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uBlock/src/js/biditrie.js

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/*******************************************************************************
uBlock Origin - a comprehensive, efficient content blocker
Copyright (C) 2019-present Raymond Hill
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, either version 3 of the License, or
(at your option) any later version.
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, see {http://www.gnu.org/licenses/}.
Home: https://github.com/gorhill/uBlock
*/
/*******************************************************************************
A BidiTrieContainer is mostly a large buffer in which distinct but related
tries are stored. The memory layout of the buffer is as follow:
0-2047: haystack section
2048-2051: number of significant characters in the haystack
2052-2055: offset to start of trie data section (=> trie0)
2056-2059: offset to end of trie data section (=> trie1)
2060-2063: offset to start of character data section (=> char0)
2064-2067: offset to end of character data section (=> char1)
2068: start of trie data section
+--------------+
Normal cell: | And | If "Segment info" matches:
(aka CELL) +--------------+ Goto "And"
| Or | Else
+--------------+ Goto "Or"
| Segment info |
+--------------+
+--------------+
Boundary cell: | Right And | "Right And" and/or "Left And"
(aka BCELL) +--------------+ can be 0 in last-segment condition.
| Left And |
+--------------+
| 0 |
+--------------+
Given following filters and assuming token is "ad" for all of them:
-images/ad-
/google_ad.
/images_ad.
_images/ad.
We get the following internal representation:
+-----------+ +-----------+ +---+
| |---->| |---->| 0 |
+-----------+ +-----------+ +---+ +-----------+
| 0 | +--| | | |---->| 0 |
+-----------+ | +-----------+ +---+ +-----------+
| ad | | | - | | 0 | | 0 |
+-----------+ | +-----------+ +---+ +-----------+
| | -images/ |
| +-----------+ +---+ +-----------+
+->| |---->| 0 |
+-----------+ +---+ +-----------+ +-----------+
| 0 | | |---->| |---->| 0 |
+-----------+ +---+ +-----------+ +-----------+
| . | | 0 | +--| | +--| |
+-----------+ +---+ | +-----------+ | +-----------+
| | _ | | | /google |
| +-----------+ | +-----------+
| |
| | +-----------+
| +->| 0 |
| +-----------+
| | 0 |
| +-----------+
| | /images |
| +-----------+
|
| +-----------+
+->| 0 |
+-----------+
| 0 |
+-----------+
| _images/ |
+-----------+
*/
const PAGE_SIZE = 65536*2;
const HAYSTACK_START = 0;
const HAYSTACK_SIZE = 2048; // i32 / i8
const HAYSTACK_SIZE_SLOT = HAYSTACK_SIZE >>> 2; // 512 / 2048
