pgm_io.cu

/*******************************************************************************
* FILE: pgm_io.c
* This code was written by Mike Heath. heath@csee.usf.edu (in 1995).
*******************************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
/******************************************************************************
* Function: read_pgm_image
* Purpose: This function reads in an image in PGM format. The image can be
* read in from either a file or from standard input. The image is only read
* from standard input when infilename = NULL. Because the PGM format includes
* the number of columns and the number of rows in the image, these are read
* from the file. Memory to store the image is allocated in this function.
* All comments in the header are discarded in the process of reading the
* image. Upon failure, this function returns 0, upon sucess it returns 1.
******************************************************************************/
int read_pgm_image(char *infilename, unsigned char **image, int *rows,
	int *cols)
{
	errno_t err;
	FILE *fp;
	char buf[71];

	/***************************************************************************
	* Open the input image file for reading if a filename was given. If no
	* filename was provided, set fp to read from standard input.
	***************************************************************************/
	if (infilename == NULL) fp = stdin;
	else{
		if ((err = fopen_s(&fp, infilename, "rb")) != 0){
			fprintf(stderr, "Error reading the file '%s' in read_pgm_image(): %d \n",
				infilename, err);
			return(0);
		}
	}

	/***************************************************************************
	* Verify that the image is in PGM format, read in the number of columns
	* and rows in the image and scan past all of the header information.
	***************************************************************************/
	fgets(buf, 70, fp);
	if (strncmp(buf, "P5", 2) != 0){
		fprintf(stderr, "The file %s is not in PGM format in ", infilename);
		fprintf(stderr, "read_pgm_image().\n");
		if (fp != stdin) fclose(fp);
		return(0);
	}
	do{
		fgets(buf, 70, fp);
	} while (buf[0] == '#' || buf[0] == '\n');  /* skip all comment lines */
	sscanf_s(buf, "%d %d", cols, rows);
	do{
		fgets(buf, 70, fp);
	} while (buf[0] == '#');  /* skip all comment lines */

	/***************************************************************************
	* Allocate memory to store the image then read the image from the file.
	***************************************************************************/
	if (((*image) = (unsigned char *)malloc((*rows)*(*cols))) == NULL){
		fprintf(stderr, "Memory allocation failure in read_pgm_image().\n");
		if (fp != stdin) fclose(fp);
		return(0);
	}
	int tmp = fread((*image), (*cols), (*rows), fp);
	if ((*rows) != tmp){
		fprintf(stderr, "Error reading the image data in read_pgm_image().\n");
		if (fp != stdin) fclose(fp);
		free((*image));
		return(0);
	}

	if (fp != stdin) fclose(fp);
	return(1);
}

/******************************************************************************
* Function: write_pgm_image
* Purpose: This function writes an image in PGM format. The file is either
* written to the file specified by outfilename or to standard output if
* outfilename = NULL. A comment can be written to the header if coment != NULL.
******************************************************************************/
int write_pgm_image(char *outfilename, unsigned char *image, int rows,
	int cols, char *comment, int maxval)
{
	FILE *fp;
	errno_t err;
	/***************************************************************************
	* Open the output image file for writing if a filename was given. If no
	* filename was provided, set fp to write to standard output.
	***************************************************************************/
	if (outfilename == NULL) fp = stdout;
	else{
		if ((err = fopen_s(&fp, outfilename, "wb")) != 0){
			fprintf(stderr, "Error writing the file %s in write_pgm_image(): %d \n",
				outfilename, err);
			return(0);
		}
	}

	/***************************************************************************
	* Write the header information to the PGM file.
	***************************************************************************/
	fprintf(fp, "P5\n%d %d\n", cols, rows);
	if (comment != NULL)
		if (strlen(comment) <= 70) fprintf(fp, "# %s\n", comment);
	fprintf(fp, "%d\n", maxval);

	/***************************************************************************
	* Write the image data to the file.
	***************************************************************************/
	if (rows != fwrite(image, cols, rows, fp)){
		fprintf(stderr, "Error writing the image data in write_pgm_image().\n");
		if (fp != stdout) fclose(fp);
		return(0);
	}

	if (fp != stdout) fclose(fp);
	return(1);
}

/******************************************************************************
* Function: read_ppm_image
* Purpose: This function reads in an image in PPM format. The image can be
* read in from either a file or from standard input. The image is only read
* from standard input when infilename = NULL. Because the PPM format includes
* the number of columns and the number of rows in the image, these are read
* from the file. Memory to store the image is allocated in this function.
* All comments in the header are discarded in the process of reading the
* image. Upon failure, this function returns 0, upon sucess it returns 1.
******************************************************************************/
int read_ppm_image(char *infilename, unsigned char **image_red,
	unsigned char **image_grn, unsigned char **image_blu, int *rows,
	int *cols)
{
	FILE *fp;
	errno_t err;
	char buf[71];
	int p, size;

