string.c

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/*
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *  Copyright (C) 2004 Tobias Lorenz
 *
 *  string handling functions
 *  based on linux/lib/string.c
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

FILE_LICENCE ( GPL2_ONLY );

/*
 * stupid library routines.. The optimized versions should generally be found
 * as inline code in <asm-xx/string.h>
 *
 * These are buggy as well..
 *
 * * Fri Jun 25 1999, Ingo Oeser <ioe@informatik.tu-chemnitz.de>
 * -  Added strsep() which will replace strtok() soon (because strsep() is
 *    reentrant and should be faster). Use only strsep() in new code, please.
 */
 
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

/* *** FROM string.c *** */

#ifndef __HAVE_ARCH_STRCPY
/**
 * strcpy - Copy a %NUL terminated string
 * @dest: Where to copy the string to
 * @src: Where to copy the string from
 */
char * strcpy(char * dest,const char *src)
{
        char *tmp = dest;

        while ((*dest++ = *src++) != '\0')
                /* nothing */;
        return tmp;
}
#endif

#ifndef __HAVE_ARCH_STRNCPY
/**
 * strncpy - Copy a length-limited, %NUL-terminated string
 * @dest: Where to copy the string to
 * @src: Where to copy the string from
 * @count: The maximum number of bytes to copy
 *
 * Note that unlike userspace strncpy, this does not %NUL-pad the buffer.
 * However, the result is not %NUL-terminated if the source exceeds
 * @count bytes.
 */
char * strncpy(char * dest,const char *src,size_t count)
{
        char *tmp = dest;

        while (count-- && (*dest++ = *src++) != '\0')
                /* nothing */;

        return tmp;
}
#endif

#ifndef __HAVE_ARCH_STRCAT
/**
 * strcat - Append one %NUL-terminated string to another
 * @dest: The string to be appended to
 * @src: The string to append to it
 */
char * strcat(char * dest, const char * src)
{
        char *tmp = dest;

        while (*dest)
                dest++;
        while ((*dest++ = *src++) != '\0')
                ;

        return tmp;
}
#endif

#ifndef __HAVE_ARCH_STRCMP
/**
 * strcmp - Compare two strings
 * @cs: One string
 * @ct: Another string
 */
int strcmp(const char * cs,const char * ct)
{
        register signed char __res;

        while (1) {
                if ((__res = *cs - *ct++) != 0 || !*cs++)
                        break;
        }

        return __res;
}
#endif

#ifndef __HAVE_ARCH_STRNCMP
/**
 * strncmp - Compare two length-limited strings
 * @cs: One string
 * @ct: Another string
 * @count: The maximum number of bytes to compare
 */
int strncmp(const char * cs,const char * ct,size_t count)
{
        register signed char __res = 0;

        while (count) {
                if ((__res = *cs - *ct++) != 0 || !*cs++)
                        break;
                count--;
        }

        return __res;
}
#endif

#ifndef __HAVE_ARCH_STRCASECMP
int strcasecmp(const char *a, const char *b)
{
        while (*a && *b && (*a & ~0x20) == (*b & ~0x20)) {a++; b++; }
        return((*a & ~0x20) - (*b & ~0x20));
}
#endif

#ifndef __HAVE_ARCH_STRCHR
/**
 * strchr - Find the first occurrence of a character in a string
 * @s: The string to be searched
 * @c: The character to search for
 */
char * strchr(const char * s, int c)
{
        for(; *s != (char) c; ++s)
                if (*s == '\0')
                        return NULL;
        return (char *) s;
}
#endif

#ifndef __HAVE_ARCH_STRRCHR
/**
 * strrchr - Find the last occurrence of a character in a string
 * @s: The string to be searched
 * @c: The character to search for
 */
char * strrchr(const char * s, int c)
{
       const char *p = s + strlen(s);
       do {
           if (*p == (char)c)
               return (char *)p;
       } while (--p >= s);
       return NULL;
}
#endif

#ifndef __HAVE_ARCH_STRLEN
/**
 * strlen - Find the length of a string
 * @s: The string to be sized
 */
size_t strlen(const char * s)
{
        const char *sc;

        for (sc = s; *sc != '\0'; ++sc)
                /* nothing */;
        return sc - s;
}
#endif