const TRIE0_SLOT = HAYSTACK_SIZE_SLOT + 1; // 513 / 2052
const TRIE1_SLOT = HAYSTACK_SIZE_SLOT + 2; // 514 / 2056
const CHAR0_SLOT = HAYSTACK_SIZE_SLOT + 3; // 515 / 2060
const CHAR1_SLOT = HAYSTACK_SIZE_SLOT + 4; // 516 / 2064
const RESULT_L_SLOT = HAYSTACK_SIZE_SLOT + 5; // 517 / 2068
const RESULT_R_SLOT = HAYSTACK_SIZE_SLOT + 6; // 518 / 2072
const RESULT_IU_SLOT = HAYSTACK_SIZE_SLOT + 7; // 519 / 2076
const TRIE0_START = HAYSTACK_SIZE_SLOT + 8 << 2; // 2080
const CELL_BYTE_LENGTH = 12;
const MIN_FREE_CELL_BYTE_LENGTH = CELL_BYTE_LENGTH * 8;
const CELL_AND = 0;
const CELL_OR = 1;
const SEGMENT_INFO = 2;
const BCELL_NEXT_AND = 0;
const BCELL_ALT_AND = 1;
const BCELL_EXTRA = 2;
const BCELL_EXTRA_MAX = 0x00FFFFFF;
const toSegmentInfo = (aL, l, r) => ((r - l) << 24) | (aL + l);
const roundToPageSize = v => (v + PAGE_SIZE-1) & ~(PAGE_SIZE-1);
// http://www.cse.yorku.ca/~oz/hash.html#djb2
const i32Checksum = (buf32) => {
const n = buf32.length;
let hash = 177573 ^ n;
for ( let i = 0; i < n; i++ ) {
hash = (hash << 5) + hash ^ buf32[i];
}
return hash;
};
class BidiTrieContainer {
constructor(extraHandler) {
const len = PAGE_SIZE * 4;
this.buf8 = new Uint8Array(len);
this.buf32 = new Uint32Array(this.buf8.buffer);
this.buf32[TRIE0_SLOT] = TRIE0_START;
this.buf32[TRIE1_SLOT] = this.buf32[TRIE0_SLOT];
this.buf32[CHAR0_SLOT] = len >>> 1;
this.buf32[CHAR1_SLOT] = this.buf32[CHAR0_SLOT];
this.haystack = this.buf8.subarray(
HAYSTACK_START,
HAYSTACK_START + HAYSTACK_SIZE
);
this.extraHandler = extraHandler;
this.textDecoder = null;
this.wasmMemory = null;
this.lastStored = '';
this.lastStoredLen = this.lastStoredIndex = 0;
}
//--------------------------------------------------------------------------
// Public methods
//--------------------------------------------------------------------------
get haystackLen() {
return this.buf32[HAYSTACK_SIZE_SLOT];
}
set haystackLen(v) {
this.buf32[HAYSTACK_SIZE_SLOT] = v;
}
reset(details) {
if (
details instanceof Object &&
typeof details.byteLength === 'number' &&
typeof details.char0 === 'number'
) {
if ( details.byteLength > this.buf8.byteLength ) {
this.reallocateBuf(details.byteLength);
}
this.buf32[CHAR0_SLOT] = details.char0;
}
this.buf32[TRIE1_SLOT] = this.buf32[TRIE0_SLOT];
this.buf32[CHAR1_SLOT] = this.buf32[CHAR0_SLOT];
this.lastStored = '';
this.lastStoredLen = this.lastStoredIndex = 0;
}
createTrie() {
// grow buffer if needed
if ( (this.buf32[CHAR0_SLOT] - this.buf32[TRIE1_SLOT]) < CELL_BYTE_LENGTH ) {
this.growBuf(CELL_BYTE_LENGTH, 0);
}
const iroot = this.buf32[TRIE1_SLOT] >>> 2;
this.buf32[TRIE1_SLOT] += CELL_BYTE_LENGTH;
this.buf32[iroot+CELL_OR] = 0;
