src/libstrongswan/utils/lexparser.c

@@ -0,0 +1,135 @@
+/**
+ * @file lexparser.c
+ * 
+ * @brief lexical parser for text-based configuration files
+ *  
+ */
+
+/*
+ * Copyright (C) 2001-2006 Andreas Steffen, Zuercher Hochschule Winterthur
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+#include <string.h>
+
+#include "lexparser.h"
+
+
+/**
+ * eat whitespace
+ */
+bool eat_whitespace(chunk_t *src)
+{
+	while (src->len > 0 && (*src->ptr == ' ' || *src->ptr == '\t'))
+	{
+		src->ptr++;  src->len--;
+	}
+    return  src->len > 0 && *src->ptr != '#';
+}
+
+/**
+ * compare string with chunk
+ */
+bool match(const char *pattern, const chunk_t *ch)
+{
+	return ch->len == strlen(pattern) && strncmp(pattern, ch->ptr, ch->len) == 0;
+}
+
+/**
+ * extracts a token ending with a given termination symbol
+ */
+bool extract_token(chunk_t *token, const char termination, chunk_t *src)
+{
+	u_char *eot = memchr(src->ptr, termination, src->len);
+	
+	/* initialize empty token */
+	*token = CHUNK_INITIALIZER;
+	
+	if (eot == NULL) /* termination symbol not found */
+	{
+		return FALSE;
+	}
+	
+	/* extract token */
+	token->ptr = src->ptr;
+	token->len = (u_int)(eot - src->ptr);
+	
+	/* advance src pointer after termination symbol */
+	src->ptr = eot + 1;
+	src->len -= (token->len + 1);
+	
+	return TRUE;
+}
+
+/**
+ *  fetches a new line terminated by \n or \r\n
+ */
+bool fetchline(chunk_t *src, chunk_t *line)
+{
+	if (src->len == 0) /* end of src reached */
+		return FALSE;
+
+	if (extract_token(line, '\n', src))
+	{
+		if (line->len > 0 && *(line->ptr + line->len -1) == '\r')
+			line->len--;  /* remove optional \r */
+	}
+	else /*last line ends without newline */
+	{
+		*line = *src;
+		src->ptr += src->len;
+		src->len = 0;
+	}
+	return TRUE;
+}
+
+err_t extract_value(chunk_t *value, chunk_t *line)
+{
+	char delimiter = ' ';
+
+	if (!eat_whitespace(line))
+	{
+		return "missing value";
+	}
+	if (*line->ptr == '\'' || *line->ptr == '"')
+	{
+		delimiter = *line->ptr;
+		line->ptr++;  line->len--;
+	}
+	if (!extract_token(value, delimiter, line))
+	{
+		if (delimiter == ' ')
+		{
+			*value = *line;
+		}
+		else
+		{
+			return "missing second delimiter";
+		}
+	}
+	return NULL;
+}
+
+/**
+ * extracts a parameter: value pair
+ */
+err_t extract_parameter_value(chunk_t *name, chunk_t *value, chunk_t *line)
+{
+	/* extract name */
+	if (!extract_token(name,':', line))
+	{
+		return "missing ':'";
+	}
+
+	/* extract value */
+	return extract_value(value, line);
+}