diff options
Diffstat (limited to 'converter/other/giftopnm.c')
| -rw-r--r-- | converter/other/giftopnm.c | 731 |
1 files changed, 496 insertions, 235 deletions
diff --git a/converter/other/giftopnm.c b/converter/other/giftopnm.c index 7337960c..4b8b0487 100644 --- a/converter/other/giftopnm.c +++ b/converter/other/giftopnm.c @@ -23,10 +23,11 @@ #include <string.h> #include <assert.h> -#include "pnm.h" -#include "shhopt.h" +#include "pm_c_util.h" #include "mallocvar.h" #include "nstring.h" +#include "shhopt.h" +#include "pnm.h" #define GIFMAXVAL 255 #define MAXCOLORMAPSIZE 256 @@ -41,6 +42,13 @@ #define LOCALCOLORMAP 0x80 #define BitSet(byte, bit) (((byte) & (bit)) == (bit)) +#if !defined(BYTE_ORDER) || !defined(LITTLE_ENDIAN) + /* make sure (BYTE_ORDER == LITTLE_ENDIAN) is FALSE */ + #define BYTE_ORDER 0 + #define LITTLE_ENDIAN 1 +#endif + + static __inline__ bool ReadOK(FILE * const fileP, unsigned char * const buffer, @@ -54,6 +62,33 @@ ReadOK(FILE * const fileP, } + +static void +readFile(FILE * const ifP, + unsigned char * const buffer, + size_t const len, + const char ** const errorP) { + + size_t bytesRead; + + bytesRead = fread(buffer, len, 1, ifP); + + if (bytesRead == len) + *errorP = NULL; + else { + if (ferror(ifP)) + asprintfN(errorP, "Error reading file. errno=%d (%s)", + errno, strerror(errno)); + else if (feof(ifP)) + asprintfN(errorP, "End of file encountered"); + else + asprintfN(errorP, "Short read -- %u bytes of %u", + (unsigned)bytesRead, (unsigned)len); + } +} + + + #define LM_to_uint(a,b) (((b)<<8)|(a)) static int const maxnum_lzwCode = (1<<MAX_LZW_BITS); @@ -72,6 +107,7 @@ struct cmdlineInfo { */ const char * alpha_filename; unsigned int quitearly; + unsigned int repair; }; @@ -101,8 +137,10 @@ parseCommandLine(int argc, char ** argv, &cmdlineP->verbose, 0); OPTENT3(0, "comments", OPT_FLAG, NULL, &cmdlineP->comments, 0); - OPTENT3(0, "quitearly", OPT_FLAG, NULL, + OPTENT3(0, "quitearly", OPT_FLAG, NULL, &cmdlineP->quitearly, 0); + OPTENT3(0, "repair", OPT_FLAG, NULL, + &cmdlineP->repair, 0); OPTENT3(0, "image", OPT_STRING, &image, &imageSpec, 0); OPTENT3(0, "alphaout", OPT_STRING, &cmdlineP->alpha_filename, @@ -232,13 +270,15 @@ readColorMap(FILE *ifP, const int colormapsize, static bool zeroDataBlock = FALSE; /* the most recently read DataBlock was an EOD marker, i.e. had - zero length */ + zero length + */ static void getDataBlock(FILE * const ifP, unsigned char * const buf, bool * const eofP, - unsigned int * const lengthP) { + unsigned int * const lengthP, + const char ** const errorP) { /*---------------------------------------------------------------------------- Read a DataBlock from file 'ifP', return it at 'buf'. @@ -258,10 +298,11 @@ getDataBlock(FILE * const ifP, unsigned char count; bool successfulRead; - long const pos=ftell(ifP); + long const pos = ftell(ifP); successfulRead = ReadOK(ifP, &count, 1); if (!successfulRead) { pm_message("EOF or error in reading DataBlock size from file" ); + *errorP = NULL; *eofP = TRUE; *lengthP = 0; } else { @@ -270,17 +311,21 @@ getDataBlock(FILE * const ifP, *eofP = FALSE; *lengthP = count; - if (count == 0) + if (count == 0) { + *errorP = NULL; zeroDataBlock = TRUE; - else { + } else { bool successfulRead; zeroDataBlock = FALSE; successfulRead = ReadOK(ifP, buf, count); - - if (!successfulRead) - pm_error("EOF or error reading data portion of %d byte " - "DataBlock from file", count); + + if (successfulRead) + *errorP = NULL; + else + asprintfN(errorP, + "EOF or error reading data portion of %u byte " + "DataBlock from file", count); } } } @@ -303,14 +348,15 @@ readThroughEod(FILE * const ifP) { while (!eod) { bool eof; unsigned int count; + const char * error; - getDataBlock(ifP, buf, &eof, &count); - if (eof) + getDataBlock(ifP, buf, &eof, &count, &error); + if (error || eof) pm_message("EOF encountered before EOD marker. The