this.buf32[iroot+CELL_AND] = 0;
this.buf32[iroot+SEGMENT_INFO] = 0;
return iroot;
}
matches(icell, ai) {
const buf32 = this.buf32;
const buf8 = this.buf8;
const char0 = buf32[CHAR0_SLOT];
const aR = buf32[HAYSTACK_SIZE_SLOT];
let al = ai, x = 0, y = 0;
for (;;) {
x = buf8[al];
al += 1;
// find matching segment
for (;;) {
y = buf32[icell+SEGMENT_INFO];
let bl = char0 + (y & 0x00FFFFFF);
if ( buf8[bl] === x ) {
y = (y >>> 24) - 1;
if ( y !== 0 ) {
x = al + y;
if ( x > aR ) { return 0; }
for (;;) {
bl += 1;
if ( buf8[bl] !== buf8[al] ) { return 0; }
al += 1;
if ( al === x ) { break; }
}
}
break;
}
icell = buf32[icell+CELL_OR];
if ( icell === 0 ) { return 0; }
}
// next segment
icell = buf32[icell+CELL_AND];
x = buf32[icell+BCELL_EXTRA];
if ( x <= BCELL_EXTRA_MAX ) {
if ( x !== 0 && this.matchesExtra(ai, al, x) !== 0 ) {
return 1;
}
x = buf32[icell+BCELL_ALT_AND];
if ( x !== 0 && this.matchesLeft(x, ai, al) !== 0 ) {
return 1;
}
icell = buf32[icell+BCELL_NEXT_AND];
if ( icell === 0 ) { return 0; }
}
if ( al === aR ) { return 0; }
}
return 0; // eslint-disable-line no-unreachable
}
matchesLeft(icell, ar, r) {
const buf32 = this.buf32;
const buf8 = this.buf8;
const char0 = buf32[CHAR0_SLOT];
let x = 0, y = 0;
for (;;) {
if ( ar === 0 ) { return 0; }
ar -= 1;
x = buf8[ar];
// find first segment with a first-character match
for (;;) {
y = buf32[icell+SEGMENT_INFO];
let br = char0 + (y & 0x00FFFFFF);
y = (y >>> 24) - 1;
br += y;
if ( buf8[br] === x ) { // all characters in segment must match
if ( y !== 0 ) {
x = ar - y;
if ( x < 0 ) { return 0; }
for (;;) {
ar -= 1; br -= 1;
if ( buf8[ar] !== buf8[br] ) { return 0; }
if ( ar === x ) { break; }
}
}
break;
}
icell = buf32[icell+CELL_OR];
if ( icell === 0 ) { return 0; }
}
// next segment
icell = buf32[icell+CELL_AND];
x = buf32[icell+BCELL_EXTRA];
if ( x <= BCELL_EXTRA_MAX ) {
if ( x !== 0 && this.matchesExtra(ar, r, x) !== 0 ) {
return 1;
}
icell = buf32[icell+BCELL_NEXT_AND];
if ( icell === 0 ) { return 0; }
}
}
return 0; // eslint-disable-line no-unreachable
}
matchesExtra(l, r, ix) {
let iu = 0;
if ( ix !== 1 ) {
iu = this.extraHandler(l, r, ix);
if ( iu === 0 ) { return 0; }
} else {
iu = -1;
}
this.buf32[RESULT_IU_SLOT] = iu;
this.buf32[RESULT_L_SLOT] = l;
this.buf32[RESULT_R_SLOT] = r;
return 1;
}
get $l() { return this.buf32[RESULT_L_SLOT] | 0; }
get $r() { return this.buf32[RESULT_R_SLOT] | 0; }
get $iu() { return this.buf32[RESULT_IU_SLOT] | 0; }
add(iroot, aL0, n, pivot = 0) {
const aR = n;
if ( aR === 0 ) { return 0; }
// Grow buffer if needed. The characters are already in our character
// data buffer, so we do not need to grow character data buffer.
