Today I was writing some range-based image-generation code, which
produces a range of ubytes representing the resulting image file. To my
astonishment, there was no function in std.stdio that could spool this
range to a File.
Initially, I tried lockingTextWriter, but quickly discovered that the
resulting file was corrupt, because it's attempting to interpret binary
data as text.
Eventually, I came upon the naive solution:
auto f = File(...);
ubyteRange
.chunks(bufSize)
.map!array
.each!(b => f.rawWrite(b));
This is rather allocation-heavy, so here's attempt #2, that allocates a
single buffer that's reused:
void bufferedWrite(R)(R range, ref File dest, size_t bufSize = 64*1024)
if (isInputRange!R && is(ElementType!R : ubyte))
{
import std.algorithm.iteration : each, map;
import std.algorithm.mutation : copy;
import std.range : chunks;
ubyte[] buf;
buf.length = bufSize;
range.chunks(bufSize)
.each!((chunk) {
auto sizeLeft = copy(chunk, buf).length;
dest.rawWrite(buf[0 .. $-sizeLeft]);
});
}
auto f = File(...);
ubyteRange.bufferedWrite(f);
What do y'all think? Is bufferedWrite (potentially under a different
name) worth submitting to Phobos?
T
--
If creativity is stifled by rigid discipline, then it is not true creativity.
