cosmopolitan/net/http/underlong.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

84 lines
3.5 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 2021 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/intrin/pcmpgtb.h"
#include "libc/intrin/pmovmskb.h"
#include "libc/mem/mem.h"
#include "libc/str/str.h"
#include "libc/str/thompike.h"
#include "net/http/escape.h"
/**
* Canonicalizes overlong Thompson-Pike encodings.
*
* Please note that the IETF banned these numbers, so if you want to
* enforce their ban you can simply strcmp() the result to check for
* the existence of banned numbers.
*
* @param p is input value
* @param n if -1 implies strlen
* @param z if non-NULL receives output length
* @return allocated NUL-terminated buffer, or NULL w/ errno
*/
char *Underlong(const char *p, size_t n, size_t *z) {
uint64_t w;
char *r, *q;
size_t i, j, m;
wint_t x, a, b;
int8_t v1[16], v2[16], vz[16];
if (z) *z = 0;
if (n == -1) n = p ? strlen(p) : 0;
if ((q = r = malloc(n * 2 + 1))) {
for (i = 0; i < n;) {
bzero(vz, 16); /* 50x speedup for ASCII */
while (i + 16 < n) {
memcpy(v1, p + i, 16);
pcmpgtb(v2, v1, vz);
if (pmovmskb((void *)v2) != 0xFFFF) break;
memcpy(q, v1, 16);
q += 16;
i += 16;
}
x = p[i++] & 0xff;
if (x >= 0300) {
a = ThomPikeByte(x);
m = ThomPikeLen(x) - 1;
if (i + m <= n) {
for (j = 0;;) {
b = p[i + j] & 0xff;
if (!ThomPikeCont(b)) break;
a = ThomPikeMerge(a, b);
if (++j == m) {
x = a;
i += j;
break;
}
}
}
}
w = tpenc(x);
do {
*q++ = w;
} while ((w >>= 8));
}
if (z) *z = q - r;
*q++ = '\0';
if ((q = realloc(r, q - r))) r = q;
}
return r;
}