pdf-lib
Version:
Create and modify PDF files with JavaScript
89 lines • 4.07 kB
JavaScript
import { ReparseError } from "../errors";
import PDFArray from "../objects/PDFArray";
import PDFName from "../objects/PDFName";
import PDFNumber from "../objects/PDFNumber";
import PDFRef from "../objects/PDFRef";
import ByteStream from "./ByteStream";
var PDFXRefStreamParser = /** @class */ (function () {
function PDFXRefStreamParser(rawStream) {
this.alreadyParsed = false;
this.dict = rawStream.dict;
this.bytes = ByteStream.fromPDFRawStream(rawStream);
this.context = this.dict.context;
var Size = this.dict.lookup(PDFName.of('Size'), PDFNumber);
var Index = this.dict.lookup(PDFName.of('Index'));
if (Index instanceof PDFArray) {
this.subsections = [];
for (var idx = 0, len = Index.size(); idx < len; idx += 2) {
var firstObjectNumber = Index.lookup(idx + 0, PDFNumber).asNumber();
var length_1 = Index.lookup(idx + 1, PDFNumber).asNumber();
this.subsections.push({ firstObjectNumber: firstObjectNumber, length: length_1 });
}
}
else {
this.subsections = [{ firstObjectNumber: 0, length: Size.asNumber() }];
}
var W = this.dict.lookup(PDFName.of('W'), PDFArray);
this.byteWidths = [-1, -1, -1];
for (var idx = 0, len = W.size(); idx < len; idx++) {
this.byteWidths[idx] = W.lookup(idx, PDFNumber).asNumber();
}
}
PDFXRefStreamParser.prototype.parseIntoContext = function () {
if (this.alreadyParsed) {
throw new ReparseError('PDFXRefStreamParser', 'parseIntoContext');
}
this.alreadyParsed = true;
this.context.trailerInfo = {
Root: this.dict.get(PDFName.of('Root')),
Encrypt: this.dict.get(PDFName.of('Encrypt')),
Info: this.dict.get(PDFName.of('Info')),
ID: this.dict.get(PDFName.of('ID')),
};
var entries = this.parseEntries();
// for (let idx = 0, len = entries.length; idx < len; idx++) {
// const entry = entries[idx];
// if (entry.deleted) this.context.delete(entry.ref);
// }
return entries;
};
PDFXRefStreamParser.prototype.parseEntries = function () {
var entries = [];
var _a = this.byteWidths, typeFieldWidth = _a[0], offsetFieldWidth = _a[1], genFieldWidth = _a[2];
for (var subsectionIdx = 0, subsectionLen = this.subsections.length; subsectionIdx < subsectionLen; subsectionIdx++) {
var _b = this.subsections[subsectionIdx], firstObjectNumber = _b.firstObjectNumber, length_2 = _b.length;
for (var objIdx = 0; objIdx < length_2; objIdx++) {
var type = 0;
for (var idx = 0, len = typeFieldWidth; idx < len; idx++) {
type = (type << 8) | this.bytes.next();
}
var offset = 0;
for (var idx = 0, len = offsetFieldWidth; idx < len; idx++) {
offset = (offset << 8) | this.bytes.next();
}
var generationNumber = 0;
for (var idx = 0, len = genFieldWidth; idx < len; idx++) {
generationNumber = (generationNumber << 8) | this.bytes.next();
}
// When the `type` field is absent, it defaults to 1
if (typeFieldWidth === 0)
type = 1;
var objectNumber = firstObjectNumber + objIdx;
var entry = {
ref: PDFRef.of(objectNumber, generationNumber),
offset: offset,
deleted: type === 0,
inObjectStream: type === 2,
};
entries.push(entry);
}
}
return entries;
};
PDFXRefStreamParser.forStream = function (rawStream) {
return new PDFXRefStreamParser(rawStream);
};
return PDFXRefStreamParser;
}());
export default PDFXRefStreamParser;
//# sourceMappingURL=PDFXRefStreamParser.js.map