Initial commit of pre-existing sources.

bf.c

@@ -0,0 +1,140 @@
+/*
+ *  Created by Lionel Sambuc on 03.dec.2009.
+ *  Copyright 2009. All rights reserved.
+ *
+ */
+
+/**************************************************************************
+ *                             Brainfuck lexer                            *
+ **************************************************************************/
+#include <string.h>
+
+#include "interpreter.h"
+#include "tokenizer.h"
+
+#include "bf.h"
+
+static char bf[NB_KWS];
+
+/**************************************************************************
+ *                            PRIVATE INTERFACE                           *
+ **************************************************************************/
+/**
+ * Brainfuck separator detector.
+ * Simply check whether the given character is one of the 8 reserved 
+ * characters, if not it is a separator.
+ */
+static int brainfuck_is_separator(char c)
+{
+	return !(c == '<' || c == '>' ||
+					 c == '+' || c == '-' || 
+					 c == '.' || c == ',' || 
+					 c == '[' || c == ']');
+}
+
+/**
+ * Read a token from the program stream, in the given direction.
+ * Parameters :
+ *  * direction			positive : go from the left to the right
+ *						negative : go from the right to the left
+ *						zero	 : invalid direction.
+ *  * program			the program from which to read a token
+ *  * token_start		the actual position within the program
+ *  * length			the length of the program
+ */
+static int read_token(int direction, char const *program, int *token_start, size_t length)
+{
+	char token;
+	size_t token_length;
+	
+	/* Check that we have a sane direction. */
+	if(direction == 0)
+		return UKW;
+	
+	/* Read the next token. */
+	if(direction > 0)
+	{
+		/* Try to find the next token. */
+		if(!tk_next_token(program, token_start, &token_length))
+			return EOT; /* It was not found. */
+		
+		/* Save the token to be analyzed. */
+		token = *(program + *token_start);
+	
+		/* Update the pointer to be __after__ the token we are analyzing.
+		 * A simple increment does the job as we have only one character tokens. 
+		 */
+		(*token_start)++;
+	}
+	
+	/* Read the previous token. */
+	if(direction < 0)
+	{
+		/* Update the pointer to be __on the last character__ of the token we
+		 * are analyzing. A simple decrement does the job as we have only one
+		 * character tokens. 
+		 */
+		(*token_start)--;
+
+		/* Try to find the previous token. */
+		if(!tk_previous_token(program, token_start, &token_length))
+			return SOT;/* It was not found. */
+		
+		/* Save the token to be analyzed. */
+		token = *(program + *token_start);
+	}
+	
+	/* Match the token characters to a known token value. */
+	if(bf[MVL] == token)
+		return MVL;
+	
+	if(bf[MVR] == token)
+		return MVR;
+	
+	if(bf[INC] == token)
+		return INC;
+	
+	if(bf[DEC] == token)
+		return DEC;
+	
+	if(bf[PUT] == token)
+		return PUT;
+	
+	if(bf[GET] == token)
+		return GET;
+	
+	if(bf[JZF] == token)
+		return JZF;
+	
+	if(bf[JNB] == token)
+		return JNB;
+	
+	return UKW;
+}
+
+/**************************************************************************
+ *                            PUBLIC  INTERFACE                           *
+ **************************************************************************/
+void brainfuck_lexer_init()
+{
+	bf[MVR] = '>';
+	bf[MVL] = '<';
+	bf[INC] = '+';
+	bf[DEC] = '-';
+	bf[PUT] = '.';
+	bf[GET] = ',';
+	bf[JZF] = '[';
+	bf[JNB] = ']';
+	
+	tk_is_separator = brainfuck_is_separator;
+}
+
+int brainfuck_read_next_token(char const *program, int *token_start, size_t length)
+{
+	return read_token(+1, program, token_start, length);
+}
+
+int brainfuck_read_previous_token(char const *program, int *token_start, size_t length)
+{
+	return read_token(-1, program, token_start, length);
+}