESTSIZE)) pData->bSuspended = MNG_TRUE; } pData->iSuspendpoint = 0; /* reset it here in case we loop back */ } if ((!pData->bSuspended) && (!pData->bEOF)) { /* return the data ! */ MNG_COPY (pBuf, pData->pSuspendbufnext, iSize) *iRead = iSize; /* returned it all */ /* adjust suspension-buffer variables */ pData->pSuspendbufnext += iSize; pData->iSuspendbufleft -= iSize; } } } else { if (!pData->fReaddata (((mng_handle)pData), (mng_ptr)pBuf, iSize, iRead)) { if (*iRead == 0) /* suspension required ? */ pData->bSuspended = MNG_TRUE; else MNG_ERROR (pData, MNG_APPIOERROR); } } pData->iSuspendpoint = 0; /* safely reset it here ! */ #ifdef MNG_SUPPORT_TRACE MNG_TRACE (pData, MNG_FN_READ_DATABUFFER, MNG_LC_END) #endif return MNG_NOERROR; } /* ************************************************************************** */ mng_retcode process_raw_chunk (mng_datap pData, mng_uint8p pBuf, mng_uint32 iBuflen) { /* the table-idea & binary search code was adapted from libpng 1.1.0 (pngread.c) */ /* NOTE1: the table must remain sorted by chunkname, otherwise the binary search will break !!! */ /* NOTE2: the layout must remain equal to the header part of all the chunk-structures (yes, that means even the pNext and pPrev fields; it's wasting a bit of space, but hey, the code is a lot easier) */ mng_chunk_header chunk_unknown = {MNG_UINT_HUH, init_unknown, free_unknown, read_unknown, write_unknown, 0, 0}; mng_chunk_header chunk_table [] = { {MNG_UINT_BACK, init_back, free_back, read_back, write_back, 0, 0}, {MNG_UINT_BASI, init_basi, free_basi, read_basi, write_basi, 0, 0}, {MNG_UINT_CLIP, init_clip, free_clip, read_clip, write_clip, 0, 0}, {MNG_UINT_CLON, init_clon, free_clon, read_clon, write_clon, 0, 0}, {MNG_UINT_DBYK, init_dbyk, free_dbyk, read_dbyk, write_dbyk, 0, 0}, {MNG_UINT_DEFI, init_defi, free_defi, read_defi, write_defi, 0, 0}, {MNG_UINT_DHDR, init_dhdr, free_dhdr, read_dhdr, write_dhdr, 0, 0}, {MNG_UINT_DISC, init_disc, free_disc, read_disc, write_disc, 0, 0}, {MNG_UINT_DROP, init_drop, free_drop, read_drop, write_drop, 0, 0}, {MNG_UINT_ENDL, init_endl, free_endl, read_endl, write_endl, 0, 0}, {MNG_UINT_FRAM, init_fram, free_fram, read_fram, write_fram, 0, 0}, {MNG_UINT_IDAT, init_idat, free_idat, read_idat, write_idat, 0, 0}, /* 12-th element! */ {MNG_UINT_IEND, init_iend, free_iend, read_iend, write_iend, 0, 0}, {MNG_UINT_IHDR, init_ihdr, free_ihdr, read_ihdr, write_ihdr, 0, 0}, {MNG_UINT_IJNG, init_ijng, free_ijng, read_ijng, write_ijng, 0, 0}, {MNG_UINT_IPNG, init_ipng, free_ipng, read_ipng, write_ipng, 0, 0}, #ifdef MNG_INCLUDE_JNG {MNG_UINT_JDAA, init_jdaa, free_jdaa, read_jdaa, write_jdaa, 0, 0}, {MNG_UINT_JDAT, init_jdat, free_jdat, read_jdat, write_jdat, 0, 0}, {MNG_UINT_JHDR, init_jhdr, free_jhdr, read_jhdr, write_jhdr, 0, 0}, {MNG_UINT_JSEP, init_jsep, free_jsep, read_jsep, write_jsep, 0, 0}, {MNG_UINT_JdAA, init_jdaa, free_jdaa, read_jdaa, write_jdaa, 0, 0}, #endif {MNG_UINT_LOOP, init_loop, free_loop, read_loop, write_loop, 0, 