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Time for an 2014 update…

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This commit is contained in:
Ingy döt Net 2014-01-17 05:32:22 +00:00
parent 372c577f83
commit 09687c4926
2520 changed files with 34227 additions and 7318 deletions
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31
Task/LZW-compression/D/lzw-compression-2.d
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@ -1,6 +1,6 @@
import std.array: empty;
struct LZW {
import std.array: empty;
// T is ubyte instead of char because D strings are UTF-8.
alias T = ubyte;
alias Tcomp = ushort;
@ -11,12 +11,11 @@ struct LZW {
static immutable ubyte[initDictSize] bytes;
static this() {
foreach (immutable i; 0 .. initDictSize)
bytes[i] = cast(T)i;
bytes[i] = cast(T)i; //*
}
//static Tcomp[] compress(in T[] original)
static Tcomp[] compress(immutable scope T[] original)
/*pure nothrow*/ out(result) {
static Tcomp[] compress(immutable scope T[] original) pure nothrow
out(result) {
if (!original.empty)
assert(result[0] < initDictSize);
} body {
@ -26,7 +25,7 @@ struct LZW {
foreach (immutable b; bytes)
dict[[b]] = b;
// In this algorithm regular slices give lower efficiency.
// Here built-in slices give lower efficiency.
struct Slice {
size_t start, end;
@property opSlice() const pure nothrow {
@ -38,16 +37,13 @@ struct LZW {
Slice w;
Tcomp[] result;
foreach (immutable i; 0 .. original.length) {
auto wc = Slice(w.start, w.end + 1);
auto wc = Slice(w.start, w.end + 1); // Extend slice.
if (wc in dict) {
w = wc;
} else {
result ~= dict[w];
// AA.length is not pure nor nothrow.
//assert(dict.length <= Tcomp.max);
//dict[wc] = cast(Tcomp)dict.length;
assert(dict.length < Tcomp.max); // Overflow guard.
dict[wc] = cast(Tcomp)(dict.length - 1);
dict[wc] = cast(Tcomp)dict.length;
w = Slice(i, i + 1);
}
}
@ -90,10 +86,11 @@ struct LZW {
}
void main() {
import std.stdio;
import std.stdio, std.string;
immutable txt = "TOBEORNOTTOBEORTOBEORNOT";
/*immutable*/ const compressed = LZW.compress(cast(LZW.Ta)txt);
writeln(compressed);
immutable decompressed = LZW.decompress(compressed);
writeln(cast(string)decompressed);
immutable compressed = LZW.compress(txt.representation);
compressed.writeln;
//LZW.decompress(compressed).unrepresentation.writeln;
writeln(cast(string)LZW.decompress(compressed));
}