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#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include "meh.h"
struct netpbm_t{
struct image img;
FILE *f;
char format;
unsigned int maxval;
};
void skipspace(FILE *f){
int c;
for(;;){
c = fgetc(f);
while(isspace(c))
c = fgetc(f);
if(c == '#')
while(fgetc(f) != '\n');
else
break;
}
ungetc(c, f);
}
struct image *netpbm_open(FILE *f){
struct netpbm_t *b;
rewind(f);
char format;
if(fgetc(f) != 'P')
return NULL;
format = fgetc(f);
if(format > '6' || format < '1')
return NULL;
b = malloc(sizeof(struct netpbm_t));
b->format = format;
skipspace(f);
fscanf(f, "%u", &b->img.bufwidth);
skipspace(f);
fscanf(f, "%u", &b->img.bufheight);
if(format == '1' || format == '4'){
b->maxval = 1;
}else{
skipspace(f);
fscanf(f, "%u", &b->maxval);
}
/* whitespace character */
fgetc(f);
b->f = f;
b->img.fmt = &netpbm;
return (struct image *)b;
}
static unsigned char readvali(struct netpbm_t *b){
skipspace(b->f);
int val;
fscanf(b->f, "%i", &val);
return val * 255 / b->maxval;
}
static unsigned char readvalb(struct netpbm_t *b){
if(b->maxval == 65535){
int val = fgetc(b->f) << 8;
val |= fgetc(b->f);
return val * 255 / b->maxval;
}else{
int val = fgetc(b->f);
return val * 255 / b->maxval;
}
}
int netpbm_read(struct image *img){
struct netpbm_t *b = (struct netpbm_t *)img;
FILE *f = b->f;
int a = 0;
int left = img->bufwidth * img->bufheight;
int j, c, val;
if(b->format == '1'){
while(left--){
skipspace(f);
val = fgetc(f);
val = val == '1' ? 0 : 255;
img->buf[a++] = val;
img->buf[a++] = val;
img->buf[a++] = val;
}
}else if(b->format == '2'){
while(left--){
val = readvali(b);
img->buf[a++] = val;
img->buf[a++] = val;
img->buf[a++] = val;
}
}else if(b->format == '3'){
while(left--){
img->buf[a++] = readvali(b);
img->buf[a++] = readvali(b);
img->buf[a++] = readvali(b);
}
}else if(b->format == '4'){
while(left){
c = fgetc(f);
for(j = 0; j < 8 && left; j++){
int val = (c & 1) ? 0 : 255;
img->buf[a++] = val;
img->buf[a++] = val;
img->buf[a++] = val;
c >>= 1;
left--;
}
}
}else if(b->format == '5'){
while(left--){
val = readvalb(b);
img->buf[a++] = val;
img->buf[a++] = val;
img->buf[a++] = val;
}
}else if(b->format == '6'){
if(b->maxval == 255){
fread(img->buf, 1, left * 3, f);
}else{
while(left--){
img->buf[a++] = readvalb(b);
img->buf[a++] = readvalb(b);
img->buf[a++] = readvalb(b);
}
}
}
img->state |= LOADED | SLOWLOADED;
return 0;
}
void netpbm_close(struct image *img){
struct netpbm_t *b = (struct netpbm_t *)img;
fclose(b->f);
}
struct imageformat netpbm = {
netpbm_open,
NULL,
netpbm_read,
netpbm_close
};
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