	/***************************************************************************
	* Open the input image file for reading if a filename was given. If no
	* filename was provided, set fp to read from standard input.
	***************************************************************************/
	if (infilename == NULL) fp = stdin;
	else{
		if ((err = fopen_s(&fp, infilename, "rb")) != 0){
			fprintf(stderr, "Error reading the file %s in read_ppm_image(): %d \n",
				infilename, err);
			return(0);
		}
	}

	/***************************************************************************
	* Verify that the image is in PPM format, read in the number of columns
	* and rows in the image and scan past all of the header information.
	***************************************************************************/
	fgets(buf, 70, fp);
	if (strncmp(buf, "P6", 2) != 0){
		fprintf(stderr, "The file %s is not in PPM format in ", infilename);
		fprintf(stderr, "read_ppm_image().\n");
		if (fp != stdin) fclose(fp);
		return(0);
	}
	do{ fgets(buf, 70, fp); } while (buf[0] == '#');  /* skip all comment lines */
	sscanf_s(buf, "%d %d", cols, rows);
	do{ fgets(buf, 70, fp); } while (buf[0] == '#');  /* skip all comment lines */

	/***************************************************************************
	* Allocate memory to store the image then read the image from the file.
	***************************************************************************/
	if (((*image_red) = (unsigned char *)malloc((*rows)*(*cols))) == NULL){
		fprintf(stderr, "Memory allocation failure in read_ppm_image().\n");
		if (fp != stdin) fclose(fp);
		return(0);
	}
	if (((*image_grn) = (unsigned char *)malloc((*rows)*(*cols))) == NULL){
		fprintf(stderr, "Memory allocation failure in read_ppm_image().\n");
		if (fp != stdin) fclose(fp);
		return(0);
	}
	if (((*image_blu) = (unsigned char *)malloc((*rows)*(*cols))) == NULL){
		fprintf(stderr, "Memory allocation failure in read_ppm_image().\n");
		if (fp != stdin) fclose(fp);
		return(0);
	}

	size = (*rows)*(*cols);
	for (p = 0; p<size; p++){
		(*image_red)[p] = (unsigned char)fgetc(fp);
		(*image_grn)[p] = (unsigned char)fgetc(fp);
		(*image_blu)[p] = (unsigned char)fgetc(fp);
	}

	if (fp != stdin) fclose(fp);
	return(1);
}

/******************************************************************************
* Function: write_ppm_image
* Purpose: This function writes an image in PPM format. The file is either
* written to the file specified by outfilename or to standard output if
* outfilename = NULL. A comment can be written to the header if coment != NULL.
******************************************************************************/
int write_ppm_image(char *outfilename, unsigned char *image_red,
	unsigned char *image_grn, unsigned char *image_blu, int rows,
	int cols, char *comment, int maxval)
{
	FILE *fp;
	errno_t err;
	long size, p;

	/***************************************************************************
	* Open the output image file for writing if a filename was given. If no
	* filename was provided, set fp to write to standard output.
	***************************************************************************/
	if (outfilename == NULL) fp = stdout;
	else{
		if ((err = fopen_s(&fp, outfilename, "wb")) != 0){
			fprintf(stderr, "Error writing the file %s in write_pgm_image(): %d \n",
				outfilename, err);
			return(0);
		}
	}

	/***************************************************************************
	* Write the header information to the PGM file.
	***************************************************************************/
	fprintf(fp, "P6\n%d %d\n", cols, rows);
	if (comment != NULL)
		if (strlen(comment) <= 70) fprintf(fp, "# %s\n", comment);
	fprintf(fp, "%d\n", maxval);

	/***************************************************************************
	* Write the image data to the file.
	***************************************************************************/
	size = (long)rows * (long)cols;
	for (p = 0; p<size; p++){      /* Write the image in pixel interleaved format. */
		fputc(image_red[p], fp);
		fputc(image_grn[p], fp);
		fputc(image_blu[p], fp);
	}

	if (fp != stdout) fclose(fp);
	return(1);
}