newlib-2.4.0: wide character strings

git-svn-id: svn://kolibrios.org@6557 a494cfbc-eb01-0410-851d-a64ba20cac60

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

@@ -0,0 +1,44 @@
+/*
+FUNCTION
+	<<swab>>---swap adjacent bytes
+
+ANSI_SYNOPSIS
+	#include <unistd.h>
+	void swab(const void *<[in]>, void *<[out]>, ssize_t <[n]>);
+
+TRAD_SYNOPSIS
+	void swab(<[in]>, <[out]>, <[n]>
+	void *<[in]>;
+	void *<[out]>;
+	ssize_t <[n]>;
+
+DESCRIPTION
+	This function copies <[n]> bytes from the memory region
+	pointed to by <[in]> to the memory region pointed to by
+	<[out]>, exchanging adjacent even and odd bytes.
+
+PORTABILITY
+<<swab>> requires no supporting OS subroutines.
+*/
+
+#include <unistd.h>
+
+void
+_DEFUN (swab, (b1, b2, length),
+	_CONST void *b1 _AND
+	void *b2 _AND
+	ssize_t length)
+{
+  const char *from = b1;
+  char *to = b2;
+  ssize_t ptr;
+  for (ptr = 1; ptr < length; ptr += 2)
+    {
+      char p = from[ptr];
+      char q = from[ptr-1];
+      to[ptr-1] = p;
+      to[ptr  ] = q;
+    }
+  if (ptr == length) /* I.e., if length is odd, */
+    to[ptr-1] = 0;   /* then pad with a NUL. */
+}