Update stb_image to 2.25

src/libraries/stb/stb_image.h

@@ -1,4 +1,4 @@
-/* stb_image - v2.22 - public domain image loader - http://nothings.org/stb
+/* stb_image - v2.25 - public domain image loader - http://nothings.org/stb
                                   no warranty implied; use at your own risk
 
    Do this:
@@ -48,9 +48,12 @@ LICENSE
 
 RECENT REVISION HISTORY:
 
+      2.25  (2020-02-02) fix warnings
+      2.24  (2020-02-02) fix warnings; thread-local failure_reason and flip_vertically
+      2.23  (2019-08-11) fix clang static analysis warning
       2.22  (2019-03-04) gif fixes, fix warnings
       2.21  (2019-02-25) fix typo in comment
-      2.20  (2019-02-07) support utf8 filenames in Windows; fix warnings and platform ifdefs 
+      2.20  (2019-02-07) support utf8 filenames in Windows; fix warnings and platform ifdefs
       2.19  (2018-02-11) fix warning
       2.18  (2018-01-30) fix warnings
       2.17  (2018-01-29) bugfix, 1-bit BMP, 16-bitness query, fix warnings
@@ -104,7 +107,8 @@ RECENT REVISION HISTORY:
     Oriol Ferrer Mesia      Josh Tobin         Matthew Gregan     github:phprus
     Julian Raschke          Gregory Mullen     Baldur Karlsson    github:poppolopoppo
     Christian Floisand      Kevin Schmidt      JR Smith           github:darealshinji
-    Blazej Dariusz Roszkowski                                     github:Michaelangel007
+    Brad Weinberger         Matvey Cherevko                       github:Michaelangel007
+    Blazej Dariusz Roszkowski                  Alexander Veselov
 */
 
 #ifndef STBI_INCLUDE_STB_IMAGE_H
@@ -433,7 +437,7 @@ STBIDEF int      stbi_is_hdr_from_file(FILE *f);
 
 
 // get a VERY brief reason for failure
-// NOT THREADSAFE
+// on most compilers (and ALL modern mainstream compilers) this is threadsafe
 STBIDEF const char *stbi_failure_reason  (void);
 
 // free the loaded image -- this is just free()
@@ -466,6 +470,11 @@ STBIDEF void stbi_convert_iphone_png_to_rgb(int flag_true_if_should_convert);
 // flip the image vertically, so the first pixel in the output array is the bottom left
 STBIDEF void stbi_set_flip_vertically_on_load(int flag_true_if_should_flip);
 
+// as above, but only applies to images loaded on the thread that calls the function
+// this function is only available if your compiler supports thread-local variables;
+// calling it will fail to link if your compiler doesn't
+STBIDEF void stbi_set_flip_vertically_on_load_thread(int flag_true_if_should_flip);
+
 // ZLIB client - used by PNG, available for other purposes
 
 STBIDEF char *stbi_zlib_decode_malloc_guesssize(const char *buffer, int len, int initial_size, int *outlen);
@@ -562,6 +571,17 @@ STBIDEF int   stbi_zlib_decode_noheader_buffer(char *obuffer, int olen, const ch
    #define stbi_inline __forceinline
 #endif
 
+#ifndef STBI_NO_THREAD_LOCALS
+   #if defined(__cplusplus) &&  __cplusplus >= 201103L
+      #define STBI_THREAD_LOCAL       thread_local
+   #elif defined (__STDC_VERSION__) && __STDC_VERSION__ >= 201112L
+      #define STBI_THREAD_LOCAL       _Thread_local
+   #elif defined(__GNUC__)
+      #define STBI_THREAD_LOCAL       __thread
+   #elif defined(_MSC_VER)
+      #define STBI_THREAD_LOCAL       __declspec(thread)
+#endif
+#endif
 
 #ifdef _MSC_VER
 typedef unsigned short stbi__uint16;
@@ -872,19 +892,24 @@ static void    *stbi__pnm_load(stbi__context *s, int *x, int *y, int *comp, int
 static int      stbi__pnm_info(stbi__context *s, int *x, int *y, int *comp);
 #endif
 
-// this is not threadsafe
-static const char *stbi__g_failure_reason;
+static
+#ifdef STBI_THREAD_LOCAL
+STBI_THREAD_LOCAL
+#endif
+const char *stbi__g_failure_reason;
 
