mirrors/cosmopolitan
1
0
Fork 0
mirror of https://github.com/jart/cosmopolitan.git synced 2025-06-28 07:18:30 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 1

Apply fixes and speedups

Browse source
This commit is contained in:
Justine Tunney 2021-10-04 03:23:31 -07:00
parent 7521bf9e73
commit 725f4d79f6
36 changed files with 682 additions and 334 deletions
Download patch file Download diff file Expand all files Collapse all files

43
libc/bits/bextra.c Normal file
View file

@ -0,0 +1,43 @@
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net 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/bits/bits.h"
/**
* Extracts bit field from array.
*/
unsigned bextra(const unsigned *p, size_t i, char b) {
unsigned k, r, w;
w = sizeof(unsigned) * CHAR_BIT;
if (b) {
b &= w - 1;
i *= b;
k = i & (w - 1);
i /= w;
if (k <= w - b) {
return (p[i] >> k) & ((1u << (b - 1)) | ((1u << (b - 1)) - 1));
} else {
r = p[i] >> k;
r |= p[i + 1] << (w - k);
r &= (1ul << b) - 1;
return r;
}
} else {
return 0;
}
}