stb_image: pbm support

stb_image.h

@@ -1018,7 +1018,7 @@ static int stbi__mul2sizes_valid(int a, int b)
    return a <= INT_MAX/b;
 }
 
-#if !defined(STBI_NO_JPEG) || !defined(STBI_NO_PNG) || !defined(STBI_NO_TGA) || !defined(STBI_NO_HDR)
+#if !defined(STBI_NO_JPEG) || !defined(STBI_NO_PNG) || !defined(STBI_NO_TGA) || !defined(STBI_NO_HDR) || !defined(STBI_NO_PNM)
 // returns 1 if "a*b + add" has no negative terms/factors and doesn't overflow
 static int stbi__mad2sizes_valid(int a, int b, int add)
 {
@@ -1042,7 +1042,7 @@ static int stbi__mad4sizes_valid(int a, int b, int c, int d, int add)
 }
 #endif
 
-#if !defined(STBI_NO_JPEG) || !defined(STBI_NO_PNG) || !defined(STBI_NO_TGA) || !defined(STBI_NO_HDR)
+#if !defined(STBI_NO_JPEG) || !defined(STBI_NO_PNG) || !defined(STBI_NO_TGA) || !defined(STBI_NO_HDR) || !defined(STBI_NO_PNM)
 // mallocs with size overflow checking
 static void *stbi__malloc_mad2(int a, int b, int add)
 {
@@ -7493,7 +7493,7 @@ static int      stbi__pnm_test(stbi__context *s)
    char p, t;
    p = (char) stbi__get8(s);
    t = (char) stbi__get8(s);
-   if (p != 'P' || (t != '5' && t != '6')) {
+   if (p != 'P' || (t != '4' && t != '5' && t != '6')) {
        stbi__rewind( s );
        return 0;
    }
@@ -7503,12 +7503,12 @@ static int      stbi__pnm_test(stbi__context *s)
 static void *stbi__pnm_load(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri)
 {
    stbi_uc *out;
+   int bytes_per_channel;
    STBI_NOTUSED(ri);
 
    ri->bits_per_channel = stbi__pnm_info(s, (int *)&s->img_x, (int *)&s->img_y, (int *)&s->img_n);
    if (ri->bits_per_channel == 0)
       return 0;
-
    if (s->img_y > STBI_MAX_DIMENSIONS) return stbi__errpuc("too large","Very large image (corrupt?)");
    if (s->img_x > STBI_MAX_DIMENSIONS) return stbi__errpuc("too large","Very large image (corrupt?)");
 
@@ -7519,11 +7519,65 @@ static void *stbi__pnm_load(stbi__context *s, int *x, int *y, int *comp, int req
    if (!stbi__mad4sizes_valid(s->img_n, s->img_x, s->img_y, ri->bits_per_channel / 8, 0))
       return stbi__errpuc("too large", "PNM too large");
 
-   out = (stbi_uc *) stbi__malloc_mad4(s->img_n, s->img_x, s->img_y, ri->bits_per_channel / 8, 0);
+   if (ri->bits_per_channel == 16) bytes_per_channel = 2; else bytes_per_channel = 1;
+   out = (stbi_uc *) stbi__malloc_mad4(s->img_n, s->img_x, s->img_y, bytes_per_channel, 0);
    if (!out) return stbi__errpuc("outofmem", "Out of memory");
-   if (!stbi__getn(s, out, s->img_n * s->img_x * s->img_y * (ri->bits_per_channel / 8))) {
-      STBI_FREE(out);
-      return stbi__errpuc("bad PNM", "PNM file truncated");
+   if (ri->bits_per_channel == 1) {
+      stbi_uc *filebuf, *p_in, *p_out;
+      stbi__uint32 line, x, y, offset;
+
+      ri->bits_per_channel = 8;
+      line = s->img_x/8+((s->img_x%8>0)?1:0);
+
+      filebuf = (stbi_uc *) stbi__malloc_mad2(line, s->img_y, 0);
+      if (!filebuf) {
+         STBI_FREE(out);
+         return stbi__errpuc("outofmem", "Out of memory");
+      }
+      if (!stbi__getn(s, filebuf, line*s->img_y)) {
+         STBI_FREE(out);
+         STBI_FREE(filebuf);
+         return stbi__errpuc("bad PNM", "PNM file truncated");
+      }
+
+      p_in = filebuf;
+      p_out = out;
+      offset = 8;
+      for(y = 0; y < s->img_y; y++) {
+         for(x = 0; x < s->img_x; x++) {
+            offset--;
+            *(p_out++) = ((*p_in>>offset)&0x1)?0:255;
+            if(offset == 0) {
+               offset = 8;
+               p_in++;
+            }
+         }
+         if(offset != 8) {
+            offset = 8;
+            p_in++;
+         }
+      }
+
+      STBI_FREE(filebuf);
+   } else {
+      if (!stbi__getn(s, out, s->img_n * s->img_x * s->img_y * (ri->bits_per_channel / 8))) {
+         STBI_FREE(out);
+         return stbi__errpuc("bad PNM", "PNM file truncated");
+      }
+      if (ri->bits_per_channel == 16) {
+         stbi_uc *p8;
+         stbi__uint16 *p16;
+         size_t filesize;
+
+         p8 = out;
+         p16 = (stbi__uint16 *) out;
+         filesize = s->img_n * s->img_x * s->img_y;
+         while(filesize--) {
+            // Convert from BIG-ENDIAN
+            *(p16++) = p8[1] + p8[0]*256;
+            p8 += 2;
+         }
+      }
    }
 
    if (req_comp && req_comp != s->img_n) {
@@ -7589,12 +7643,12 @@ static int      stbi__pnm_info(stbi__context *s, int *x, int *y, int *comp)
    // Get identifier
    p = (char) stbi__get8(s);
    t = (char) stbi__get8(s);
-   if (p != 'P' || (t != '5' && t != '6')) {
+   if (p != 'P' || (t != '4' && t != '5' && t != '6')) {
        stbi__rewind(s);
        return 0;
    }
 
-   *comp = (t == '6') ? 3 : 1;  // '5' is 1-component .pgm; '6' is 3-component .ppm
+   *comp = (t == '6') ? 3 : 1;  // '4' is monochrome .pbm, '5' is 1-component .pgm; '6' is 3-component .ppm
 
    c = (char) stbi__get8(s);
    stbi__pnm_skip_whitespace(s, &c);
@@ -7607,6 +7661,7 @@ static int      stbi__pnm_info(stbi__context *s, int *x, int *y, int *comp)
    *y = stbi__pnm_getinteger(s, &c); // read height
    if (*y == 0)
        return stbi__err("invalid width", "PPM image header had zero or overflowing width");
+   if(t == '4') return 1; // Header ends here for PBM files
    stbi__pnm_skip_whitespace(s, &c);
 
    maxv = stbi__pnm_getinteger(s, &c);  // read max value

tests/ossfuzz.sh

@@ -22,7 +22,7 @@ unzip    $SRC/stbi/tga.zip    -d $SRC/stb/tests
 
 find $SRC/stb/tests -name "*.png" -o -name "*.jpg" -o -name "*.gif" \
                  -o -name "*.bmp" -o -name "*.tga" -o -name "*.TGA" \
-                 -o -name "*.ppm" -o -name "*.pgm" \
+                 -o -name "*.ppm" -o -name "*.pgm" -o -name "*.pbm" \
     | xargs zip $OUT/stbi_read_fuzzer_seed_corpus.zip
 
 echo "" >> $SRC/stbi/gif.dict