Sakurai/pdf.js
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Reduce the number of isCmd calls slightly in the XRef class

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This reduces the total number of function calls, when reading the XRef table respectively when fetching uncompressed XRef entries.
Note in particular the `XRef.readXRefTable` method, where there're *two* back-to-back `isCmd` checks rather than just one.
This commit is contained in:
Jonas Jenwald 2019-06-29 16:24:08 +02:00
parent 2800962285
commit 41745a5996
1 changed files with 11 additions and 6 deletions

13
src/core/obj.js

@ -20,7 +20,7 @@ import {
warn
} from '../shared/util';
import {
clearPrimitiveCaches, Dict, isCmd, isDict, isName, isRef, isRefsEqual,
clearPrimitiveCaches, Cmd, Dict, isCmd, isDict, isName, isRef, isRefsEqual,
isStream, Ref, RefSet, RefSetCache
} from './primitives';
import { Lexer, Parser } from './parser';
@ -1200,10 +1200,15 @@ var XRef = (function XRefClosure() {
entry.gen = parser.getObj();
var type = parser.getObj();
if (isCmd(type, 'f')) {
if (type instanceof Cmd) {
switch (type.cmd) {
case 'f':
entry.free = true;
} else if (isCmd(type, 'n')) {
break;
case 'n':
entry.uncompressed = true;
break;
}
}
// Validate entry obj
@ -1685,7 +1690,7 @@ var XRef = (function XRefClosure() {
if (!Number.isInteger(obj2)) {
obj2 = parseInt(obj2, 10);
}
if (obj1 !== num || obj2 !== gen || !isCmd(obj3)) {
if (obj1 !== num || obj2 !== gen || !(obj3 instanceof Cmd)) {
throw new XRefEntryException(`Bad (uncompressed) XRef entry: ${ref}`);
}
if (obj3.cmd !== 'obj') {