1 files changed, 106 insertions, 0 deletions
diff --git a/shared/src/main/scala/spray/json/JsonPrinter.scala b/shared/src/main/scala/spray/json/JsonPrinter.scala
new file mode 100644
index 0000000..42cbab4
--- /dev/null
+++ b/shared/src/main/scala/spray/json/JsonPrinter.scala
@@ -0,0 +1,106 @@
+/*
+ * Copyright (C) 2009-2011 Mathias Doenitz
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package spray.json
+
+import annotation.tailrec
+import java.lang.{StringBuilder => JStringBuilder}
+
+/**
+  * A JsonPrinter serializes a JSON AST to a String.
+ */
+trait JsonPrinter extends (JsValue => String) {
+
+  def apply(x: JsValue): String = apply(x, None)
+
+  def apply(x: JsValue,
+            jsonpCallback: Option[String] = None,
+            sb: JStringBuilder = new JStringBuilder(256)): String = {
+    jsonpCallback match {
+      case Some(callback) =>
+        sb.append(callback).append('(')
+        print(x, sb)
+        sb.append(')')
+      case None => print(x, sb)
+    }
+    sb.toString
+  }
+  
+  def print(x: JsValue, sb: JStringBuilder): Unit
+  
+  protected def printLeaf(x: JsValue, sb: JStringBuilder): Unit = {
+    x match {
+      case JsNull      => sb.append("null")
+      case JsTrue      => sb.append("true")
+      case JsFalse     => sb.append("false")
+      case JsNumber(x) => sb.append(x)
+      case JsString(x) => printString(x, sb)
+      case _           => throw new IllegalStateException
+    }
+  }
+
+  protected def printString(s: String, sb: JStringBuilder): Unit = {
+    import JsonPrinter._
+    @tailrec def firstToBeEncoded(ix: Int = 0): Int =
+      if (ix == s.length) -1 else if (requiresEncoding(s.charAt(ix))) ix else firstToBeEncoded(ix + 1)
+
+    sb.append('"')
+    firstToBeEncoded() match {
+      case -1 => sb.append(s)
+      case first =>
+        sb.append(s, 0, first)
+        @tailrec def append(ix: Int): Unit =
+          if (ix < s.length) {
+            s.charAt(ix) match {
+              case c if !requiresEncoding(c) => sb.append(c)
+              case '"' => sb.append("\\\"")
+              case '\\' => sb.append("\\\\")
+              case '\b' => sb.append("\\b")
+              case '\f' => sb.append("\\f")
+              case '\n' => sb.append("\\n")
+              case '\r' => sb.append("\\r")
+              case '\t' => sb.append("\\t")
+              case x if x <= 0xF => sb.append("\\u000").append(Integer.toHexString(x))
+              case x if x <= 0xFF => sb.append("\\u00").append(Integer.toHexString(x))
+              case x if x <= 0xFFF => sb.append("\\u0").append(Integer.toHexString(x))
+              case x => sb.append("\\u").append(Integer.toHexString(x))
+            }
+            append(ix + 1)
+          }
+        append(first)
+    }
+    sb.append('"')
+  }
+  
+  protected def printSeq[A](iterable: Iterable[A], printSeparator: => Unit)(f: A => Unit): Unit = {
+    var first = true
+    iterable.foreach { a =>
+      if (first) first = false else printSeparator
+      f(a)
+    }
+  }
+}
+
+object JsonPrinter {
+  def requiresEncoding(c: Char): Boolean =
+    // from RFC 4627
+    // unescaped = %x20-21 / %x23-5B / %x5D-10FFFF
+    c match {
+      case '"'  => true
+      case '\\' => true
+      case c    => c < 0x20
+    }
+}
+\ No newline at end of file