GIF " "file is malformed, but we are proceeding " "anyway as if an EOD marker were at the end " "of the file."); - if (eof || count == 0) + if (error || eof || count == 0) eod = TRUE; } } @@ -334,7 +380,11 @@ doCommentExtension(FILE * const ifP) { done = FALSE; while (!done) { bool eof; - getDataBlock(ifP, (unsigned char*) buf, &eof, &blocklen); + const char * error; + getDataBlock(ifP, (unsigned char*) buf, &eof, &blocklen, &error); + if (error) + pm_error("Error reading a data block in a comment extension. %s", + error); if (blocklen == 0 || eof) done = TRUE; else { @@ -355,8 +405,11 @@ doGraphicControlExtension(FILE * const ifP, bool eof; unsigned int length; static unsigned char buf[256]; + const char * error; - getDataBlock(ifP, buf, &eof, &length); + getDataBlock(ifP, buf, &eof, &length, &error); + if (error) + pm_error("Error reading 1st data block of Graphic Control Extension"); if (eof) pm_error("EOF/error encountered reading " "1st DataBlock of Graphic Control Extension."); @@ -451,28 +504,16 @@ struct getCodeState { */ bool streamExhausted; /* The last time we read from the input stream, we got an EOD marker - or EOF + or EOF or an error that prevents further reading of the stream. */ }; static void -initGetCode(struct getCodeState * const getCodeStateP) { - - /* Fake a previous data block */ - getCodeStateP->buf[0] = 0; - getCodeStateP->buf[1] = 0; - getCodeStateP->bufCount = 2; - getCodeStateP->curbit = getCodeStateP->bufCount * 8; - getCodeStateP->streamExhausted = FALSE; -} - - - -static void -getAnotherBlock(FILE * const ifP, - struct getCodeState * const gsP) { +getAnotherBlock(FILE * const ifP, + struct getCodeState * const gsP, + const char ** const errorP) { unsigned int count; unsigned int assumed_count; @@ -490,98 +531,145 @@ getAnotherBlock(FILE * const ifP, gsP->bufCount = 2; /* Add the next block to the buffer */ - getDataBlock(ifP, &gsP->buf[gsP->bufCount], &eof, &count); - if (eof) { - pm_message("EOF encountered in image " - "before EOD marker. The GIF " - "file is malformed, but we are proceeding " - "anyway as if an EOD marker were at the end " - "of the file."); - assumed_count = 0; - } else - assumed_count = count; - - gsP->streamExhausted = (assumed_count == 0); + getDataBlock(ifP, &gsP->buf[gsP->bufCount], &eof, &count, errorP); + if (*errorP) + gsP->streamExhausted = TRUE; + else { + if (eof) { + pm_message("EOF encountered in image " + "before EOD marker. The GIF " + "file is malformed, but we are proceeding " + "anyway as if an EOD marker were at the end " + "of the file."); + assumed_count = 0; + } else + assumed_count = count; - gsP->bufCount += assumed_count; + gsP->streamExhausted = (assumed_count == 0); + + gsP->bufCount += assumed_count; + } } +static struct getCodeState getCodeState; + static void -doGetCode(FILE * const ifP, - int const codeSize, - struct getCodeState * const gsP, - int * const retvalP) { +getCode_init(struct getCodeState * const getCodeStateP) { + + /* Fake a previous data block */ + getCodeStateP->buf[0] = 0; + getCodeStateP->buf[1] = 0; + getCodeStateP->bufCount = 2; + getCodeStateP->curbit = getCodeStateP->bufCount * 8; + getCodeStateP->streamExhausted = FALSE; +} - while (gsP->curbit + codeSize > gsP->bufCount * 8 && - !gsP->streamExhausted) - /* Not enough left in buffer to satisfy request. Get the next - data block into the buffer. - Note that a data block may be as small as one byte, so we may need - to do this multiple times to get the full code. (This probably - never happens in practice). - */ - getAnotherBlock(ifP, gsP); - if ((gsP->curbit+codeSize) > gsP->bufCount*8) { - /* If the buffer still doesn't have enough bits in it, that means - there were no data blocks left to read. +static unsigned int +bitsOfLeBuffer(const unsigned char * const buf, + unsigned int const start, + unsigned int const