From aeda7b341454f243ff8a3d742222c24bf75c338d Mon Sep 17 00:00:00 2001
From: "Steinar H. Gunderson" <sgunderson@bigfoot.com>
Date: Fri, 12 Apr 2013 01:52:29 +0200
Subject: [PATCH] Split config parsing out of parse.h.

---
 config.cpp | 126 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 config.h   |  32 ++++++++++++++
 2 files changed, 158 insertions(+)
 create mode 100644 config.cpp
 create mode 100644 config.h

diff --git a/config.cpp b/config.cpp
new file mode 100644
index 0000000..b6ad99b
--- /dev/null
+++ b/config.cpp
@@ -0,0 +1,126 @@
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <assert.h>
+#include <vector>
+#include <string>
+
+#include "config.h"
+#include "parse.h"
+
+using namespace std;
+
+vector<ConfigLine> parse_config(const string &filename)
+{
+	vector<ConfigLine> ret;
+
+	FILE *fp = fopen(filename.c_str(), "r");
+	if (fp == NULL) {
+		perror(filename.c_str());
+		exit(1);
+	}
+
+	char buf[4096];
+	while (!feof(fp)) {
+		if (fgets(buf, sizeof(buf), fp) == NULL) {
+			break;
+		}
+
+		// Chop off the string at the first #, \r or \n.
+		buf[strcspn(buf, "#\r\n")] = 0;
+
+		// Remove all whitespace from the end of the string.
+		size_t len = strlen(buf);
+		while (len > 0 && isspace(buf[len - 1])) {
+			buf[--len] = 0;
+		}
+
+		// If the line is now all blank, ignore it.
+		if (len == 0) {
+			continue;
+		}
+
+		vector<string> tokens = split_tokens(buf);
+		assert(!tokens.empty());
+		
+		ConfigLine line;
+		line.keyword = tokens[0];
+
+		for (size_t i = 1; i < tokens.size(); ++i) {
+			// foo=bar is a parameter; anything else is an argument.
+			size_t equals_pos = tokens[i].find_first_of('=');
+			if (equals_pos == string::npos) {
+				line.arguments.push_back(tokens[i]);
+			} else {
+				string key = tokens[i].substr(0, equals_pos);
+				string value = tokens[i].substr(equals_pos + 1, string::npos);
+				line.parameters.insert(make_pair(key, value));
+			}
+		}
+
+		ret.push_back(line);
+	}
+
+	fclose(fp);
+	return ret;
+}
+
+string fetch_config_string(const vector<ConfigLine> &config, const string &keyword,
+                           ParameterType parameter_type, const string &default_value)
+{
+	assert(parameter_type == PARAMATER_MANDATORY || parameter_type == PARAMETER_OPTIONAL);
+	for (unsigned i = 0; i < config.size(); ++i) {
+		if (config[i].keyword != keyword) {
+			continue;
+		}
+		if (config[i].parameters.size() > 0 ||
+		    config[i].arguments.size() != 1) {
+			fprintf(stderr, "ERROR: '%s' takes one argument and no parameters\n", keyword.c_str());
+			exit(1);
+		}
+		return config[i].arguments[0];
+	}
+	if (parameter_type == PARAMATER_MANDATORY) {
+		fprintf(stderr, "ERROR: Missing '%s' statement in config file.\n",
+			keyword.c_str());
+		exit(1);
+	} else {
+		return default_value;
+	}
+}
+
+int fetch_config_int(const std::vector<ConfigLine> &config, const std::string &keyword,
+                     int min_limit, int max_limit,
+                     ParameterType parameter_type, int default_value)
+{
+	assert(parameter_type == PARAMATER_MANDATORY || parameter_type == PARAMETER_OPTIONAL);
+	bool value_found = false;
+	int value = -1;
+	for (unsigned i = 0; i < config.size(); ++i) {
+		if (config[i].keyword != keyword) {
+			continue;
+		}
+		if (config[i].parameters.size() > 0 ||
+		    config[i].arguments.size() != 1) {
+			fprintf(stderr, "ERROR: '%s' takes one argument and no parameters\n", keyword.c_str());
+			exit(1);
+		}
+		value_found = true;
+		value = atoi(config[i].arguments[0].c_str());  // TODO: verify int validity.
+	}
+	if (!value_found) {
+		if (parameter_type == PARAMETER_OPTIONAL) {
+			return default_value;
+		}
+		fprintf(stderr, "ERROR: Missing '%s' statement in config file.\n",
+			keyword.c_str());
+		exit(1);
+	}
+	if (value < min_limit || value > max_limit) {
+		fprintf(stderr, "ERROR: '%s' is set to %d, must be in [%d,%d]\n",
+			keyword.c_str(), value, min_limit, max_limit);
+		exit(1);
+	}
+	return value;
+}
diff --git a/config.h b/config.h
new file mode 100644
index 0000000..0600083
--- /dev/null
+++ b/config.h
@@ -0,0 +1,32 @@
+#ifndef _CONFIG_H
+#define _CONFIG_H
+
+// Various routines that deal with parsing the configuration file.
+
+#include <map>
+#include <vector>
+#include <string>
+
+struct ConfigLine {
+	std::string keyword;
+	std::vector<std::string> arguments;
+	std::map<std::string, std::string> parameters;
+};
+
+// Parse the configuration file.
+std::vector<ConfigLine> parse_config(const std::string &filename);
+
+enum ParameterType {
+	PARAMETER_OPTIONAL,
+	PARAMATER_MANDATORY,
+};
+
+std::string fetch_config_string(const std::vector<ConfigLine> &config, const std::string &keyword,
+                                ParameterType parameter_type, const std::string &default_value = "");
+
+// Note: Limits are inclusive.
+int fetch_config_int(const std::vector<ConfigLine> &config, const std::string &keyword,
+                     int min_limit, int max_limit,
+                     ParameterType parameter_type, int default_value = -1);
+
+#endif  // !defined(_CONFIG_H)
-- 
2.39.2