source: mainline/boot/generic/string.c@ 86018c1

/*
 * 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 
 * @{
 */

#include <string.h>

/**
 * @file
 * @brief       String manipulation functions.
 */

/** 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)
{
        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)
{
        int i;
        for (i = 0; i < len; i++) {
                if (!(dest[i] = src[i]))
                        return;
        }
        dest[i-1] = '\0';
}

/** Convert ascii representation to unative_t.
 *
 * Supports 0x for hexa & 0 for octal notation.
 * Does not check for overflows, does not support negative numbers
 *
 * @param text          Textual representation of number.
 * @return              Converted number or 0 if no valid number found.
 */
unative_t atoi(const char *text)
{
        int base = 10;
        unative_t result = 0;

        if (text[0] == '0' && text[1] == 'x') {
                base = 16;
                text += 2;
        } else if (text[0] == '0')
                base = 8;

        while (*text) {
                if (base != 16 &&
                    ((*text >= 'A' && *text <= 'F') ||
                    (*text >='a' && *text <='f')))
                        break;
                if (base == 8 && *text >='8')
                        break;

                if (*text >= '0' && *text <= '9') {
                        result *= base;
                        result += *text - '0';
                } else if (*text >= 'A' && *text <= 'F') {
                        result *= base;
                        result += *text - 'A' + 10;
                } else if (*text >= 'a' && *text <= 'f') {
                        result *= base;
                        result += *text - 'a' + 10;
                } else
                        break;
                text++;
        }

        return result;
}

/** Move piece of memory to another, possibly overlapping, location.
 *
 * @param dst           Destination address.
 * @param src           Source address.
 * @param len           Number of bytes to move.
 *
 * @return              Destination address.
 */
void *memmove(void *dst, const void *src, size_t len)
{
        char *d = dst;
        const char *s = src;
        if (s < d) {
                while (len--)
                        *(d + len) = *(s + len);
        } else {
                while (len--)
                        *d++ = *s++;
        }
        
        return dst;
}

/** @}
 */