 STBIDEF const char *stbi_failure_reason(void)
 {
    return stbi__g_failure_reason;
 }
 
+#ifndef STBI_NO_FAILURE_STRINGS
 static int stbi__err(const char *str)
 {
    stbi__g_failure_reason = str;
    return 0;
 }
+#endif
 
 static void *stbi__malloc(size_t size)
 {
@@ -923,11 +948,13 @@ 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)
 // 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)
 {
    return stbi__mul2sizes_valid(a, b) && stbi__addsizes_valid(a*b, add);
 }
+#endif
 
 // returns 1 if "a*b*c + add" has no negative terms/factors and doesn't overflow
 static int stbi__mad3sizes_valid(int a, int b, int c, int add)
@@ -945,12 +972,14 @@ 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)
 // mallocs with size overflow checking
 static void *stbi__malloc_mad2(int a, int b, int add)
 {
    if (!stbi__mad2sizes_valid(a, b, add)) return NULL;
    return stbi__malloc(a*b + add);
 }
+#endif
 
 static void *stbi__malloc_mad3(int a, int b, int c, int add)
 {
@@ -994,13 +1023,29 @@ static float   *stbi__ldr_to_hdr(stbi_uc *data, int x, int y, int comp);
 static stbi_uc *stbi__hdr_to_ldr(float   *data, int x, int y, int comp);
 #endif
 
-static int stbi__vertically_flip_on_load = 0;
+static int stbi__vertically_flip_on_load_global = 0;
 
 STBIDEF void stbi_set_flip_vertically_on_load(int flag_true_if_should_flip)
 {
-    stbi__vertically_flip_on_load = flag_true_if_should_flip;
+   stbi__vertically_flip_on_load_global = flag_true_if_should_flip;
 }
 
+#ifndef STBI_THREAD_LOCAL
+#define stbi__vertically_flip_on_load  stbi__vertically_flip_on_load_global
+#else
+static STBI_THREAD_LOCAL int stbi__vertically_flip_on_load_local, stbi__vertically_flip_on_load_set;
+
+STBIDEF void stbi_set_flip_vertically_on_load_thread(int flag_true_if_should_flip)
+{
+   stbi__vertically_flip_on_load_local = flag_true_if_should_flip;
+   stbi__vertically_flip_on_load_set = 1;
+}
+
+#define stbi__vertically_flip_on_load  (stbi__vertically_flip_on_load_set       \
+                                         ? stbi__vertically_flip_on_load_local  \
+                                         : stbi__vertically_flip_on_load_global)
+#endif // STBI_THREAD_LOCAL
+
 static void *stbi__load_main(stbi__context *s, int *x, int *y, int *comp, int req_comp, stbi__result_info *ri, int bpc)
 {
    memset(ri, 0, sizeof(*ri)); // make sure it's initialized if we add new fields
@@ -1022,6 +1067,8 @@ static void *stbi__load_main(stbi__context *s, int *x, int *y, int *comp, int re
    #endif
    #ifndef STBI_NO_PSD
    if (stbi__psd_test(s))  return stbi__psd_load(s,x,y,comp,req_comp, ri, bpc);
+   #else
+   STBI_NOTUSED(bpc);
    #endif
    #ifndef STBI_NO_PIC
    if (stbi__pic_test(s))  return stbi__pic_load(s,x,y,comp,req_comp, ri);
@@ -1110,8 +1157,8 @@ static void stbi__vertical_flip_slices(void *image, int w, int h, int z, int byt
 
    stbi_uc *bytes = (stbi_uc *)image;
    for (slice = 0; slice < z; ++slice) {
-      stbi__vertical_flip(bytes, w, h, bytes_per_pixel); 
-      bytes += slice_size; 
+      stbi__vertical_flip(bytes, w, h, bytes_per_pixel);
+      bytes += slice_size;
    }
 }
 #endif
@@ -1197,7 +1244,7 @@ static FILE *stbi__fopen(char const *filename, char const *mode)
    wchar_t wFilename[1024];
 	if (0 == MultiByteToWideChar(65001 /* UTF8 */, 0, filename, -1, wFilename, sizeof(wFilename)))
       return 0;
-	
+
 	if (0 == MultiByteToWideChar(65001 /* UTF8 */, 0, mode, -1, wMode, sizeof(wMode)))
       return 0;
 
