1 files changed, 111 insertions, 0 deletions
diff --git a/inputmethods/dasher/AlphabetMap.h b/inputmethods/dasher/AlphabetMap.h
new file mode 100644
index 0000000..3aac1f5
--- a/dev/null
+++ b/inputmethods/dasher/AlphabetMap.h
@@ -0,0 +1,111 @@
+// AlphabetMap.h
+//
+/////////////////////////////////////////////////////////////////////////////
+//
+// Copyright (c) 2002 Iain Murray
+//
+/////////////////////////////////////////////////////////////////////////////
+
+
+/*
+If I were just using GCC, which comes with the CGI "STL" implementation, I would
+use hash_map (which isn't part of the ANSI/ISO standard C++ STL, but hey it's nice).
+Using a plain map is just too slow for training on large files (or it is with certain
+STL implementations). I'm sure training could be made much faster still, but that's
+another matter...
+
+While I could (and probably should) get a hash_map for VC++ from
+http://www.stlport.org I thought it would be nicer if people didn't have
+to download extra stuff and then have to get it working alongside the STL
+with VC++, especially for just one small part of Dasher.
+
+The result is this:
+***************************************************
+very much thrown together to get Dasher out ASAP.
+***************************************************
+It is deliberately not like an STL container.
+However, as it has a tiny interface, it should still be easy to replace.
+Sorry if this seems really unprofressional.
+
+Replacing it might be a good idea. On the other hand it could be customised
+to the needs of the alphabet, so that it works faster. For example,
+currently if I have a string "asdf", it might be that "a" is checked
+then "as" is checked then "asd" is checked. I shouldn't need to keep
+rehashing the leading characters. I plan to fix that here. Doing so with
+a standard hash_map would be hard.
+
+
+Usage:
+alphabet_map MyMap(NumberOfEntriesWeExpect); // Can omit NumberOfEntriesWeExpect
+MyMap.add("asdf", 15);
+symbol i = MyMap.get("asdf") // i=15
+symbol j = MyMap.get("fdsa") // j=0
+
+You can't remove items once they are added as Dasher has no need for that.
+
+IAM 08/2002
+*/
+
+#ifndef __AlphabetMap_h__
+#define __AlphabetMap_h__
+
+#include "MSVC_Unannoy.h"
+#include <vector>
+#include <string>
+
+#include "DasherTypes.h"
+
+namespace Dasher {class alphabet_map;}
+class Dasher::alphabet_map
+{
+public:
+	alphabet_map(uint InitialTableSize=255);
+	void Add(const std::string& Key, symbol Value);
+	symbol Get(const std::string& Key, bool* KeyIsPrefix=0) const;
+	
+private:
+	class Entry
+	{
+	public:
+		Entry(std::string Key, symbol Symbol, Entry* Next)
+			: Key(Key), Symbol(Symbol), Next(Next), KeyIsPrefix(false) {}
+		
+		std::string Key;
+		bool KeyIsPrefix;
+		symbol Symbol;
+		Entry* Next;
+	};
+	
+	void RecursiveAdd(const std::string& Key, symbol Value, bool PrefixFlag);
+	
+	// A standard hash -- could try and research something specific.
+	inline uint Hash(const std::string& Input) const {
+		uint Result = 0;
+	
+		typedef std::string::const_iterator CI;
+		CI Cur = Input.begin();
+		CI end = Input.end();
+		
+		while (Cur!=end) Result = (Result<<1)^*Cur++;
+		Result %= HashTable.size();
+		
+		return Result;
+		/*
+		if (Input.size()==1) // Speedup for ASCII text
+			return Input[0];
+		
+		for (int i=0; i<Input.size(); i++)
+			Result = (Result<<1)^Input[i];
+
+		
+		return Result%HashTable.size();
+		*/
+	}
+	
+	std::vector<Entry> Entries;
+	std::vector<Entry*> HashTable;
+	const symbol Undefined;
+};
+
+
+#endif /* #ifndef __AlphabetMap_h__ */