support for netpbm color and bw binary format (P4 and P6)

2 files changed, 107 insertions, 0 deletions

diff --git a/src/main.c b/src/main.c
index cddb436..3a669c6 100644
--- a/src/main.c
+++ b/src/main.c
@@ -26,10 +26,12 @@ extern struct imageformat libjpeg;
 extern struct imageformat giflib;
 extern struct imageformat libpng;
 extern struct imageformat bmp;
+extern struct imageformat netpbm;
 struct imageformat *formats[] = {
 	&libjpeg,
 	&bmp,
 	&libpng,
+	&netpbm,
 	&giflib, /* HACK! make gif last (uses read()) */
 	NULL
 };
diff --git a/src/netpbm.c b/src/netpbm.c
new file mode 100644
index 0000000..e6f6851
--- /dev/null
+++ b/src/netpbm.c
@@ -0,0 +1,105 @@
+
+#include <stdio.h>
+#include <stdlib.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;
+
+	return (struct image *)b;
+}
+
+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;
+
+	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 == '6'){
+		while(left){
+			img->buf[a++] = fgetc(f);
+			img->buf[a++] = fgetc(f);
+			img->buf[a++] = fgetc(f);
+			left--;
+		}
+	}
+
+	img->state = LOADED;
+	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
+};
+