From 1cf6e37dc356144f3da2a2dcde75d1ced8bc5ad6 Mon Sep 17 00:00:00 2001
From: Jakob Odersky <jodersky@gmail.com>
Date: Thu, 19 Mar 2015 16:08:46 +0100
Subject: initial commit

---
 .../scala/com/github/jodersky/mavlink/Parser.scala | 110 +++++++++++++++++++++
 1 file changed, 110 insertions(+)
 create mode 100644 mavlink-library/src/main/scala/com/github/jodersky/mavlink/Parser.scala

(limited to 'mavlink-library/src/main/scala/com/github/jodersky/mavlink/Parser.scala')

diff --git a/mavlink-library/src/main/scala/com/github/jodersky/mavlink/Parser.scala b/mavlink-library/src/main/scala/com/github/jodersky/mavlink/Parser.scala
new file mode 100644
index 0000000..e2dda42
--- /dev/null
+++ b/mavlink-library/src/main/scala/com/github/jodersky/mavlink/Parser.scala
@@ -0,0 +1,110 @@
+package com.github.jodersky.mavlink
+
+import scala.language.postfixOps
+
+import scala.xml.Node
+import scala.util.Try
+
+import trees._
+
+/**
+ * Provides means to parse a MAVLink dialect definition into a
+ * scala object representation.
+ */
+object Parser {
+
+  def fatal(error: String, node: Node) = throw new ParseError("Parse error at " + node + ": " + error)
+  def warn(warning: String, node: Node) = Console.err.println("Warning " + node + ": " + warning)
+
+  def parseDialect(node: Node): Dialect = parse(node) match {
+    case p: Dialect => p
+    case _ => fatal("expected mavlink protocol definition", node)
+  } 
+  
+  def parse(node: Node): Tree = node match {
+    case <field>{_*}</field> =>
+      val description = node.text
+      val name = (node \ "@name").map(_.text).headOption getOrElse fatal("no name defined for field", node)
+      val enum = (node \ "@enum").map(_.text).headOption
+      val (tpe, native) = (node \ "@type") map (_.text) headOption match {
+        case Some(t) => (parseType(t, node), t)
+        case None => fatal("no field type specified", node)
+      }
+      Field(tpe, native, name, enum, description)
+
+    case <entry>{_*}</entry> =>
+      val value = (node \ "@value").map(_.text).headOption map { str =>
+        Try { Integer.parseInt(str) } getOrElse fatal("value must be an integer", node)
+      } getOrElse fatal("no value defined", node)
+      val name = (node \ "@name").map(_.text).headOption getOrElse fatal("no name defined for enum entry", node)
+      val description = (node \ "description").text
+      EnumEntry(value, name, description)
+
+    case <enum>{_*}</enum> =>
+      val name = (node \ "@name").map(_.text).headOption getOrElse fatal("no name defined for enum", node)
+      val entries = (node \ "entry").toSet map { n: Node =>
+        parse(n) match {
+          case e: EnumEntry => e
+          case _ => fatal("illegal definition in enum, only entries are allowed", n)
+        }
+      }
+      Enum(name, entries)
+
+    case <message>{_*}</message> =>
+      val id = (node \ "@id").map(_.text).headOption map { str =>
+        val id = Try { Integer.parseInt(str) } getOrElse fatal("id must be an integer", node)
+        if (id < 0 || id > 255) warn("message id is not in the range [0-255]", node)
+        id.toByte
+      } getOrElse fatal("no id defined", node)
+      val name = (node \ "@name").map(_.text).headOption getOrElse fatal("no name defined for message", node)
+      val description = (node \ "description").text
+
+      val fields = (node \ "field") map { n: Node =>
+        parse(n) match {
+          case e: Field => e
+          case _ => fatal("illegal definition in message, only fields are allowed", n)
+        }
+      }
+      Message(id, name, description, fields)
+
+    case <mavlink>{_*}</mavlink> =>
+      val version = (node \ "version").text
+
+      val enums = (node \ "enums" \ "_").toSet map { n: Node =>
+        parse(n) match {
+          case e: Enum => e
+          case _ => fatal("illegal definition in enums, only enum declarations are allowed", n)
+        }
+      }
+
+      val messages = (node \ "messages" \ "_").toSet map { n: Node =>
+        parse(n) match {
+          case e: Message => e
+          case e => fatal("illegal definition in messages, only message declarations are allowed", n)
+        }
+      }
+      Dialect(version, enums, messages)
+      
+    case x => fatal("unknown", x)
+
+  }
+  
+  val ArrayPattern = """(.*)\[(\d+)\]""".r
+  def parseType(typeStr: String, node: Node): Type = typeStr match {
+    case "int8_t" => IntType(1, true)
+    case "int16_t" => IntType(2, true)
+    case "int32_t" => IntType(4, true)
+    case "int64_t" => IntType(8, true)
+    case "uint8_t" => IntType(1, false)
+    case "uint16_t" => IntType(2, false)
+    case "uint32_t" => IntType(4, false)
+    case "uint64_t" => IntType(8, false)
+    case "float" => FloatType(4)
+    case "double" => FloatType(8)
+    case "char" => IntType(1, true)
+    case ArrayPattern("char", l) => StringType(l.toInt)
+    case ArrayPattern(u, l) => ArrayType(parseType(u, node), l.toInt)
+    case unknown => fatal("unknown field type " + unknown, node)
+  }
+
+}
\ No newline at end of file
-- 
cgit v1.2.3