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Add takeExactly 

Fix #43.
This commit is contained in:
Eugen Wissner 2018-06-10 18:40:14 +02:00
parent 37b0afe290
commit 15f7994187
2 changed files with 376 additions and 255 deletions
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375
source/tanya/range/adapter.d Normal file
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@ -0,0 +1,375 @@
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/**
* Range adapters.
*
* A range adapter wraps another range and modifies the way, how the original
* range is iterated, or the order in which its elements are accessed.
*
* All adapters are lazy algorithms, they request the next element of the
* adapted range on demand.
*
* Copyright: Eugene Wissner 2018.
* License: $(LINK2 https://www.mozilla.org/en-US/MPL/2.0/,
* Mozilla Public License, v. 2.0).
* Authors: $(LINK2 mailto:info@caraus.de, Eugene Wissner)
* Source: $(LINK2 https://github.com/caraus-ecms/tanya/blob/master/source/tanya/range/adapter.d,
* tanya/range/adapter.d)
*/
module tanya.range.adapter;
import tanya.algorithm.mutation;
import tanya.math;
import tanya.range.primitive;
private mixin template Take(R, bool exactly)
{
private R source;
size_t length_;
@disable this();
private this(R source, size_t length)
{
this.source = source;
static if (!exactly && hasLength!R)
{
this.length_ = min(source.length, length);
}
else
{
this.length_ = length;
}
}
@property auto ref front()
in
{
assert(!empty);
}
do
{
return this.source.front;
}
void popFront()
in
{
assert(!empty);
}
do
{
this.source.popFront();
--this.length_;
}
@property bool empty()
{
static if (exactly || isInfinite!R)
{
return length == 0;
}
else
{
return length == 0 || this.source.empty;
}
}
@property size_t length()
{
return this.length_;
}
static if (hasAssignableElements!R)
{
@property void front(ref ElementType!R value)
in
{
assert(!empty);
}
do
{
this.source.front = value;
}
@property void front(ElementType!R value)
in
{
assert(!empty);
}
do
{
this.source.front = move(value);
}
}
static if (isForwardRange!R)
{
typeof(this) save()
{
return typeof(this)(this.source.save(), length);
}
}
static if (isRandomAccessRange!R)
{
@property auto ref back()
in
{
assert(!empty);
}
do
{
return this.source[this.length - 1];
}
void popBack()
in
{
assert(!empty);
}
do
{
--this.length_;
}
auto ref opIndex(size_t i)
in
{
assert(i < length);
}
do
{
return this.source[i];
}
static if (hasAssignableElements!R)
{
@property void back(ref ElementType!R value)
in
{
assert(!empty);
}
do
{
this.source[length - 1] = value;
}
@property void back(ElementType!R value)
in
{
assert(!empty);
}
do
{
this.source[length - 1] = move(value);
}
void opIndexAssign(ref ElementType!R value, size_t i)
in
{
assert(i < length);
}
do
{
this.source[i] = value;
}
void opIndexAssign(ElementType!R value, size_t i)
in
{
assert(i < length);
}
do
{
this.source[i] = move(value);
}
}
}
static if (hasSlicing!R)
{
auto opSlice(size_t i, size_t j)
in
{
assert(i <= j);
assert(j <= length);
}
do
{
return take(this.source[i .. j], length);
}
}
}
/**
* Takes $(D_PARAM n) elements from $(D_PARAM range).
*
* If $(D_PARAM range) doesn't have $(D_PARAM n) elements, the resulting range
* spans all elements of $(D_PARAM range).
*
* $(D_PSYMBOL take) is particulary useful with infinite ranges. You can take
` $(B n) elements from such range and pass the result to an algorithm which
* expects a finit range.
*
* Params:
* R = Type of the adapted range.
* range = The range to take the elements from.
* n = The number of elements to take.
*
* Returns: A range containing maximum $(D_PARAM n) first elements of
* $(D_PARAM range).
*
* See_Also: $(D_PSYMBOL takeExactly).
*/
auto take(R)(R range, size_t n)
if (isInputRange!R)
{
struct Take
{
mixin .Take!(R, false);
}
return Take(range, n);
}
///
@nogc nothrow pure @safe unittest
{
static struct InfiniteRange
{
private size_t front_ = 1;
enum bool empty = false;
@property size_t front() @nogc nothrow pure @safe
{
return this.front_;
}
@property void front(size_t i) @nogc nothrow pure @safe
{
this.front_ = i;
}
void popFront() @nogc nothrow pure @safe
{
++this.front_;
}
size_t opIndex(size_t i) @nogc nothrow pure @safe
{
return this.front_ + i;
}
void opIndexAssign(size_t value, size_t i) @nogc nothrow pure @safe
{
this.front = i + value;
}
InfiniteRange save() @nogc nothrow pure @safe
{
return this;
}
}
auto t = InfiniteRange().take(3);
assert(t.length == 3);
assert(t.front == 1);
assert(t.back == 3);
t.popFront();
assert(t.front == 2);
assert(t.back == 3);
t.popBack();
assert(t.front == 2);
assert(t.back == 2);
t.popFront();
assert(t.empty);
}
/**
* Takes exactly $(D_PARAM n) elements from $(D_PARAM range).
*
* $(D_PARAM range) must have at least $(D_PARAM n) elements.
*
* $(D_PSYMBOL takeExactly) is particulary useful with infinite ranges. You can
` take $(B n) elements from such range and pass the result to an algorithm
* which expects a finit range.
