mirrors/cosmopolitan
1
0
Fork 0
mirror of https://github.com/jart/cosmopolitan.git synced 2025-06-27 06:48:31 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 1

Initial import

Browse source
This commit is contained in:
Justine Tunney 2020-06-15 07:18:57 -07:00
commit c91b3c5006
14915 changed files with 590219 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

88
libc/alg/critbit0_emplace.c Normal file
View file

@ -0,0 +1,88 @@
/*-*- 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 2020 Justine Alexandra Roberts Tunney │
│ │
│ This program is free software; you can redistribute it and/or modify │
│ it under the terms of the GNU General Public License as published by │
│ the Free Software Foundation; version 2 of the License. │
│ │
│ This program is distributed in the hope that it will be useful, but │
│ WITHOUT ANY WARRANTY; without even the implied warranty of │
│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
│ General Public License for more details. │
│ │
│ You should have received a copy of the GNU General Public License │
│ along with this program; if not, write to the Free Software │
│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
│ 02110-1301 USA │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/alg/alg.h"
#include "libc/alg/internal.h"
#include "libc/mem/mem.h"
#include "libc/str/str.h"
/**
* Inserts 𝑢 into 𝑡 without copying.
* @param t tree
* @param u NUL-terminated string which must be 8+ byte aligned and
* becomes owned by the tree afterwards
* @return true if 𝑡 was mutated
* @note h/t djb and agl
*/
bool critbit0_emplace(struct critbit0 *t, char *u, size_t ulen) {
unsigned char *p = t->root;
if (!p) {
t->root = u;
t->count = 1;
return true;
}
const unsigned char *const ubytes = (void *)u;
while (1 & (intptr_t)p) {
struct CritbitNode *q = (void *)(p - 1);
unsigned char c = 0;
if (q->byte < ulen) c = ubytes[q->byte];
const int direction = (1 + (q->otherbits | c)) >> 8;
p = q->child[direction];
}
uint32_t newbyte;
uint32_t newotherbits;
for (newbyte = 0; newbyte < ulen; ++newbyte) {
if (p[newbyte] != ubytes[newbyte]) {
newotherbits = p[newbyte] ^ ubytes[newbyte];
goto different_byte_found;
}
}
if (p[newbyte] != 0) {
newotherbits = p[newbyte];
goto different_byte_found;
}
return false;
different_byte_found:
newotherbits |= newotherbits >> 1;
newotherbits |= newotherbits >> 2;
newotherbits |= newotherbits >> 4;
newotherbits = (newotherbits & ~(newotherbits >> 1)) ^ 255;
unsigned char c = p[newbyte];
int newdirection = (1 + (newotherbits | c)) >> 8;
struct CritbitNode *newnode = malloc(sizeof(struct CritbitNode));
newnode->byte = newbyte;
newnode->otherbits = newotherbits;
newnode->child[1 - newdirection] = ubytes;
void **wherep = &t->root;
for (;;) {
unsigned char *wp = *wherep;
if (!(1 & (intptr_t)wp)) break;
struct CritbitNode *q = (void *)(wp - 1);
if (q->byte > newbyte) break;
if (q->byte == newbyte && q->otherbits > newotherbits) break;
unsigned char c2 = 0;
if (q->byte < ulen) c2 = ubytes[q->byte];
const int direction = (1 + (q->otherbits | c2)) >> 8;
wherep = q->child + direction;
}
newnode->child[newdirection] = *wherep;
*wherep = (void *)(1 + (char *)newnode);
t->count++;
return true;
}