Initial commit

node_modules/postgres-bytea/decoder.js

@@ -0,0 +1,56 @@
+'use strict'
+
+const BufferList = require('obuf')
+const { Transform } = require('stream')
+
+const State = {
+  READ_PREFIX: 1,
+  READ_DATA: 2
+}
+
+class ByteaDecoder extends Transform {
+  constructor () {
+    super()
+    this._incomingChunks = new BufferList()
+    this._state = State.READ_PREFIX
+  }
+
+  _transform (chunk, encoding, callback) {
+    this._incomingChunks.push(chunk)
+
+    while (true) {
+      if (this._state === State.READ_PREFIX) {
+        if (this._incomingChunks.has(3)) {
+          const prefix = this._incomingChunks.take(3)
+          const prefixString = prefix.toString()
+          if (prefixString !== '\\\\x') {
+            return this.emit('error', new Error(`Expected double-escaped postgres bytea hex format prefix, received: '${prefixString}'`))
+          }
+          this._state = State.READ_DATA
+          continue
+        } else {
+          break
+        }
+      }
+
+      if (this._state === State.READ_DATA) {
+        if (this._incomingChunks.size >= 2) {
+          // two hex characters are needed to parse a byte. read even number of chars, and let remainder roll over
+          let evenChunk
+          const isEvenLength = this._incomingChunks.size % 2 === 0
+          if (isEvenLength) {
+            evenChunk = this._incomingChunks.take(this._incomingChunks.size)
+          } else {
+            evenChunk = this._incomingChunks.take(this._incomingChunks.size - 1)
+          }
+          this.push(Buffer.from(evenChunk.toString(), 'hex'))
+        }
+        break
+      }
+    }
+
+    callback()
+  }
+}
+
+module.exports = ByteaDecoder