Settings.hpp

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/*
    Copyright (c) 2009-2010 Christopher A. Taylor.  All rights reserved.

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions are met:

    * Redistributions of source code must retain the above copyright notice,
      this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above copyright notice,
      this list of conditions and the following disclaimer in the documentation
      and/or other materials provided with the distribution.
    * Neither the name of LibCat nor the names of its contributors may be used
      to endorse or promote products derived from this software without
      specific prior written permission.

    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
    AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
    IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
    ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
    LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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*/

#ifndef CAT_SETTINGS_HPP
#define CAT_SETTINGS_HPP

#include <cat/Singleton.hpp>
#include <cat/threads/Mutex.hpp>
#include <fstream>

namespace cat {


enum SettingsValueFlags
{
    CAT_SETTINGS_FILLED = 1, // s[] array has been set
    CAT_SETTINGS_INT = 2,    // value has been promoted to int 'i'
};

struct SettingsValue
{
    u8 flags;    // sum of SettingsValueFlags
    char s[256]; // always nul-terminated
    int i;
};


class SettingsKey
{
public:
    SettingsKey(SettingsKey *lnode, SettingsKey *gnode, const char *name);
    ~SettingsKey();

public:
    SettingsKey *lnode, *gnode;

    char name[64]; // not necessarily nul-terminated

    SettingsValue value;

public:
    void write(std::ofstream &file);
};


// User settings manager
class Settings : public Singleton<Settings>
{
    CAT_SINGLETON(Settings);

    Mutex _lock;

protected:
    static const u32 KEY_HASH_SALT = 0xbaddecaf;
    static const int SETTINGS_HASH_BINS = 256;

    SettingsKey *hbtrees[SETTINGS_HASH_BINS]; // hash table of binary trees

    bool readSettings; // Flag set when settings have been read from disk
    bool modified;     // Flag set when settings have been modified since last write

    std::string _settings_file;

protected:
    SettingsKey *addKey(const char *name);
    SettingsKey *getKey(const char *name);

    SettingsKey *initInt(const char *name, int n, bool overwrite);
    SettingsKey *initStr(const char *name, const char *value, bool overwrite);

    void clear();
    
public:
    void readSettingsFromFile(const char *file_path = "settings.txt", const char *override_file = "override.txt");
    void readSettingsFromBuffer(const char *data, int len);
    void write();

public:
    int getInt(const char *name);
    const char *getStr(const char *name);

    int getInt(const char *name, int init);
    const char *getStr(const char *name, const char *init);

    void setInt(const char *name, int n);
    void setStr(const char *name, const char *value);
};


} // namespace cat

#endif // CAT_SETTINGS_HPP