source: mainline/kernel/generic/src/lib/string.c@ 20f1597

/*
 * Copyright (c) 2001-2004 Jakub Jermar
 * 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 generic 
 * @{
 */

/**
 * @file
 * @brief       Miscellaneous functions.
 */

#include <string.h>
#include <print.h>
#include <cpu.h>
#include <arch/asm.h>
#include <arch.h>
#include <console/kconsole.h>

/** Return number of characters in a string.
 *
 * @param str NULL terminated string.
 *
 * @return Number of characters in str.
 */
size_t strlen(const char *str)
{
        int i;
        
        for (i = 0; str[i]; i++)
                ;
        
        return i;
}

/** Compare two NULL terminated strings
 *
 * Do a char-by-char comparison of two NULL terminated strings.
 * The strings are considered equal iff they consist of the same
 * characters on the minimum of their lengths.
 *
 * @param src First string to compare.
 * @param dst Second string to compare.
 *
 * @return 0 if the strings are equal, -1 if first is smaller, 1 if second smaller.
 *
 */
int strcmp(const char *src, const char *dst)
{
        for (; *src && *dst; src++, dst++) {
                if (*src < *dst)
                        return -1;
                if (*src > *dst)
                        return 1;
        }
        if (*src == *dst)
                return 0;
        if (!*src)
                return -1;
        return 1;
}


/** Compare two NULL terminated strings
 *
 * Do a char-by-char comparison of two NULL terminated strings.
 * The strings are considered equal iff they consist of the same
 * characters on the minimum of their lengths and specified maximal
 * length.
 *
 * @param src First string to compare.
 * @param dst Second string to compare.
 * @param len Maximal length for comparison.
 *
 * @return 0 if the strings are equal, -1 if first is smaller, 1 if second smaller.
 *
 */
int strncmp(const char *src, const char *dst, size_t len)
{
        unsigned int i;
        
        for (i = 0; (*src) && (*dst) && (i < len); src++, dst++, i++) {
                if (*src < *dst)
                        return -1;
                if (*src > *dst)
                        return 1;
        }
        if (i == len || *src == *dst)
                return 0;
        if (!*src)
                return -1;
        return 1;
}



/** Copy NULL terminated string.
 *
 * Copy at most 'len' characters from string 'src' to 'dest'.
 * If 'src' is shorter than 'len', '\0' is inserted behind the
 * last copied character.
 *
 * @param src Source string.
 * @param dest Destination buffer.
 * @param len Size of destination buffer.
 */
void strncpy(char *dest, const char *src, size_t len)
{
        unsigned int i;

        for (i = 0; i < len; i++) {
                if (!(dest[i] = src[i]))
                        return;
        }

        dest[i - 1] = '\0';
}

/** Copy string.
 *
 * Copy string from src address to dst address.  The copying is done
 * char-by-char until the null character. The source and destination memory
 * areas cannot overlap.
 *
 * @param src           Source string to copy from.
 * @param dst           Destination string to copy to.
 *
 * @return              Address of the destination string.
 */
char *strcpy(char *dest, const char *src)
{
        char *orig = dest;
        
        while ((*dest++ = *src++) != '\0');

        return orig;
}

/** Find first occurence of character in string.
 *
 * @param s     String to search.
 * @param i     Character to look for.
 *
 * @return      Pointer to character in @a s or NULL if not found.
 */
extern char *strchr(const char *s, int i)
{
        while (*s != '\0') {
                if (*s == i) return (char *) s;
                ++s;
        }

        return NULL;
}

/** Find last occurence of character in string.
 *
 * @param s     String to search.
 * @param i     Character to look for.
 *
 * @return      Pointer to character in @a s or NULL if not found.
 */
extern char *strrchr(const char *s, int i)
{
        const char *start;

        start = s;
        if (*s == '\0') return NULL;

        while (*s != '\0') ++s;

        while (s != start) {
                --s;
                if (*s == i) return (char *) s;
        }

        return NULL;
}

/** @}
 */