source: mainline/uspace/lib/posix/source/strings.c@ d948095

/*
 * Copyright (c) 2011 Jiri Zarevucky
 * Copyright (c) 2011 Petr Koupy
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup libposix
 * @{
 */
/** @file Additional string manipulation.
 */

#define LIBPOSIX_INTERNAL

#include "internal/common.h"
#include "posix/strings.h"

#include "posix/string.h"
#include "posix/ctype.h"

#include "libc/mem.h"

/**
 * Find first set bit (beginning with the least significant bit).
 *
 * @param i Integer in which to look for the first set bit.
 * @return Index of first set bit. Bits are numbered starting at one.
 */
int posix_ffs(int i)
{
        if (i == 0) {
                return 0;
        }

        int result = 0;

        // XXX: assumes at most 32-bit int
        if (!(i & 0xFFFF)) {
                result |= 16;
                i >>= 16;
        }
        if (!(i & 0xFF)) {
                result |= 8;
                i >>= 8;
        }
        if (!(i & 0xF)) {
                result |= 4;
                i >>= 4;
        }
        if (!(i & 0x3)) {
                result |= 2;
                i >>= 2;
        }
        if (!(i & 0x1)) {
                result |= 1;
        }

        return result + 1;
}

/**
 * Compare two strings (case-insensitive).
 *
 * @param s1 First string to be compared.
 * @param s2 Second string to be compared.
 * @return Difference of the first pair of inequal characters,
 *     or 0 if strings have the same content.
 */
int posix_strcasecmp(const char *s1, const char *s2)
{
        return posix_strncasecmp(s1, s2, STR_NO_LIMIT);
}

/**
 * Compare part of two strings (case-insensitive).
 *
 * @param s1 First string to be compared.
 * @param s2 Second string to be compared.
 * @param n Maximum number of characters to be compared.
 * @return Difference of the first pair of inequal characters,
 *     or 0 if strings have the same content.
 */
int posix_strncasecmp(const char *s1, const char *s2, size_t n)
{
        for (size_t i = 0; i < n; ++i) {
                int cmp = tolower(s1[i]) - tolower(s2[i]);
                if (cmp != 0) {
                        return cmp;
                }
                
                if (s1[i] == 0) {
                        return 0;
                }
        }
        
        return 0;
}

/**
 * Compare two memory areas.
 *
 * @param mem1 Pointer to the first area to compare.
 * @param mem2 Pointer to the second area to compare.
 * @param n Common size of both areas.
 * @return If n is 0, return zero. If the areas match, return
 *     zero. Otherwise return non-zero.
 */
int posix_bcmp(const void *mem1, const void *mem2, size_t n)
{
        return bcmp(mem1, mem2, n);
}

/**
 * Copy bytes in memory with overlapping areas.
 *
 * @param src Source area.
 * @param dest Destination area.
 * @param n Number of bytes to copy.
 */
void posix_bcopy(const void *src, void *dest, size_t n)
{
        /* Note that memmove has different order of arguments. */
        memmove(dest, src, n);
}

/**
 * Reset bytes in memory area to zero.
 *
 * @param mem Memory area to be zeroed.
 * @param n Number of bytes to reset.
 */
void posix_bzero(void *mem, size_t n)
{
        bzero(mem, n);
}

/**
 * Scan string for a first occurence of a character.
 *
 * @param s String in which to look for the character.
 * @param c Character to look for.
 * @return Pointer to the specified character on success,
 *     NULL pointer otherwise.
 */
char *posix_index(const char *s, int c)
{
        return posix_strchr(s, c);
}

/**
 * Scan string for a last occurence of a character.
 *
 * @param s String in which to look for the character.
 * @param c Character to look for.
 * @return Pointer to the specified character on success,
 *     NULL pointer otherwise.
 */
char *posix_rindex(const char *s, int c)
{
        return posix_strrchr(s, c);
}

/** @}
 */