Data commit

Task/Bitmap-Read-a-PPM-file/C/bitmap-read-a-ppm-file-1.c

@@ -0,0 +1 @@
+image get_ppm(FILE *pf);

Task/Bitmap-Read-a-PPM-file/C/bitmap-read-a-ppm-file-2.c

@@ -0,0 +1,38 @@
+#include "imglib.h"
+
+#define PPMREADBUFLEN 256
+image get_ppm(FILE *pf)
+{
+        char buf[PPMREADBUFLEN], *t;
+        image img;
+        unsigned int w, h, d;
+        int r;
+
+        if (pf == NULL) return NULL;
+        t = fgets(buf, PPMREADBUFLEN, pf);
+        /* the code fails if the white space following "P6" is not '\n' */
+        if ( (t == NULL) || ( strncmp(buf, "P6\n", 3) != 0 ) ) return NULL;
+        do
+        { /* Px formats can have # comments after first line */
+           t = fgets(buf, PPMREADBUFLEN, pf);
+           if ( t == NULL ) return NULL;
+        } while ( strncmp(buf, "#", 1) == 0 );
+        r = sscanf(buf, "%u %u", &w, &h);
+        if ( r < 2 ) return NULL;
+
+        r = fscanf(pf, "%u", &d);
+        if ( (r < 1) || ( d != 255 ) ) return NULL;
+        fseek(pf, 1, SEEK_CUR); /* skip one byte, should be whitespace */
+
+        img = alloc_img(w, h);
+        if ( img != NULL )
+        {
+            size_t rd = fread(img->buf, sizeof(pixel), w*h, pf);
+            if ( rd < w*h )
+            {
+               free_img(img);
+               return NULL;
+            }
+            return img;
+        }
+}

Task/Bitmap-Read-a-PPM-file/C/bitmap-read-a-ppm-file-3.c

@@ -0,0 +1,16 @@
+#include <stdio.h>
+#include "imglib.h"
+
+int main()
+{
+   image source;
+   grayimage idest;
+
+   source = get_ppm(stdin);
+   idest = tograyscale(source);
+   free_img(source);
+   source = tocolor(idest);
+   output_ppm(stdout, source);
+   free_img(source); free_img((image)idest);
+   return 0;
+}