Upgrade libjpeg 8c -> 9e

extern/libjpeg/jdct.h

@@ -2,6 +2,7 @@
  * jdct.h
  *
  * Copyright (C) 1994-1996, Thomas G. Lane.
+ * Modified 2002-2019 by Guido Vollbeding.
  * This file is part of the Independent JPEG Group's software.
  * For conditions of distribution and use, see the accompanying README file.
  *
@@ -78,13 +79,15 @@ typedef FAST_FLOAT FLOAT_MULT_TYPE; /* preferred floating type */
  * converting them to unsigned form (0..MAXJSAMPLE).  The raw outputs could
  * be quite far out of range if the input data is corrupt, so a bulletproof
  * range-limiting step is required.  We use a mask-and-table-lookup method
- * to do the combined operations quickly.  See the comments with
+ * to do the combined operations quickly, assuming that RANGE_CENTER
+ * (defined in jpegint.h) is a power of 2.  See the comments with
  * prepare_range_limit_table (in jdmaster.c) for more info.
  */
 
-#define IDCT_range_limit(cinfo)  ((cinfo)->sample_range_limit + CENTERJSAMPLE)
+#define RANGE_MASK  (RANGE_CENTER * 2 - 1)
+#define RANGE_SUBSET  (RANGE_CENTER - CENTERJSAMPLE)
 
-#define RANGE_MASK  (MAXJSAMPLE * 4 + 3) /* 2 bits wider than legal samples */
+#define IDCT_range_limit(cinfo)  ((cinfo)->sample_range_limit - RANGE_SUBSET)
 
 
 /* Short forms of external names for systems with brain-damaged linkers. */
@@ -355,13 +358,6 @@ EXTERN(void) jpeg_idct_1x2
 
 #define FIX(x)	((INT32) ((x) * CONST_SCALE + 0.5))
 
-/* Descale and correctly round an INT32 value that's scaled by N bits.
- * We assume RIGHT_SHIFT rounds towards minus infinity, so adding
- * the fudge factor is correct for either sign of X.
- */
-
-#define DESCALE(x,n)  RIGHT_SHIFT((x) + (ONE << ((n)-1)), n)
-
 /* Multiply an INT32 variable by an INT32 constant to yield an INT32 result.
  * This macro is used only when the two inputs will actually be no more than
  * 16 bits wide, so that a 16x16->32 bit multiply can be used instead of a
@@ -391,3 +387,23 @@ EXTERN(void) jpeg_idct_1x2
 #ifndef MULTIPLY16V16		/* default definition */
 #define MULTIPLY16V16(var1,var2)  ((var1) * (var2))
 #endif
+
+/* Like RIGHT_SHIFT, but applies to a DCTELEM.
+ * We assume that int right shift is unsigned if INT32 right shift is.
+ */
+
+#ifdef RIGHT_SHIFT_IS_UNSIGNED
+#define ISHIFT_TEMPS	DCTELEM ishift_temp;
+#if BITS_IN_JSAMPLE == 8
+#define DCTELEMBITS  16		/* DCTELEM may be 16 or 32 bits */
+#else
+#define DCTELEMBITS  32		/* DCTELEM must be 32 bits */
+#endif
+#define IRIGHT_SHIFT(x,shft)  \
+    ((ishift_temp = (x)) < 0 ? \
+     (ishift_temp >> (shft)) | ((~((DCTELEM) 0)) << (DCTELEMBITS-(shft))) : \
+     (ishift_temp >> (shft)))
+#else
+#define ISHIFT_TEMPS
+#define IRIGHT_SHIFT(x,shft)	((x) >> (shft))
+#endif