This commit was manufactured by cvs2svn to create branch 'chise-r21-4-19'.

[chise/xemacs-chise.git] / src / strcmp.c

diff --git a/src/strcmp.c b/src/strcmp.c
new file mode 100644 (file)
index 0000000..722cd0d
--- /dev/null
+++ b/src/strcmp.c
@@ -0,0 +1,150 @@
+/* This file is part of XEmacs.
+
+XEmacs is free software; you can redistribute it and/or modify it
+under the terms of the GNU General Public License as published by the
+Free Software Foundation; either version 2, or (at your option) any
+later version.
+
+XEmacs is distributed in the hope that it will be useful, but WITHOUT
+ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with XEmacs; see the file COPYING.  If not, write to
+the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+Boston, MA 02111-1307, USA.  */
+
+/* Synched up with: Not in FSF. */
+
+/* In SunOS 4.1.1 the strcmp and strncmp functions reference memory
+   past the last byte of the string! This will core dump if the memory 
+   following the last byte is not mapped.
+
+   Here are correct versions by hbs@lucid.com.
+*/
+
+# include <config.h>
+# ifndef REGISTER      /* Strictly enforced in 20.3 */
+# define REGISTER
+# endif
+
+#include <string.h>
+#define ALIGNED(x) (!(((unsigned long) (x)) & (sizeof (unsigned long) - 1)))
+
+#define MAGIC    0x7efefeff
+#define HIGH_BIT_P(c) ((c) & hi_bit)
+#define HAS_ZERO(c) (((((c) + magic) ^ (c)) & not_magic) != not_magic)
+
+int
+strcmp (const char *x, const char *y)
+{
+  if (x == y)
+    return 0;
+  else if (ALIGNED (x) && ALIGNED (y))
+    {
+      const unsigned long *x1 = (const unsigned long *) x;
+      const unsigned long *y1 = (const unsigned long *) y;
+      unsigned long c;
+      unsigned long magic = MAGIC;
+      unsigned long not_magic = ~magic;
+      unsigned long hi_bit = 0x80000000;
+
+      while ((c = *x1) == *y1)
+        {
+          if (HAS_ZERO(c)) 
+            {
+              if (!HIGH_BIT_P (c))
+                return 0;
+              else
+                {
+                  x = (const char *) x1;
+                  y = (const char *) y1;
+                  goto slow_loop;
+                }
+            }
+              
+          x1++; 
+          y1++;
+        }
+
+      x = (const char *) x1;
+      y = (const char *) y1;
+      goto slow_loop;
+    }
+  else
+    {
+      char c;
+
+    slow_loop:
+
+      while ((c = *x) == *y)
+        {
+          if (c == (char) 0) return 0;
+          x++; 
+          y++;
+        }
+      return (*x - *y);
+    }
+}
+
+
+int
+strncmp (const char *x, const char *y, size_t n)
+{
+  if ((x == y) || (n <= 0))
+    return 0;
+  else if (ALIGNED (x) && ALIGNED (y))
+    {
+      const unsigned long *x1 = (const unsigned long *) x;
+      const unsigned long *y1 = (const unsigned long *) y;
+      unsigned long c;
+      unsigned long magic = MAGIC;
+      unsigned long not_magic = ~magic;
+      unsigned long hi_bit = 0x80000000;
+
+      while ((c = *x1) == *y1)
+        {
+          n -= sizeof (unsigned long);
+          if (n <= 0)
+            return 0;
+          
+          if (HAS_ZERO(c)) 
+            {
+              if (!HIGH_BIT_P (c))
+                return 0;
+              else
+                {
+                  x = (const char *) x1;
+                  y = (const char *) y1;
+                  goto slow_loop;
+                }
+            }
+              
+          x1++; 
+          y1++;
+        }
+
+      x = (const char *) x1;
+      y = (const char *) y1;
+      goto slow_loop;
+    }
+  else
+    {
+      char c;
+
+    slow_loop:
+
+      while ((c = *x) == *y)
+        {
+          n--;
+          if (n <= 0)
+            return 0;
+          if (c == (char) 0) 
+            return 0;
+          x++; 
+          y++;
+        }
+      return (*x - *y);
+    }
+}