Avoid tautological comparisons

Several TurboJPEG functions store their return value in an unsigned
long long intermediate and compare it against the maximum value of
unsigned long or size_t in order to avoid integer overflow.  However,
such comparisons are tautological (always true, i.e. redundant) unless
the size of unsigned long or size_t is less than the size of unsigned
long long.  Explicitly guarding the comparisons with #if avoids compiler
warnings with -Wtautological-constant-in-range-compare in Clang and also
makes it clear to the reader that the comparisons are only intended for
32-bit code.

Refer to #752

tjbench.c

@@ -37,6 +37,9 @@
 #include <math.h>
 #include <errno.h>
 #include <limits.h>
+#if !defined(_MSC_VER) || _MSC_VER > 1600
+#include <stdint.h>
+#endif
 #include <cdjpeg.h>
 #include "./tjutil.h"
 #include "./turbojpeg.h"
@@ -223,9 +226,11 @@ static int decomp(unsigned char **jpegBufs, size_t *jpegSizes, void *dstBuf,
   pitch = scaledw * ps;
 
   if (dstBuf == NULL) {
+#if ULLONG_MAX > SIZE_MAX
     if ((unsigned long long)pitch * (unsigned long long)scaledh *
         (unsigned long long)sampleSize > (unsigned long long)((size_t)-1))
       THROW("allocating destination buffer", "Image is too large");
+#endif
     if ((dstBuf = malloc((size_t)pitch * scaledh * sampleSize)) == NULL)
       THROW_UNIX("allocating destination buffer");
     dstBufAlloc = 1;
@@ -382,9 +387,11 @@ static int fullTest(tjhandle handle, void *srcBuf, int w, int h, int subsamp,
   int ntilesw = 1, ntilesh = 1, pitch = w * ps;
   const char *pfStr = pixFormatStr[pf];
 
+#if ULLONG_MAX > SIZE_MAX
   if ((unsigned long long)pitch * (unsigned long long)h *
       (unsigned long long)sampleSize > (unsigned long long)((size_t)-1))
     THROW("allocating temporary image buffer", "Image is too large");
+#endif
   if ((tmpBuf = malloc((size_t)pitch * h * sampleSize)) == NULL)
     THROW_UNIX("allocating temporary image buffer");
 

tjexample.c

@@ -40,6 +40,10 @@
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
+#include <limits.h>
+#if !defined(_MSC_VER) || _MSC_VER > 1600
+#include <stdint.h>
+#endif
 #include <turbojpeg.h>
 
 
@@ -335,9 +339,11 @@ int main(int argc, char **argv)
       outSubsamp = inSubsamp;
 
     pixelFormat = TJPF_BGRX;
+#if ULLONG_MAX > SIZE_MAX
     if ((unsigned long long)width * height * tjPixelSize[pixelFormat] >
         (unsigned long long)((size_t)-1))
       THROW("allocating uncompressed image buffer", "Image is too large");
+#endif
     if ((imgBuf =
          (unsigned char *)malloc(sizeof(unsigned char) * width * height *
                                  tjPixelSize[pixelFormat])) == NULL)

turbojpeg-mp.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (C)2009-2023 D. R. Commander.  All Rights Reserved.
+ * Copyright (C)2009-2024 D. R. Commander.  All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -366,8 +366,11 @@ DLLEXPORT _JSAMPLE *GET_NAME(tj3LoadImage, BITS_IN_JSAMPLE)
   *pixelFormat = cs2pf[cinfo->in_color_space];
 
   pitch = PAD((*width) * tjPixelSize[*pixelFormat], align);
-  if ((unsigned long long)pitch * (unsigned long long)(*height) >
+  if (
+#if ULLONG_MAX > SIZE_MAX
+      (unsigned long long)pitch * (unsigned long long)(*height) >
       (unsigned long long)((size_t)-1) ||
+#endif
       (dstBuf = (_JSAMPLE *)malloc(pitch * (*height) *
                                    sizeof(_JSAMPLE))) == NULL)
     THROW("Memory allocation failure");

turbojpeg.c

@@ -32,6 +32,9 @@
 
 #include <ctype.h>
 #include <limits.h>
+#if !defined(_MSC_VER) || _MSC_VER > 1600
+#include <stdint.h>
+#endif
 #include <jinclude.h>
 #define JPEG_INTERNALS
 #include <jpeglib.h>
@@ -946,8 +949,10 @@ DLLEXPORT size_t tj3JPEGBufSize(int width, int height, int jpegSubsamp)
   mcuh = tjMCUHeight[jpegSubsamp];
   chromasf = jpegSubsamp == TJSAMP_GRAY ? 0 : 4 * 64 / (mcuw * mcuh);
   retval = PAD(width, mcuw) * PAD(height, mcuh) * (2ULL + chromasf) + 2048ULL;
+#if ULLONG_MAX > ULONG_MAX
   if (retval > (unsigned long long)((unsigned long)-1))
     THROWG("Image is too large", 0);
+#endif
 
 bailout:
   return (size_t)retval;
@@ -981,8 +986,10 @@ DLLEXPORT unsigned long TJBUFSIZE(int width, int height)
      larger than the uncompressed input (we wouldn't mention it if it hadn't
      happened before.) */
   retval = PAD(width, 16) * PAD(height, 16) * 6ULL + 2048ULL;
+#if ULLONG_MAX > ULONG_MAX
   if (retval > (unsigned long long)((unsigned long)-1))
     THROWG("Image is too large", (unsigned long)-1);
+#endif
 
 bailout:
   return (unsigned long)retval;
@@ -1008,8 +1015,10 @@ DLLEXPORT size_t tj3YUVBufSize(int width, int align, int height, int subsamp)
     if (pw == 0 || ph == 0) return 0;
     else retval += (unsigned long long)stride * ph;
   }
+#if ULLONG_MAX > ULONG_MAX
   if (retval > (unsigned long long)((unsigned long)-1))
     THROWG("Image is too large", 0);
+#endif
 
 bailout:
   return (size_t)retval;
@@ -1123,8 +1132,10 @@ DLLEXPORT size_t tj3YUVPlaneSize(int componentID, int width, int stride,
   else stride = abs(stride);
 
   retval = (unsigned long long)stride * (ph - 1) + pw;
+#if ULLONG_MAX > ULONG_MAX
   if (retval > (unsigned long long)((unsigned long)-1))
     THROWG("Image is too large", 0);
+#endif
 
 bailout:
   return (size_t)retval;