len) { +/*---------------------------------------------------------------------------- + Return a string of 'len' bits (up to 16) starting at bit 'start' of buffer + buf[]. + + In the buffer, the bits are numbered Intel-style, with the first bit of a + byte being the least significant bit. So bit 3 is the "16" bit of the + first byte of buf[]. + + We return the string as an integer such that its pure binary encoding with + the bits numbered Intel-style is the string. E.g. the string 0,1,1 + yields six. +-----------------------------------------------------------------------------*/ + uint32_t codeBlock; + /* The 3 whole bytes of the buffer that contain the requested + bit string */ - *retvalP = -1; /* EOF */ - - { - int const bitsUnused = gsP->bufCount*8 - gsP->curbit; - if (bitsUnused > 0) - pm_message("Stream ends with a partial code " - "(%d bits left in file; " - "expected a %d bit code). Ignoring.", - bitsUnused, codeSize); - } - } else { - int i, j; - int code; - unsigned char * const buf = gsP->buf; - - code = 0; /* initial value */ - for (i = gsP->curbit, j = 0; j < codeSize; ++i, ++j) - code |= ((buf[ i / 8 ] & (1 << (i % 8))) != 0) << j; - gsP->curbit += codeSize; - *retvalP = code; - } + + assert(len <= 16); + + if (BYTE_ORDER == LITTLE_ENDIAN) + /* Fast path */ + codeBlock = *(uint32_t *) & buf[start/8]; + else + /* logic works for little endian too */ + codeBlock = + (buf[start/8+0] << 0) | + (buf[start/8+1] << 8) | + (buf[start/8+2] << 16); + + return (unsigned int) + (codeBlock >> (start % 8)) & ((1 << len) - 1); } -static int -getCode(FILE * const ifP, - int const codeSize, - bool const init) -{ +static void +getCode_get(struct getCodeState * const gsP, + FILE * const ifP, + int const codeSize, + bool * const eofP, + unsigned int * const codeP, + const char ** const errorP) { /*---------------------------------------------------------------------------- - If 'init', initialize the code getter. + Read and return the next lzw code from the file *ifP. + + 'codeSize' is the number of bits in the code we are to get. - Otherwise, read and return the next lzw code from the file *ifP. + Return *eofP == TRUE iff we hit the end of the stream. That means a legal + end of stream, marked by an EOD marker, not just end of file. An end of + file in the middle of the GIF stream is an error. - 'codeSize' is the number of bits in the code we are to get. + If there are bits left in the stream, but not 'codeSize' of them, we + call that a success with *eofP == TRUE. - Return -1 instead of a code if we encounter the end of the file. + Return the code read (assuming *eofP == FALSE and *errorP == NULL) + as *codeP. -----------------------------------------------------------------------------*/ - static struct getCodeState getCodeState; - int retval; + *errorP = NULL; + + while (gsP->curbit + codeSize > gsP->bufCount * 8 && + !gsP->streamExhausted && !*errorP) + /* Not enough left in buffer to satisfy request. Get the next + data block into the buffer. + + Note that a data block may be as small as one byte, so we may need + to do this multiple times to get the full code. (This probably + never happens in practice). + */ + getAnotherBlock(ifP, gsP, errorP); - if (init) { - initGetCode(&getCodeState); - retval = 0; - } else - doGetCode(ifP, codeSize, &getCodeState, &retval); + if (!