tanya/source/tanya/conv.d

857 lines
20 KiB
D

/* 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/. */
/**
* This module provides functions for converting between different types.
*
* Copyright: Eugene Wissner 2017-2018.
* 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/conv.d,
* tanya/conv.d)
*/
module tanya.conv;
import tanya.container.string;
import tanya.format;
import tanya.memory;
import tanya.memory.op;
import tanya.meta.trait;
import tanya.meta.transform;
import tanya.range.array;
import tanya.range.primitive;
version (unittest)
{
import tanya.test.assertion;
}
/**
* Constructs a new object of type $(D_PARAM T) in $(D_PARAM memory) with the
* given arguments.
*
* If $(D_PARAM T) is a $(D_KEYWORD class), emplace returns a class reference
* of type $(D_PARAM T), otherwise a pointer to the constructed object is
* returned.
*
* If $(D_PARAM T) is a nested class inside another class, $(D_PARAM outer)
* should be an instance of the outer class.
*
* $(D_PARAM args) are arguments for the constructor of $(D_PARAM T). If
* $(D_PARAM T) isn't an aggregate type and doesn't have a constructor,
* $(D_PARAM memory) can be initialized to `args[0]` if `Args.length == 1`,
* `Args[0]` should be implicitly convertible to $(D_PARAM T) then.
*
* Params:
* T = Constructed type.
* U = Type of the outer class if $(D_PARAM T) is a nested class.
* Args = Types of the constructor arguments if $(D_PARAM T) has a constructor
* or the type of the initial value.
* outer = Outer class instance if $(D_PARAM T) is a nested class.
* args = Constructor arguments if $(D_PARAM T) has a constructor or the
* initial value.
*
* Returns: New instance of type $(D_PARAM T) constructed in $(D_PARAM memory).
*
* Precondition: `memory.length == stateSize!T`.
* Postcondition: $(D_PARAM memory) and the result point to the same memory.
*/
T emplace(T, U, Args...)(void[] memory, U outer, auto ref Args args)
if (!isAbstractClass!T && isInnerClass!T && is(typeof(T.outer) == U))
in
{
assert(memory.length >= stateSize!T);
}
out (result)
{
assert(memory.ptr is (() @trusted => cast(void*) result)());
}
do
{
copy(typeid(T).initializer, memory);
auto result = (() @trusted => cast(T) memory.ptr)();
result.outer = outer;
static if (is(typeof(result.__ctor(args))))
{
result.__ctor(args);
}
return result;
}
/// ditto
T emplace(T, Args...)(void[] memory, auto ref Args args)
if (is(T == class) && !isAbstractClass!T && !isInnerClass!T)
in
{
assert(memory.length == stateSize!T);
}
out (result)
{
assert(memory.ptr is (() @trusted => cast(void*) result)());
}
do
{
copy(typeid(T).initializer, memory);
auto result = (() @trusted => cast(T) memory.ptr)();
static if (is(typeof(result.__ctor(args))))
{
result.__ctor(args);
}
return result;
}
///
@nogc nothrow pure @safe unittest
{
import tanya.memory : stateSize;
class C
{
int i = 5;
class Inner
{
int i;
this(int param) pure nothrow @safe @nogc
{
this.i = param;
}
}
}
ubyte[stateSize!C] memory1;
ubyte[stateSize!(C.Inner)] memory2;
auto c = emplace!C(memory1);
assert(c.i == 5);
auto inner = emplace!(C.Inner)(memory2, c, 8);
assert(c.i == 5);
assert(inner.i == 8);
assert(inner.outer is c);
}
/// ditto
T* emplace(T, Args...)(void[] memory, auto ref Args args)
if (!isAggregateType!T && (Args.length <= 1))
in
{
assert(memory.length >= T.sizeof);
}
out (result)
{
assert(memory.ptr is result);
}
do
{
auto result = (() @trusted => cast(T*) memory.ptr)();
static if (Args.length == 1)
{
*result = T(args[0]);
}
else
{
*result = T.init;
}
return result;
}
/// ditto
T* emplace(T, Args...)(void[] memory, auto ref Args args)
if (!isPolymorphicType!T && isAggregateType!T)
in
{
assert(memory.length >= T.sizeof);
}
out (result)
{
assert(memory.ptr is result);
}
do
{
auto result = (() @trusted => cast(T*) memory.ptr)();
static if (!hasElaborateAssign!T && isAssignable!T)
{
*result = T.init;
}
else
{
static const T init = T.init;
copy((cast(void*) &init)[0 .. T.sizeof], memory);
}
static if (Args.length == 0)
{
static assert(is(typeof({ static T t; })),
"Default constructor is disabled");
}
else static if (is(typeof(T(args))))
{
*result = T(args);
}
else static if (is(typeof(result.__ctor(args))))
{
result.__ctor(args);
}
else
{
static assert(false,
"Unable to construct value with the given arguments");
}
return result;
}
///
@nogc nothrow pure @safe unittest
{
ubyte[4] memory;
auto i = emplace!int(memory);
static assert(is(typeof(i) == int*));
assert(*i == 0);
i = emplace!int(memory, 5);
assert(*i == 5);
static struct S
{
int i;
@disable this();
@disable this(this);
this(int i) @nogc nothrow pure @safe
{
this.i = i;
}
}
auto s = emplace!S(memory, 8);
static assert(is(typeof(s) == S*));
assert(s.i == 8);
}
// Handles "Cannot access frame pointer" error.