if (
(this.buf32[CHAR0_SLOT] - this.buf32[TRIE1_SLOT]) <
MIN_FREE_CELL_BYTE_LENGTH
) {
this.growBuf(MIN_FREE_CELL_BYTE_LENGTH, 0);
}
const buf32 = this.buf32;
const char0 = buf32[CHAR0_SLOT];
let icell = iroot;
let aL = char0 + aL0;
// special case: first node in trie
if ( buf32[icell+SEGMENT_INFO] === 0 ) {
buf32[icell+SEGMENT_INFO] = toSegmentInfo(aL0, pivot, aR);
return this.addLeft(icell, aL0, pivot);
}
const buf8 = this.buf8;
let al = pivot;
let inext;
// find a matching cell: move down
for (;;) {
const binfo = buf32[icell+SEGMENT_INFO];
// length of segment
const bR = binfo >>> 24;
// skip boundary cells
if ( bR === 0 ) {
icell = buf32[icell+BCELL_NEXT_AND];
continue;
}
let bl = char0 + (binfo & 0x00FFFFFF);
// if first character is no match, move to next descendant
if ( buf8[bl] !== buf8[aL+al] ) {
inext = buf32[icell+CELL_OR];
if ( inext === 0 ) {
inext = this.addCell(0, 0, toSegmentInfo(aL0, al, aR));
buf32[icell+CELL_OR] = inext;
return this.addLeft(inext, aL0, pivot);
}
icell = inext;
continue;
}
// 1st character was tested
let bi = 1;
al += 1;
// find 1st mismatch in rest of segment
if ( bR !== 1 ) {
for (;;) {
if ( bi === bR ) { break; }
if ( al === aR ) { break; }
if ( buf8[bl+bi] !== buf8[aL+al] ) { break; }
bi += 1;
al += 1;
}
}
// all segment characters matched
if ( bi === bR ) {
// needle remainder: no
if ( al === aR ) {
return this.addLeft(icell, aL0, pivot);
}
// needle remainder: yes
inext = buf32[icell+CELL_AND];
if ( buf32[inext+CELL_AND] !== 0 ) {
icell = inext;
continue;
}
// add needle remainder
icell = this.addCell(0, 0, toSegmentInfo(aL0, al, aR));
buf32[inext+CELL_AND] = icell;
return this.addLeft(icell, aL0, pivot);
}
// some characters matched
// split current segment
bl -= char0;
buf32[icell+SEGMENT_INFO] = bi << 24 | bl;
inext = this.addCell(
buf32[icell+CELL_AND], 0, bR - bi << 24 | bl + bi
);
buf32[icell+CELL_AND] = inext;
// needle remainder: no = need boundary cell
if ( al === aR ) {
return this.addLeft(icell, aL0, pivot);
}
// needle remainder: yes = need new cell for remaining characters
icell = this.addCell(0, 0, toSegmentInfo(aL0, al, aR));
buf32[inext+CELL_OR] = icell;
return this.addLeft(icell, aL0, pivot);
}
}
addLeft(icell, aL0, pivot) {
const buf32 = this.buf32;
const char0 = buf32[CHAR0_SLOT];
let aL = aL0 + char0;
// fetch boundary cell
let iboundary = buf32[icell+CELL_AND];
// add boundary cell if none exist
if (
iboundary === 0 ||
buf32[iboundary+SEGMENT_INFO] > BCELL_EXTRA_MAX
) {
const inext = iboundary;
iboundary = this.allocateCell();
buf32[icell+CELL_AND] = iboundary;
buf32[iboundary+BCELL_NEXT_AND] = inext;
if ( pivot === 0 ) { return iboundary; }
}
// shortest match with no extra conditions will always win
if ( buf32[iboundary+BCELL_EXTRA] === 1 ) {
return iboundary;
}
// bail out if no left segment
if ( pivot === 0 ) { return iboundary; }
// fetch root cell of left segment
icell = buf32[iboundary+BCELL_ALT_AND];