@@ -1299,15 +1346,15 @@ STBIDEF stbi_uc *stbi_load_from_callbacks(stbi_io_callbacks const *clbk, void *u
 STBIDEF stbi_uc *stbi_load_gif_from_memory(stbi_uc const *buffer, int len, int **delays, int *x, int *y, int *z, int *comp, int req_comp)
 {
    unsigned char *result;
-   stbi__context s; 
-   stbi__start_mem(&s,buffer,len); 
-   
+   stbi__context s;
+   stbi__start_mem(&s,buffer,len);
+
    result = (unsigned char*) stbi__load_gif_main(&s, delays, x, y, z, comp, req_comp);
    if (stbi__vertically_flip_on_load) {
-      stbi__vertical_flip_slices( result, *x, *y, *z, *comp ); 
+      stbi__vertical_flip_slices( result, *x, *y, *z, *comp );
    }
 
-   return result; 
+   return result;
 }
 #endif
 
@@ -1476,6 +1523,9 @@ stbi_inline static stbi_uc stbi__get8(stbi__context *s)
    return 0;
 }
 
+#if defined(STBI_NO_JPEG) && defined(STBI_NO_HDR) && defined(STBI_NO_PIC) && defined(STBI_NO_PNM)
+// nothing
+#else
 stbi_inline static int stbi__at_eof(stbi__context *s)
 {
    if (s->io.read) {
@@ -1487,7 +1537,11 @@ stbi_inline static int stbi__at_eof(stbi__context *s)
 
    return s->img_buffer >= s->img_buffer_end;
 }
+#endif
 
+#if defined(STBI_NO_JPEG) && defined(STBI_NO_PNG) && defined(STBI_NO_BMP) && defined(STBI_NO_PSD) && defined(STBI_NO_TGA) && defined(STBI_NO_GIF) && defined(STBI_NO_PIC)
+// nothing
+#else
 static void stbi__skip(stbi__context *s, int n)
 {
    if (n < 0) {
@@ -1504,7 +1558,11 @@ static void stbi__skip(stbi__context *s, int n)
    }
    s->img_buffer += n;
 }
+#endif
 
+#if defined(STBI_NO_PNG) && defined(STBI_NO_TGA) && defined(STBI_NO_HDR) && defined(STBI_NO_PNM)
+// nothing
+#else
 static int stbi__getn(stbi__context *s, stbi_uc *buffer, int n)
 {
    if (s->io.read) {
@@ -1528,18 +1586,27 @@ static int stbi__getn(stbi__context *s, stbi_uc *buffer, int n)
    } else
       return 0;
 }
+#endif
 
+#if defined(STBI_NO_JPEG) && defined(STBI_NO_PNG) && defined(STBI_NO_PSD) && defined(STBI_NO_PIC)
+// nothing
+#else
 static int stbi__get16be(stbi__context *s)
 {
    int z = stbi__get8(s);
    return (z << 8) + stbi__get8(s);
 }
+#endif
 
+#if defined(STBI_NO_PNG) && defined(STBI_NO_PSD) && defined(STBI_NO_PIC)
+// nothing
+#else
 static stbi__uint32 stbi__get32be(stbi__context *s)
 {
    stbi__uint32 z = stbi__get16be(s);
    return (z << 16) + stbi__get16be(s);
 }
+#endif
 
 #if defined(STBI_NO_BMP) && defined(STBI_NO_TGA) && defined(STBI_NO_GIF)
 // nothing
@@ -1561,7 +1628,9 @@ static stbi__uint32 stbi__get32le(stbi__context *s)
 
 #define STBI__BYTECAST(x)  ((stbi_uc) ((x) & 255))  // truncate int to byte without warnings
 
