First commit

node_modules/@ldapjs/dn/lib/utils/parse-string/read-hex-string.js

@@ -0,0 +1,61 @@
+'use strict'
+
+const { BerReader } = require('@ldapjs/asn1')
+
+const isValidHexCode = code => /[0-9a-fA-F]{2}/.test(code) === true
+
+/**
+ * @typedef {object} ReadHexStringResult
+ * @property {number} endPos The position in the buffer where the end of the
+ * hex string was encountered.
+ * @property {import('@ldapjs/asn1').BerReader} berReader The parsed hex string
+ * as an BER object.
+ */
+
+/**
+ * Read a sequence of bytes as a hex encoded octet string. The sequence is
+ * assumed to be a spec compliant encoded BER object.
+ *
+ * @param {Buffer} searchBuffer The buffer to read.
+ * @param {number} startPos The position in the buffer to start reading from.
+ *
+ * @returns {ReadHexStringResult}
+ *
+ * @throws When an invalid hex pair has been encountered.
+ */
+module.exports = function readHexString ({ searchBuffer, startPos }) {
+  const bytes = []
+
+  let pos = startPos
+  while (pos < searchBuffer.byteLength) {
+    if (isEndChar(searchBuffer[pos])) {
+      break
+    }
+
+    const hexPair = String.fromCharCode(searchBuffer[pos]) +
+      String.fromCharCode(searchBuffer[pos + 1])
+    if (isValidHexCode(hexPair) === false) {
+      throw Error('invalid hex pair encountered: 0x' + hexPair)
+    }
+
+    bytes.push(parseInt(hexPair, 16))
+    pos += 2
+  }
+
+  return {
+    endPos: pos,
+    berReader: new BerReader(Buffer.from(bytes))
+  }
+}
+
+function isEndChar (c) {
+  switch (c) {
+    case 0x20: // space
+    case 0x2b: // +
+    case 0x2c: // ,
+    case 0x3b: // ;
+      return true
+    default:
+      return false
+  }
+}