@nogc nothrow pure @safe unittest
{
struct F
{
~this() @nogc nothrow pure @safe
{
}
}
static assert(is(typeof(emplace!F((void[]).init))));
}
/**
* Thrown if a type conversion fails.
*/
final class ConvException : Exception
{
/**
* Params:
* msg = The message for the exception.
* file = The file where the exception occurred.
* line = The line number where the exception occurred.
* next = The previous exception in the chain of exceptions, if any.
*/
this(string msg,
string file = __FILE__,
size_t line = __LINE__,
Throwable next = null) @nogc @safe pure nothrow
{
super(msg, file, line, next);
}
}
/*
* Converts a string $(D_PARAM range) into an integral value of type
* $(D_PARAM T) in $(D_PARAM base).
*
* The convertion stops when $(D_PARAM range) is empty of if the next character
* cannot be converted because it is not a digit (with respect to the
* $(D_PARAM base)) or if the reading the next character would cause integer
* overflow. The function returns the value converted so far then. The front
* element of the $(D_PARAM range) points to the first character cannot be
* converted or $(D_PARAM range) is empty if the whole string could be
* converted.
*
* Base must be between 2 and 36 inclursive. Default base is 10.
*
* The function doesn't handle the sign (+ or -) or number prefixes (like 0x).
*/
package T readIntegral(T, R)(ref R range, ubyte base = 10)
if (isForwardRange!R
&& isSomeChar!(ElementType!R)
&& isIntegral!T
&& isUnsigned!T)
in
{
assert(base >= 2);
assert(base <= 36);
}
do
{
T boundary = cast(T) (T.max / base);
if (range.empty)
{
return T.init;
}
T n;
while (n <= boundary)
{
int digit;
if (range.front >= 'a')
{
digit = range.front - 'W';
}
else if (range.front >= 'A')
{
digit = range.front - '7';
}
else if (range.front >= '0')
{
digit = range.front - '0';
}
else
{
return n;
}
if (digit >= base)
{
return n;
}
n = cast(T) (n * base + digit);
range.popFront();
if (range.empty)
{
return n;
}
}
if (range.length > 1)
{
return n;
}
int digit = range.front - '0';
if (n > cast(T) ((T.max - digit) / base))
{
return n;
}
n = cast(T) (n * base + digit);
return n;
}
// reads ubyte.max
@nogc nothrow pure @safe unittest
{
string number = "255";
assert(readIntegral!ubyte(number) == 255);
assert(number.empty);
}
// detects integer overflow
@nogc nothrow pure @safe unittest
{
string number = "500";
readIntegral!ubyte(number);
assert(number.front == '0');
assert(number.length == 1);
}
// stops on a non-digit
@nogc nothrow pure @safe unittest
{
string number = "10-";
readIntegral!ubyte(number);
assert(number.front == '-');
}
// returns false if the number string is empty
@nogc nothrow pure @safe unittest
{
string number = "";
readIntegral!ubyte(number);
assert(number.empty);
}
@nogc nothrow pure @safe unittest
{
string number = "29";
assert(readIntegral!ubyte(number) == 29);
assert(number.empty);
}
@nogc nothrow pure @safe unittest
{
string number = "25467";
readIntegral!ubyte(number);
assert(number.front == '6');
}
// Converts lower case hexadecimals
@nogc nothrow pure @safe unittest
{
string number = "a";
assert(readIntegral!ubyte(number, 16) == 10);
assert(number.empty);
}
// Converts upper case hexadecimals
@nogc nothrow pure @safe unittest
{
string number = "FF";
assert(readIntegral!ubyte(number, 16) == 255);
assert(number.empty);
}
/**
* If the source type $(D_PARAM From) and the target type $(D_PARAM To) are
* equal, does nothing. If $(D_PARAM From) can be implicitly converted to
* $(D_PARAM To), just returns $(D_PARAM from).
