set default newlib dir's structure

git-svn-id: svn://kolibrios.org@4874 a494cfbc-eb01-0410-851d-a64ba20cac60

contrib/sdk/sources/newlib/libc/string/strchr.c

@@ -0,0 +1,123 @@
+/*
+FUNCTION
+	<<strchr>>---search for character in string
+
+INDEX
+	strchr
+
+ANSI_SYNOPSIS
+	#include <string.h>
+	char * strchr(const char *<[string]>, int <[c]>);
+
+TRAD_SYNOPSIS
+	#include <string.h>
+	char * strchr(<[string]>, <[c]>);
+	const char *<[string]>;
+	int <[c]>;
+
+DESCRIPTION
+	This function finds the first occurence of <[c]> (converted to
+	a char) in the string pointed to by <[string]> (including the
+	terminating null character).
+
+RETURNS
+	Returns a pointer to the located character, or a null pointer
+	if <[c]> does not occur in <[string]>.
+
+PORTABILITY
+<<strchr>> is ANSI C.
+
+<<strchr>> requires no supporting OS subroutines.
+
+QUICKREF
+	strchr ansi pure
+*/
+
+#include <string.h>
+#include <limits.h>
+
+/* Nonzero if X is not aligned on a "long" boundary.  */
+#define UNALIGNED(X) ((long)X & (sizeof (long) - 1))
+
+/* How many bytes are loaded each iteration of the word copy loop.  */
+#define LBLOCKSIZE (sizeof (long))
+
+#if LONG_MAX == 2147483647L
+#define DETECTNULL(X) (((X) - 0x01010101) & ~(X) & 0x80808080)
+#else
+#if LONG_MAX == 9223372036854775807L
+/* Nonzero if X (a long int) contains a NULL byte. */
+#define DETECTNULL(X) (((X) - 0x0101010101010101) & ~(X) & 0x8080808080808080)
+#else
+#error long int is not a 32bit or 64bit type.
+#endif
+#endif
+
+/* DETECTCHAR returns nonzero if (long)X contains the byte used
+   to fill (long)MASK. */
+#define DETECTCHAR(X,MASK) (DETECTNULL(X ^ MASK))
+
+char *
+_DEFUN (strchr, (s1, i),
+	_CONST char *s1 _AND
+	int i)
+{
+  _CONST unsigned char *s = (_CONST unsigned char *)s1;
+  unsigned char c = i;
+
+#if !defined(PREFER_SIZE_OVER_SPEED) && !defined(__OPTIMIZE_SIZE__)
+  unsigned long mask,j;
+  unsigned long *aligned_addr;
+
+  /* Special case for finding 0.  */
+  if (!c)
+    {
+      while (UNALIGNED (s))
+        {
+          if (!*s)
+            return (char *) s;
+          s++;
+        }
+      /* Operate a word at a time.  */
+      aligned_addr = (unsigned long *) s;
+      while (!DETECTNULL (*aligned_addr))
+        aligned_addr++;
+      /* Found the end of string.  */
+      s = (const unsigned char *) aligned_addr;
+      while (*s)
+        s++;
+      return (char *) s;
+    }
+
+  /* All other bytes.  Align the pointer, then search a long at a time.  */
+  while (UNALIGNED (s))
+    {
+      if (!*s)
+        return NULL;
+      if (*s == c)
+        return (char *) s;
+      s++;
+    }
+
+  mask = c;
+  for (j = 8; j < LBLOCKSIZE * 8; j <<= 1)
+    mask = (mask << j) | mask;
+
+  aligned_addr = (unsigned long *) s;
+  while (!DETECTNULL (*aligned_addr) && !DETECTCHAR (*aligned_addr, mask))
+    aligned_addr++;
+
+  /* The block of bytes currently pointed to by aligned_addr
+     contains either a null or the target char, or both.  We
+     catch it using the bytewise search.  */
+
+  s = (unsigned char *) aligned_addr;
+
+#endif /* not PREFER_SIZE_OVER_SPEED */
+
+  while (*s && *s != c)
+    s++;
+  if (*s == c)
+    return (char *)s;
+  return NULL;
+}