diff options
Diffstat (limited to 'tk8.6/generic/tkImgPPM.c')
| -rw-r--r-- | tk8.6/generic/tkImgPPM.c | 854 |
1 files changed, 0 insertions, 854 deletions
diff --git a/tk8.6/generic/tkImgPPM.c b/tk8.6/generic/tkImgPPM.c deleted file mode 100644 index 6f084f0..0000000 --- a/tk8.6/generic/tkImgPPM.c +++ /dev/null @@ -1,854 +0,0 @@ -/* - * tkImgPPM.c -- - * - * A photo image file handler for PPM (Portable PixMap) files. - * - * Copyright (c) 1994 The Australian National University. - * Copyright (c) 1994-1997 Sun Microsystems, Inc. - * - * See the file "license.terms" for information on usage and redistribution of - * this file, and for a DISCLAIMER OF ALL WARRANTIES. - * - * Author: Paul Mackerras (paulus@cs.anu.edu.au), - * Department of Computer Science, - * Australian National University. - */ - -#include "tkInt.h" - -/* - * The maximum amount of memory to allocate for data read from the file. If we - * need more than this, we do it in pieces. - */ - -#define MAX_MEMORY 10000 /* don't allocate > 10KB */ - -/* - * Define PGM and PPM, i.e. gray images and color images. - */ - -#define PGM 1 -#define PPM 2 - -/* - * The format record for the PPM file format: - */ - -static int FileMatchPPM(Tcl_Channel chan, const char *fileName, - Tcl_Obj *format, int *widthPtr, int *heightPtr, - Tcl_Interp *interp); -static int FileReadPPM(Tcl_Interp *interp, Tcl_Channel chan, - const char *fileName, Tcl_Obj *format, - Tk_PhotoHandle imageHandle, int destX, int destY, - int width, int height, int srcX, int srcY); -static int FileWritePPM(Tcl_Interp *interp, const char *fileName, - Tcl_Obj *format, Tk_PhotoImageBlock *blockPtr); -static int StringWritePPM(Tcl_Interp *interp, Tcl_Obj *format, - Tk_PhotoImageBlock *blockPtr); -static int StringMatchPPM(Tcl_Obj *dataObj, Tcl_Obj *format, - int *widthPtr, int *heightPtr, Tcl_Interp *interp); -static int StringReadPPM(Tcl_Interp *interp, Tcl_Obj *dataObj, - Tcl_Obj *format, Tk_PhotoHandle imageHandle, - int destX, int destY, int width, int height, - int srcX, int srcY); - -Tk_PhotoImageFormat tkImgFmtPPM = { - "ppm", /* name */ - FileMatchPPM, /* fileMatchProc */ - StringMatchPPM, /* stringMatchProc */ - FileReadPPM, /* fileReadProc */ - StringReadPPM, /* stringReadProc */ - FileWritePPM, /* fileWriteProc */ - StringWritePPM, /* stringWriteProc */ - NULL -}; - -/* - * Prototypes for local functions defined in this file: - */ - -static int ReadPPMFileHeader(Tcl_Channel chan, int *widthPtr, - int *heightPtr, int *maxIntensityPtr); -static int ReadPPMStringHeader(Tcl_Obj *dataObj, int *widthPtr, - int *heightPtr, int *maxIntensityPtr, - unsigned char **dataBufferPtr, int *dataSizePtr); - -/* - *---------------------------------------------------------------------- - * - * FileMatchPPM -- - * - * This function is invoked by the photo image type to see if a file - * contains image data in PPM format. - * - * Results: - * The return value is >0 if the first characters in file "f" look like - * PPM data, and 0 otherwise. - * - * Side effects: - * The access position in f may change. - * - *---------------------------------------------------------------------- - */ - -static int -FileMatchPPM( - Tcl_Channel chan, /* The image file, open for reading. */ - const char *fileName, /* The name of the image file. */ - Tcl_Obj *format, /* User-specified format string, or NULL. */ - int *widthPtr, int *heightPtr, - /* The dimensions of the image are returned - * here if the file is a valid raw PPM - * file. */ - Tcl_Interp *interp) /* unused */ -{ - int dummy; - - return ReadPPMFileHeader(chan, widthPtr, heightPtr, &dummy); -} - -/* - *---------------------------------------------------------------------- - * - * FileReadPPM -- - * - * This function is called by the photo image type to read PPM format - * data from a file and write it into a given photo image. - * - * Results: - * A standard TCL completion code. If TCL_ERROR is returned then an error - * message is left in the interp's result. - * - * Side effects: - * The access position in file f is changed, and new data is added to the - * image given by imageHandle. - * - *---------------------------------------------------------------------- - */ - -static int -FileReadPPM( - Tcl_Interp *interp, /* Interpreter to use for reporting errors. */ - Tcl_Channel chan, /* The image file, open for reading. */ - const char *fileName, /* The name of the image file. */ - Tcl_Obj *format, /* User-specified format string, or NULL. */ - Tk_PhotoHandle imageHandle, /* The photo image to write into. */ - int destX, int destY, /* Coordinates of top-left pixel in photo - * image to be written to. */ - int width, int height, /* Dimensions of block of photo image to be - * written to. */ - int srcX, int srcY) /* Coordinates of top-left pixel to be used in - * image being read. */ -{ - int fileWidth, fileHeight, maxIntensity; - int nLines, nBytes, h, type, count, bytesPerChannel = 1; - unsigned char *pixelPtr; - Tk_PhotoImageBlock block; - - type = ReadPPMFileHeader(chan, &fileWidth, &fileHeight, &maxIntensity); - if (type == 0) { - Tcl_SetObjResult(interp, Tcl_ObjPrintf( - "couldn't read raw PPM header from file \"%s\"", fileName)); - Tcl_SetErrorCode(interp, "TK", "IMAGE", "PPM", "NO_HEADER", NULL); - return TCL_ERROR; - } - if ((fileWidth <= 0) || (fileHeight <= 0)) { - Tcl_SetObjResult(interp, Tcl_ObjPrintf( - "PPM image file \"%s\" has dimension(s) <= 0", fileName)); - Tcl_SetErrorCode(interp, "TK", "IMAGE", "PPM", "DIMENSIONS", NULL); - return TCL_ERROR; - } - if ((maxIntensity <= 0) || (maxIntensity > 0xffff)) { - Tcl_SetObjResult(interp, Tcl_ObjPrintf( - "PPM image file \"%s\" has bad maximum intensity value %d", - fileName, maxIntensity)); - Tcl_SetErrorCode(interp, "TK", "IMAGE", "PPM", "INTENSITY", NULL); - return TCL_ERROR; - } else if (maxIntensity > 0x00ff) { - bytesPerChannel = 2; - } - - if ((srcX + width) > fileWidth) { - width = fileWidth - srcX; - } - if ((srcY + height) > fileHeight) { - height = fileHeight - srcY; - } - if ((width <= 0) || (height <= 0) - || (srcX >= fileWidth) || (srcY >= fileHeight)) { - return TCL_OK; - } - - if (type == PGM) { - block.pixelSize = 1 * bytesPerChannel; - block.offset[0] = 0; - block.offset[1] = 0; - block.offset[2] = 0; - } else { - block.pixelSize = 3 * bytesPerChannel; - block.offset[0] = 0; - block.offset[1] = 1 * bytesPerChannel; - block.offset[2] = 2 * bytesPerChannel; - } - block.offset[3] = 0; - block.width = width; - block.pitch = block.pixelSize * fileWidth; - - if (Tk_PhotoExpand(interp, imageHandle, - destX + width, destY + height) != TCL_OK) { - return TCL_ERROR; - } - - if (srcY > 