*errorP) { + if (gsP->curbit + codeSize > gsP->bufCount * 8) { + /* The buffer still doesn't have enough bits in it; that means + there were no data blocks left to read. + */ + *eofP = TRUE; + + { + int const bitsUnused = gsP->bufCount * 8 - gsP->curbit; + if (bitsUnused > 0) + pm_message("Stream ends with a partial code " + "(%d bits left in file; " + "expected a %d bit code). Ignoring.", + bitsUnused, codeSize); + } + } else { + *codeP = bitsOfLeBuffer(gsP->buf, gsP->curbit, codeSize); - return retval; + gsP->curbit += codeSize; + *eofP = FALSE; + } + } } + + struct stack { /* Stack grows from low addresses to high addresses */ int * stack; /* malloc'ed array */ @@ -638,6 +726,7 @@ termStack(struct stack * const stackP) { stackP->stack = NULL; } + /*---------------------------------------------------------------------------- Some notes on LZW. @@ -657,7 +746,7 @@ termStack(struct stack * const stackP) { max_dataVal. The first byte in the stream tells you what dataWidth is. - LZW codes 0 - max_dataVal are direct codes. Each on represents + LZW codes 0 - max_dataVal are direct codes. Each one represents the true data element whose value is that of the LZW code itself. No decompression is required. @@ -694,7 +783,7 @@ struct decompressor { */ int next_tableSlot; /* Index in the code translation table of the next free entry */ - int firstcode; + unsigned int firstcode; /* This is always a true data element code */ int prevcode; /* The code just before, in the image, the one we're processing now */ @@ -759,7 +848,7 @@ lzwInit(struct decompressor * const decompP, } resetDecompressor(decompP); - getCode(decompP->ifP, 0, TRUE); + getCode_init(&getCodeState); decompP->fresh = TRUE; @@ -779,7 +868,7 @@ lzwTerm(struct decompressor * const decompP) { static void expandCodeOntoStack(struct decompressor * const decompP, int const incode, - bool * const errorP) { + const char ** const errorP) { /*---------------------------------------------------------------------------- 'incode' is an LZW string code. It represents a string of true data elements, as defined by the string translation table in *decompP. @@ -790,12 +879,13 @@ expandCodeOntoStack(struct decompressor * const decompP, Also add to the translation table where appropriate. Iff the translation table contains a cycle (which means the LZW stream - from which it was built is invalid), return *errorP == TRUE. + from which it was built is invalid), fail (return text explanation + as *errorP). -----------------------------------------------------------------------------*/ int code; - bool error; + const char * error; - error = FALSE; + error = NULL; /* Initial value */ if (incode < decompP->next_tableSlot) code = incode; @@ -810,15 +900,15 @@ expandCodeOntoStack(struct decompressor * const decompP, represents and push it onto the code stack so the leftmost code is on top. Set decompP->firstcode to the first (leftmost) code in that string. - */ + */ unsigned int stringCount; stringCount = 0; while (code > decompP->max_dataVal && !error) { if (stringCount > maxnum_lzwCode) { - pm_message("Error in GIF image: contains LZW string loop"); - error = TRUE; + asprintfN(&error, + "Error in GIF image: contains LZW string loop"); } else { ++stringCount; pushStack(&decompP->stack, decompP->table[1][code]); @@ -847,78 +937,106 @@ expandCodeOntoStack(struct decompressor * const decompP, } } - decompP->prevcode = incode; *errorP = error; + + decompP->prevcode = incode; } -static int -lzwReadByte(struct decompressor * const decompP) { +static void +lzwReadByteFresh(struct getCodeState * const getCodeStateP, + struct decompressor * const decompP, + bool * const endOfImageP, + unsigned int * const dataReadP, + const char ** const errorP) { + + /* Read off all initial clear codes, read the first non-clear code, + and return it. There are no strings in the table yet, so the next + code must be a direct true data code. + */ + bool eof; + do { + getCode_get(getCodeStateP, decompP->ifP, decompP->codeSize, + &eof, &decompP->firstcode, errorP); + decompP->prevcode = decompP->firstcode; + } while (decompP->firstcode == decompP->clear_code && !*errorP && !eof); + + if (!