🚚 ➕ add node-signpdf copy to signing packgage until npm includes fix

packages/signing/node-signpdf/dist/helpers/extractSignature.js

@@ -0,0 +1,71 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.default = void 0;
+
+var _SignPdfError = _interopRequireDefault(require("../SignPdfError"));
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
+
+const getSubstringIndex = (str, substring, n) => {
+  let times = 0;
+  let index = null;
+
+  while (times < n && index !== -1) {
+    index = str.indexOf(substring, index + 1);
+    times += 1;
+  }
+
+  return index;
+};
+/**
+ * Basic implementation of signature extraction.
+ *
+ * Really basic. Would work in the simplest of cases where there is only one signature
+ * in a document and ByteRange is only used once in it.
+ *
+ * @param {Buffer} pdf
+ * @returns {Object} {ByteRange: Number[], signature: Buffer, signedData: Buffer}
+ */
+
+
+const extractSignature = (pdf, signatureCount = 1) => {
+  if (!(pdf instanceof Buffer)) {
+    throw new _SignPdfError.default('PDF expected as Buffer.', _SignPdfError.default.TYPE_INPUT);
+  } // const byteRangePos = pdf.indexOf('/ByteRange [');
+
+
+  const byteRangePos = getSubstringIndex(pdf, '/ByteRange [', signatureCount);
+
+  if (byteRangePos === -1) {
+    throw new _SignPdfError.default('Failed to locate ByteRange.', _SignPdfError.default.TYPE_PARSE);
+  }
+
+  const byteRangeEnd = pdf.indexOf(']', byteRangePos);
+
+  if (byteRangeEnd === -1) {
+    throw new _SignPdfError.default('Failed to locate the end of the ByteRange.', _SignPdfError.default.TYPE_PARSE);
+  }
+
+  const byteRange = pdf.slice(byteRangePos, byteRangeEnd + 1).toString();
+  const matches = /\/ByteRange \[(\d+) +(\d+) +(\d+) +(\d+) *\]/.exec(byteRange);
+
+  if (matches === null) {
+    throw new _SignPdfError.default('Failed to parse the ByteRange.', _SignPdfError.default.TYPE_PARSE);
+  }
+
+  const ByteRange = matches.slice(1).map(Number);
+  const signedData = Buffer.concat([pdf.slice(ByteRange[0], ByteRange[0] + ByteRange[1]), pdf.slice(ByteRange[2], ByteRange[2] + ByteRange[3])]);
+  const signatureHex = pdf.slice(ByteRange[0] + ByteRange[1] + 1, ByteRange[2]).toString('binary').replace(/(?:00|>)+$/, '');
+  const signature = Buffer.from(signatureHex, 'hex').toString('binary');
+  return {
+    ByteRange: matches.slice(1, 5).map(Number),
+    signature,
+    signedData
+  };
+};
+
+var _default = extractSignature;
+exports.default = _default;