From 50a6ca39ad4ed01922aa4f755f0ca579788226cf Mon Sep 17 00:00:00 2001
From: Thomas Martitz <kugel@rockbox.org>
Date: Thu, 6 May 2010 21:04:40 +0000
Subject: Move c/h files implementing/defining standard library stuff into a
 new libc directory, also standard'ify some parts of the code base (almost
 entirely #include fixes). This is to a) to cleanup firmware/common and
 firmware/include a bit, but also b) for Rockbox as an application which
 should use the host system's c library and headers, separating makes it easy
 to exclude our files from the build.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@25850 a1c6a512-1295-4272-9138-f99709370657
---
 firmware/libc/strcmp.c | 106 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 106 insertions(+)
 create mode 100644 firmware/libc/strcmp.c

(limited to 'firmware/libc/strcmp.c')

diff --git a/firmware/libc/strcmp.c b/firmware/libc/strcmp.c
new file mode 100644
index 0000000000..bbbf4b174a
--- /dev/null
+++ b/firmware/libc/strcmp.c
@@ -0,0 +1,106 @@
+/*
+FUNCTION
+        <<strcmp>>---character string compare
+        
+INDEX
+        strcmp
+
+ANSI_SYNOPSIS
+        #include <string.h>
+        int strcmp(const char *<[a]>, const char *<[b]>);
+
+TRAD_SYNOPSIS
+        #include <string.h>
+        int strcmp(<[a]>, <[b]>)
+        char *<[a]>;
+        char *<[b]>;
+
+DESCRIPTION
+        <<strcmp>> compares the string at <[a]> to
+        the string at <[b]>.
+
+RETURNS
+        If <<*<[a]>>> sorts lexicographically after <<*<[b]>>>,
+        <<strcmp>> returns a number greater than zero.  If the two
+        strings match, <<strcmp>> returns zero.  If <<*<[a]>>>
+        sorts lexicographically before <<*<[b]>>>, <<strcmp>> returns a
+        number less than zero.
+
+PORTABILITY
+<<strcmp>> is ANSI C.
+
+<<strcmp>> requires no supporting OS subroutines.
+
+QUICKREF
+        strcmp ansi pure
+*/
+
+#include <string.h>
+#include <limits.h>
+
+/* Nonzero if either X or Y is not aligned on a "long" boundary.  */
+#define UNALIGNED(X, Y) \
+  (((long)X & (sizeof (long) - 1)) | ((long)Y & (sizeof (long) - 1)))
+
+/* DETECTNULL returns nonzero if (long)X contains a NULL byte. */
+#if LONG_MAX == 2147483647L
+#define DETECTNULL(X) (((X) - 0x01010101) & ~(X) & 0x80808080)
+#else
+#if LONG_MAX == 9223372036854775807L
+#define DETECTNULL(X) (((X) - 0x0101010101010101) & ~(X) & 0x8080808080808080)
+#else
+#error long int is not a 32bit or 64bit type.
+#endif
+#endif
+
+#ifndef DETECTNULL
+#error long int is not a 32bit or 64bit byte
+#endif
+
+int
+_DEFUN (strcmp, (s1, s2),
+        _CONST char *s1 _AND
+        _CONST char *s2)
+{ 
+#if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__)
+  while (*s1 != '\0' && *s1 == *s2)
+    {
+      s1++;
+      s2++;
+    }
+
+  return (*(unsigned char *) s1) - (*(unsigned char *) s2);
+#else
+  unsigned long *a1;
+  unsigned long *a2;
+
+  /* If s1 or s2 are unaligned, then compare bytes. */
+  if (!UNALIGNED (s1, s2))
+    {  
+      /* If s1 and s2 are word-aligned, compare them a word at a time. */
+      a1 = (unsigned long*)s1;
+      a2 = (unsigned long*)s2;
+      while (*a1 == *a2)
+        {
+          /* To get here, *a1 == *a2, thus if we find a null in *a1,
+             then the strings must be equal, so return zero.  */
+          if (DETECTNULL (*a1))
+            return 0;
+
+          a1++;
+          a2++;
+        }
+
+      /* A difference was detected in last few bytes of s1, so search bytewise */
+      s1 = (char*)a1;
+      s2 = (char*)a2;
+    }
+
+  while (*s1 != '\0' && *s1 == *s2)
+    {
+      s1++;
+      s2++;
+    }
+  return (*(unsigned char *) s1) - (*(unsigned char *) s2);
+#endif /* not PREFER_SIZE_OVER_SPEED */
+}
-- 
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