0) { - Tcl_Seek(chan, (Tcl_WideInt)(srcY * block.pitch), SEEK_CUR); - } - - nLines = (MAX_MEMORY + block.pitch - 1) / block.pitch; - if (nLines > height) { - nLines = height; - } - if (nLines <= 0) { - nLines = 1; - } - nBytes = nLines * block.pitch; - pixelPtr = ckalloc(nBytes); - block.pixelPtr = pixelPtr + srcX * block.pixelSize; - - for (h = height; h > 0; h -= nLines) { - if (nLines > h) { - nLines = h; - nBytes = nLines * block.pitch; - } - count = Tcl_Read(chan, (char *) pixelPtr, nBytes); - if (count != nBytes) { - Tcl_SetObjResult(interp, Tcl_ObjPrintf( - "error reading PPM image file \"%s\": %s", fileName, - Tcl_Eof(chan)?"not enough data":Tcl_PosixError(interp))); - if (Tcl_Eof(chan)) { - Tcl_SetErrorCode(interp, "TK", "IMAGE", "PPM", "EOF", NULL); - } - ckfree(pixelPtr); - return TCL_ERROR; - } - if (maxIntensity < 0x00ff) { - unsigned char *p; - - for (p = pixelPtr; count > 0; count--, p++) { - *p = (((int) *p) * 255)/maxIntensity; - } - } else if (maxIntensity > 0x00ff) { - unsigned char *p; - unsigned int value; - - for (p = pixelPtr; count > 0; count--, p += 2) { - value = ((unsigned int) p[0]) * 256 + ((unsigned int) p[1]); - value = value * 255 / maxIntensity; - p[0] = p[1] = (unsigned char) value; - } - } - block.height = nLines; - if (Tk_PhotoPutBlock(interp, imageHandle, &block, destX, destY, - width, nLines, TK_PHOTO_COMPOSITE_SET) != TCL_OK) { - ckfree(pixelPtr); - return TCL_ERROR; - } - destY += nLines; - } - - ckfree(pixelPtr); - return TCL_OK; -} - -/* - *---------------------------------------------------------------------- - * - * FileWritePPM -- - * - * This function is invoked to write image data to a file in PPM format - * (although we can read PGM files, we never write them). - * - * Results: - * A standard TCL completion code. If TCL_ERROR is returned then an error - * message is left in the interp's result. - * - * Side effects: - * Data is written to the file given by "fileName". - * - *---------------------------------------------------------------------- - */ - -static int -FileWritePPM( - Tcl_Interp *interp, - const char *fileName, - Tcl_Obj *format, - Tk_PhotoImageBlock *blockPtr) -{ - Tcl_Channel chan; - int w, h, greenOffset, blueOffset, nBytes; - unsigned char *pixelPtr, *pixLinePtr; - char header[16 + TCL_INTEGER_SPACE * 2]; - - chan = Tcl_OpenFileChannel(interp, fileName, "w", 0666); - if (chan == NULL) { - return TCL_ERROR; - } - - if (Tcl_SetChannelOption(interp, chan, "-translation", "binary") - != TCL_OK) { - Tcl_Close(NULL, chan); - return TCL_ERROR; - } - if (Tcl_SetChannelOption(interp, chan, "-encoding", "binary") - != TCL_OK) { - Tcl_Close(NULL, chan); - return TCL_ERROR; - } - - sprintf(header, "P6\n%d %d\n255\n", blockPtr->width, blockPtr->height); - Tcl_Write(chan, header, -1); - - pixLinePtr = blockPtr->pixelPtr + blockPtr->offset[0]; - greenOffset = blockPtr->offset[1] - blockPtr->offset[0]; - blueOffset = blockPtr->offset[2] - blockPtr->offset[0]; - - if ((greenOffset == 1) && (blueOffset == 2) && (blockPtr->pixelSize == 3) - && (blockPtr->pitch == (blockPtr->width * 3))) { - nBytes = blockPtr->height * blockPtr->pitch; - if (Tcl_Write(chan, (char *) pixLinePtr, nBytes) != nBytes) { - goto writeerror; - } - } else { - for (h = blockPtr->height; h > 0; h--) { - pixelPtr = pixLinePtr; - for (w = blockPtr->width; w > 0; w--) { - if ( Tcl_Write(chan,(char *)&pixelPtr[0], 1) == -1 || - Tcl_Write(chan,(char *)&pixelPtr[greenOffset],1)==-1 || - Tcl_Write(chan,(char *)&pixelPtr[blueOffset],1) ==-1) { - goto writeerror; - } - pixelPtr += blockPtr->pixelSize; - } - pixLinePtr += blockPtr->pitch; - } - } - - if (Tcl_Close(NULL, chan) == 0) { - return TCL_OK; - } - chan = NULL; - - writeerror: - Tcl_SetObjResult(interp, Tcl_ObjPrintf("error writing \"%s\": %s", - fileName, Tcl_PosixError(interp))); - if (chan != NULL) { - Tcl_Close(NULL, chan); - } - return TCL_ERROR; -} - -/* - *---------------------------------------------------------------------- - * - * StringWritePPM -- - * - * This function is invoked to write image data to a string in PPM - * format. - * - * Results: - * A standard TCL completion code. If TCL_ERROR is returned then an error - * message is left in the interp's result. - * - * Side effects: - * None. - * - *---------------------------------------------------------------------- - */ - -static int -StringWritePPM( - Tcl_Interp *interp, - Tcl_Obj *format, - Tk_PhotoImageBlock *blockPtr) -{ - int w, h, size, greenOffset, blueOffset; - unsigned char *pixLinePtr, *byteArray; - char header[16 + TCL_INTEGER_SPACE * 2]; - Tcl_Obj *byteArrayObj; - - sprintf(header, "P6\n%d %d\n255\n", blockPtr->width, blockPtr->height); - - /* - * Construct a byte array of the right size with the header and - * get a pointer to the data part of it. - */ - - size = strlen(header); - byteArrayObj = Tcl_NewByteArrayObj((unsigned char *)header, size); - byteArray = Tcl_SetByteArrayLength(byteArrayObj, - size + 3*blockPtr->width*blockPtr->height); - byteArray += size; - - pixLinePtr = blockPtr->pixelPtr + blockPtr->offset[0]; - greenOffset = blockPtr->offset[1] - blockPtr->offset[0]; - blueOffset = blockPtr->offset[2] - blockPtr->offset[0]; - - /* - * Check if we can do the data move in single action. - */ - - if ((greenOffset == 1) && (blueOffset == 2) && (blockPtr->pixelSize == 3) - && (blockPtr->pitch == (blockPtr->width * 3))) { - memcpy(byteArray, pixLinePtr, - (unsigned)blockPtr->height * blockPtr->pitch); - } else { - for (h = blockPtr->height; h > 0; h--) { - unsigned char *pixelPtr = pixLinePtr; - - for (w = blockPtr->width; w > 0; w--) { - *byteArray++ = pixelPtr[0]; - *byteArray++ = pixelPtr[greenOffset]; - *byteArray++ = pixelPtr[blueOffset]; - pixelPtr += blockPtr->pixelSize; - } - pixLinePtr += blockPtr->pitch; - } - } - - /* - * Return the object in the interpreter result. - */ - - Tcl_SetObjResult(interp, byteArrayObj); - return TCL_OK; -} - -/* - *---------------------------------------------------------------------- - * - * StringMatchPPM -- - * - * This function is invoked by the photo image type to see if a string - * contains image data in PPM format. - * - * Results: - * The return value is >0 if the first characters in file "f" look like - * PPM data, and 0 otherwise. - * - * Side effects: - * The access position in f may change. - * - *---------------------------------------------------------------------- - */ - -static int -StringMatchPPM( - Tcl_Obj *dataObj, /* The image data. */ - Tcl_Obj *format, /* User-specified format string, or NULL. */ - int *widthPtr, int *heightPtr, - /* The dimensions of the image are returned - * here