if ( icell === 0 ) {
icell = this.allocateCell();
buf32[iboundary+BCELL_ALT_AND] = icell;
}
// special case: first node in trie
if ( buf32[icell+SEGMENT_INFO] === 0 ) {
buf32[icell+SEGMENT_INFO] = toSegmentInfo(aL0, 0, pivot);
iboundary = this.allocateCell();
buf32[icell+CELL_AND] = iboundary;
return iboundary;
}
const buf8 = this.buf8;
let ar = pivot, inext;
// find a matching cell: move down
for (;;) {
const binfo = buf32[icell+SEGMENT_INFO];
// skip boundary cells
if ( binfo <= BCELL_EXTRA_MAX ) {
inext = buf32[icell+CELL_AND];
if ( inext !== 0 ) {
icell = inext;
continue;
}
iboundary = this.allocateCell();
buf32[icell+CELL_AND] =
this.addCell(iboundary, 0, toSegmentInfo(aL0, 0, ar));
// TODO: boundary cell might be last
// add remainder + boundary cell
return iboundary;
}
const bL = char0 + (binfo & 0x00FFFFFF);
const bR = bL + (binfo >>> 24);
let br = bR;
// if first character is no match, move to next descendant
if ( buf8[br-1] !== buf8[aL+ar-1] ) {
inext = buf32[icell+CELL_OR];
if ( inext === 0 ) {
iboundary = this.allocateCell();
inext = this.addCell(
iboundary, 0, toSegmentInfo(aL0, 0, ar)
);
buf32[icell+CELL_OR] = inext;
return iboundary;
}
icell = inext;
continue;
}
// 1st character was tested
br -= 1;
ar -= 1;
// find 1st mismatch in rest of segment
if ( br !== bL ) {
for (;;) {
if ( br === bL ) { break; }
if ( ar === 0 ) { break; }
if ( buf8[br-1] !== buf8[aL+ar-1] ) { break; }
br -= 1;
ar -= 1;
}
}
// all segment characters matched
// a: ...vvvvvvv
// b: vvvvvvv
if ( br === bL ) {
inext = buf32[icell+CELL_AND];
// needle remainder: no
// a: vvvvvvv
// b: vvvvvvv
// r: 0 & vvvvvvv
if ( ar === 0 ) {
// boundary cell already present
if ( buf32[inext+BCELL_EXTRA] <= BCELL_EXTRA_MAX ) {
return inext;
}
// need boundary cell
iboundary = this.allocateCell();
buf32[iboundary+CELL_AND] = inext;
buf32[icell+CELL_AND] = iboundary;
return iboundary;
}
// needle remainder: yes
// a: yyyyyyyvvvvvvv
// b: vvvvvvv
else {
if ( inext !== 0 ) {
icell = inext;
continue;
}
// TODO: we should never reach here because there will
// always be a boundary cell.
// eslint-disable-next-line no-debugger
debugger; // jshint ignore:line
// boundary cell + needle remainder
inext = this.addCell(0, 0, 0);
buf32[icell+CELL_AND] = inext;
buf32[inext+CELL_AND] =
this.addCell(0, 0, toSegmentInfo(aL0, 0, ar));
}
}
// some segment characters matched
// a: ...vvvvvvv
// b: yyyyyyyvvvvvvv
else {
// split current cell
buf32[icell+SEGMENT_INFO] = (bR - br) << 24 | (br - char0);
inext = this.addCell(
buf32[icell+CELL_AND],
0,
(br - bL) << 24 | (bL - char0)
);
// needle remainder: no = need boundary cell
// a: vvvvvvv
// b: yyyyyyyvvvvvvv
// r: yyyyyyy & 0 & vvvvvvv
if ( ar === 0 ) {
iboundary = this.allocateCell();
buf32[icell+CELL_AND] = iboundary;
buf32[iboundary+CELL_AND] = inext;
return iboundary;
}
// needle remainder: yes = need new cell for remaining
// characters
