/*
 * String library 
 * Copyright (c) 2001,2003,2004 David H. Hovemeyer <daveho@cs.umd.edu>
 * Copyright (c) 2003, Jeffrey K. Hollingsworth <hollings@cs.umd.edu>
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without restriction,
 * including without limitation the rights to use, copy, modify, merge,
 * publish, distribute, sublicense, and/or sell copies of the Software,
 * and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
 * ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
 * TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
 * SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
 * FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR
 * THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
/* Modifications by Jack Lange <jarusl@cs.northwestern.edu> */



/*
 * NOTE:
 * These are slow and simple implementations of a subset of
 * the standard C library string functions.
 * We also have an implementation of snprintf().
 */



#define NEED_MEMSET 0
#define NEED_MEMCPY 0
#define NEED_MEMCMP 0
#define NEED_STRLEN 0
#define NEED_STRNLEN 0
#define NEED_STRCMP 0
#define NEED_STRNCMP 0
#define NEED_STRCAT 0
#define NEED_STRNCAT 0
#define NEED_STRCPY 0
#define NEED_STRNCPY 0
#define NEED_STRDUP 0
#define NEED_ATOI 0
#define NEED_STRCHR 0
#define NEED_STRRCHR 0
#define NEED_STRPBRK 0



#include <palacios/vmm_string.h>
#include <palacios/vmm.h>


#if NEED_MEMSET
void* memset(void* s, int c, size_t n)
{
    unsigned char* p = (unsigned char*) s;

    while (n > 0) {
	*p++ = (unsigned char) c;
	--n;
    }

    return s;
}
#endif

#if NEED_MEMCPY
void* memcpy(void *dst, const void* src, size_t n)
{
    unsigned char* d = (unsigned char*) dst;
    const unsigned char* s = (const unsigned char*) src;

    while (n > 0) {
	*d++ = *s++;
	--n;
    }

    return dst;
}
#endif


#if NEED_CMP
int memcmp(const void *s1_, const void *s2_, size_t n)
{
    const signed char *s1 = s1_, *s2 = s2_;

    while (n > 0) {
	int cmp = *s1 - *s2;
	if (cmp != 0)
	    return cmp;
	++s1;
	++s2;
    }

    return 0;
}
#endif


#if NEED_STRLEN
size_t strlen(const char* s)
{
    size_t len = 0;
    while (*s++ != '\0')
	++len;
    return len;
}
#endif



#if NEED_STRNLEN
/*
 * This it a GNU extension.
 * It is like strlen(), but it will check at most maxlen
 * characters for the terminating nul character,
 * returning maxlen if it doesn't find a nul.
 * This is very useful for checking the length of untrusted
 * strings (e.g., from user space).
 */
size_t strnlen(const char *s, size_t maxlen)
{
    size_t len = 0;
    while (len < maxlen && *s++ != '\0')
	++len;
    return len;
}
#endif


#if NEED_STRCMP
int strcmp(const char* s1, const char* s2)
{
    while (1) {
	int cmp = *s1 - *s2;
	if (cmp != 0 || *s1 == '\0' || *s2 == '\0')
	    return cmp;
	++s1;
	++s2;
    }
}
#endif


#if NEED_STRNCMP
int strncmp(const char* s1, const char* s2, size_t limit)
{
    size_t i = 0;
    while (i < limit) {
	int cmp = *s1 - *s2;
	if (cmp != 0 || *s1 == '\0' || *s2 == '\0')
	    return cmp;
	++s1;
	++s2;
	++i;
    }

    /* limit reached and equal */
    return 0;
}
#endif


#if NEED_STRCAT
char *strcat(char *s1, const char *s2)
{
    char *t1;

    t1 = s1;
    while (*s1) s1++;
    while(*s2) *s1++ = *s2++;
    *s1 = '\0';

    return t1;
}
#endif


#if NEED_STRNCAT
char *strncat(char *s1, const char *s2, size_t limit)
{
    size_t i = 0;
    char *t1;
    t1 = s1;
    while (*s1) s1++;
    while (i < limit) {
	if(*s2 == '\0') break;
	*s1++ = *s2++;		
    }
    *s1 = '\0';
    return t1;
}
#endif



#if NEED_STRCPY
char *strcpy(char *dest, const char *src)
{
    char *ret = dest;

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

    return ret;
}
#endif


#if NEED_STRNCPY
char *strncpy(char *dest, const char *src, size_t limit)
{
    char *ret = dest;

    while (*src != '\0' && limit > 0) {
	*dest++ = *src++;
	--limit;
    }
    if (limit > 0)
	*dest = '\0';

    return ret;
}
#endif



#if NEED_STRDUP
char *strdup(const char *s1)
{
    char *ret;

    ret = V3_Malloc(strlen(s1) + 1);
    strcpy(ret, s1);

    return ret;
}
#endif




#if NEED_ATOI
int atoi(const char *buf) 
{
    int ret = 0;

    while (*buf >= '0' && *buf <= '9') {
	ret *= 10;
	ret += *buf - '0';
	buf++;
    }

    return ret;
}
#endif


#if NEED_STRCHR
char *strchr(const char *s, int c)
{
    while (*s != '\0') {
	if (*s == c)
	    return (char *) s;
	++s;
    }
    return 0;
}
#endif


#if NEED_STRRCHR
char *strrchr(const char *s, int c)
{
    size_t len = strlen(s);
    const char *p = s + len;

    while (p > s) {
	--p;
	if (*p == c)
	    return (char*) p;
    }
    return 0;
}
#endif

#if NEED_STRPBRK
char *strpbrk(const char *s, const char *accept)
{
    size_t setLen = strlen(accept);

    while (*s != '\0') {
	size_t i;
	for (i = 0; i < setLen; ++i) {
	    if (*s == accept[i])
		return (char *) s;
	}
	++s;
    }

    return 0;
}
#endif