Added simple keys.

There's a bug (and question): should we test simple keys' validity BEFORE stuff or AFTER stuff?

simplekey.cpp

@@ -0,0 +1,100 @@
+#include "scanner.h"
+#include "token.h"
+#include "exceptions.h"
+#include "exp.h"
+
+namespace YAML
+{
+	Scanner::SimpleKey::SimpleKey(int pos_, int line_, int column_)
+		: pos(pos_), line(line_), column(column_), required(false), pMapStart(0), pKey(0)
+	{
+	}
+
+	void Scanner::SimpleKey::Validate()
+	{
+		if(pMapStart)
+			pMapStart->isValid = true;
+		if(pKey)
+			pKey->isValid = true;
+	}
+
+	void Scanner::SimpleKey::Invalidate()
+	{
+		if(required)
+			throw RequiredSimpleKeyNotFound();
+
+		if(pMapStart)
+			pMapStart->isPossible = false;
+		if(pKey)
+			pKey->isPossible = false;
+	}
+
+	// InsertSimpleKey
+	// . Adds a potential simple key to the queue,
+	//   and saves it on a stack.
+	void Scanner::InsertSimpleKey()
+	{
+		SimpleKey key(INPUT.tellg(), m_line, m_column);
+
+		// first add a map start, if necessary
+		key.pMapStart = PushIndentTo(m_column, false);
+		if(key.pMapStart)
+			key.pMapStart->isValid = false;
+//		else
+//			key.required = true;	// TODO: is this correct?
+
+		// then add the (now invalid) key
+		key.pKey = new KeyToken;
+		key.pKey->isValid = false;
+
+		m_tokens.push(key.pKey);
+
+		m_simpleKeys.push(key);
+	}
+
+	// ValidateSimpleKey
+	// . Determines whether the latest simple key to be added is valid,
+	//   and if so, makes it valid.
+	bool Scanner::ValidateSimpleKey()
+	{
+		if(m_simpleKeys.empty())
+			return false;
+
+		// grab top key
+		SimpleKey key = m_simpleKeys.top();
+		m_simpleKeys.pop();
+
+		bool isValid = true;
+
+		// needs to be followed immediately by a value
+		if(m_flowLevel > 0 && !Exp::ValueInFlow.Matches(INPUT))
+			isValid = false;
+		if(m_flowLevel == 0 && !Exp::Value.Matches(INPUT))
+			isValid = false;
+
+		// also needs to be less than 1024 characters and inline
+		if(m_line != key.line || (int) INPUT.tellg() - key.pos > 1024)
+			isValid = false;
+
+		// invalidate key
+		if(isValid)
+			key.Validate();
+		else
+			key.Invalidate();
+
+		// In block style, remember that we've pushed an indent for this potential simple key (if it was starting).
+		// If it was invalid, then we need to pop it off.
+		// Note: we're guaranteed to be popping the right one (i.e., there couldn't have been anything in
+		//       between) since keys have to be inline, and will be invalidated immediately on a newline.
+		if(!isValid && m_flowLevel == 0)
+			m_indents.pop();
+
+		return isValid;
+	}
+
+	void Scanner::ValidateAllSimpleKeys()
+	{
+		while(!m_simpleKeys.empty())
+			ValidateSimpleKey();
+	}
+}