/**********************************************
Comparison of timings for buffered output in D.
*/

enum nLines = 10_000_000;
enum nTimes = 10;

void main(string[] argv)
{
    import std.stdio : writef;
    import std.datetime : benchmark;
    
    auto r = benchmark!(f0, f1, f2, f3, f4)(nTimes);
    foreach (i; 0 .. r.length)
        writef("fun[%d]: %6.1fs\n", i, r[i].msecs/(1000. * nTimes));
}

void f0()
{
    import std.stdio : File, writef;

    auto tmp = File("/tmp/_f0_output", "w");
    foreach(i; 0 .. nLines) {
        tmp.writef("%d %d %0.8f\n", i, i*13, i/1e7);
    }
}

void f1()
{
    import std.stdio : File;
    import std.array : appender;
    import std.format : formattedWrite;
    
    auto tmp = File("/tmp/_f1_output", "w");
    auto app = appender!(char[]);
    app.reserve(1024 * 1024);
    foreach(i; 0 .. nLines) {
        if (app.capacity < 1024) {
            tmp.rawWrite(app.data);
            app.clear();
        }
        app.formattedWrite("%d %d %0.8f\n", i, i*13, i/1e7);
    }
    if (app.data.length > 0) tmp.rawWrite(app.data);
}

void f2()
{
    import std.stdio : File;
    import std.outbuffer;
    import std.format : formattedWrite;
    import std.file : write;
    
    auto tmp = File("/tmp/_f2_output", "w");
    auto buf = new OutBuffer();
    buf.reserve(nLines * 30);
    foreach(i; 0 .. nLines) {
        buf.formattedWrite("%d %d %0.8f\n", i, i*13, i/1e7);
    }
    tmp.write(buf.toString());
}

void f3()
{
    import core.stdc.stdio;
    
    auto tmp = fopen("/tmp/_f3_output", "w");
    foreach(i; 0 .. nLines) {
        tmp.fprintf("%d %d %0.8f\n\0", i, i*13, i/1e7);
    }
}

void f4()
{
    import core.stdc.stdio;
    
    char[30] tmp;
    foreach(i; 0 .. nLines) {
        sprintf(tmp.ptr, "%d %d %0.8f\n\0", i, i*13, i/1e7);
    }
}