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/* Part of publib.
Copyright (c) 1994-2006 Lars Wirzenius. All rights reserved.
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.
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.
*/
/*
* stracat.c -- concatenate many strings into an allocated memory block
*
* Part of publib. See man page for more information.
* "@(#)publib-strutil:$Id: stracat.c,v 1.5 1994/07/16 15:29:17 liw Exp $"
*/
#include <assert.h>
#include <string.h>
#include <stdlib.h>
#include <stdarg.h>
#include "publib/strutil.h"
#include "publib/errormsg.h"
#define N 1024
char *stracat(const char *s, ...) {
va_list args;
char *q, *block;
const char *p;
size_t size, len;
size_t lentab[N];
int n, i;
assert(s != NULL);
/*
* Compute the amount of memory needed for the target string.
*
* I could use realloc to make it larger if an initial guess
* at its size would be too little, but this way we avoid doing
* calling realloc many times, which is a win, because it can
* be pretty slow. However, I haven't actually tested that
* this is faster. :-(.
*
* I use another untested speed hack (but this one should be
* obvious -- famous last words): to avoid having to compute the
* length of each string twice, I store the lengths in an array,
* lentab. If there are more strings than will fit into lentab,
* then the rest will still have their lengths computed twice.
* N, the length of lentab, should be made large enough that it
* seldom happens, and small enough that there is not significant
* memory loss. On memory-starved machines (such as PCs running
* under MS-DOS), one has to take into account also a minuscule stack
* size. On machines with real memory management, a thousand or ten
* should be a pretty good value for N.
*/
n = 1;
lentab[0] = strlen(s);
size = 1 + lentab[0];
va_start(args, s);
while ((p = va_arg(args, char *)) != NULL) {
len = strlen(p);
size += len;
if (n < N)
lentab[n++] = len;
}
va_end(args);
/*
* Allocate the block.
*/
block = malloc(size);
if (block == NULL) {
__publib_error("malloc failed");
return NULL;
}
/*
* Concatenate the strings to the allocated block.
*/
memcpy(block, s, lentab[0]);
q = block + lentab[0];
i = 1;
va_start(args, s);
while ((p = va_arg(args, const char *)) != NULL) {
len = (i < n) ? lentab[i++] : strlen(p);
memcpy(q, p, len);
q += len;
}
*q = '\0';
va_end(args);
return block;
}
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