Import Ghostscript 9.52ghostscript-9.52

Signed-off-by: Thomas Deutschmann <whissi@gentoo.org>

1 files changed, 33 insertions, 1 deletions

diff --git a/base/gsbitcom.c b/base/gsbitcom.c
index 5af03642..6c8c78fe 100644
--- a/base/gsbitcom.c
+++ b/base/gsbitcom.c
@@ -13,6 +13,7 @@
    CA 94945, U.S.A., +1(415)492-9861, for further information.
 */
 
+#include <assert.h>
 
 /* Oversampled bitmap compression */
 #include "std.h"
@@ -128,6 +129,34 @@ bits_compress_scaled(const byte * src, int srcx, uint width, uint height,
     byte *d = dest;
     uint h;
 
+    /* Assert some preconditions are satisfied: */
+
+    /* log2_x and log2_y must each be 0, 1 or 2. */
+    assert(log2_x >= 0 && log2_x < 3);
+    assert(log2_y >= 0 && log2_y < 3);
+
+    /* srcx and width must be multiple of xscale. */
+    assert(srcx % xscale == 0);
+    assert(width % xscale == 0);
+
+    /* height must be multiple of yscale. */
+    assert(height % yscale == 0);
+
+    /* because xscale is 1, 2 or 4 and srcx is a multiple of xscale,
+    in_shift_initial ends up being constrained as follows: */
+    if (log2_x == 0) {
+        /* in_shift_initial is {0,1,2,3,4,5,6,7]} */
+        assert(in_shift_initial >= 0 && in_shift_initial < 8);
+    }
+    if (log2_x == 1) {
+        /* in_shift_initial is {0,2,4,6}. */
+        assert(in_shift_initial >= 0 && in_shift_initial < 7 && in_shift_initial % 2 == 0);
+    }
+    if (log2_x == 2) {
+        /* in_shift_initial is {0,4} */
+        assert(in_shift_initial == 0 || in_shift_initial == 4);
+    }
+
     for (h = height; h; srow += sskip, h -= yscale) {
         const byte *s = srow;
 
@@ -196,8 +225,11 @@ bits_compress_scaled(const byte * src, int srcx, uint width, uint height,
 
                 for (index = 0, count = 0; index != sskip;
                      index += sraster
-                    )
+                    ) {
+                    /* Coverity 94484 incorrectly thinks in_shift can be negative. */
+                    /* coverity[negative_shift] */
                     count += half_byte_1s[(s[index] >> in_shift) & mask];
+                }
                 if (count != 0 && table[count] == 0) {	/* Look at adjacent cells to help prevent */
                     /* dropouts. */
                     uint orig_count = count;