// a: wwwwvvvvvvv
// b: yyyyyyyvvvvvvv
// r: (0 & wwww | yyyyyyy) & vvvvvvv
else {
buf32[icell+CELL_AND] = inext;
iboundary = this.allocateCell();
buf32[inext+CELL_OR] = this.addCell(
iboundary, 0, toSegmentInfo(aL0, 0, ar)
);
return iboundary;
}
}
//debugger; // jshint ignore:line
}
}
getExtra(iboundary) {
return this.buf32[iboundary+BCELL_EXTRA];
}
setExtra(iboundary, v) {
this.buf32[iboundary+BCELL_EXTRA] = v;
}
optimize(shrink = false) {
if ( shrink ) {
this.shrinkBuf();
}
return {
byteLength: this.buf8.byteLength,
char0: this.buf32[CHAR0_SLOT],
};
}
toSelfie() {
const buf32 = this.buf32.subarray(0, this.buf32[CHAR1_SLOT] + 3 >>> 2);
return { buf32, checksum: i32Checksum(buf32) };
}
fromSelfie(selfie) {
if ( selfie instanceof Object === false ) { return false; }
if ( selfie.buf32 instanceof Uint32Array === false ) { return false; }
if ( selfie.checksum !== i32Checksum(selfie.buf32) ) { return false; }
const byteLength = selfie.buf32.length << 2;
if ( byteLength === 0 ) { return false; }
this.reallocateBuf(byteLength);
this.buf32.set(selfie.buf32);
return true;
}
storeString(s) {
const n = s.length;
if ( n === this.lastStoredLen && s === this.lastStored ) {
return this.lastStoredIndex;
}
this.lastStored = s;
this.lastStoredLen = n;
if ( (this.buf8.length - this.buf32[CHAR1_SLOT]) < n ) {
this.growBuf(0, n);
}
const offset = this.buf32[CHAR1_SLOT];
this.buf32[CHAR1_SLOT] = offset + n;
const buf8 = this.buf8;
for ( let i = 0; i < n; i++ ) {
buf8[offset+i] = s.charCodeAt(i);
}
return (this.lastStoredIndex = offset - this.buf32[CHAR0_SLOT]);
}
extractString(i, n) {
if ( this.textDecoder === null ) {
this.textDecoder = new TextDecoder();
}
const offset = this.buf32[CHAR0_SLOT] + i;
return this.textDecoder.decode(
this.buf8.subarray(offset, offset + n)
);
}
// WASMable.
startsWith(haystackLeft, haystackRight, needleLeft, needleLen) {
if ( haystackLeft < 0 || (haystackLeft + needleLen) > haystackRight ) {
return 0;
}
const charCodes = this.buf8;
needleLeft += this.buf32[CHAR0_SLOT];
const needleRight = needleLeft + needleLen;
while ( charCodes[haystackLeft] === charCodes[needleLeft] ) {
needleLeft += 1;
if ( needleLeft === needleRight ) { return 1; }
haystackLeft += 1;
}
return 0;
}
// Find the left-most instance of substring in main string
// WASMable.
indexOf(haystackLeft, haystackEnd, needleLeft, needleLen) {
if ( needleLen === 0 ) { return haystackLeft; }
haystackEnd -= needleLen;
if ( haystackEnd < haystackLeft ) { return -1; }
needleLeft += this.buf32[CHAR0_SLOT];
const needleRight = needleLeft + needleLen;
const charCodes = this.buf8;
for (;;) {
let i = haystackLeft;
let j = needleLeft;
while ( charCodes[i] === charCodes[j] ) {
j += 1;
if ( j === needleRight ) { return haystackLeft; }
i += 1;
}
haystackLeft += 1;
if ( haystackLeft > haystackEnd ) { break; }
}
return -1;
}
// Find the right-most instance of substring in main string.
// WASMable.
