/*
FUNCTION
	<<strchr>>---search for character in string

INDEX
	strchr

SYNOPSIS
	#include <string.h>
	char * strchr(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>
#include "local.h"

char *
strchr (const char *s1,
	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_X(s))
        {
          if (!*s)
            return (char *) s;
          s++;
        }
      /* Operate a word at a time.  */
      aligned_addr = (unsigned long *) s;
      while (!DETECT_NULL(*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_X(s))
    {
      if (!*s)
        return NULL;
      if (*s == c)
        return (char *) s;
      s++;
    }

  mask = c;
  for (j = 8; j < sizeof(mask) * 8; j <<= 1)
    mask = (mask << j) | mask;

  aligned_addr = (unsigned long *) s;
  while (!DETECT_NULL(*aligned_addr) && !DETECT_CHAR(*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;
}