First commit.

src/JackServerSettings.cpp

@@ -0,0 +1,201 @@
+#include "pch.h"
+
+#include "Lv2Log.hpp"
+#include "JackServerSettings.hpp"
+#include <fstream>
+#include "PiPedalException.hpp"
+
+#define DRC_FILENAME "/etc/jackdrc"
+
+using namespace std;
+using namespace pipedal;
+
+JackServerSettings::JackServerSettings()
+{
+}
+
+static std::vector<std::string> SplitArgs(const char *szBuff)
+{
+    std::vector<std::string> result;
+
+    while (*szBuff != '\0')
+    {
+        while (*szBuff == ' ' || *szBuff == '\t' || *szBuff == '\r' || *szBuff == '\n')
+            ++szBuff;
+        if (*szBuff == 0)
+            break;
+
+        std::stringstream s;
+        while (*szBuff != ' ' && *szBuff != '\t' && *szBuff != '\0' && *szBuff != '\r' && *szBuff != '\n')
+        {
+            s.put(*szBuff++);
+        }
+        result.push_back(s.str());
+    }
+
+    return result;
+}
+
+static uint64_t GetJackArg(const std::vector<std::string> &args, const char *shortOption, const char *longOption)
+{
+    int pos = -1;
+    for (size_t i = 1; i < args.size(); ++i)
+    {
+        if (args[i] == shortOption || args[i] == longOption)
+        {
+            pos = i;
+            break;
+        }
+    }
+    if (pos == -1 || pos == args.size() - 1)
+    {
+        throw PiPedalException("Can't read Jack configuration.");
+    }
+    try
+    {
+        unsigned long value = std::stoul(args[pos + 1]);
+        return value;
+    }
+    catch (const std::exception &)
+    {
+        throw PiPedalException("Can't read Jack configuration.");
+    }
+}
+static void SetJackArg(std::vector<std::string> &args, const char *shortOption, const char *longOption,uint64_t value)
+{
+    int pos = -1;
+    for (size_t i = 1; i < args.size(); ++i)
+    {
+        if (args[i] == shortOption || args[i] == longOption)
+        {
+            pos = i;
+            break;
+        }
+    }
+    if (pos == -1 || pos == args.size() - 1)
+    {
+        throw PiPedalException("Can't read Jack configuration.");
+    }
+    stringstream s;
+    s << value;
+    args[pos+1] = s.str();
+    return;
+}
+
+
+
+void JackServerSettings::ReadJackConfiguration()
+{
+    this->valid_ = false;
+
+    char firstLine[1024];
+
+    {
+        ifstream input(DRC_FILENAME);
+
+        if (!input.is_open())
+        {
+            Lv2Log::error("Can't read " DRC_FILENAME);
+            return;
+        }
+
+        while (true)
+        {
+            if (input.eof())
+            {
+                Lv2Log::error("Premature end of file in " DRC_FILENAME);
+                return;
+            }
+            input.getline(firstLine, sizeof(firstLine));
+            if (firstLine[0] != '#')
+                break;
+        }
+        try {
+            std::vector < std::string> argv = SplitArgs(firstLine);
+            this->bufferSize_ = GetJackArg(argv, "-p", "-period");
+            this->numberOfBuffers_ = (uint32_t)GetJackArg(argv, "-n", "-nperiods");
+            this->sampleRate_ = (uint32_t)GetJackArg(argv, "-r", "-rate");
+            valid_ = true;
+        } catch (std::exception &)
+        {
+            Lv2Log::error("Can't parse " DRC_FILENAME);
+        }
+    }
+}
+
+void JackServerSettings::Write()
+{
+    this->valid_ = false;
+
+    std::vector<std::string> precedingLines;
+    std::vector < std::string> argv;
+
+    {
+        char firstLine[1024];
+        ifstream input(DRC_FILENAME);
+
+        if (!input.is_open())
+        {
+            Lv2Log::error("Can't read " DRC_FILENAME);
+            return;
+        }
+
+        while (true)
+        {
+            if (input.eof())
+            {
+                Lv2Log::error("Premature end of file in " DRC_FILENAME);
+                return;
+            }
+            input.getline(firstLine, sizeof(firstLine));
+            if (firstLine[0] != '#')
+                break;
+            precedingLines.push_back(firstLine);
+        }
+
+        // set new values for arguments.
+        argv = SplitArgs(firstLine);
+        try {
+            SetJackArg(argv, "-p", "-period", this->bufferSize_);
+            SetJackArg(argv, "-n", "-nperiods", this->numberOfBuffers_);
+            SetJackArg(argv, "-r", "-rate",this->sampleRate_);
+        } catch (std::exception &)
+        {
+            Lv2Log::error("Can't parse " DRC_FILENAME);
+            return;
+        }
+    }
+    // write to the output.
+    try {
+        ofstream output(DRC_FILENAME);
+        if (!output.is_open())
+        {
+            throw PiPedalException("Can't write " DRC_FILENAME);
+        }
+        for (auto line: precedingLines)
+        {
+            output << line << endl;
+        }
+        for (size_t i = 0; i < argv.size(); ++i)
+        {
+            if (i != 0) {
+                output << " ";
+            }
+            output << argv[i];
+        }
+        output << endl;
+    } catch (const std::exception &e) {
+        stringstream s;
+        s << "jack - " << e.what();
+        Lv2Log::error(s.str());
+    }
+}
+
+JSON_MAP_BEGIN(JackServerSettings)
+    JSON_MAP_REFERENCE(JackServerSettings,valid)
+    JSON_MAP_REFERENCE(JackServerSettings,rebootRequired)
+    JSON_MAP_REFERENCE(JackServerSettings,sampleRate)
+    JSON_MAP_REFERENCE(JackServerSettings,bufferSize)
+    JSON_MAP_REFERENCE(JackServerSettings,numberOfBuffers)
+JSON_MAP_END()
+