stb_image: Check results of all mallocs.

A few were missing. Make sure to always report ouf-of-memory
errors.

Fixes issue #1056.

stb_image.h

@@ -48,7 +48,7 @@ LICENSE
 
 RECENT REVISION HISTORY:
 
-      2.27  (          ) document stbi_info better, 16-bit PNM support
+      2.27  (          ) document stbi_info better, 16-bit PNM support, bug fixes
       2.26  (2020-07-13) many minor fixes
       2.25  (2020-02-02) fix warnings
       2.24  (2020-02-02) fix warnings; thread-local failure_reason and flip_vertically
@@ -3936,6 +3936,7 @@ static void *stbi__jpeg_load(stbi__context *s, int *x, int *y, int *comp, int re
 {
    unsigned char* result;
    stbi__jpeg* j = (stbi__jpeg*) stbi__malloc(sizeof(stbi__jpeg));
+   if (!j) return stbi__errpuc("outofmem", "Out of memory");
    STBI_NOTUSED(ri);
    j->s = s;
    stbi__setup_jpeg(j);
@@ -3948,6 +3949,7 @@ static int stbi__jpeg_test(stbi__context *s)
 {
    int r;
    stbi__jpeg* j = (stbi__jpeg*)stbi__malloc(sizeof(stbi__jpeg));
+   if (!j) return stbi__err("outofmem", "Out of memory");
    j->s = s;
    stbi__setup_jpeg(j);
    r = stbi__decode_jpeg_header(j, STBI__SCAN_type);
@@ -3972,6 +3974,7 @@ static int stbi__jpeg_info(stbi__context *s, int *x, int *y, int *comp)
 {
    int result;
    stbi__jpeg* j = (stbi__jpeg*) (stbi__malloc(sizeof(stbi__jpeg)));
+   if (!j) return stbi__err("outofmem", "Out of memory");
    j->s = s;
    result = stbi__jpeg_info_raw(j, x, y, comp);
    STBI_FREE(j);
@@ -4771,6 +4774,7 @@ static int stbi__create_png_image(stbi__png *a, stbi_uc *image_data, stbi__uint3
 
    // de-interlacing
    final = (stbi_uc *) stbi__malloc_mad3(a->s->img_x, a->s->img_y, out_bytes, 0);
+   if (!final) return stbi__err("outofmem", "Out of memory");
    for (p=0; p < 7; ++p) {
       int xorig[] = { 0,4,0,2,0,1,0 };
       int yorig[] = { 0,0,4,0,2,0,1 };
@@ -6354,6 +6358,7 @@ static void *stbi__pic_load(stbi__context *s,int *px,int *py,int *comp,int req_c
 
    // intermediate buffer is RGBA
    result = (stbi_uc *) stbi__malloc_mad3(x, y, 4, 0);
+   if (!result) return stbi__errpuc("outofmem", "Out of memory");
    memset(result, 0xff, x*y*4);
 
    if (!stbi__pic_load_core(s,x,y,comp, result)) {
@@ -6469,6 +6474,7 @@ static int stbi__gif_header(stbi__context *s, stbi__gif *g, int *comp, int is_in
 static int stbi__gif_info_raw(stbi__context *s, int *x, int *y, int *comp)
 {
    stbi__gif* g = (stbi__gif*) stbi__malloc(sizeof(stbi__gif));
+   if (!g) return stbi__err("outofmem", "Out of memory");
    if (!stbi__gif_header(s, g, comp, 1)) {
       STBI_FREE(g);
       stbi__rewind( s );
@@ -6778,6 +6784,17 @@ static stbi_uc *stbi__gif_load_next(stbi__context *s, stbi__gif *g, int *comp, i
    }
 }
 
+static void *stbi__load_gif_main_outofmem(stbi__gif *g, stbi_uc *out, int **delays)
+{
+   STBI_FREE(g->out);
+   STBI_FREE(g->history);
+   STBI_FREE(g->background);
+
+   if (out) STBI_FREE(out);
+   if (delays && *delays) STBI_FREE(*delays);
+   return stbi__errpuc("outofmem", "Out of memory");
+}
+
 static void *stbi__load_gif_main(stbi__context *s, int **delays, int *x, int *y, int *z, int *comp, int req_comp)
 {
    if (stbi__gif_test(s)) {
@@ -6810,12 +6827,8 @@ static void *stbi__load_gif_main(stbi__context *s, int **delays, int *x, int *y,
 
             if (out) {
                void *tmp = (stbi_uc*) STBI_REALLOC_SIZED( out, out_size, layers * stride );
-               if (NULL == tmp) {
-                  STBI_FREE(g.out);
-                  STBI_FREE(g.history);
-                  STBI_FREE(g.background);
-                  return stbi__errpuc("outofmem", "Out of memory");
-               }
+               if (!tmp)
+                  return stbi__load_gif_main_outofmem(&g, out, delays);
                else {
                    out = (stbi_uc*) tmp;
                    out_size = layers * stride;
@@ -6823,13 +6836,19 @@ static void *stbi__load_gif_main(stbi__context *s, int **delays, int *x, int *y,
 
                if (delays) {
                   *delays = (int*) STBI_REALLOC_SIZED( *delays, delays_size, sizeof(int) * layers );
+                  if (!*delays)
+                     return stbi__load_gif_main_outofmem(&g, out, delays);
                   delays_size = layers * sizeof(int);
                }
             } else {
                out = (stbi_uc*)stbi__malloc( layers * stride );
+               if (!out)
+                  return stbi__load_gif_main_outofmem(&g, out, delays);
                out_size = layers * stride;
                if (delays) {
                   *delays = (int*) stbi__malloc( layers * sizeof(int) );
+                  if (!*delays)
+                     return stbi__load_gif_main_outofmem(&g, out, delays);
                   delays_size = layers * sizeof(int);
                }
             }