if the file is a valid raw PPM - * file. */ - Tcl_Interp *interp) /* unused */ -{ - int dummy; - - return ReadPPMStringHeader(dataObj, widthPtr, heightPtr, - &dummy, NULL, NULL); -} - -/* - *---------------------------------------------------------------------- - * - * StringReadPPM -- - * - * This function is called by the photo image type to read PPM format - * data from a string and write it into a given photo image. - * - * Results: - * A standard TCL completion code. If TCL_ERROR is returned then an error - * message is left in the interp's result. - * - * Side effects: - * New data is added to the image given by imageHandle. - * - *---------------------------------------------------------------------- - */ - -static int -StringReadPPM( - Tcl_Interp *interp, /* Interpreter to use for reporting errors. */ - Tcl_Obj *dataObj, /* The image data. */ - Tcl_Obj *format, /* User-specified format string, or NULL. */ - Tk_PhotoHandle imageHandle, /* The photo image to write into. */ - int destX, int destY, /* Coordinates of top-left pixel in photo - * image to be written to. */ - int width, int height, /* Dimensions of block of photo image to be - * written to. */ - int srcX, int srcY) /* Coordinates of top-left pixel to be used in - * image being read. */ -{ - int fileWidth, fileHeight, maxIntensity; - int nLines, nBytes, h, type, count, dataSize, bytesPerChannel = 1; - unsigned char *pixelPtr, *dataBuffer; - Tk_PhotoImageBlock block; - - type = ReadPPMStringHeader(dataObj, &fileWidth, &fileHeight, - &maxIntensity, &dataBuffer, &dataSize); - if (type == 0) { - Tcl_SetObjResult(interp, Tcl_NewStringObj( - "couldn't read raw PPM header from string", -1)); - Tcl_SetErrorCode(interp, "TK", "IMAGE", "PPM", "NO_HEADER", NULL); - return TCL_ERROR; - } - if ((fileWidth <= 0) || (fileHeight <= 0)) { - Tcl_SetObjResult(interp, Tcl_NewStringObj( - "PPM image data has dimension(s) <= 0", -1)); - Tcl_SetErrorCode(interp, "TK", "IMAGE", "PPM", "DIMENSIONS", NULL); - return TCL_ERROR; - } - if ((maxIntensity <= 0) || (maxIntensity > 0xffff)) { - Tcl_SetObjResult(interp, Tcl_ObjPrintf( - "PPM image data has bad maximum intensity value %d", - maxIntensity)); - Tcl_SetErrorCode(interp, "TK", "IMAGE", "PPM", "INTENSITY", NULL); - return TCL_ERROR; - } else if (maxIntensity > 0x00ff) { - bytesPerChannel = 2; - } - - if ((srcX + width) > fileWidth) { - width = fileWidth - srcX; - } - if ((srcY + height) > fileHeight) { - height = fileHeight - srcY; - } - if ((width <= 0) || (height <= 0) - || (srcX >= fileWidth) || (srcY >= fileHeight)) { - return TCL_OK; - } - - if (type == PGM) { - block.pixelSize = 1 * bytesPerChannel; - block.offset[0] = 0; - block.offset[1] = 0; - block.offset[2] = 0; - } else { - block.pixelSize = 3 * bytesPerChannel; - block.offset[0] = 0; - block.offset[1] = 1 * bytesPerChannel; - block.offset[2] = 2 * bytesPerChannel; - } - block.offset[3] = 0; - block.width = width; - block.pitch = block.pixelSize * fileWidth; - - if (srcY > 0) { - dataBuffer += srcY * block.pitch; - dataSize -= srcY * block.pitch; - } - - if (maxIntensity == 0x00ff) { - /* - * We have all the data in memory, so write everything in one go. - */ - - if (block.pitch*height > dataSize) { - Tcl_SetObjResult(interp, Tcl_NewStringObj( - "truncated PPM