*
* Params:
* R = Type of the adapted range.
* range = The range to take the elements from.
* n = The number of elements to take.
*
* Returns: A range containing $(D_PARAM n) first elements of $(D_PARAM range).
*
* See_Also: $(D_PSYMBOL take).
*/
auto takeExactly(R)(R range, size_t n)
if (isInputRange!R)
{
struct TakeExactly
{
mixin Take!(R, true);
}
return TakeExactly(range, n);
}
///
@nogc nothrow pure @safe unittest
{
static struct InfiniteRange
{
private size_t front_ = 1;
enum bool empty = false;
@property size_t front() @nogc nothrow pure @safe
{
return this.front_;
}
@property void front(size_t i) @nogc nothrow pure @safe
{
this.front_ = i;
}
void popFront() @nogc nothrow pure @safe
{
++this.front_;
}
size_t opIndex(size_t i) @nogc nothrow pure @safe
{
return this.front_ + i;
}
void opIndexAssign(size_t value, size_t i) @nogc nothrow pure @safe
{
this.front = i + value;
}
InfiniteRange save() @nogc nothrow pure @safe
{
return this;
}
}
auto t = InfiniteRange().takeExactly(3);
assert(t.length == 3);
assert(t.front == 1);
assert(t.back == 3);
t.popFront();
assert(t.front == 2);
assert(t.back == 3);
t.popBack();
assert(t.front == 2);
assert(t.back == 2);
t.popFront();
assert(t.empty);
}

256
source/tanya/range/package.d
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@ -15,260 +15,6 @@
*/
module tanya.range;
import tanya.algorithm.mutation;
import tanya.math;
public import tanya.range.adapter;
public import tanya.range.array;
public import tanya.range.primitive;
struct Take(R)
if (isInputRange!R)
{
private R source;
size_t length_;
@disable this();
private this(R source, size_t length)
{
this.source = source;
static if (hasLength!R)
{
this.length_ = min(source.length, length);
}
else
{
this.length_ = length;
}
}
@property auto ref front()
in
{
assert(!empty);
}
do
{
return this.source.front;
}
void popFront()
in
{
assert(!empty);
}
do
{
this.source.popFront();
--this.length_;
}
@property bool empty()
{
static if (isInfinite!R)
{
return length == 0;
}
else
{
return length == 0 || this.source.empty;
}
}
@property size_t length()
{
return this.length_;
}
static if (hasAssignableElements!R)
{
@property void front(ref ElementType!R value)
in
{
assert(!empty);
}
do
{
this.source.front = value;
}
@property void front(ElementType!R value)
in
{
assert(!empty);
}
do
{
this.source.front = move(value);
}
}
static if (isForwardRange!R)
{
typeof(this) save()
{
return typeof(this)(this.source.save(), length);
}
}
static if (isRandomAccessRange!R)
{
@property auto ref back()
in
{
assert(!empty);
}
do
{
return this.source[this.length - 1];
}
void popBack()
in
{
assert(!empty);
}
do
{
--this.length_;
}
auto ref opIndex(size_t i)
in
{
assert(i < length);
}
do
{
return this.source[i];
}
static if (hasAssignableElements!R)
{
@property void back(ref ElementType!R value)
in
{
assert(!empty);
}
do
{
this.source[length - 1] = value;
}
@property void back(ElementType!R value)
in
{
assert(!empty);
}
do
{
this.source[length - 1] = move(value);
}
void opIndexAssign(ref ElementType!R value, size_t i)
in
{
assert(i < length);
}
do
{
this.source[i] = value;
}
void opIndexAssign(ElementType!R value, size_t i)
in
{
assert(i < length);
}
do
{
this.source[i] = move(value);
}
}
}
static if (hasSlicing!R)
{
auto opSlice(size_t i, size_t j)
in
{
assert(i <= j);
assert(j <= length);
}
do
{
return take(this.source[i .. j], length);
}
}
}
/**
* Takes $(D_PARAM n) elements from $(D_PARAM range).
*
* Params:
* R = Type of the original range.
* range = The range to take elements from.
* n = The number of elements to take.
*
* Returns: A range containing maximum $(D_PARAM n) first elements of
* $(D_PARAM range).
*/
Take!R take(R)(R range, size_t n)
if (isInputRange!R)
{
return Take!R(range, n);
}
///
@nogc nothrow pure @safe unittest
{
static struct InfiniteRange
{
private size_t front_ = 1;
enum bool empty = false;
@property size_t front() @nogc nothrow pure @safe
{
return this.front_;
}
@property void front(size_t i) @nogc nothrow pure @safe
{
this.front_ = i;
}
void popFront() @nogc nothrow pure @safe
{
++this.front_;
}
size_t opIndex(size_t i) @nogc nothrow pure @safe
{
return this.front_ + i;
}
void opIndexAssign(size_t value, size_t i) @nogc nothrow pure @safe
{
this.front = i + value;
}
InfiniteRange save() @nogc nothrow pure @safe
{
return this;
}
}
auto t = InfiniteRange().take(3);
assert(t.length == 3);
assert(t.front == 1);
assert(t.back == 3);
t.popFront();
assert(t.front == 2);
assert(t.back == 3);
t.popBack();
assert(t.front == 2);
assert(t.back == 2);
t.popFront();
assert(t.empty);
}