Sakurai/pdf.js
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Make type 1 font program decryption faster.

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Discard the values first so we don't have to slice the array.
This commit is contained in:
Brendan Dahl 2016-01-28 13:25:52 -08:00
parent 252b9d5910
commit 02331f6e33
1 changed files with 11 additions and 5 deletions
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16
src/core/fonts.js
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@ -5326,15 +5326,21 @@ var Type1Parser = (function Type1ParserClosure() {
} }
function decrypt(data, key, discardNumber) { function decrypt(data, key, discardNumber) {
var r = key | 0, c1 = 52845, c2 = 22719; if (discardNumber >= data.length) {
var count = data.length; return new Uint8Array(0);
}
var r = key | 0, c1 = 52845, c2 = 22719, i, j;
for (i = 0; i < discardNumber; i++) {
r = ((data[i] + r) * c1 + c2) & ((1 << 16) - 1);
}
var count = data.length - discardNumber;
var decrypted = new Uint8Array(count); var decrypted = new Uint8Array(count);
for (var i = 0; i < count; i++) { for (i = discardNumber, j = 0; j < count; i++, j++) {
var value = data[i]; var value = data[i];
decrypted[i] = value ^ (r >> 8); decrypted[j] = value ^ (r >> 8);
r = ((value + r) * c1 + c2) & ((1 << 16) - 1); r = ((value + r) * c1 + c2) & ((1 << 16) - 1);
} }
return Array.prototype.slice.call(decrypted, discardNumber); return decrypted;
} }
function decryptAscii(data, key, discardNumber) { function decryptAscii(data, key, discardNumber) {