data", -1)); - Tcl_SetErrorCode(interp, "TK", "IMAGE", "PPM", "TRUNCATED", NULL); - return TCL_ERROR; - } - block.pixelPtr = dataBuffer + srcX * block.pixelSize; - block.height = height; - return Tk_PhotoPutBlock(interp, imageHandle, &block, destX, destY, - width, height, TK_PHOTO_COMPOSITE_SET); - } - - if (Tk_PhotoExpand(interp, imageHandle, - destX + width, destY + height) != TCL_OK) { - return TCL_ERROR; - } - - nLines = (MAX_MEMORY + block.pitch - 1) / block.pitch; - if (nLines > height) { - nLines = height; - } - if (nLines <= 0) { - nLines = 1; - } - nBytes = nLines * block.pitch; - pixelPtr = ckalloc(nBytes); - block.pixelPtr = pixelPtr + srcX * block.pixelSize; - - for (h = height; h > 0; h -= nLines) { - unsigned char *p; - - if (nLines > h) { - nLines = h; - nBytes = nLines * block.pitch; - } - if (dataSize < nBytes) { - ckfree(pixelPtr); - Tcl_SetObjResult(interp, Tcl_NewStringObj( - "truncated PPM data", -1)); - Tcl_SetErrorCode(interp, "TK", "IMAGE", "PPM", "TRUNCATED", NULL); - return TCL_ERROR; - } - if (maxIntensity < 0x00ff) { - for (p=pixelPtr,count=nBytes ; count>0 ; count--,p++,dataBuffer++) { - *p = (((int) *dataBuffer) * 255)/maxIntensity; - } - } else { - unsigned char *p; - unsigned int value; - - for (p = pixelPtr,count=nBytes; count > 1; count-=2, p += 2) { - value = ((unsigned int) p[0]) * 256 + ((unsigned int) p[1]); - value = value * 255 / maxIntensity; - p[0] = p[1] = (unsigned char) value; - } - } - dataSize -= nBytes; - block.height = nLines; - if (Tk_PhotoPutBlock(interp, imageHandle, &block, destX, destY, - width, nLines, TK_PHOTO_COMPOSITE_SET) != TCL_OK) { - ckfree(pixelPtr); - return TCL_ERROR; - } - destY += nLines; - } - - ckfree(pixelPtr); - return TCL_OK; -} - -/* - *---------------------------------------------------------------------- - * - * ReadPPMFileHeader -- - * - * This function reads the PPM header from the beginning of a PPM file - * and returns information from the header. - * - * Results: - * The return value is PGM if file "f" appears to start with a valid PGM - * header, PPM if "f" appears to start with a valid PPM header, and 0 - * otherwise. If the header is valid, then *widthPtr and *heightPtr are - * modified to hold the dimensions of the image and *maxIntensityPtr is - * modified to hold the value of a "fully on" intensity value. - * - * Side effects: - * The access position in f advances. - * - *---------------------------------------------------------------------- - */ - -static int -ReadPPMFileHeader( - Tcl_Channel chan, /* Image file to read the header from. */ - int *widthPtr, int *heightPtr, - /* The dimensions of the image are returned - * here. */ - int *maxIntensityPtr) /* The maximum intensity value for the image - * is stored here. */ -{ -#define BUFFER_SIZE 1000 - char buffer[BUFFER_SIZE], c; - int i, numFields, type = 0; - - /* - * Read 4 space-separated fields from the file, ignoring comments (any - * line that starts with "#"). - */ - - if (Tcl_Read(chan, &c, 1) != 1) { - return 0; - } - i = 0; - for (numFields = 0; numFields < 4; numFields++) { - /* - * Skip comments and white space. - */ - - while (1) { - while (isspace(UCHAR(c))) { - if (Tcl_Read(chan, &c, 1) != 1) { - return 0; - } - } - if (c != '#') { - break; - } - do { - if (Tcl_Read(chan, &c, 1) != 1) { - return 0; - } - } while (c != '\n'); - } - - /* - * Read