*errorP) { + if (eof) + *endOfImageP = TRUE; + else if (decompP->firstcode == decompP->end_code) { + if (!zeroDataBlock) + readThroughEod(decompP->ifP); + *endOfImageP = TRUE; + } else { + *endOfImageP = FALSE; + *dataReadP = decompP->firstcode; + } + } +} + + + +static void +lzwReadByte(struct decompressor * const decompP, + unsigned int * const dataReadP, + bool * const endOfImageP, + const char ** const errorP) { /*---------------------------------------------------------------------------- Return the next data element of the decompressed image. In the context of a GIF, a data element is the color table index of one pixel. - We read and return the next byte of the decompressed image, or: + We read and return the next byte of the decompressed image. - Return -1 if we hit EOF prematurely (i.e. before an "end" code. We - forgive the case that the "end" code is followed by EOF instead of - an EOD marker (zero length DataBlock)). + If we can't, because the stream is too corrupted to make sense out of + it or the stream ends, we fail (return text description of why as + *errorP). - Return -2 if there are no more bytes in the image. In that case, - make sure the file is positioned immediately after the image (i.e. - after the EOD marker that marks the end of the image or EOF). + We forgive the case that the "end" code is the end of the stream -- + not followed by an EOD marker (zero length DataBlock). - Return -3 if we encounter errors in the LZW stream. + Iff we can't read a byte because we've hit the end of the image, + we return *endOfImageP = true. -----------------------------------------------------------------------------*/ - int retval; - - if (!stackIsEmpty(&decompP->stack)) - retval = popStack(&decompP->stack); - else if (decompP->fresh) { + if (!stackIsEmpty(&decompP->stack)) { + *errorP = NULL; + *endOfImageP = FALSE; + *dataReadP = popStack(&decompP->stack); + } else if (decompP->fresh) { decompP->fresh = FALSE; - /* Read off all initial clear codes, read the first non-clear code, - and return it. There are no strings in the table yet, so the next - code must be a direct true data code. - */ - do { - decompP->firstcode = - getCode(decompP->ifP, decompP->codeSize, FALSE); - decompP->prevcode = decompP->firstcode; - } while (decompP->firstcode == decompP->clear_code); - if (decompP->firstcode == decompP->end_code) { - if (!zeroDataBlock) - readThroughEod(decompP->ifP); - retval = -2; - } else - retval = decompP->firstcode; + + lzwReadByteFresh(&getCodeState, decompP, endOfImageP, dataReadP, + errorP); } else { - int code; - code = getCode(decompP->ifP, decompP->codeSize, FALSE); - if (code == -1) - retval = -1; - else { - assert(code >= 0); /* -1 is only possible error return */ - if (code == decompP->clear_code) { - resetDecompressor(decompP); - retval = lzwReadByte(decompP); - } else { - if (code == decompP->end_code) { - if (!zeroDataBlock) - readThroughEod(decompP->ifP); - retval = -2; + unsigned int code; + bool eof; + getCode_get(&getCodeState, decompP->ifP, decompP->codeSize, + &eof, &code, errorP); + if (!*errorP) { + if (eof) + asprintfN(errorP, + "Premature end of file; no proper GIF closing"); + else { + if (code == decompP->clear_code) { + resetDecompressor(decompP); + lzwReadByte(decompP, dataReadP, endOfImageP, errorP); } else { - bool error; - expandCodeOntoStack(decompP, code, &error); - if (error) - retval = -3; - else - retval = popStack(&decompP->stack); + if (code == decompP->end_code) { + if (!zeroDataBlock) + readThroughEod(decompP->ifP); + *endOfImageP = TRUE; + *errorP = NULL; + } else { + *endOfImageP = FALSE; + expandCodeOntoStack(decompP, code, errorP); + if (!