Split config parsing out of parse.h.
authorSteinar H. Gunderson <sgunderson@bigfoot.com>
Thu, 11 Apr 2013 23:52:29 +0000 (01:52 +0200)
committerSteinar H. Gunderson <sgunderson@bigfoot.com>
Thu, 11 Apr 2013 23:52:29 +0000 (01:52 +0200)
config.cpp [new file with mode: 0644]
config.h [new file with mode: 0644]

diff --git a/config.cpp b/config.cpp
new file mode 100644 (file)
index 0000000..b6ad99b
--- /dev/null
@@ -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 (file)
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)