-
+#if defined(STBI_NO_JPEG) && defined(STBI_NO_PNG) && defined(STBI_NO_BMP) && defined(STBI_NO_PSD) && defined(STBI_NO_TGA) && defined(STBI_NO_GIF) && defined(STBI_NO_PIC) && defined(STBI_NO_PNM)
+// nothing
+#else
 //////////////////////////////////////////////////////////////////////////////
 //
 //  generic converter from built-in img_n to req_comp
@@ -1577,7 +1646,11 @@ static stbi_uc stbi__compute_y(int r, int g, int b)
 {
    return (stbi_uc) (((r*77) + (g*150) +  (29*b)) >> 8);
 }
+#endif
 
+#if defined(STBI_NO_PNG) && defined(STBI_NO_BMP) && defined(STBI_NO_PSD) && defined(STBI_NO_TGA) && defined(STBI_NO_GIF) && defined(STBI_NO_PIC) && defined(STBI_NO_PNM)
+// nothing
+#else
 static unsigned char *stbi__convert_format(unsigned char *data, int img_n, int req_comp, unsigned int x, unsigned int y)
 {
    int i,j;
@@ -1621,12 +1694,20 @@ static unsigned char *stbi__convert_format(unsigned char *data, int img_n, int r
    STBI_FREE(data);
    return good;
 }
+#endif
 
+#if defined(STBI_NO_PNG) && defined(STBI_NO_PSD)
+// nothing
+#else
 static stbi__uint16 stbi__compute_y_16(int r, int g, int b)
 {
    return (stbi__uint16) (((r*77) + (g*150) +  (29*b)) >> 8);
 }
+#endif
 
+#if defined(STBI_NO_PNG) && defined(STBI_NO_PSD)
+// nothing
+#else
 static stbi__uint16 *stbi__convert_format16(stbi__uint16 *data, int img_n, int req_comp, unsigned int x, unsigned int y)
 {
    int i,j;
@@ -1670,6 +1751,7 @@ static stbi__uint16 *stbi__convert_format16(stbi__uint16 *data, int img_n, int r
    STBI_FREE(data);
    return good;
 }
+#endif
 
 #ifndef STBI_NO_LINEAR
 static float   *stbi__ldr_to_hdr(stbi_uc *data, int x, int y, int comp)
@@ -4941,6 +5023,8 @@ static int stbi__parse_png_file(stbi__png *z, int scan, int req_comp)
                ++s->img_n;
             }
             STBI_FREE(z->expanded); z->expanded = NULL;
+            // end of PNG chunk, read and skip CRC
+            stbi__get32be(s);
             return 1;
          }
 
@@ -5079,7 +5163,7 @@ static int stbi__high_bit(unsigned int z)
    if (z >= 0x00100) { n +=  8; z >>=  8; }
    if (z >= 0x00010) { n +=  4; z >>=  4; }
    if (z >= 0x00004) { n +=  2; z >>=  2; }
-   if (z >= 0x00002) { n +=  1; z >>=  1; }
+   if (z >= 0x00002) { n +=  1;/* >>=  1;*/ }
    return n;
 }
 
@@ -5110,7 +5194,7 @@ static int stbi__shiftsigned(unsigned int v, int shift, int bits)
       v <<= -shift;
    else
       v >>= shift;
-   STBI_ASSERT(v >= 0 && v < 256);
+   STBI_ASSERT(v < 256);
    v >>= (8-bits);
    STBI_ASSERT(bits >= 0 && bits <= 8);
    return (int) ((unsigned) v * mul_table[bits]) >> shift_table[bits];
@@ -5120,6 +5204,7 @@ typedef struct
 {
    int bpp, offset, hsz;
    unsigned int mr,mg,mb,ma, all_a;
+   int extra_read;
 } stbi__bmp_data;
 
 static void *stbi__bmp_parse_header(stbi__context *s, stbi__bmp_data *info)
@@ -5132,6 +5217,7 @@ static void *stbi__bmp_parse_header(stbi__context *s, stbi__bmp_data *info)
    info->offset = stbi__get32le(s);
    info->hsz = hsz = stbi__get32le(s);
    info->mr = info->mg = info->mb = info->ma = 0;
+   info->extra_read = 14;
 
