Add SimpleConfig.

https://godocs.io/git.wntrmute.dev/kyle/goutils/config is one of the
more useful Go packages in my standard go library that gets used for
building services. I needed something similar for another Shimmering
Clarity project, and thus I figured I'd add it into SCSL.

src/bin/phonebook.cc

@@ -80,7 +80,7 @@ hasKey(std::vector<std::string> argv)
 	}
 
 	cout << "not found\n";
-	return true;
+	return false;
 }
 
 

src/sl/Flags.cc

@@ -20,7 +20,6 @@
 /// PERFORMANCE OF THIS SOFTWARE.
 ///
 
-
 #include <cassert>
 #include <iostream>
 #include <regex>
@@ -172,6 +171,18 @@ Flags::Register(std::string fName, std::string defaultValue, std::string fDescri
 }
 
 
+bool
+Flags::Register(std::string fName, const char *defaultValue, std::string fDescription)
+{
+	if (!this->Register(fName, FlagType::String, std::move(fDescription))) {
+		return false;
+	}
+
+	this->flags[fName]->Value.s = new std::string(defaultValue);
+	return true;
+}
+
+
 size_t
 Flags::Size()
 {
@@ -206,7 +217,7 @@ Flags::ParseStatus
 Flags::parseArg(int argc, char **argv, int &index)
 {
 	std::string arg(argv[index]);
-	string::TrimWhitespace(arg);
+	scstring::TrimWhitespace(arg);
 
 	if (!std::regex_search(arg, isFlag)) {
 		return ParseStatus::EndOfFlags;
@@ -302,7 +313,7 @@ Flags::Usage(std::ostream &os, int exitCode)
 	os << this->name << ":\t";
 	auto indent = this->name.size() + 7;
 
-	string::WriteTabIndented(os, description, 72 - indent, indent / 8, false);
+	scstring::WriteTabIndented(os, description, 72 - indent, indent / 8, false);
 	os << "\n\n";
 
 	for (const auto &pair : this->flags) {
@@ -312,16 +323,16 @@ Flags::Usage(std::ostream &os, int exitCode)
 			argLine += "\t\t";
 			break;
 		case FlagType::Integer:
-			argLine += "int\t\t";
+			argLine += " int\t\t";
 			break;
 		case FlagType::UnsignedInteger:
-			argLine += "uint\t\t";
+			argLine += " uint\t\t";
 			break;
 		case FlagType::SizeT:
-			argLine += "size_t\t";
+			argLine += " size_t\t";
 			break;
 		case FlagType::String:
-			argLine += "string\t";
+			argLine += " string\t";
 			break;
 		case FlagType::Unknown:
 			// fallthrough
@@ -336,7 +347,7 @@ Flags::Usage(std::ostream &os, int exitCode)
 
 		os << argLine;
 		indent = argLine.size();
-		string::WriteTabIndented(os, pair.second->Description,
+		scstring::WriteTabIndented(os, pair.second->Description,
 				       72-indent, (indent/8)+2, false);
 	}
 

src/sl/SimpleConfig.cc

@@ -0,0 +1,189 @@
+///
+/// \file src/sl/SimpleConfig.cc
+/// \author K. Isom <kyle@imap.cc>
+/// \date 2023-10-21
+/// \brief Simple project configuration.
+///
+/// This is an implementation of a simple global configuration system
+/// for projects based on a Go version I've used successfully in
+/// several projects.
+///
+/// Copyright 2023 K. Isom <kyle@imap.cc>
+///
+/// Permission to use, copy, modify, and/or distribute this software for
+/// any purpose with or without fee is hereby granted, provided that
+/// the above copyright notice and this permission notice appear in all /// copies.
+///
+/// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
+/// WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
+/// WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
+/// AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
+/// DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA
+/// OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+/// TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+/// PERFORMANCE OF THIS SOFTWARE.
+///
+
+#include <cstdlib>
+#include <fstream>
+#include <regex>
+
+#include <scsl/SimpleConfig.h>
+#include <scsl/StringUtil.h>
+
+
+namespace scsl {
+
+
+#if defined(SCSL_DESKTOP_BUILD)
+static SimpleConfig globalConfig;
+#endif
+
+
+static constexpr auto regexOpts = std::regex_constants::nosubs |
+				  std::regex_constants::optimize |
+				  std::regex_constants::ECMAScript;
+
+static const std::regex commentLine("^\\s*#.*$", regexOpts);
+static const std::regex keyValueLine("^\\s*\\w+\\s*=\\s*\\w+", regexOpts);
+
+
+int
+SimpleConfig::LoadGlobal(const char *path)
+{
+	return globalConfig.Load(path);
+}
+
+
+int
+SimpleConfig::LoadGlobal(std::string &path)
+{
+	return globalConfig.Load(path);
+}
+
+
+void
+SimpleConfig::SetPrefixGlobal(const std::string prefix)
+{
+	globalConfig.SetPrefix(prefix);
+}
+
+
+std::vector<std::string>
+SimpleConfig::KeyListGlobal()
+{
+	return globalConfig.KeyList();
+}
+
+
+std::string
+SimpleConfig::GetGlobal(std::string key)
+{
+	return globalConfig.Get(key);
+}
+
+
+std::string
+SimpleConfig::GetGlobal(std::string key, std::string defaultValue)
+{
+	return globalConfig.Get(key, defaultValue);
+}
+
+
+SimpleConfig::SimpleConfig()
+{
+}
+
+
+SimpleConfig::SimpleConfig(std::string prefix)
+: envPrefix(prefix)
+{
+}
+
+
+int
+SimpleConfig::Load(const char *path)
+{
+	auto spath = std::string(path);
+	return this->Load(spath);
+}
+
+
+int
+SimpleConfig::Load(std::string &path)
+{
+	std::ifstream	configFile(path);
+	std::string	line;
+
+	while (std::getline(configFile, line)) {
+		scstring::TrimWhitespace(line);
+		if (line.size() == 0) {
+			continue;
+		}
+
+		if (std::regex_search(line, commentLine)) {
+			return -1;
+		}
+
+		if (std::regex_search(line, keyValueLine)) {
+			auto pair = scstring::SplitKeyValuePair(line, "=");
+			if (pair.size() < 2) {
+				return -1;
+			}
+
+			this->vars[pair[0]] = pair[1];
+		}
+	}
+
+	return 0;
+}
+
+
+void
+SimpleConfig::SetPrefix(const std::string prefix)
+{
+	this->envPrefix = std::move(prefix);
+}
+
+
+std::string
+SimpleConfig::Get(std::string key)
+{
+	return this->Get(key, "");
+}
+
+
+std::string
+SimpleConfig::Get(std::string key, std::string defaultValue)
+{
+	if (this->vars.count(key)) {
+		return this->vars[key];
+	}
+
+	auto envKey = this->envPrefix + key;
+
+	const char *envValue = getenv(envKey.c_str());
+	if (envValue != nullptr) {
+		this->vars[key] = std::string(envValue);
+		return this->Get(key);
+	}
+
+	this->vars[key] = defaultValue;
+	return this->Get(key);
+}
+
+
+std::vector<std::string>
+SimpleConfig::KeyList()
+{
+	std::vector<std::string>	keyList;
+
+	for (auto &entry : this->vars) {
+		keyList.push_back(entry.first);
+	}
+
+	return keyList;
+}
+
+
+} // namespace SimpleConfig

src/sl/StringUtil.cc

@@ -28,7 +28,7 @@
 
 
 namespace scsl {
-namespace string {
+namespace scstring {
 
 
 std::vector<std::string>