0}, {MNG_UINT_MAGN, init_magn, free_magn, read_magn, write_magn, 0, 0}, {MNG_UINT_MEND, init_mend, free_mend, read_mend, write_mend, 0, 0}, {MNG_UINT_MHDR, init_mhdr, free_mhdr, read_mhdr, write_mhdr, 0, 0}, {MNG_UINT_MOVE, init_move, free_move, read_move, write_move, 0, 0}, {MNG_UINT_ORDR, init_ordr, free_ordr, read_ordr, write_ordr, 0, 0}, {MNG_UINT_PAST, init_past, free_past, read_past, write_past, 0, 0}, {MNG_UINT_PLTE, init_plte, free_plte, read_plte, write_plte, 0, 0}, {MNG_UINT_PPLT, init_pplt, free_pplt, read_pplt, write_pplt, 0, 0}, {MNG_UINT_PROM, init_prom, free_prom, read_prom, write_prom, 0, 0}, {MNG_UINT_SAVE, init_save, free_save, read_save, write_save, 0, 0}, {MNG_UINT_SEEK, init_seek, free_seek, read_seek, write_seek, 0, 0}, {MNG_UINT_SHOW, init_show, free_show, read_show, write_show, 0, 0}, {MNG_UINT_TERM, init_term, free_term, read_term, write_term, 0, 0}, {MNG_UINT_bKGD, init_bkgd, free_bkgd, read_bkgd, write_bkgd, 0, 0}, {MNG_UINT_cHRM, init_chrm, free_chrm, read_chrm, write_chrm, 0, 0}, {MNG_UINT_eXPI, init_expi, free_expi, read_expi, write_expi, 0, 0}, {MNG_UINT_fPRI, init_fpri, free_fpri, read_fpri, write_fpri, 0, 0}, {MNG_UINT_gAMA, init_gama, free_gama, read_gama, write_gama, 0, 0}, {MNG_UINT_hIST, init_hist, free_hist, read_hist, write_hist, 0, 0}, {MNG_UINT_iCCP, init_iccp, free_iccp, read_iccp, write_iccp, 0, 0}, {MNG_UINT_iTXt, init_itxt, free_itxt, read_itxt, write_itxt, 0, 0}, {MNG_UINT_nEED, init_need, free_need, read_need, write_need, 0, 0}, /* TODO: {MNG_UINT_oFFs, 0, 0, 0, 0, 0, 0}, */ /* TODO: {MNG_UINT_pCAL, 0, 0, 0, 0, 0, 0}, */ {MNG_UINT_pHYg, init_phyg, free_phyg, read_phyg, write_phyg, 0, 0}, {MNG_UINT_pHYs, init_phys, free_phys, read_phys, write_phys, 0, 0}, {MNG_UINT_sBIT, init_sbit, free_sbit, read_sbit, write_sbit, 0, 0}, /* TODO: {MNG_UINT_sCAL, 0, 0, 0, 0, 0, 0}, */ {MNG_UINT_sPLT, init_splt, free_splt, read_splt, write_splt, 0, 0}, {MNG_UINT_sRGB, init_srgb, free_srgb, read_srgb, write_srgb, 0, 0}, {MNG_UINT_tEXt, init_text, free_text, read_text, write_text, 0, 0}, {MNG_UINT_tIME, init_time, free_time, read_time, write_time, 0, 0}, {MNG_UINT_tRNS, init_trns, free_trns, read_trns, write_trns, 0, 0}, {MNG_UINT_zTXt, init_ztxt, free_ztxt, read_ztxt, write_ztxt, 0, 0}, }; /* binary search variables */ mng_int32 iTop, iLower, iUpper, iMiddle; mng_chunk_headerp pEntry; /* pointer to found entry */ mng_chunkid iChunkname; /* the chunk's tag */ mng_chunkp pChunk; /* chunk structure (if #define MNG_STORE_CHUNKS) */ mng_retcode iRetcode; /* temporary error-code */ #ifdef MNG_SUPPORT_TRACE MNG_TRACE (pData, MNG_FN_PROCESS_RAW_CHUNK, MNG_LC_START) #endif /* get the chunkname */ iChunkname = (mng_chunkid)(mng_get_uint32 (pBuf)); pBuf += sizeof (mng_chunkid); /* adjust the buffer */ iBuflen -= sizeof (mng_chunkid); /* determine max index of table */ iTop = (sizeof (chunk_table) / sizeof (chunk_table [0])) - 1; /* binary search; with 52 chunks, worst-case is 7 comparisons */ iLower = 0; iMiddle = 11; /* start