    if (hsz != 12 && hsz != 40 && hsz != 56 && hsz != 108 && hsz != 124) return stbi__errpuc("unknown BMP", "BMP type not supported: unknown");
    if (hsz == 12) {
@@ -5175,6 +5261,7 @@ static void *stbi__bmp_parse_header(stbi__context *s, stbi__bmp_data *info)
                info->mr = stbi__get32le(s);
                info->mg = stbi__get32le(s);
                info->mb = stbi__get32le(s);
+               info->extra_read += 12;
                // not documented, but generated by photoshop and handled by mspaint
                if (info->mr == info->mg && info->mg == info->mb) {
                   // ?!?!?
@@ -5231,13 +5318,19 @@ static void *stbi__bmp_load(stbi__context *s, int *x, int *y, int *comp, int req
 
    if (info.hsz == 12) {
       if (info.bpp < 24)
-         psize = (info.offset - 14 - 24) / 3;
+         psize = (info.offset - info.extra_read - 24) / 3;
    } else {
       if (info.bpp < 16)
-         psize = (info.offset - 14 - info.hsz) >> 2;
+         psize = (info.offset - info.extra_read - info.hsz) >> 2;
+   }
+   if (psize == 0) {
+      STBI_ASSERT(info.offset == (s->img_buffer - s->buffer_start));
    }
 
-   s->img_n = ma ? 4 : 3;
+   if (info.bpp == 24 && ma == 0xff000000)
+      s->img_n = 3;
+   else
+      s->img_n = ma ? 4 : 3;
    if (req_comp && req_comp >= 3) // we can directly decode 3 or 4
       target = req_comp;
    else
@@ -5259,7 +5352,7 @@ static void *stbi__bmp_load(stbi__context *s, int *x, int *y, int *comp, int req
          if (info.hsz != 12) stbi__get8(s);
          pal[i][3] = 255;
       }
-      stbi__skip(s, info.offset - 14 - info.hsz - psize * (info.hsz == 12 ? 3 : 4));
+      stbi__skip(s, info.offset - info.extra_read - info.hsz - psize * (info.hsz == 12 ? 3 : 4));
       if (info.bpp == 1) width = (s->img_x + 7) >> 3;
       else if (info.bpp == 4) width = (s->img_x + 1) >> 1;
       else if (info.bpp == 8) width = s->img_x;
@@ -5308,7 +5401,7 @@ static void *stbi__bmp_load(stbi__context *s, int *x, int *y, int *comp, int req
       int rshift=0,gshift=0,bshift=0,ashift=0,rcount=0,gcount=0,bcount=0,acount=0;
       int z = 0;
       int easy=0;
-      stbi__skip(s, info.offset - 14 - info.hsz);
+      stbi__skip(s, info.offset - info.extra_read - info.hsz);
       if (info.bpp == 24) width = 3 * s->img_x;
       else if (info.bpp == 16) width = 2*s->img_x;
       else /* bpp = 32 and pad = 0 */ width=0;
@@ -5547,6 +5640,8 @@ static void *stbi__tga_load(stbi__context *s, int *x, int *y, int *comp, int req
    int RLE_repeating = 0;
    int read_next_pixel = 1;
    STBI_NOTUSED(ri);
+   STBI_NOTUSED(tga_x_origin); // @TODO
+   STBI_NOTUSED(tga_y_origin); // @TODO
 
    //   do a tiny bit of precessing
    if ( tga_image_type >= 8 )
@@ -5710,6 +5805,7 @@ static void *stbi__tga_load(stbi__context *s, int *x, int *y, int *comp, int req
    //   Microsoft's C compilers happy... [8^(
    tga_palette_start = tga_palette_len = tga_palette_bits =
          tga_x_origin = tga_y_origin = 0;
+   STBI_NOTUSED(tga_palette_start);
    //   OK, done
    return tga_data;
 }
@@ -6195,7 +6291,7 @@ typedef struct
    int w,h;
    stbi_uc *out;                 // output buffer (always 4 components)
    stbi_uc *background;          // The current "background" as far as a gif is concerned
-   stbi_uc *history; 
+   stbi_uc *history;
    int flags, bgindex, ratio, transparent, eflags;
    stbi_uc  pal[256][4];
    stbi_uc lpal[256][4];
@@ -6283,7 +6379,7 @@ static int stbi__gif_info_raw(stbi__context *s, int *x, int *y, int *comp)
 static void stbi__out_gif_code(stbi__gif *g, stbi__uint16 code)
 {
    stbi_uc *p, *c;
-   int idx; 
+   int idx;
 