a field (everything up to the next white space). - */ - - while (!isspace(UCHAR(c))) { - if (i < (BUFFER_SIZE-2)) { - buffer[i] = c; - i++; - } - if (Tcl_Read(chan, &c, 1) != 1) { - goto done; - } - } - if (i < (BUFFER_SIZE-1)) { - buffer[i] = ' '; - i++; - } - } - - done: - buffer[i] = 0; - - /* - * Parse the fields, which are: id, width, height, maxIntensity. - */ - - if (strncmp(buffer, "P6 ", 3) == 0) { - type = PPM; - } else if (strncmp(buffer, "P5 ", 3) == 0) { - type = PGM; - } else { - return 0; - } - if (sscanf(buffer+3, "%d %d %d", widthPtr, heightPtr, maxIntensityPtr) - != 3) { - return 0; - } - return type; -} - -/* - *---------------------------------------------------------------------- - * - * ReadPPMStringHeader -- - * - * This function reads the PPM header from the beginning of a PPM-format - * string and returns information from the header. - * - * Results: - * The return value is PGM if the string appears to start with a valid - * PGM header, PPM if the string appears to start with a valid PPM - * header, and 0 otherwise. If the header is valid, then *widthPtr and - * *heightPtr are modified to hold the dimensions of the image and - * *maxIntensityPtr is modified to hold the value of a "fully on" - * intensity value. - * - * Side effects: - * None - * - *---------------------------------------------------------------------- - */ - -static int -ReadPPMStringHeader( - Tcl_Obj *dataPtr, /* Object to read the header from. */ - int *widthPtr, int *heightPtr, - /* The dimensions of the image are returned - * here. */ - int *maxIntensityPtr, /* The maximum intensity value for the image - * is stored here. */ - unsigned char **dataBufferPtr, - int *dataSizePtr) -{ -#define BUFFER_SIZE 1000 - char buffer[BUFFER_SIZE], c; - int i, numFields, dataSize, type = 0; - unsigned char *dataBuffer; - - dataBuffer = Tcl_GetByteArrayFromObj(dataPtr, &dataSize); - - /* - * Read 4 space-separated fields from the string, ignoring comments (any - * line that starts with "#"). - */ - - if (dataSize-- < 1) { - return 0; - } - c = (char) (*dataBuffer++); - i = 0; - for (numFields = 0; numFields < 4; numFields++) { - /* - * Skip comments and white space. - */ - - while (1) { - while (isspace(UCHAR(c))) { - if (dataSize-- < 1) { - return 0; - } - c = (char) (*dataBuffer++); - } - if (c != '#') { - break; - } - do { - if (dataSize-- < 1) { - return 0; - } - c = (char) (*dataBuffer++); - } while (c != '\n'); - } - - /* - * Read a field (everything up to the next white space). - */ - - while (!isspace(UCHAR(c))) { - if (i < (BUFFER_SIZE-2)) { - buffer[i] = c; - i++; - } - if (dataSize-- < 1) { - goto done; - } - c = (char) (*dataBuffer++); - } - if (i < (BUFFER_SIZE-1)) { - buffer[i] = ' '; - i++; - } - } - - done: - buffer[i] = 0; - - /* - * Parse the fields, which are: id, width, height, maxIntensity. - */ - - if (strncmp(buffer, "P6 ", 3) == 0) { - type = PPM; - } else if (strncmp(buffer, "P5 ", 3) == 0) { - type = PGM; - } else { - return 0; - } - if (sscanf(buffer+3, "%d %d %d", widthPtr, heightPtr, maxIntensityPtr) - != 3) { - return 0; - } - if (dataBufferPtr != NULL) { - *dataBufferPtr = dataBuffer; - *dataSizePtr = dataSize; - } - return type; -} - -/* - * Local Variables: - * mode: c - * c-basic-offset: 4 - * fill-column: 78 - * End: - */ |