#ifndef __HAVE_ARCH_STRNLEN
/**
 * strnlen - Find the length of a length-limited string
 * @s: The string to be sized
 * @count: The maximum number of bytes to search
 */
size_t strnlen(const char * s, size_t count)
{
        const char *sc;

        for (sc = s; count-- && *sc != '\0'; ++sc)
                /* nothing */;
        return sc - s;
}
#endif

#ifndef __HAVE_ARCH_MEMSET
/**
 * memset - Fill a region of memory with the given value
 * @s: Pointer to the start of the area.
 * @c: The byte to fill the area with
 * @count: The size of the area.
 *
 * Do not use memset() to access IO space, use memset_io() instead.
 */
void * memset(void * s,int c,size_t count)
{
        char *xs = (char *) s;

        while (count--)
                *xs++ = c;

        return s;
}
#endif

#ifndef __HAVE_ARCH_MEMCPY
/**
 * memcpy - Copy one area of memory to another
 * @dest: Where to copy to
 * @src: Where to copy from
 * @count: The size of the area.
 *
 * You should not use this function to access IO space, use memcpy_toio()
 * or memcpy_fromio() instead.
 */
void * memcpy(void * dest,const void *src,size_t count)
{
        char *tmp = (char *) dest, *s = (char *) src;

        while (count--)
                *tmp++ = *s++;

        return dest;
}
#endif

#ifndef __HAVE_ARCH_MEMMOVE
/**
 * memmove - Copy one area of memory to another
 * @dest: Where to copy to
 * @src: Where to copy from
 * @count: The size of the area.
 *
 * Unlike memcpy(), memmove() copes with overlapping areas.
 */
void * memmove(void * dest,const void *src,size_t count)
{
        char *tmp, *s;

        if (dest <= src) {
                tmp = (char *) dest;
                s = (char *) src;
                while (count--)
                        *tmp++ = *s++;
                }
        else {
                tmp = (char *) dest + count;
                s = (char *) src + count;
                while (count--)
                        *--tmp = *--s;
                }

        return dest;
}
#endif

#ifndef __HAVE_ARCH_MEMCMP
/**
 * memcmp - Compare two areas of memory
 * @cs: One area of memory
 * @ct: Another area of memory
 * @count: The size of the area.
 */
int memcmp(const void * cs,const void * ct,size_t count)
{
        const unsigned char *su1, *su2;
        int res = 0;

        for( su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--)
                if ((res = *su1 - *su2) != 0)
                        break;
        return res;
}
#endif

#ifndef __HAVE_ARCH_STRSTR
/**
 * strstr - Find the first substring in a %NUL terminated string
 * @s1: The string to be searched
 * @s2: The string to search for
 */
char * strstr(const char * s1,const char * s2)
{
        int l1, l2;

        l2 = strlen(s2);
        if (!l2)
                return (char *) s1;
        l1 = strlen(s1);
        while (l1 >= l2) {
                l1--;
                if (!memcmp(s1,s2,l2))
                        return (char *) s1;
                s1++;
        }
        return NULL;
}
#endif

#ifndef __HAVE_ARCH_MEMCHR
/**
 * memchr - Find a character in an area of memory.
 * @s: The memory area
 * @c: The byte to search for
 * @n: The size of the area.
 *
 * returns the address of the first occurrence of @c, or %NULL
 * if @c is not found
 */
void * memchr(const void *s, int c, size_t n)
{
        const unsigned char *p = s;
        while (n-- != 0) {
                if ((unsigned char)c == *p++) {
                        return (void *)(p-1);
                }
        }
        return NULL;
}

#endif

char * strndup(const char *s, size_t n)
{
        size_t len = strlen(s);
        char *new;

        if (len>n)
                len = n;
        new = malloc(len+1);
        if (new) {
                new[len] = '\0';
                memcpy(new,s,len);
        }
        return new;
}

char * strdup(const char *s) {
        return strndup(s, ~((size_t)0));
}