#ifndef _PGM_H_
#define _PGM_H_
 
#include <math.h>
#include <string.h>
 
#define PGM_MAGIC "P5"
 
#ifdef _WIN32
#define STRTOK_R(ptr, del, saveptr) strtok_s(ptr, del, saveptr)
#else
#define STRTOK_R(ptr, del, saveptr) strtok_r(ptr, del, saveptr)
#endif
 
typedef struct _pgm_t {
int width;
int height;
unsigned char *buf;
} pgm_t;
 
int readPGM(pgm_t* pgm, const char* filename)
{
char *token, *pc, *saveptr;
char *buf;
size_t bufsize;
char del[] = " \t\n";
unsigned char *dot;
 
long begin, end;
int filesize;
int i, w, h, luma, pixs;
 
 
FILE* fp;
if ((fp = fopen(filename, "rb"))==NULL) {
fprintf(stderr, "Failed to open file\n");
return -1;
}
 
fseek(fp, 0, SEEK_SET);
begin = ftell(fp);
fseek(fp, 0, SEEK_END);
end = ftell(fp);
filesize = (int)(end - begin);
 
buf = (char*)malloc(filesize * sizeof(char));
fseek(fp, 0, SEEK_SET);
bufsize = fread(buf, filesize * sizeof(char), 1, fp);
 
fclose(fp);
 
token = (char *)STRTOK_R(buf, del, &saveptr);
if (strncmp(token, PGM_MAGIC, 2) != 0) {
return -1;
}
 
token = (char *)STRTOK_R(NULL, del, &saveptr);
if (token[0] == '#' ) {
token = (char *)STRTOK_R(NULL, "\n", &saveptr);
token = (char *)STRTOK_R(NULL, del, &saveptr);
}
 
w = strtoul(token, &pc, 10);
token = (char *)STRTOK_R(NULL, del, &saveptr);
h = strtoul(token, &pc, 10);
token = (char *)STRTOK_R(NULL, del, &saveptr);
luma = strtoul(token, &pc, 10);
 
token = pc + 1;
pixs = w * h;
 
pgm->buf = (unsigned char *)malloc(pixs * sizeof(unsigned char));
 
dot = pgm->buf;
 
for (i=0; i< pixs; i++, dot++) {
*dot = *token++;
}
 
pgm->width = w;
pgm->height = h;
 
return 0;
}
 
int writePGM(pgm_t* pgm, const char* filename)
{
int i, w, h, pixs;
FILE* fp;
unsigned char* dot;
 
w = pgm->width;
h = pgm->height;
pixs = w * h;
 
if ((fp = fopen(filename, "wb+")) ==NULL) {
fprintf(stderr, "Failed to open file\n");
return -1;
}
 
fprintf (fp, "%s\n%d %d\n255\n", PGM_MAGIC, w, h);
 
dot = pgm->buf;
 
for (i=0; i<pixs; i++, dot++) {
putc((unsigned char)*dot, fp);
}
 
fclose(fp);
 
return 0;
}
 
int normalizeD2PGM(pgm_t* pgm, double* x)
{
int i, j, w, h;
 
w = pgm->width;
h = pgm->height;
 
pgm->buf = (unsigned char*)malloc(w * h * sizeof(unsigned char));
 
double min = 0;
double max = 0;
for (i=0; i < h; i++) {
for (j=0; j < w; j++) {
if (max < x[i*w+j])
max = x[i*w+j];
if (min > x[i*w+j])
min = x[i*w+j];
}
}
 
for (i=0; i < h; i++) {
for (j=0; j < w; j++) {
if((max-min)!=0)
pgm->buf[i*w+j] = (unsigned char)(255*(x[i*w+j]-min)/(max-min));
else
pgm->buf[i*w+j]= 0;
}
}
 
return 0;
}
 
int normalizeF2PGM(pgm_t* pgm, float* x)
{
int i, j, w, h;
 
w = pgm->width;
h = pgm->height;
 
pgm->buf = (unsigned char*)malloc(w * h * sizeof(unsigned char));
 
float min = 0;
float max = 0;
for (i=0; i < h; i++) {
for (j=0; j < w; j++) {
if (max < x[i*w+j])
max = x[i*w+j];
if (min > x[i*w+j])
min = x[i*w+j];
}
}
 
for (i=0; i < h; i++) {
for (j=0; j < w; j++) {
if((max-min)!=0)
pgm->buf[i*w+j] = (unsigned char)(255*(x[i*w+j]-min)/(max-min));
else
pgm->buf[i*w+j]= 0;
}
}
 
return 0;
}
 
int destroyPGM(pgm_t* pgm)
{
if (pgm->buf) {
free(pgm->buf);
}
 
return 0;
}
 
#endif /* _PGM_H_ */