mirrors/cosmopolitan
1
0
Fork 0
mirror of https://github.com/jart/cosmopolitan.git synced 2025-07-06 03:08:31 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

Fold LIBC_ALG into LIBC_MEM

Browse source
This commit is contained in:
Justine Tunney 2022-08-13 08:32:34 -07:00
parent 7cf66bc161
commit 17aea99bb3
162 changed files with 265 additions and 430 deletions
Download patch file Download diff file Expand all files Collapse all files

92
libc/mem/critbit0_emplace.c Normal file
View file

@ -0,0 +1,92 @@
/*-*- 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 │
│ │
│ 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/mem/critbit0.h"
#include "libc/mem/internal.h"
#include "libc/mem/mem.h"
#include "libc/str/str.h"
/**
* Inserts 𝑢 into 𝑡 without copying.
*
* @param t is critical bit tree
* @param u is nul-terminated string which must be 8+ byte aligned
* and becomes owned by the tree afterwards
* @return true if 𝑡 was mutated, or -1 w/ errno
* @note h/t djb and agl
*/
int critbit0_emplace(struct critbit0 *t, char *u, size_t ulen) {
unsigned char *p = t->root;
if (!p) {
t->root = u;
t->count = 1;
return 1;
}
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 DifferentByteFound;
}
}
if (p[newbyte] != 0) {
newotherbits = p[newbyte];
goto DifferentByteFound;
}
return 0;
DifferentByteFound:
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;
if ((newnode = malloc(sizeof(struct CritbitNode)))) {
newnode->byte = newbyte;
newnode->otherbits = newotherbits;
newnode->child[1 - newdirection] = (void *)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 1;
} else {
return -1;
}
}