libgo/go/bytes/indexbyte.c

   1 /* indexbyte.c -- implement bytes.IndexByte for Go.
   2
   3    Copyright 2009 The Go Authors. All rights reserved.
   4    Use of this source code is governed by a BSD-style
   5    license that can be found in the LICENSE file.  */
   6
   7 #include <stddef.h>
   8
   9 #include "runtime.h"
  10 #include "array.h"
  11
  12 /* This is in C so that the compiler can optimize it appropriately.
  13    We deliberately don't split the stack in case it does call the
  14    library function, which shouldn't need much stack space.  */
  15
  16 intgo IndexByte (struct __go_open_array, char)
  17   __asm__ (GOSYM_PREFIX "bytes.IndexByte")
  18   __attribute__ ((no_split_stack));
  19
  20 intgo
  21 IndexByte (struct __go_open_array s, char b)
  22 {
  23   char *p;
  24
  25   p = __builtin_memchr (s.__values, b, s.__count);
  26   if (p == NULL)
  27     return -1;
  28   return p - (char *) s.__values;
  29 }
  30
  31 /* Comparison.  */
  32
  33 _Bool Equal (struct __go_open_array a, struct __go_open_array b)
  34   __asm__ (GOSYM_PREFIX "bytes.Equal")
  35   __attribute__ ((no_split_stack));
  36
  37 _Bool
  38 Equal (struct __go_open_array a, struct __go_open_array b)
  39 {
  40   if (a.__count != b.__count)
  41     return 0;
  42   return __builtin_memcmp (a.__values, b.__values, a.__count) == 0;
  43 }
  44
  45 intgo Compare (struct __go_open_array a, struct __go_open_array b)
  46   __asm__ (GOSYM_PREFIX "bytes.Compare")
  47   __attribute__ ((no_split_stack));
  48
  49 intgo
  50 Compare (struct __go_open_array a, struct __go_open_array b)
  51 {
  52   intgo len;
  53
  54   len = a.__count;
  55   if (len > b.__count)
  56     len = b.__count;
  57   if (len > 0)
  58     {
  59       intgo ret;
  60
  61       ret = __builtin_memcmp (a.__values, b.__values, len);
  62       if (ret < 0)
  63         return -1;
  64       else if (ret > 0)
  65         return 1;
  66     }
  67   if (a.__count < b.__count)
  68     return -1;
  69   else if (a.__count > b.__count)
  70     return 1;
  71   else
  72     return 0;
  73 }