pdf-lib
Version:
Create and modify PDF files with JavaScript
73 lines • 2.53 kB
JavaScript
/*
* Copyright 2012 Mozilla Foundation
*
* The AsciiHexStream class contained in this file is a TypeScript port of the
* JavaScript AsciiHexStream class in Mozilla's pdf.js project, made available
* under the Apache 2.0 open source license.
*/
import { __extends } from "tslib";
import DecodeStream from "./DecodeStream";
var AsciiHexStream = /** @class */ (function (_super) {
__extends(AsciiHexStream, _super);
function AsciiHexStream(stream, maybeLength) {
var _this = _super.call(this, maybeLength) || this;
_this.stream = stream;
_this.firstDigit = -1;
// Most streams increase in size when decoded, but AsciiHex streams shrink
// by 50%.
if (maybeLength) {
maybeLength = 0.5 * maybeLength;
}
return _this;
}
AsciiHexStream.prototype.readBlock = function () {
var UPSTREAM_BLOCK_SIZE = 8000;
var bytes = this.stream.getBytes(UPSTREAM_BLOCK_SIZE);
if (!bytes.length) {
this.eof = true;
return;
}
var maxDecodeLength = (bytes.length + 1) >> 1;
var buffer = this.ensureBuffer(this.bufferLength + maxDecodeLength);
var bufferLength = this.bufferLength;
var firstDigit = this.firstDigit;
for (var i = 0, ii = bytes.length; i < ii; i++) {
var ch = bytes[i];
var digit = void 0;
if (ch >= 0x30 && ch <= 0x39) {
// '0'-'9'
digit = ch & 0x0f;
}
else if ((ch >= 0x41 && ch <= 0x46) || (ch >= 0x61 && ch <= 0x66)) {
// 'A'-'Z', 'a'-'z'
digit = (ch & 0x0f) + 9;
}
else if (ch === 0x3e) {
// '>'
this.eof = true;
break;
}
else {
// probably whitespace
continue; // ignoring
}
if (firstDigit < 0) {
firstDigit = digit;
}
else {
buffer[bufferLength++] = (firstDigit << 4) | digit;
firstDigit = -1;
}
}
if (firstDigit >= 0 && this.eof) {
// incomplete byte
buffer[bufferLength++] = firstDigit << 4;
firstDigit = -1;
}
this.firstDigit = firstDigit;
this.bufferLength = bufferLength;
};
return AsciiHexStream;
}(DecodeStream));
export default AsciiHexStream;
//# sourceMappingURL=AsciiHexStream.js.map