lastIndexOf(haystackBeg, haystackEnd, needleLeft, needleLen) {
if ( needleLen === 0 ) { return haystackBeg; }
let haystackLeft = haystackEnd - needleLen;
if ( haystackLeft < haystackBeg ) { return -1; }
needleLeft += this.buf32[CHAR0_SLOT];
const needleRight = needleLeft + needleLen;
const charCodes = this.buf8;
for (;;) {
let i = haystackLeft;
let j = needleLeft;
while ( charCodes[i] === charCodes[j] ) {
j += 1;
if ( j === needleRight ) { return haystackLeft; }
i += 1;
}
if ( haystackLeft === haystackBeg ) { break; }
haystackLeft -= 1;
}
return -1;
}
dumpTrie(iroot) {
for ( const s of this.trieIterator(iroot) ) {
console.log(s);
}
}
trieIterator(iroot) {
return {
value: undefined,
done: false,
next() {
if ( this.icell === 0 ) {
if ( this.forks.length === 0 ) {
this.value = undefined;
this.done = true;
return this;
}
this.pattern = this.forks.pop();
this.dir = this.forks.pop();
this.icell = this.forks.pop();
}
const buf32 = this.container.buf32;
const buf8 = this.container.buf8;
for (;;) {
const ialt = buf32[this.icell+CELL_OR];
const v = buf32[this.icell+SEGMENT_INFO];
const offset = v & 0x00FFFFFF;
let i0 = buf32[CHAR0_SLOT] + offset;
const len = v >>> 24;
for ( let i = 0; i < len; i++ ) {
this.charBuf[i] = buf8[i0+i];
}
if ( len !== 0 && ialt !== 0 ) {
this.forks.push(ialt, this.dir, this.pattern);
}
const inext = buf32[this.icell+CELL_AND];
if ( len !== 0 ) {
const s = this.textDecoder.decode(
new Uint8Array(this.charBuf.buffer, 0, len)
);
if ( this.dir > 0 ) {
this.pattern += s;
} else if ( this.dir < 0 ) {
this.pattern = s + this.pattern;
}
}
this.icell = inext;
if ( len !== 0 ) { continue; }
// boundary cell
if ( ialt !== 0 ) {
if ( inext === 0 ) {
this.icell = ialt;
this.dir = -1;
} else {
this.forks.push(ialt, -1, this.pattern);
}
}
if ( offset !== 0 ) {
this.value = { pattern: this.pattern, iextra: offset };
return this;
}
}
},
container: this,
icell: iroot,
charBuf: new Uint8Array(256),
pattern: '',
dir: 1,
forks: [],
textDecoder: new TextDecoder(),
[Symbol.iterator]() { return this; },
};
}
async enableWASM(wasmModuleFetcher, path) {
if ( typeof WebAssembly !== 'object' ) { return false; }
if ( this.wasmMemory instanceof WebAssembly.Memory ) { return true; }
const module = await getWasmModule(wasmModuleFetcher, path);
if ( module instanceof WebAssembly.Module === false ) { return false; }
const memory = new WebAssembly.Memory({
initial: roundToPageSize(this.buf8.length) >>> 16
});
const instance = await WebAssembly.instantiate(module, {
imports: { memory, extraHandler: this.extraHandler }
});
if ( instance instanceof WebAssembly.Instance === false ) {
return false;
}
this.wasmMemory = memory;
const curPageCount = memory.buffer.byteLength >>> 16;
const newPageCount = roundToPageSize(this.buf8.byteLength) >>> 16;
if ( newPageCount > curPageCount ) {
memory.grow(newPageCount - curPageCount);
}
const buf8 = new Uint8Array(memory.buffer);
buf8.set(this.buf8);
this.buf8 = buf8;
this.buf32 = new Uint32Array(this.buf8.buffer);
this.haystack = this.buf8.subarray(
HAYSTACK_START,
HAYSTACK_START + HAYSTACK_SIZE
);
this.matches = instance.exports.matches;
this.startsWith = instance.exports.startsWith;
this.indexOf = instance.exports.indexOf;
this.lastIndexOf = instance.exports.lastIndexOf;
return true;
}
dumpInfo() {
return [
`Buffer size (Uint8Array): ${this.buf32[CHAR1_SLOT].toLocaleString('en')}`,
`WASM: ${this.wasmMemory === null ? 'disabled' : 'enabled'}`,
].join('\n');
}
