1 files changed, 54 insertions, 0 deletions
diff --git a/fastify-busboy/lib/utils/Decoder.js b/fastify-busboy/lib/utils/Decoder.js
new file mode 100644
index 0000000..7917678
--- /dev/null
+++ b/fastify-busboy/lib/utils/Decoder.js
@@ -0,0 +1,54 @@
+'use strict'
+
+const RE_PLUS = /\+/g
+
+const HEX = [
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0,
+  0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
+]
+
+function Decoder () {
+  this.buffer = undefined
+}
+Decoder.prototype.write = function (str) {
+  // Replace '+' with ' ' before decoding
+  str = str.replace(RE_PLUS, ' ')
+  let res = ''
+  let i = 0; let p = 0; const len = str.length
+  for (; i < len; ++i) {
+    if (this.buffer !== undefined) {
+      if (!HEX[str.charCodeAt(i)]) {
+        res += '%' + this.buffer
+        this.buffer = undefined
+        --i // retry character
+      } else {
+        this.buffer += str[i]
+        ++p
+        if (this.buffer.length === 2) {
+          res += String.fromCharCode(parseInt(this.buffer, 16))
+          this.buffer = undefined
+        }
+      }
+    } else if (str[i] === '%') {
+      if (i > p) {
+        res += str.substring(p, i)
+        p = i
+      }
+      this.buffer = ''
+      ++p
+    }
+  }
+  if (p < len && this.buffer === undefined) { res += str.substring(p) }
+  return res
+}
+Decoder.prototype.reset = function () {
+  this.buffer = undefined
+}
+
+module.exports = Decoder