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// $Id: string.c,v 1.1.1.1 2013/12/11 20:49:20 bcbrock Exp $
// $Source: /afs/awd/projects/eclipz/KnowledgeBase/.cvsroot/eclipz/chips/p8/working/procedures/lib/string.c,v $
//-----------------------------------------------------------------------------
// *! (C) Copyright International Business Machines Corp. 2013
// *! All Rights Reserved -- Property of IBM
// *! *** IBM Confidential ***
//-----------------------------------------------------------------------------
/// \file string.c
/// \brief strlen(), strcmp() etc. functions
#include "ssx.h"
#include "string.h"
/// Compute the length of a string
///
/// The strlen() function calculates the length of the string \a s, not
/// including the terminating \b '\0' character. The strlen() function
/// returns the number of characters in \a s.
size_t
strlen(const char *s)
{
const char *p = s;
while (*p) {
p++;
}
return p - s;
}
/// Compare two strings
///
/// The strcmp() function compares the two strings \a s1 and \a s2. It
/// returns an integer less than, equal to, or greater than zero if \a s1 is
/// found, respectively, to be less than, to match, or be greater than \a s2.
int
strcmp(const char* s1, const char* s2)
{
int rc;
if (s1 == s2) {
rc = 0;
} else {
while(*s1 && (*s1 == *s2)) {
s1++;
s2++;
}
rc = *((unsigned char *)s1) - *((unsigned char *)s2);
}
return rc;
}
/// Compare a portion of two strings
///
/// The strncmp() function compares at most the first \n characters of the two
/// strings \a s1 and \a s2. It returns an integer less than, equal to, or
/// greater than zero if (the prefix of) \a s1 is found, respectively, to be
/// less than, to match, or be greater than (the prefix of) \a s2.
int
strncmp(const char* s1, const char* s2, size_t n)
{
int rc;
if ((s1 == s2) || (n == 0)) {
rc = 0;
} else {
while(*s1 && (*s1 == *s2) && n--) {
s1++;
s2++;
}
rc = *((unsigned char *)s1) - *((unsigned char *)s2);
}
return rc;
}
/// Copy a string
///
/// The strcpy() function copies the string pointed to by \a src (including
/// the terminating null character) to the array pointed to by \a dest. The
/// strings may not overlap, and the destination string \a dest must be large
/// enough to receive the copy.
///
/// The strcpy() function return a pointer to the destination string \a dest.
char *
strcpy(char *dest, const char *src)
{
char *rv = dest;
while (*src) {
*dest++ = *src++;
}
*dest = '\0';
return rv;
}
/// Safely copy all or part of a string
///
/// The strncpy() function copies the string pointed to by \a src (including
/// the terminating null character) to the array pointed to by \a dest, except
/// that no more than \a n bytes of \a src are copied. This, if there is no
/// null byte among the first \a n bytes of \a src, the result will not be
/// null-terminated. In the case where the length of \a src is less than \a n,
/// the remainder of \a dest will be padded with null bytes. The strings may
/// not overlap.
///
/// The strncpy() function return a pointer to the destination string \a dest.
char *
strncpy(char *dest, const char *src, size_t n)
{
char *rv = dest;
while (*src && n--) {
*dest++ = *src++;
}
memset(dest, 0, n);
return rv;
}
/// Compare two memory areas
///
/// The memcmp() function compares the first \a n bytes of the memory areas \a
/// s1 and \a s2. It returns an integer less than, equal to, or greater than
/// zero if \a s1 is found, respectively, to be less than, to match, or be
/// greater than \a s2.
int
memcmp(const void* s1, const void* s2, size_t n)
{
unsigned char *p1, *p2;
int rc;
p1 = (unsigned char*) s1;
p2 = (unsigned char*) s2;
if (s1 == s2) {
rc = 0;
} else {
while (n && (*p1 == *p2)) {
n--;
p1++;
p2++;
}
if (n == 0) {
rc = 0;
} else {
rc = (*p1 - *p2);
}
}
return rc;
}
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