coreboot-kgpe-d16/payloads/libpayload/libc/string.c

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/*
* This file is part of the libpayload project.
*
* Copyright (C) 2007 Uwe Hermann <uwe@hermann-uwe.de>
* Copyright (C) 2008 Advanced Micro Devices, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
* 3. 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
*/
#include <libpayload.h>
/**
* Calculate the length of a fixed-size string.
*
* @param str The input string.
* @param maxlen Return at most maxlen characters as length of the string.
* @return The length of the string, not including the final NUL character.
* The maximum length returned is maxlen.
*/
size_t strnlen(const char *str, size_t maxlen)
{
size_t len = 0;
/* NULL and empty strings have length 0. */
if (!str)
return 0;
/* Loop until we find a NUL character, or maxlen is reached. */
while ((*str++ != '\0') && (len < maxlen))
len++;
return len;
}
/**
* Calculate the length of a string.
*
* @param str The input string.
* @return The length of the string, not including the final NUL character.
*/
size_t strlen(const char *str)
{
size_t len = 0;
/* NULL and empty strings have length 0. */
if (!str)
return 0;
/* Loop until we find a NUL character. */
while (*str++ != '\0')
len++;
return len;
}
/**
* Compare two strings.
*
* @param s1 The first string.
* @param s2 The second string.
* @return Returns a value less than zero, if s1 is shorter than s2. Returns
* zero, if s1 equals s2. Returns a value greater than zero, if
* s1 is longer than s2.
*/
int strcmp(const char *s1, const char *s2)
{
char c1, c2;
/* Set c1 == c2, so that we can enter the while loop. */
c1 = 0;
c2 = 0;
/* Compare characters until they differ, or one of the strings ends. */
while (c1 == c2) {
/* Read the next character from each string. */
c1 = *s1++;
c2 = *s2++;
/* Return something negative (if s1 is shorter than s2), or
zero (if s1 equals s2). */
if (c1 == '\0')
return c1 - c2;
}
/* Return something positive (if s1 is longer than s2), or zero (if s1
and s2 are equal). */
return c1 - c2;
}
/**
* Compare two strings with fixed length.
*
* @param s1 The first string.
* @param s2 The second string.
* @param maxlen Return at most maxlen characters as length of the string.
* @return A non-zero value if s1 and s2 differ, or zero if s1 equals s2.
*/
int strncmp(const char *s1, const char *s2, size_t maxlen)
{
int i;
for (i = 0; i < maxlen; i++) {
if (s1[i] != s2[i])
return s1[i] - s2[i];
}
return 0;
}
/**
* Copy a string with a maximum length.
*
* @param d The destination memory.
* @param s The source string.
* @param n Copy at most n characters as length of the string.
* @return A pointer to the destination memory.
*/
char *strncpy(char *d, const char *s, size_t n)
{
/* Use +1 to get the NUL terminator. */
int max = n > strlen(s) + 1 ? strlen(s) + 1 : n;
int i;
for (i = 0; i < max; i++)
d[i] = (char)s[i];
return d;
}
/**
* Copy a string.
*
* @param d The destination memory.
* @param s The source string.
* @return A pointer to the destination memory.
*/
char *strcpy(char *d, const char *s)
{
return strncpy(d, s, strlen(s) + 1);
}
/**
* Concatenates two strings with a maximum length.
*
* @param d The destination string.
* @param s The source string.
* @param n The target string will have a length of n characters at most.
* @return A pointer to the destination string.
*/
char *strncat(char *d, const char *s, size_t n)
{
char *p = d + strlen(d);
int max = n > strlen(s) ? strlen(s) : n;
int i;
for (i = 0; i < max; i++)
p[i] = s[i];
p[i] = '\0';
return d;
}
/**
* Find a character in a string.
*
* @param s The string.
* @param c The character.
* @return A pointer to the first occurence of the character in the
* string, or NULL if the character was not encountered within the string.
*/
char *strchr(const char *s, int c)
{
char *p = (char *)s;
for (; *p != 0; p++) {
if (*p == c)
return p;
}
return NULL;
}
/**
* Duplicate a string.
*
* @param s The string to duplicate.
* @return A pointer to the copy of the original string.
*/
char *strdup(const char *s)
{
int n = strlen(s);
char *p = malloc(n + 1);
if (p != NULL)
strncpy(p, s, n);
p[n] = 0;
return p;
}
/**
* Find a substring within a string.
*
* @param h The haystack string.
* @param n The needle string (substring).
* @return A pointer to the first occurence of the substring in
* the string, or NULL if the substring was not encountered within the string.
*/
char *strstr(const char *h, const char *n)
{
int hn = strlen(h);
int nn = strlen(n);
int i;
for (i = 0; i <= hn - nn; i++)
if (!strcmp(&h[i], n))
return (char *)&h[i];
return NULL;
}
/**
* Separate strings.
*
* @param stringp reference of the string to separate.
* @param delim string containing all delimiters.
* @return Token string.
*/
char *strsep(char **stringp, const char *delim)
{
char *walk, *token;
if (!stringp || !*stringp || !**stringp)
return NULL;
token = walk = *stringp;
/* Walk, search for delimiters */
while(*walk && !strchr(delim, *walk))
walk++;
if (*walk) {
/* NUL terminate */
*walk = '\0';
walk++;
}
*stringp = walk;
return token;
}