90 lines
2.6 KiB
D
90 lines
2.6 KiB
D
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// Copyright Ferdinand Majerech 2011.
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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///Compact storage of multiple boolean values.
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module dyaml.flags;
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import std.conv;
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package:
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/**
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* Struct holding multiple named boolean values in a single byte.
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*
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* Can hold at most 8 values.
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*
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* Example:
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* --------------------
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* Flags!("empty", "multiline") flags;
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* assert(flags.empty == false && flags.multiline == false);
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* flags.multiline = true;
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* assert(flags.empty == false && flags.multiline == true);
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* flags.empty = true;
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* assert(flags.empty == true && flags.multiline == true);
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* flags.multiline = false;
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* assert(flags.empty == true && flags.multiline == false);
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* flags.empty = false;
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* assert(flags.empty == false && flags.multiline == false);
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* --------------------
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*/
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struct Flags(names ...) if(names.length <= 8)
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{
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private:
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///Byte storing the flags.
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ubyte flags_;
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///Generate a setter and a getter for each flag.
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static string flags(string[] names ...)
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in
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{
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assert(names.length <= 8, "Flags struct can only hold 8 flags");
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}
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body
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{
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string result;
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foreach(index, name; names)
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{
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string istr = to!string(index);
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result ~= "\n"
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"@property bool " ~ name ~ "(bool value)\n"
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"{\n"
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" flags_ = value ? flags_ | (1 <<" ~ istr ~ ")\n"
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" : flags_ & (0xFF ^ (1 << " ~ istr ~"));\n"
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" return value;\n"
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"}\n"
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"\n"
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"@property bool " ~ name ~ "() const pure\n"
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"{\n"
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" return (flags_ >> " ~ istr ~ ") & 1;\n"
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"}\n";
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}
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return result;
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}
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public:
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///Flag accessors.
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mixin(flags(names));
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}
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unittest
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{
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import std.stdio;
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writeln("Flags unittest");
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Flags!("empty", "multiline") flags;
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assert(flags.empty == false && flags.multiline == false);
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flags.multiline = true;
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assert(flags.empty == false && flags.multiline == true);
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flags.empty = true;
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assert(flags.empty == true && flags.multiline == true);
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flags.multiline = false;
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assert(flags.empty == true && flags.multiline == false);
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flags.empty = false;
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assert(flags.empty == false && flags.multiline == false);
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}
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