with the IDAT entry */ iUpper = iTop; pEntry = 0; /* no goods yet! */ pChunk = 0; do /* the binary search itself */ { if (chunk_table [iMiddle].iChunkname < iChunkname) iLower = iMiddle + 1; else if (chunk_table [iMiddle].iChunkname > iChunkname) iUpper = iMiddle - 1; else { pEntry = &chunk_table [iMiddle]; break; } iMiddle = (iLower + iUpper) >> 1; } while (iLower <= iUpper); if (!pEntry) /* unknown chunk ? */ pEntry = &chunk_unknown; /* make it so! */ pData->iChunkname = iChunkname; /* keep track of where we are */ pData->iChunkseq++; if (pEntry->fRead) /* read-callback available ? */ { iRetcode = pEntry->fRead (pData, pEntry, iBuflen, (mng_ptr)pBuf, &pChunk); if (!iRetcode) /* everything oke ? */ { /* remember unknown chunk's id */ if ((pChunk) && (pEntry == &chunk_unknown)) ((mng_chunk_headerp)pChunk)->iChunkname = iChunkname; } } else iRetcode = MNG_NOERROR; if (pChunk) /* store this chunk ? */ add_chunk (pData, pChunk); /* do it */ #ifdef MNG_INCLUDE_JNG /* implicit EOF ? */ if ((!pData->bHasMHDR) && (!pData->bHasIHDR) && (!pData->bHasJHDR)) #else if ((!pData->bHasMHDR) && (!pData->bHasIHDR)) #endif iRetcode = process_eof (pData); /* then do some EOF processing */ if (iRetcode) /* on error bail out */ return iRetcode; #ifdef MNG_SUPPORT_TRACE MNG_TRACE (pData, MNG_FN_PROCESS_RAW_CHUNK, MNG_LC_END) #endif return MNG_NOERROR; } /* ************************************************************************** */ mng_retcode read_chunk (mng_datap pData) { mng_uint32 iBufmax = pData->iReadbufsize; mng_uint8p pBuf = pData->pReadbuf; mng_uint32 iBuflen = 0; /* number of bytes requested */ mng_uint32 iRead = 0; /* number of bytes read */ mng_uint32 iCrc; /* calculated CRC */ mng_retcode iRetcode = MNG_NOERROR; #ifdef MNG_SUPPORT_TRACE MNG_TRACE (pData, MNG_FN_READ_CHUNK, MNG_LC_START) #endif #ifdef MNG_SUPPORT_DISPLAY if (pData->pCurraniobj) /* processing an animation object ? */ { do /* process it then */ { iRetcode = ((mng_object_headerp)pData->pCurraniobj)->fProcess (pData, pData->pCurraniobj); /* refresh needed ? */ /* if ((!iRetcode) && (!pData->bTimerset) && (pData->bNeedrefresh)) iRetcode = display_progressive_refresh (pData, 1); */ /* can we advance to next object ? */ if ((!iRetcode) && (pData->pCurraniobj) && (!pData->bTimerset) && (!pData->bSectionwait)) { pData->pCurraniobj = ((mng_object_headerp)pData->pCurraniobj)->pNext; /* TERM processing to be done ? */ if ((!pData->pCurraniobj) && (pData->bHasTERM) && (!pData->bHasMHDR)) iRetcode = process_display_mend (pData); } } /* until error or a break or no more objects */ while ((!iRetcode) && (pData->pCurraniobj) && (!pData->bTimerset) && (!pData->bSectionwait) && (!pData->bFreezing)); } else { if (pData->iBreakpoint) /* do we need to finish something first ? */ { switch (pData->iBreakpoint) /* return to broken display routine */ { case 1 : { iRetcode = process_display_fram2 (pData); break; } case 2 : { iRetcode = process_display_ihdr (pData); break; } case 3 : ; /* same as 4 !!! */ case 4 : { iRetcode = process_display_show (pData); break; } case 5 : { iRetcode = process_display_clon2 (pData); break; } #ifdef MNG_INCLUDE_JNG case 7 : { iRetcode = process_display_jhdr (pData); break; } #endif case 6 : ; /* same as 8 !!! */ case 8 : { iRetcode = process_display_iend (pData); break; } case 9 : { iRetcode = process_display_magn2 (pData); break; } } } } if (iRetcode) /* on error bail out */ return iRetcode; #endif /* MNG_SUPPORT_DISPLAY */ /* can we continue processing now, or do we */ /* need to wait for the timer to finish (again) ? */ #ifdef MNG_SUPPORT_DISPLAY if ((!pData->bTimerset) && (!pData->bSectionwait) && (!pData->bEOF)) #else if (!pData->bEOF) #endif { /* freezing in progress ? */ if ((pData->bFreezing) && (pData->iSuspendpoint == 0)) pData->bRunning = MNG_FALSE; /* then this is the right moment to do it */ if (pData->iSuspendpoint <= 2) { iBuflen = sizeof (mng_uint32); /* read length */ iRetcode = read_databuffer (pData, pBuf, iBuflen, &iRead); if (iRetcode) /* bail on errors */ return iRetcode; if (pData->bSuspended) /* suspended ? */ pData->iSuspendpoint = 2; else /* save the length */ pData->iChunklen = mng_get_uint32 (pBuf); } if (!pData->bSuspended) /* still going ? */ { /* previously suspended or not eof ? */ if ((pData->iSuspendpoint > 2) || (iRead == iBuflen)) { /* determine length chunkname + data + crc */ iBuflen = pData->iChunklen + (mng_uint32)(sizeof (mng_chunkid) + sizeof (iCrc)); if (iBuflen < iBufmax) /* does it fit in default buffer ? */ { /* note that we don't use the full size so there's always a zero-byte at the very end !!! */ iRetcode = read_databuffer (pData, pBuf, iBuflen, &iRead); if (iRetcode) /* bail on errors */ return iRetcode; if (pData->bSuspended) /* suspended ? */ pData->iSuspendpoint = 3; else { if (iRead != iBuflen) /* did we get all the data ? */ iRetcode = MNG_UNEXPECTEDEOF; else { mng_uint32 iL = iBuflen - (mng_uint32)(sizeof (iCrc)); /* calculate the crc */ iCrc = crc (pData, pBuf, iL); /* and check it */ if (!(iCrc == mng_get_uint32 (pBuf + iL))) iRetcode = MNG_INVALIDCRC; else iRetcode = process_raw_chunk (pData, pBuf, iL); } } } else { if (!pData->iSuspendpoint) /* create additional large buffer ? */ { /* again reserve space for the last zero-byte */ pData->iLargebufsize = iBuflen + 1; MNG_ALLOC (pData, pData->pLargebuf, pData->iLargebufsize) } iRetcode = read_databuffer (pData, pData->pLargebuf, iBuflen, &iRead); if (iRetcode) return iRetcode; if (pData->bSuspended) /* suspended ? */ pData->iSuspendpoint = 4; else { if (iRead != iBuflen) /* did we get all the data ? */ iRetcode = MNG_UNEXPECTEDEOF; else { mng_uint32 iL = iBuflen - (mng_uint32)(sizeof (iCrc)); /* calculate the crc */ iCrc = crc (pData, pData->pLargebuf, iL); /* and check it */ if (!