sendmail/libsm/strcasecmp.c

/*
 * Copyright (c) 2000-2001 Sendmail, Inc. and its suppliers.
 *  All rights reserved.
 * Copyright (c) 1983, 1995-1997 Eric P. Allman.  All rights reserved.
 * Copyright (c) 1987, 1988, 1993
 *  The Regents of the University of California.  All rights reserved.
 *
 * By using this file, you agree to the terms and conditions set
 * forth in the LICENSE file which can be found at the top level of
 * the sendmail distribution.
 *
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <sm/gen.h>
SM_RCSID("@(#)$Id: strcasecmp.c,v 1.12 2001/08/27 22:09:15 gshapiro Exp $")

#include <sm/config.h>
#include <sm/string.h>
#include <string.h>

/*
**  SM_STRCASECMP -- 8-bit clean version of strcasecmp
**
**  Thank you, vendors, for making this all necessary.
*/

/*
**  This array is designed for mapping upper and lower case letter
**  together for a case independent comparison.  The mappings are
**  based upon ascii character sequences.
*/

const unsigned char charmap[] =
{
    0000, 0001, 0002, 0003, 0004, 0005, 0006, 0007,
    0010, 0011, 0012, 0013, 0014, 0015, 0016, 0017,
    0020, 0021, 0022, 0023, 0024, 0025, 0026, 0027,
    0030, 0031, 0032, 0033, 0034, 0035, 0036, 0037,
    0040, 0041, 0042, 0043, 0044, 0045, 0046, 0047,
    0050, 0051, 0052, 0053, 0054, 0055, 0056, 0057,
    0060, 0061, 0062, 0063, 0064, 0065, 0066, 0067,
    0070, 0071, 0072, 0073, 0074, 0075, 0076, 0077,
    0100, 0141, 0142, 0143, 0144, 0145, 0146, 0147,
    0150, 0151, 0152, 0153, 0154, 0155, 0156, 0157,
    0160, 0161, 0162, 0163, 0164, 0165, 0166, 0167,
    0170, 0171, 0172, 0133, 0134, 0135, 0136, 0137,
    0140, 0141, 0142, 0143, 0144, 0145, 0146, 0147,
    0150, 0151, 0152, 0153, 0154, 0155, 0156, 0157,
    0160, 0161, 0162, 0163, 0164, 0165, 0166, 0167,
    0170, 0171, 0172, 0173, 0174, 0175, 0176, 0177,
    0200, 0201, 0202, 0203, 0204, 0205, 0206, 0207,
    0210, 0211, 0212, 0213, 0214, 0215, 0216, 0217,
    0220, 0221, 0222, 0223, 0224, 0225, 0226, 0227,
    0230, 0231, 0232, 0233, 0234, 0235, 0236, 0237,
    0240, 0241, 0242, 0243, 0244, 0245, 0246, 0247,
    0250, 0251, 0252, 0253, 0254, 0255, 0256, 0257,
    0260, 0261, 0262, 0263, 0264, 0265, 0266, 0267,
    0270, 0271, 0272, 0273, 0274, 0275, 0276, 0277,
    0300, 0301, 0302, 0303, 0304, 0305, 0306, 0307,
    0310, 0311, 0312, 0313, 0314, 0315, 0316, 0317,
    0320, 0321, 0322, 0323, 0324, 0325, 0326, 0327,
    0330, 0331, 0332, 0333, 0334, 0335, 0336, 0337,
    0340, 0341, 0342, 0343, 0344, 0345, 0346, 0347,
    0350, 0351, 0352, 0353, 0354, 0355, 0356, 0357,
    0360, 0361, 0362, 0363, 0364, 0365, 0366, 0367,
    0370, 0371, 0372, 0373, 0374, 0375, 0376, 0377,
};

int
sm_strcasecmp(s1, s2)
    const char *s1, *s2;
{
    const unsigned char *us1 = (const unsigned char *)s1;
    const unsigned char *us2 = (const unsigned char *)s2;

    while (charmap[*us1] == charmap[*us2])
    {
        if (*us1 == '\0')
            return 0;
        ++us1;
        ++us2;
    }
    return charmap[*us1] - charmap[*us2];
}

int
sm_strncasecmp(s1, s2, n)
    const char *s1, *s2;
    register size_t n;
{
    if (n != 0)
    {
        register const unsigned char *cm = charmap;
        register const unsigned char *us1 = (const unsigned char *)s1;
        register const unsigned char *us2 = (const unsigned char *)s2;

        do
        {
            if (cm[*us1] != cm[*us2++])
                return (cm[*us1] - cm[*--us2]);
            if (*us1++ == '\0')
                break;
        } while (--n != 0);
    }
    return 0;
}