publicsuffixlist.wat (9334B) - View raw
;; ;; uBlock Origin - a browser extension to block requests. ;; Copyright (C) 2019-present Raymond Hill ;; ;; License: pick the one which suits you: ;; GPL v3 see <https://www.gnu.org/licenses/gpl.html> ;; APL v2 see <http://www.apache.org/licenses/LICENSE-2.0> ;; ;; Home: https://github.com/gorhill/publicsuffixlist.js ;; File: publicsuffixlist.wat ;; ;; Description: WebAssembly implementation for core lookup method in ;; publicsuffixlist.js ;; ;; How to compile: ;; ;; wat2wasm publicsuffixlist.wat -o publicsuffixlist.wasm ;; ;; The `wat2wasm` tool can be downloaded from an official WebAssembly ;; project: ;; https://github.com/WebAssembly/wabt/releases (module ;; ;; module start ;; (memory (import "imports" "memory") 1) ;; ;; Tree encoding in array buffer: ;; ;; Node: ;; + u8: length of char data ;; + u8: flags => bit 0: is_publicsuffix, bit 1: is_exception ;; + u16: length of array of children ;; + u32: char data or offset to char data ;; + u32: offset to array of children ;; = 12 bytes ;; ;; // i32 / i8 ;; const HOSTNAME_SLOT = 0; // jshint ignore:line ;; const LABEL_INDICES_SLOT = 256; // -- / 256 ;; const RULES_PTR_SLOT = 100; // 100 / 400 ;; const SUFFIX_NOT_FOUND_SLOT = 399; // -- / 399 ;; const CHARDATA_PTR_SLOT = 101; // 101 / 404 ;; const EMPTY_STRING = ''; ;; const SELFIE_MAGIC = 2; ;; ;; ;; Public functions ;; ;; ;; unsigned int getPublicSuffixPos() ;; ;; Returns an offset to the start of the public suffix. ;; (func (export "getPublicSuffixPos") (result i32) ;; result = match index, -1 = miss (local $iCharData i32) ;; offset to start of character data (local $iNode i32) ;; offset to current node (local $iLabel i32) ;; offset to label indices (local $cursorPos i32) ;; position of cursor within hostname argument (local $labelBeg i32) (local $labelLen i32) (local $nCandidates i32) (local $iCandidates i32) (local $iFound i32) (local $l i32) (local $r i32) (local $d i32) (local $iCandidate i32) (local $iCandidateNode i32) (local $candidateLen i32) (local $iCandidateChar i32) (local $_1 i32) (local $_2 i32) (local $_3 i32) ;; ;; const iCharData = buf32[CHARDATA_PTR_SLOT]; i32.const 404 i32.load local.set $iCharData ;; let iNode = pslBuffer32[RULES_PTR_SLOT]; i32.const 400 i32.load i32.const 2 i32.shl local.set $iNode ;; let iLabel = LABEL_INDICES_SLOT; i32.const 256 local.set $iLabel ;; let cursorPos = -1; i32.const -1 local.set $cursorPos ;; label-lookup loop ;; for (;;) { block $labelLookupDone loop $labelLookup ;; // Extract label indices ;; const labelBeg = buf8[iLabel+1]; ;; const labelLen = buf8[iLabel+0] - labelBeg; local.get $iLabel i32.load8_u local.get $iLabel i32.load8_u offset=1 local.tee $labelBeg i32.sub local.set $labelLen ;; // Match-lookup loop: binary search ;; let r = buf32[iNode+0] >>> 16; ;; if ( r === 0 ) { break; } local.get $iNode i32.load16_u offset=2 local.tee $r i32.eqz br_if $labelLookupDone ;; const iCandidates = buf32[iNode+2]; local.get $iNode i32.load offset=8 i32.const 2 i32.shl local.set $iCandidates ;; let l = 0; ;; let iFound = 0; i32.const 0 local.tee $l local.set $iFound ;; while ( l < r ) { block $binarySearchDone loop $binarySearch local.get $l local.get $r i32.ge_u br_if $binarySearchDone ;; const iCandidate = l + r >>> 1; local.get $l local.get $r i32.add i32.const 1 i32.shr_u local.tee $iCandidate ;; const iCandidateNode = iCandidates + iCandidate + (iCandidate << 1); i32.const 2 i32.shl local.tee $_1 local.get $_1 i32.const 1 i32.shl i32.add local.get $iCandidates i32.add local.tee $iCandidateNode ;; const candidateLen = buf32[iCandidateNode+0] & 0x000000FF; i32.load8_u local.set $candidateLen ;; let d = labelLen - candidateLen; local.get $labelLen local.get $candidateLen i32.sub local.tee $d ;; if ( d === 0 ) { i32.eqz if ;; const iCandidateChar = candidateLen <= 4 local.get $candidateLen i32.const 4 i32.le_u if ;; ? iCandidateNode + 1 << 2 local.get $iCandidateNode i32.const 4 i32.add local.set $iCandidateChar else ;; : buf32[CHARDATA_PTR_SLOT] + buf32[iCandidateNode+1]; local.get $iCharData local.get $iCandidateNode i32.load offset=4 i32.add local.set $iCandidateChar end ;; for ( let i = 0; i < labelLen; i++ ) { local.get $labelBeg local.tee $_1 local.get $labelLen i32.add local.set $_3 local.get $iCandidateChar local.set $_2 block $findDiffDone loop $findDiff ;; d = buf8[labelBeg+i] - buf8[iCandidateChar+i]; ;; if ( d !== 0 ) { break; } local.get $_1 i32.load8_u local.get $_2 i32.load8_u i32.sub local.tee $d br_if $findDiffDone local.get $_1 i32.const 1 i32.add local.tee $_1 local.get $_3 i32.eq br_if $findDiffDone local.get $_2 i32.const 1 i32.add local.set $_2 br $findDiff ;; } end end ;; } end ;; if ( d < 0 ) { ;; r = iCandidate; local.get $d i32.const 0 i32.lt_s if local.get $iCandidate local.set $r br $binarySearch end ;; } else if ( d > 0 ) { ;; l = iCandidate + 1; local.get $d i32.const 0 i32.gt_s if local.get $iCandidate i32.const 1 i32.add local.set $l br $binarySearch end ;; } else /* if ( d === 0 ) */ { ;; iFound = iCandidateNode; ;; break; ;; } local.get $iCandidateNode local.set $iFound end end ;; } ;; // 2. If no rules match, the prevailing rule is "*". ;; if ( iFound === 0 ) { ;; if ( buf32[iCandidates + 1] !== 0x2A /* '*' */ ) { break; } ;; buf8[SUFFIX_NOT_FOUND_SLOT] = 1; ;; iFound = iCandidates; ;; } local.get $iFound i32.eqz if local.get $iCandidates i32.load offset=4 i32.const 0x2A i32.ne br_if $labelLookupDone i32.const 399 i32.const 1 i32.store8 local.get $iCandidates local.set $iFound end ;; iNode = iFound; local.get $iFound local.tee $iNode ;; // 5. If the prevailing rule is a exception rule, modify it by ;; // removing the leftmost label. ;; if ( (buf32[iNode+0] & 0x00000200) !== 0 ) { ;; if ( iLabel > LABEL_INDICES_SLOT ) { ;; return iLabel - 2; ;; } ;; break; ;; } i32.load8_u offset=1 local.tee $_1 i32.const 0x02 i32.and if local.get $iLabel i32.const 256 i32.gt_u if local.get $iLabel i32.const -2 i32.add return end br $labelLookupDone end ;; if ( (buf32[iNode+0] & 0x00000100) !== 0 ) { ;; cursorPos = labelBeg; ;; } local.get $_1 i32.const 0x01 i32.and if local.get $iLabel local.set $cursorPos end ;; if ( labelBeg === 0 ) { break; } local.get $labelBeg i32.eqz br_if $labelLookupDone ;; iLabel += 2; local.get $iLabel i32.const 2 i32.add local.set $iLabel br $labelLookup end end local.get $cursorPos ) ;; ;; module end ;; )