//--------------------------------------------------------------------------
// Private methods
//--------------------------------------------------------------------------
allocateCell() {
let icell = this.buf32[TRIE1_SLOT];
this.buf32[TRIE1_SLOT] = icell + CELL_BYTE_LENGTH;
icell >>>= 2;
this.buf32[icell+0] = 0;
this.buf32[icell+1] = 0;
this.buf32[icell+2] = 0;
return icell;
}
addCell(iand, ior, v) {
const icell = this.allocateCell();
this.buf32[icell+CELL_AND] = iand;
this.buf32[icell+CELL_OR] = ior;
this.buf32[icell+SEGMENT_INFO] = v;
return icell;
}
growBuf(trieGrow, charGrow) {
const char0 = Math.max(
roundToPageSize(this.buf32[TRIE1_SLOT] + trieGrow),
this.buf32[CHAR0_SLOT]
);
const char1 = char0 + this.buf32[CHAR1_SLOT] - this.buf32[CHAR0_SLOT];
const bufLen = Math.max(
roundToPageSize(char1 + charGrow),
this.buf8.length
);
if ( bufLen > this.buf8.length ) {
this.reallocateBuf(bufLen);
}
if ( char0 !== this.buf32[CHAR0_SLOT] ) {
this.buf8.copyWithin(
char0,
this.buf32[CHAR0_SLOT],
this.buf32[CHAR1_SLOT]
);
this.buf32[CHAR0_SLOT] = char0;
this.buf32[CHAR1_SLOT] = char1;
}
}
shrinkBuf() {
const char0 = this.buf32[TRIE1_SLOT] + MIN_FREE_CELL_BYTE_LENGTH;
const char1 = char0 + this.buf32[CHAR1_SLOT] - this.buf32[CHAR0_SLOT];
const bufLen = char1 + 256;
if ( char0 !== this.buf32[CHAR0_SLOT] ) {
this.buf8.copyWithin(
char0,
this.buf32[CHAR0_SLOT],
this.buf32[CHAR1_SLOT]
);
this.buf32[CHAR0_SLOT] = char0;
this.buf32[CHAR1_SLOT] = char1;
}
if ( bufLen < this.buf8.length ) {
this.reallocateBuf(bufLen);
}
}
reallocateBuf(newSize) {
newSize = roundToPageSize(newSize);
if ( newSize === this.buf8.length ) { return; }
if ( this.wasmMemory === null ) {
const newBuf = new Uint8Array(newSize);
newBuf.set(
newBuf.length < this.buf8.length
? this.buf8.subarray(0, newBuf.length)
: this.buf8
);
this.buf8 = newBuf;
} else {
const growBy =
((newSize + 0xFFFF) >>> 16) - (this.buf8.length >>> 16);
if ( growBy <= 0 ) { return; }
this.wasmMemory.grow(growBy);
this.buf8 = new Uint8Array(this.wasmMemory.buffer);
}
this.buf32 = new Uint32Array(this.buf8.buffer);
this.haystack = this.buf8.subarray(
HAYSTACK_START,
HAYSTACK_START + HAYSTACK_SIZE
);
}
}
/******************************************************************************/
// Code below is to attempt to load a WASM module which implements:
//
// - BidiTrieContainer.startsWith()
//
// The WASM module is entirely optional, the JS implementations will be
// used should the WASM module be unavailable for whatever reason.
const getWasmModule = (( ) => {
let wasmModulePromise;
return async function(wasmModuleFetcher, path) {
if ( wasmModulePromise instanceof Promise ) {
return wasmModulePromise;
}
if ( typeof WebAssembly !== 'object' ) { return; }
// Soft-dependency on vAPI so that the code here can be used outside of
// uBO (i.e. tests, benchmarks)
if ( typeof vAPI === 'object' && vAPI.canWASM !== true ) { return; }
// The wasm module will work only if CPU is natively little-endian,
// as we use native uint32 array in our js code.
const uint32s = new Uint32Array(1);
const uint8s = new Uint8Array(uint32s.buffer);
uint32s[0] = 1;
if ( uint8s[0] !== 1 ) { return; }
wasmModulePromise = wasmModuleFetcher(`${path}biditrie`).catch(reason => {
console.info(reason);
});
return wasmModulePromise;
};
})();
/******************************************************************************/
export default BidiTrieContainer;
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