add libc building to agbcc.

1 files changed, 125 insertions, 0 deletions

diff --git a/libc/string/strncpy.c b/libc/string/strncpy.c
new file mode 100644
index 0000000..7c1973b
--- /dev/null
+++ b/libc/string/strncpy.c
@@ -0,0 +1,125 @@
+/*
+FUNCTION
+	<<strncpy>>---counted copy string
+
+INDEX
+	strncpy
+
+ANSI_SYNOPSIS
+	#include <string.h>
+	char *strncpy(char *<[dst]>, const char *<[src]>, size_t <[length]>);
+
+TRAD_SYNOPSIS
+	#include <string.h>
+	char *strncpy(<[dst]>, <[src]>, <[length]>)
+	char *<[dst]>;
+	char *<[src]>;
+	size_t <[length]>;
+
+DESCRIPTION
+	<<strncpy>> copies not more than <[length]> characters from the
+	the string pointed to by <[src]> (including the terminating
+	null character) to the array pointed to by <[dst]>.  If the
+	string pointed to by <[src]> is shorter than <[length]>
+	characters, null characters are appended to the destination
+	array until a total of <[length]> characters have been
+	written.
+
+RETURNS
+	This function returns the initial value of <[dst]>.
+
+PORTABILITY
+<<strncpy>> is ANSI C.
+
+<<strncpy>> requires no supporting OS subroutines.
+
+QUICKREF
+	strncpy ansi pure
+*/
+
+#include <string.h>
+#include <limits.h>
+
+/*SUPPRESS 560*/
+/*SUPPRESS 530*/
+
+/* 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)))
+
+#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
+
+#ifndef DETECTNULL
+#error long int is not a 32bit or 64bit byte
+#endif
+
+#define TOO_SMALL(LEN) ((LEN) < sizeof (long))
+
+char *
+_DEFUN (strncpy, (dst0, src0),
+	char *dst0 _AND
+	_CONST char *src0 _AND
+	size_t count)
+{
+#if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__)
+  char *dscan;
+  _CONST char *sscan;
+
+  dscan = dst0;
+  sscan = src0;
+  while (count > 0)
+    {
+      --count;
+      if ((*dscan++ = *sscan++) == '\0')
+	break;
+    }
+  while (count-- > 0)
+    *dscan++ = '\0';
+
+  return dst0;
+#else
+  char *dst = dst0;
+  _CONST char *src = src0;
+  long *aligned_dst;
+  _CONST long *aligned_src;
+
+  /* If SRC and DEST is aligned and count large enough, then copy words.  */
+  if (!UNALIGNED (src, dst) && !TOO_SMALL (count))
+    {
+      aligned_dst = (long*)dst;
+      aligned_src = (long*)src;
+
+      /* SRC and DEST are both "long int" aligned, try to do "long int"
+	 sized copies.  */
+      while (count >= sizeof (long int) && !DETECTNULL(*aligned_src))
+	{
+	  count -= sizeof (long int);
+	  *aligned_dst++ = *aligned_src++;
+	}
+
+      dst = (char*)aligned_dst;
+      src = (char*)aligned_src;
+    }
+
+  while (count > 0)
+    {
+      --count;
+      if ((*dst++ = *src++) == '\0')
+	break;
+    }
+
+  while (count-- > 0)
+    *dst++ = '\0';
+
+  return dst0;
+#endif /* not PREFER_SIZE_OVER_SPEED */
+}