*errorP) + *dataReadP = popStack(&decompP->stack); + } } } } } - return retval; } @@ -1027,6 +1145,124 @@ addPixelToRaster(unsigned int const cmapIndex, static void +verifyPixelRead(bool const endOfImage, + const char * const readError, + unsigned int const cols, + unsigned int const rows, + unsigned int const failedRowNum, + const char ** const errorP) { + + if (readError) + *errorP = strdup(readError); + else { + if (endOfImage) + asprintfN(errorP, + "Error in GIF image: Not enough raster data to fill " + "%u x %u dimensions. Ran out of raster data in " + "row %u. The image has proper ending sequence, so " + "this is not just a truncated file.", + cols, rows, failedRowNum); + else + *errorP = NULL; + } +} + + + +static void +readRaster(struct decompressor * const decompP, + xel ** const xels, + unsigned int const cols, + unsigned int const rows, + gifColorMap cmap, + unsigned int const cmapSize, + bool const interlace, + int const transparentIndex, + bit ** const alphabits, + bool const tolerateBadInput) { + + struct pnmBuffer pnmBuffer; + enum pass pass; + bool fillingMissingPixels; + + pass = MULT8PLUS0; + pnmBuffer.xels = xels; + pnmBuffer.col = 0; + pnmBuffer.row = 0; + fillingMissingPixels = false; /* initial value */ + + while (pnmBuffer.row < rows) { + unsigned int colorIndex; + + if (fillingMissingPixels) + colorIndex = 0; + else { + const char * error; + + const char * readError; + unsigned int readColorIndex; + bool endOfImage; + + lzwReadByte(decompP, &readColorIndex, &endOfImage, &readError); + + verifyPixelRead(endOfImage, readError, cols, rows, pnmBuffer.row, + &error); + + if (readError) + strfree(readError); + + if (error) { + if (tolerateBadInput) { + pm_message("WARNING: %s. " + "Filling bottom %u rows with arbitrary color", + error, rows - pnmBuffer.row); + fillingMissingPixels = true; + } else + pm_error("Unable to read input image. %s. Use the " + "-repair option to try to salvage some of " + "the image", + error); + + colorIndex = 0; + } else + colorIndex = readColorIndex; + } + addPixelToRaster(colorIndex, &pnmBuffer, cols, rows, cmap, cmapSize, + interlace, transparentIndex, alphabits, &pass); + } +} + + + +static void +skipExtraneousData(struct decompressor * const decompP) { + + unsigned int byteRead; + bool endOfImage; + const char * error; + + lzwReadByte(decompP, &byteRead, &endOfImage, &error); + + if (error) + strfree(error); + else if (!endOfImage) { + pm_message("Extraneous data at end of image. " + "Skipped to end of image"); + + while (!endOfImage && !error) + lzwReadByte(decompP, &byteRead, &endOfImage, &error); + + if (error) { + pm_message("Error encountered skipping to end of image: %s", + error); + strfree(error); + } + } +} + + + +static void readImageData(FILE * const ifP, xel ** const xels, unsigned int const cols, @@ -1035,20 +1271,13 @@ readImageData(FILE * const ifP, unsigned int const cmapSize, bool const interlace, int const transparentIndex, - bit ** const alphabits) { + bit ** const alphabits, + bool const tolerateBadInput) { unsigned char lzwMinCodeSize; - enum pass pass; struct decompressor decomp; - struct pnmBuffer pnmBuffer; bool gotMinCodeSize; - pass = MULT8PLUS0; - - pnmBuffer.xels = xels; - pnmBuffer.col = 0; - pnmBuffer.row = 0; - gotMinCodeSize = ReadOK(ifP, &lzwMinCodeSize, 1); if (!gotMinCodeSize) pm_error("GIF stream ends (or read error) " @@ -1062,29 +1291,10 @@ readImageData(FILE * const ifP, lzwInit(&decomp, ifP, lzwMinCodeSize); - while (pnmBuffer.row < rows) { - int const rc = lzwReadByte(&decomp); + readRaster(&decomp, xels, cols, rows, cmap, cmapSize, interlace, + transparentIndex, alphabits, tolerateBadInput); - switch (rc) { - case -3: - pm_error("Error in GIF input stream"); - break; - case -2: - pm_error("Error in GIF image: Not enough raster data to fill " - "%u x %u dimensions. Ran out of raster data in " - "row %u", cols, rows, pnmBuffer.row); - break; - case -1: - pm_error("Premature end of file; no proper GIF closing"); - break; - default: - addPixelToRaster(rc, &pnmBuffer, cols, rows, cmap, cmapSize, - interlace, transparentIndex, alphabits, &pass); - } - } - if (lzwReadByte(&decomp) >= 0) - pm_message("Extraneous data at end of image. " - "Skipped to end of image"); + skipExtraneousData(&decomp); lzwTerm(&decomp); } @@ -1092,33 +1302,36 @@ readImageData(FILE * const ifP, static void -writePnm(FILE *outfile, xel ** const xels, - const int cols, const int rows, - const int hasGray, const int hasColor) { +writePnm(FILE * const outfileP, + xel ** const xels, + int const cols, + int const rows, + int const hasGray, + int const hasColor) { /*---------------------------------------------------------------------------- - Write a PNM image to the current position of file 'outfile' with + Write a PNM image to the current position of file *outfileP with dimensions 'cols' x 'rows' and raster 'xels'. Make it PBM, PGM, or PBM according to 'hasGray' and 'hasColor'. -----------------------------------------------------------------------------*/ int format; - const char *format_name; + const char * formatName; if (hasColor) { format = PPM_FORMAT; - format_name = "PPM"; + formatName = "PPM"; } else if (hasGray) { format = PGM_FORMAT; - format_name = "PGM"; + formatName = "PGM"; } else { format = PBM_FORMAT; - format_name = "PBM"; + formatName = "PBM"; } if (verbose) - pm_message("writing a %s file", format_name); + pm_message("writing a %s file", formatName); - if (outfile) - pnm_writepnm(outfile, xels, cols, rows, + if (outfileP) + pnm_writepnm(outfileP, xels, cols, rows, (xelval) GIFMAXVAL, format, FALSE); } @@ -1172,7 +1385,7 @@ readGifHeader(FILE * const gifFile, struct gifScreen * const gifScreenP) { if (verbose) pm_message("GIF format version is '%s'", version); - if ((!STREQ(version, "87a")) && (!STREQ(version, "89a"))) + if ((!streq(version, "87a")) && (!streq(version, "89a"))) pm_error("bad version number, not '87a' or '89a'" ); if (! ReadOK(gifFile,buf,7)) @@ -1223,7 +1436,8 @@ readGifHeader(FILE * const gifFile, struct gifScreen * const gifScreenP) { static void readExtensions(FILE* const ifP, struct gif89 * const gif89P, - bool * const eodP) { + bool * const eodP, + const char ** const errorP) { /*---------------------------------------------------------------------------- Read extension blocks from the GIF stream to which the file *ifP is positioned. Read up through the image separator that begins the @@ -1232,33 +1446,50 @@ readExtensions(FILE* const ifP, If we encounter EOD (end of GIF stream) before we find an image separator, we return *eodP == TRUE. Else *eodP == FALSE. - If we hit end of file before an EOD marker, we abort the program with - an error message. + If we hit end of file before an EOD marker, we fail. -----------------------------------------------------------------------------*/ bool imageStart; bool eod; + *errorP = NULL; /* initial value */ + eod = FALSE; imageStart = FALSE; /* Read the image descriptor */ - while (!imageStart && !eod) { + while (!imageStart && !eod && !*errorP) { unsigned char c; + const char * error; - if (! ReadOK(ifP,&c,1)) - pm_error("EOF / read error on image data" ); + readFile(ifP, &c, 1, &error); - if (c == ';') { /* GIF terminator */ - eod = TRUE; - } else if (c == '!') { /* Extension */ - if (! ReadOK(ifP,&c,1)) - pm_error("EOF / " - "read error on extension function code"); - doExtension(ifP, c, gif89P); - } else if (c == ',') - imageStart = TRUE; - else - pm_message("bogus character 0x%02x, ignoring", (int) c ); + if (error) { + asprintfN(errorP, "File read error where start of image " + "descriptor or end of GIF expected. %s", + error); + strfree(error); + } else { + if (c == ';') { /* GIF terminator */ + eod = TRUE; + } else if (c == '!') { /* Extension */ + unsigned char functionCode; + const char * error; + + readFile(ifP, &functionCode, 1, &error); + + if (error) { + asprintfN(errorP, "Failed to read function code " + "of GIF extension (immediately after the '!' " + "extension delimiter) from input. %s", error); + strfree(error); + } else { + doExtension(ifP, functionCode, gif89P); + } + } else if (c == ',') + imageStart = TRUE; + else + pm_message("bogus character 0x%02x, ignoring", (int)c); + } } *eodP = eod; } @@ -1272,9 +1503,9 @@ reportImageInfo(unsigned