    // recurse to decode the prefixes, since the linked-list is backwards,
    // and working backwards through an interleaved image would be nasty
@@ -6292,12 +6388,12 @@ static void stbi__out_gif_code(stbi__gif *g, stbi__uint16 code)
 
    if (g->cur_y >= g->max_y) return;
 
-   idx = g->cur_x + g->cur_y; 
+   idx = g->cur_x + g->cur_y;
    p = &g->out[idx];
-   g->history[idx / 4] = 1;  
+   g->history[idx / 4] = 1;
 
    c = &g->color_table[g->codes[code].suffix * 4];
-   if (c[3] > 128) { // don't render transparent pixels; 
+   if (c[3] > 128) { // don't render transparent pixels;
       p[0] = c[2];
       p[1] = c[1];
       p[2] = c[0];
@@ -6406,14 +6502,14 @@ static stbi_uc *stbi__process_gif_raster(stbi__context *s, stbi__gif *g)
 // two back is the image from two frames ago, used for a very specific disposal format
 static stbi_uc *stbi__gif_load_next(stbi__context *s, stbi__gif *g, int *comp, int req_comp, stbi_uc *two_back)
 {
-   int dispose; 
-   int first_frame; 
-   int pi; 
-   int pcount; 
+   int dispose;
+   int first_frame;
+   int pi;
+   int pcount;
    STBI_NOTUSED(req_comp);
 
    // on first frame, any non-written pixels get the background colour (non-transparent)
-   first_frame = 0; 
+   first_frame = 0;
    if (g->out == 0) {
       if (!stbi__gif_header(s, g, comp,0)) return 0; // stbi__g_failure_reason set by stbi__gif_header
       if (!stbi__mad3sizes_valid(4, g->w, g->h, 0))
@@ -6425,17 +6521,17 @@ static stbi_uc *stbi__gif_load_next(stbi__context *s, stbi__gif *g, int *comp, i
       if (!g->out || !g->background || !g->history)
          return stbi__errpuc("outofmem", "Out of memory");
 
-      // image is treated as "transparent" at the start - ie, nothing overwrites the current background; 
+      // image is treated as "transparent" at the start - ie, nothing overwrites the current background;
       // background colour is only used for pixels that are not rendered first frame, after that "background"
-      // color refers to the color that was there the previous frame. 
+      // color refers to the color that was there the previous frame.
       memset(g->out, 0x00, 4 * pcount);
       memset(g->background, 0x00, 4 * pcount); // state of the background (starts transparent)
       memset(g->history, 0x00, pcount);        // pixels that were affected previous frame
-      first_frame = 1; 
+      first_frame = 1;
    } else {
       // second frame - how do we dispoase of the previous one?
-      dispose = (g->eflags & 0x1C) >> 2; 
-      pcount = g->w * g->h; 
+      dispose = (g->eflags & 0x1C) >> 2;
+      pcount = g->w * g->h;
 
       if ((dispose == 3) && (two_back == 0)) {
          dispose = 2; // if I don't have an image to revert back to, default to the old background
@@ -6444,32 +6540,32 @@ static stbi_uc *stbi__gif_load_next(stbi__context *s, stbi__gif *g, int *comp, i
       if (dispose == 3) { // use previous graphic
          for (pi = 0; pi < pcount; ++pi) {
             if (g->history[pi]) {
-               memcpy( &g->out[pi * 4], &two_back[pi * 4], 4 ); 
+               memcpy( &g->out[pi * 4], &two_back[pi * 4], 4 );
             }
          }
-      } else if (dispose == 2) { 
-         // restore what was changed last frame to background before that frame; 
+      } else if (dispose == 2) {
+         // restore what was changed last frame to background before that frame;
          for (pi = 0; pi < pcount; ++pi) {
             if (g->history[pi]) {
-               memcpy( &g->out[pi * 4], &g->background[pi * 4], 4 ); 
+               memcpy( &g->out[pi * 4], &g->background[pi * 4], 4 );
             }
          }
       } else {
-         // This is a non-disposal case eithe way, so just 
+         // This is a non-disposal case eithe way, so just
          // leave the pixels as is, and they will become the new background
          // 1: do not dispose
          // 0:  not specified.
       }
 
