Splitter: first rewrite

bio/std/range/splitter.d

@@ -71,49 +71,47 @@ unittest {
   assert(array(SimpleSplitConv!(ubyte[])(cast(ubyte[])"chr1:55365,55365,1")) == ["chr1:55365","55365","1"]);
 }
 
-
-struct FastSplitConv(R)
-  if (isInputRange!R)
-{
-  R list, split_on;
-
-  this(R range, R splits_on = cast(R)SPLIT_ON) {
-    list = range;
-    split_on = splits_on;
-  }
-
-  int opApply(scope int delegate(R) dg) {
-    size_t start = 0;
-    bool in_whitespace = false;
-    foreach(size_t pos, c; list) {
-      if (canFind(split_on,c)) { // hit split char
-        if (!in_whitespace) { // emit
-          auto token = list[start..pos];
-          dg(token);
-        }
-        start = pos+1;
-        in_whitespace = true;
-      } else {
-        in_whitespace = false;
+R[] fast_splitter(R)(R range, R splits_on = cast(R)SPLIT_ON) {
+  R[] tokens = new R[range.length]; // pre-allocate optimistially
+  auto j = 0, prev_j = 0;
+  bool in_whitespace = false;
+  auto token_num = 0;
+  for (; j<range.length ;) {
+    if (canFind(splits_on,range[j])) { // hit split char
+      if (!in_whitespace && j>0) {
+        tokens[token_num] = range[prev_j..j];
+        token_num++;
       }
+      prev_j = j+1;
+      in_whitespace = true;
     }
-    if (!in_whitespace) { // emit final
-      auto token = list[start..$];
-      dg(token);
+    else {
+      in_whitespace = false;
     }
-    return 0;
+    j++;
+  }
+  if (!in_whitespace) { // emit final
+    tokens[token_num] = range[prev_j..$];
+    token_num++;
   }
+  tokens.length = token_num;
+  return tokens;
 }
 
 unittest {
-  auto s = cast(ubyte[])"hello 1 2 \t3  4 \n";
+  auto s = "hello 1 2 \t3  4 \n";
+  writeln(fast_splitter(s).map!"to!string(a)");
   for (int x = 0; x < 4_000_000; x++) {
-    assert(array(FastSplitConv!(ubyte[])(s)) == ["hello","1","2","3","4"]);
+    assert(fast_splitter(s) == ["hello", "1", "2", "3", "4"]);
     // assert(array(FastSplitConv!(ubyte[])(cast(ubyte[])"  hello, 1 2 \t3  4 \n")) == ["","hello","1","2","3","4"]);
     // assert(array(FastSplitConv!(ubyte[])(cast(ubyte[])"hello, 1 2 \n\t3  4 \n")) == ["hello","1","2","3","4"]);
     // assert(array(FastSplitConv!(ubyte[])(cast(ubyte[])"chr1:55365,55365,1")) == ["chr1:55365","55365","1"]);
   }
   /*
+    real    0m2.675s
+    user    0m2.676s
+    sys     0m0.000s
+
     real    0m3.733s
     user    0m3.736s
     sys     0m0.000s