int const cols, unsigned int const localColorMapSize, bool const interlaced) { - pm_message("reading %u by %u%s GIF image", cols, rows, interlaced ? " interlaced" : "" ); + if (useGlobalColormap) pm_message(" Uses global colormap"); else @@ -1289,7 +1520,8 @@ convertImage(FILE * const ifP, FILE * const imageout_file, FILE * const alphafile, struct gifScreen gifScreen, - struct gif89 const gif89) { + struct gif89 const gif89, + bool const tolerateBadInput) { /*---------------------------------------------------------------------------- Read a single GIF image from the current position of file 'ifP'. @@ -1340,7 +1572,8 @@ convertImage(FILE * const ifP, &hasGray, &hasColor); transparencyMessage(gif89.transparent, localColorMap); readImageData(ifP, xels, cols, rows, localColorMap, localColorMapSize, - interlaced, gif89.transparent, alphabits); + interlaced, gif89.transparent, alphabits, + tolerateBadInput); if (!skipIt) { writePnm(imageout_file, xels, cols, rows, hasGray, hasColor); @@ -1349,7 +1582,8 @@ convertImage(FILE * const ifP, transparencyMessage(gif89.transparent, gifScreen.ColorMap); readImageData(ifP, xels, cols, rows, gifScreen.ColorMap, gifScreen.ColorMapSize, - interlaced, gif89.transparent, alphabits); + interlaced, gif89.transparent, alphabits, + tolerateBadInput); if (!skipIt) { writePnm(imageout_file, xels, cols, rows, gifScreen.hasGray, gifScreen.hasColor); @@ -1367,12 +1601,33 @@ convertImage(FILE * const ifP, static void +disposeOfReadExtensionsError(const char * const error, + bool const tolerateBadInput, + unsigned int const imageSeq, + bool * const eodP) { + if (error) { + if (tolerateBadInput) + pm_message("Error accessing Image %u of stream; no further " + "images can be accessed. %s", + imageSeq, error); + else + pm_error("Error accessing Image %u of stream. %s", + imageSeq, error); + strfree(error); + *eodP = TRUE; + } +} + + + +static void convertImages(FILE * const ifP, bool const allImages, int const requestedImageSeq, bool const drainStream, FILE * const imageout_file, - FILE * const alphafile) { + FILE * const alphafile, + bool const tolerateBadInput) { /*---------------------------------------------------------------------------- Read a GIF stream from file 'ifP' and write one or more images from it as PNM images to file 'imageout_file'. If the images have transparency @@ -1407,20 +1662,25 @@ convertImages(FILE * const ifP, !eod && (imageSeq <= requestedImageSeq || allImages || drainStream); ++imageSeq) { - readExtensions(ifP, &gif89, &eod); + const char * error; + + readExtensions(ifP, &gif89, &eod, &error); + + disposeOfReadExtensionsError(error, tolerateBadInput, imageSeq, &eod); if (eod) { /* GIF stream ends before image with sequence imageSeq */ if (!allImages && (imageSeq <= requestedImageSeq)) pm_error("You requested Image %d, but " "only %d image%s found in GIF stream", - requestedImageSeq+1, - imageSeq, imageSeq>1?"s":"" ); + requestedImageSeq + 1, + imageSeq, imageSeq > 1 ? "s" : ""); } else { if (verbose) pm_message("Reading Image Sequence %d", imageSeq); convertImage(ifP, !allImages && (imageSeq != requestedImageSeq), - imageout_file, alphafile, gifScreen, gif89); + imageout_file, alphafile, gifScreen, gif89, + tolerateBadInput); } } } @@ -1447,19 +1707,20 @@ main(int argc, char **argv) { else alpha_file = pm_openw(cmdline.alpha_filename); - if (alpha_file && STREQ(cmdline.alpha_filename, "-")) + if (alpha_file && streq(cmdline.alpha_filename, "-")) imageout_file = NULL; else imageout_file = stdout; convertImages(ifP, cmdline.all_images, cmdline.image_no, - !cmdline.quitearly, imageout_file, alpha_file); + !cmdline.quitearly, imageout_file, alpha_file, + cmdline.repair); pm_close(ifP); if (imageout_file != NULL) - pm_close( imageout_file ); + pm_close(imageout_file); if (alpha_file != NULL) - pm_close( alpha_file ); + pm_close(alpha_file); return 0; } |