pdf-lib/es/core/pdf-parser/parseString.js

Library for creating and modifying PDF files in JavaScript

import { PDFString } from '../pdf-objects';
import { arrayCharAt, arrayToString, trimArrayAndRemoveComments } from '../../utils';
/**
 * Accepts an array of bytes as input. Checks to see if the first characters in the
 * trimmed input make up a PDF String.
 *
 * If so, returns a tuple containing (1) an object representing the parsed PDF
 * String and (2) a subarray of the input with the characters making up the parsed
 * string removed. The "onParseString" parse handler will also be called with the
 * PDFString object.
 *
 * If not, returns null.
 */
var parseString = function (input, _a) {
    var onParseString = (_a === void 0 ? {} : _a).onParseString;
    var trimmed = trimArrayAndRemoveComments(input);
    if (arrayCharAt(trimmed, 0) !== '(')
        return undefined;
    var parensStack = [];
    var isEscaped = false;
    for (var idx = 0; idx < trimmed.length; idx += 1) {
        var c = arrayCharAt(trimmed, idx);
        // Check for unescaped parenthesis
        if (!isEscaped) {
            if (c === '(')
                parensStack.push(c);
            else if (c === ')')
                parensStack.pop();
        }
        // Track whether current character is being escaped or not
        if (c === '\\') {
            if (!isEscaped) {
                isEscaped = true;
            }
            else {
                isEscaped = false;
            }
        }
        else if (isEscaped)
            isEscaped = false;
        // Once (if) the unescaped parenthesis balance out, return their contents
        if (parensStack.length === 0) {
            var str = arrayToString(trimmed, 1, idx);
            var pdfString = PDFString.fromString(str);
            if (onParseString)
                onParseString(pdfString);
            return [pdfString, trimmed.subarray(idx + 1)];
        }
    }
    return undefined; // Parenthesis didn't balance out
};
export default parseString;