-      // background is what out is after the undoing of the previou frame; 
-      memcpy( g->background, g->out, 4 * g->w * g->h ); 
+      // background is what out is after the undoing of the previou frame;
+      memcpy( g->background, g->out, 4 * g->w * g->h );
    }
 
-   // clear my history; 
+   // clear my history;
    memset( g->history, 0x00, g->w * g->h );        // pixels that were affected previous frame
 
    for (;;) {
-      int tag = stbi__get8(s); 
+      int tag = stbi__get8(s);
       switch (tag) {
          case 0x2C: /* Image Descriptor */
          {
@@ -6514,19 +6610,19 @@ static stbi_uc *stbi__gif_load_next(stbi__context *s, stbi__gif *g, int *comp, i
             } else if (g->flags & 0x80) {
                g->color_table = (stbi_uc *) g->pal;
             } else
-               return stbi__errpuc("missing color table", "Corrupt GIF");            
-            
+               return stbi__errpuc("missing color table", "Corrupt GIF");
+
             o = stbi__process_gif_raster(s, g);
             if (!o) return NULL;
 
-            // if this was the first frame, 
-            pcount = g->w * g->h; 
+            // if this was the first frame,
+            pcount = g->w * g->h;
             if (first_frame && (g->bgindex > 0)) {
                // if first frame, any pixel not drawn to gets the background color
                for (pi = 0; pi < pcount; ++pi) {
                   if (g->history[pi] == 0) {
-                     g->pal[g->bgindex][3] = 255; // just in case it was made transparent, undo that; It will be reset next frame if need be; 
-                     memcpy( &g->out[pi * 4], &g->pal[g->bgindex], 4 ); 
+                     g->pal[g->bgindex][3] = 255; // just in case it was made transparent, undo that; It will be reset next frame if need be;
+                     memcpy( &g->out[pi * 4], &g->pal[g->bgindex], 4 );
                   }
                }
             }
@@ -6537,7 +6633,7 @@ static stbi_uc *stbi__gif_load_next(stbi__context *s, stbi__gif *g, int *comp, i
          case 0x21: // Comment Extension.
          {
             int len;
-            int ext = stbi__get8(s); 
+            int ext = stbi__get8(s);
             if (ext == 0xF9) { // Graphic Control Extension.
                len = stbi__get8(s);
                if (len == 4) {
@@ -6546,23 +6642,23 @@ static stbi_uc *stbi__gif_load_next(stbi__context *s, stbi__gif *g, int *comp, i
 
                   // unset old transparent
                   if (g->transparent >= 0) {
-                     g->pal[g->transparent][3] = 255; 
-                  } 
+                     g->pal[g->transparent][3] = 255;
+                  }
                   if (g->eflags & 0x01) {
                      g->transparent = stbi__get8(s);
                      if (g->transparent >= 0) {
-                        g->pal[g->transparent][3] = 0; 
+                        g->pal[g->transparent][3] = 0;
                      }
                   } else {
                      // don't need transparent
-                     stbi__skip(s, 1); 
-                     g->transparent = -1; 
+                     stbi__skip(s, 1);
+                     g->transparent = -1;
                   }
                } else {
                   stbi__skip(s, len);
                   break;
                }
-            } 
+            }
             while ((len = stbi__get8(s)) != 0) {
                stbi__skip(s, len);
             }
@@ -6581,15 +6677,15 @@ static stbi_uc *stbi__gif_load_next(stbi__context *s, stbi__gif *g, int *comp, i
 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)) {
-      int layers = 0; 
+      int layers = 0;
       stbi_uc *u = 0;
       stbi_uc *out = 0;
-      stbi_uc *two_back = 0; 
+      stbi_uc *two_back = 0;
       stbi__gif g;
-      int stride; 
+      int stride;
       memset(&g, 0, sizeof(g));
       if (delays) {
-         *delays = 0; 
+         *delays = 0;
       }
 