(iCrc == mng_get_uint32 (pData->pLargebuf + iL))) iRetcode = MNG_INVALIDCRC; else iRetcode = process_raw_chunk (pData, pData->pLargebuf, iL); } /* cleanup additional large buffer */ MNG_FREE (pData, pData->pLargebuf, pData->iLargebufsize) } } if (iRetcode) /* on error bail out */ return iRetcode; } else { /* that's final */ iRetcode = process_eof (pData); if (iRetcode) /* on error bail out */ return iRetcode; if ((iRead != 0) || /* did we get an unexpected eof ? */ #ifdef MNG_INCLUDE_JNG (pData->bHasIHDR || pData->bHasMHDR || pData->bHasJHDR)) #else (pData->bHasIHDR || pData->bHasMHDR)) #endif MNG_ERROR (pData, MNG_UNEXPECTEDEOF); } } } #ifdef MNG_SUPPORT_DISPLAY /* refresh needed ? */ if ((!pData->bTimerset) && (!pData->bSuspended) && (pData->bNeedrefresh)) { iRetcode = display_progressive_refresh (pData, 1); if (iRetcode) /* on error bail out */ return iRetcode; } #endif #ifdef MNG_SUPPORT_TRACE MNG_TRACE (pData, MNG_FN_READ_CHUNK, MNG_LC_END) #endif return MNG_NOERROR; } /* ************************************************************************** */ mng_retcode read_graphic (mng_datap pData) { mng_uint32 iBuflen; /* number of bytes requested */ mng_uint32 iRead; /* number of bytes read */ mng_retcode iRetcode; /* temporary error-code */ #ifdef MNG_SUPPORT_TRACE MNG_TRACE (pData, MNG_FN_READ_GRAPHIC, MNG_LC_START) #endif if (!pData->pReadbuf) /* buffer allocated ? */ { pData->iReadbufsize = 4200; /* allocate a default read buffer */ MNG_ALLOC (pData, pData->pReadbuf, pData->iReadbufsize) } /* haven't processed the signature ? */ if ((!pData->bHavesig) || (pData->iSuspendpoint == 1)) { iBuflen = 2 * sizeof (mng_uint32); /* read signature */ iRetcode = read_databuffer (pData, pData->pReadbuf, iBuflen, &iRead); if (iRetcode) return iRetcode; if (pData->bSuspended) /* input suspension ? */ pData->iSuspendpoint = 1; else { if (iRead != iBuflen) /* full signature received ? */ MNG_ERROR (pData, MNG_UNEXPECTEDEOF); /* is it a valid signature ? */ if (mng_get_uint32 (pData->pReadbuf) == PNG_SIG) pData->eSigtype = mng_it_png; else if (mng_get_uint32 (pData->pReadbuf) == JNG_SIG) pData->eSigtype = mng_it_jng; else if (mng_get_uint32 (pData->pReadbuf) == MNG_SIG) pData->eSigtype = mng_it_mng; else MNG_ERROR (pData, MNG_INVALIDSIG); /* all of it ? */ if (mng_get_uint32 (pData->pReadbuf+4) != POST_SIG) MNG_ERROR (pData, MNG_INVALIDSIG); pData->bHavesig = MNG_TRUE; } } if (!pData->bSuspended) /* still going ? */ { do { iRetcode = read_chunk (pData); /* process a chunk */ if (iRetcode) /* on error bail out */ return iRetcode; } #ifdef MNG_SUPPORT_DISPLAY /* until EOF or a break-request */ while (((!pData->bEOF) || (pData->pCurraniobj)) && (!pData->bSuspended) && (!pData->bTimerset) && (!pData->bSectionwait)); #else while ((!pData->bEOF) && (!pData->bSuspended)); #endif } #ifdef MNG_SUPPORT_TRACE MNG_TRACE (pData, MNG_FN_READ_GRAPHIC, MNG_LC_END) #endif return MNG_NOERROR; } /* ************************************************************************** */ #endif /* MNG_INCLUDE_READ_PROCS */ /* ************************************************************************** */ /* * end of file * */ /* ************************************************************************** */