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Reactos
1/***
2*strcmp.c - routine to compare two strings (for equal, less, or greater)
3*
4* Copyright (c) Microsoft Corporation. All rights reserved.
5*
6*Purpose:
7* Compares two string, determining their ordinal order.
8*
9*******************************************************************************/
10
11#include <string.h>
12
13#pragma function(strcmp)
14
15/***
16*strcmp - compare two strings, returning less than, equal to, or greater than
17*
18*Purpose:
19* STRCMP compares two strings and returns an integer
20* to indicate whether the first is less than the second, the two are
21* equal, or whether the first is greater than the second.
22*
23* Comparison is done byte by byte on an UNSIGNED basis, which is to
24* say that Null (0) is less than any other character (1-255).
25*
26*Entry:
27* const char * src - string for left-hand side of comparison
28* const char * dst - string for right-hand side of comparison
29*
30*Exit:
31* returns -1 if src < dst
32* returns 0 if src == dst
33* returns +1 if src > dst
34*
35*Exceptions:
36*
37*******************************************************************************/
38
39int __cdecl strcmp (
40 const char * src,
41 const char * dst
42 )
43{
44 int ret = 0 ;
45
46 while((ret = *(unsigned char *)src - *(unsigned char *)dst) == 0 && *dst)
47 {
48 ++src, ++dst;
49 }
50
51 return ((-ret) < 0) - (ret < 0); // (if positive) - (if negative) generates branchless code
52}