       do {
@@ -6599,44 +6695,52 @@ static void *stbi__load_gif_main(stbi__context *s, int **delays, int *x, int *y,
          if (u) {
             *x = g.w;
             *y = g.h;
-            ++layers; 
-            stride = g.w * g.h * 4; 
-         
+            ++layers;
+            stride = g.w * g.h * 4;
+
             if (out) {
-               out = (stbi_uc*) STBI_REALLOC( out, layers * stride ); 
+               void *tmp = (stbi_uc*) STBI_REALLOC( out, layers * stride );
+               if (NULL == tmp) {
+                  STBI_FREE(g.out);
+                  STBI_FREE(g.history);
+                  STBI_FREE(g.background);
+                  return stbi__errpuc("outofmem", "Out of memory");
+               }
+               else
+                  out = (stbi_uc*) tmp;
                if (delays) {
-                  *delays = (int*) STBI_REALLOC( *delays, sizeof(int) * layers ); 
+                  *delays = (int*) STBI_REALLOC( *delays, sizeof(int) * layers );
                }
             } else {
-               out = (stbi_uc*)stbi__malloc( layers * stride ); 
+               out = (stbi_uc*)stbi__malloc( layers * stride );
                if (delays) {
-                  *delays = (int*) stbi__malloc( layers * sizeof(int) ); 
+                  *delays = (int*) stbi__malloc( layers * sizeof(int) );
                }
             }
-            memcpy( out + ((layers - 1) * stride), u, stride ); 
+            memcpy( out + ((layers - 1) * stride), u, stride );
             if (layers >= 2) {
-               two_back = out - 2 * stride; 
+               two_back = out - 2 * stride;
             }
 
             if (delays) {
-               (*delays)[layers - 1U] = g.delay; 
+               (*delays)[layers - 1U] = g.delay;
             }
          }
-      } while (u != 0); 
+      } while (u != 0);
 
-      // free temp buffer; 
-      STBI_FREE(g.out); 
-      STBI_FREE(g.history); 
-      STBI_FREE(g.background); 
+      // free temp buffer;
+      STBI_FREE(g.out);
+      STBI_FREE(g.history);
+      STBI_FREE(g.background);
 
-      // do the final conversion after loading everything; 
+      // do the final conversion after loading everything;
       if (req_comp && req_comp != 4)
          out = stbi__convert_format(out, 4, req_comp, layers * g.w, g.h);
 
-      *z = layers; 
+      *z = layers;
       return out;
    } else {
-      return stbi__errpuc("not GIF", "Image was not as a gif type."); 
+      return stbi__errpuc("not GIF", "Image was not as a gif type.");
    }
 }
 
@@ -6654,7 +6758,7 @@ static void *stbi__gif_load(stbi__context *s, int *x, int *y, int *comp, int req
       *y = g.h;
 
       // moved conversion to after successful load so that the same
-      // can be done for multiple frames. 
+      // can be done for multiple frames.
       if (req_comp && req_comp != 4)
          u = stbi__convert_format(u, 4, req_comp, g.w, g.h);
    } else if (g.out) {
@@ -6662,9 +6766,9 @@ static void *stbi__gif_load(stbi__context *s, int *x, int *y, int *comp, int req
       STBI_FREE(g.out);
    }
 
-   // free buffers needed for multiple frame loading; 
+   // free buffers needed for multiple frame loading;
    STBI_FREE(g.history);
-   STBI_FREE(g.background); 
+   STBI_FREE(g.background);
 
    return u;
 }
@@ -6936,7 +7040,12 @@ static int stbi__bmp_info(stbi__context *s, int *x, int *y, int *comp)
       return 0;
    if (x) *x = s->img_x;
    if (y) *y = s->img_y;
-   if (comp) *comp = info.ma ? 4 : 3;
+   if (comp) {
+      if (info.bpp == 24 && info.ma == 0xff000000)
+         *comp = 3;
+      else
+         *comp = info.ma ? 4 : 3;
+   }
    return 1;
 }
 #endif
@@ -7322,7 +7431,7 @@ STBIDEF int stbi_is_16_bit_from_callbacks(stbi_io_callbacks const *c, void *user
 
 /*
    revision history:
-      2.20  (2019-02-07) support utf8 filenames in Windows; fix warnings and platform ifdefs 
+      2.20  (2019-02-07) support utf8 filenames in Windows; fix warnings and platform ifdefs
       2.19  (2018-02-11) fix warning
       2.18  (2018-01-30) fix warnings
       2.17  (2018-01-29) change sbti__shiftsigned to avoid clang -O2 bug