add a parser to read the UID per user

src/config/IdentifierFileFormat.cpp

@@ -0,0 +1,94 @@
+/*
+ * Author:
+ *   Sven Czarnian <devel@svcz.de>
+ * Brief:
+ *   Implements the identifier file format
+ * Copyright:
+ *   2021 Sven Czarnian
+ * License:
+ *   GNU General Public License v3 (GPLv3)
+ */
+
+#include <fstream>
+
+#include <gsl/gsl>
+
+#include <aman/config/IdentifierFileFormat.h>
+#include <aman/helper/String.h>
+
+using namespace aman;
+
+IdentifierFileFormat::IdentifierFileFormat() :
+        FileFormat() { }
+
+bool IdentifierFileFormat::parse(const std::string& filename, Communication& config) {
+    config.valid = true;
+
+    std::ifstream stream(filename);
+    if (false == stream.is_open()) {
+        this->m_errorMessage = "Unable to open the configuration file: " + filename;
+        this->m_errorLine = 0;
+        config.valid = false;
+        return false;
+    }
+
+    std::string line;
+    std::uint32_t lineOffset = 0;
+    while (std::getline(stream, line)) {
+        std::string value;
+
+        lineOffset += 1;
+
+        /* skip a new line */
+        if (0 == line.length())
+            continue;
+
+        /* trimm the line and check if a comment line is used */
+        std::string trimmed = String::trim(line);
+        if (0 == trimmed.find_first_of('#', 0))
+            continue;
+
+        auto entry = String::splitString(trimmed, "=");
+        if (2 > entry.size()) {
+            this->m_errorLine = lineOffset;
+            this->m_errorMessage = "Invalid configuration entry";
+            config.valid = false;
+            return false;
+        }
+        else if (2 < entry.size()) {
+            for (std::size_t idx = 1; idx < entry.size() - 1; ++idx)
+                value += gsl::at(entry, idx) + "=";
+            value += entry.back();
+        }
+        else {
+            value = gsl::at(entry, 1);
+        }
+
+        /* found an invalid line */
+        if (0 == value.length()) {
+            this->m_errorLine = lineOffset;
+            this->m_errorMessage = "Invalid entry";
+            config.valid = false;
+            return false;
+        }
+
+        if ("UID" == gsl::at(entry, 0)) {
+            config.identifier = gsl::at(entry, 1);
+        }
+        else {
+            this->m_errorLine = lineOffset;
+            this->m_errorMessage = "Unknown entry: " + gsl::at(entry, 0);
+            config.valid = false;
+            return false;
+        }
+    }
+
+    if (0 == lineOffset) {
+        this->m_errorLine = 0;
+        this->m_errorMessage = "No data found in " + filename;
+        config.valid = false;
+        return false;
+    }
+
+    return true;
+}