cosmopolitan/libc/x/xstrcat.c
Jōshin e16a7d8f3b
flip et / noet in modelines
`et` means `expandtab`.

```sh
rg 'vi: .* :vi' -l -0 | \
  xargs -0 sed -i '' 's/vi: \(.*\) et\(.*\)  :vi/vi: \1 xoet\2:vi/'
rg 'vi: .*  :vi' -l -0 | \
  xargs -0 sed -i '' 's/vi: \(.*\)noet\(.*\):vi/vi: \1et\2  :vi/'
rg 'vi: .*  :vi' -l -0 | \
  xargs -0 sed -i '' 's/vi: \(.*\)xoet\(.*\):vi/vi: \1noet\2:vi/'
```
2023-12-07 22:17:11 -05:00

68 lines
2.8 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/str/str.h"
#include "libc/x/x.h"
/**
* Concatenates strings / chars to newly allocated memory, e.g.
*
* xstrcat("hi", ' ', "there")
*
* Or without the C99 helper macro:
*
* (xstrcat)("hi", ' ', "there", NULL)
*
* This goes twice as fast as the more powerful xasprintf(). It's not
* quadratic like strcat(). It's much slower than high-effort stpcpy(),
* particularly with string literals.
*
* @see gc()
*/
char *(xstrcat)(const char *s, ...) {
va_list va;
intptr_t q;
char *p, b[2];
size_t n, m, c;
n = 0;
c = 32;
p = xmalloc(c);
va_start(va, s);
do {
q = (intptr_t)s;
if (q > 0 && q <= 255) {
b[0] = q;
b[1] = '\0';
s = b;
m = 1;
} else {
m = strlen(s);
}
if (n + m + 1 > c) {
do {
c += c >> 1;
} while (n + m + 1 > c);
p = xrealloc(p, c);
}
memcpy(p + n, s, m + 1);
n += m;
} while ((s = va_arg(va, const char *)));
va_end(va);
return p;
}