*
* Params:
* To = Target type.
*
* Returns: $(D_PARAM from).
*/
template to(To)
{
/**
* Params:
* From = Source type.
* from = Source value.
*/
ref To to(From)(ref From from)
if (is(To == From))
{
return from;
}
/// ditto
To to(From)(From from)
if (is(Unqual!To == Unqual!From) || (isNumeric!From && isFloatingPoint!To))
{
return from;
}
}
///
@nogc nothrow pure @safe unittest
{
auto val = 5.to!int();
assert(val == 5);
static assert(is(typeof(val) == int));
}
@nogc nothrow pure @safe unittest
{
int val = 5;
assert(val.to!int() == 5);
}
/**
* Performs checked conversion from an integral type $(D_PARAM From) to an
* integral type $(D_PARAM To).
*
* Params:
* From = Source type.
* To = Target type.
* from = Source value.
*
* Returns: $(D_PARAM from) converted to $(D_PARAM To).
*
* Throws: $(D_PSYMBOL ConvException) if $(D_PARAM from) is too small or too
* large to be represented by $(D_PARAM To).
*/
To to(To, From)(From from)
if (isIntegral!From
&& isIntegral!To
&& !is(Unqual!To == Unqual!From)
&& !is(To == enum))
{
static if ((isUnsigned!From && isSigned!To && From.sizeof == To.sizeof)
|| From.sizeof > To.sizeof)
{
if (from > To.max)
{
throw make!ConvException(defaultAllocator,
"Positive integer overflow");
}
}
static if (isSigned!From)
{
static if (isUnsigned!To)
{
if (from < 0)
{
throw make!ConvException(defaultAllocator,
"Negative integer overflow");
}
}
else static if (From.sizeof > To.sizeof)
{
if (from < To.min)
{
throw make!ConvException(defaultAllocator,
"Negative integer overflow");
}
}
}
static if (From.sizeof <= To.sizeof)
{
return from;
}
else static if (isSigned!To)
{
return cast(To) from;
}
else
{
return from & To.max;
}
}
@nogc nothrow pure @safe unittest
{
// ubyte -> ushort
assert((cast(ubyte) 0).to!ushort == 0);
assert((cast(ubyte) 1).to!ushort == 1);
assert((cast(ubyte) (ubyte.max - 1)).to!ushort == ubyte.max - 1);
assert((cast(ubyte) ubyte.max).to!ushort == ubyte.max);
// ubyte -> short
assert((cast(ubyte) 0).to!short == 0);
assert((cast(ubyte) 1).to!short == 1);
assert((cast(ubyte) (ubyte.max - 1)).to!short == ubyte.max - 1);
assert((cast(ubyte) ubyte.max).to!short == ubyte.max);
}
@nogc pure @safe unittest
{
// ubyte <- ushort
assert((cast(ushort) 0).to!ubyte == 0);
assert((cast(ushort) 1).to!ubyte == 1);
assert((cast(ushort) (ubyte.max - 1)).to!ubyte == ubyte.max - 1);
assert((cast(ushort) ubyte.max).to!ubyte == ubyte.max);
// ubyte <- short
assert((cast(short) 0).to!ubyte == 0);
assert((cast(short) 1).to!ubyte == 1);
assert((cast(short) (ubyte.max - 1)).to!ubyte == ubyte.max - 1);
assert((cast(short) ubyte.max).to!ubyte == ubyte.max);
// short <-> int
assert(short.min.to!int == short.min);
assert((short.min + 1).to!int == short.min + 1);
assert((cast(short) -1).to!int == -1);
assert((cast(short) 0).to!int == 0);
assert((cast(short) 1).to!int == 1);
assert((short.max - 1).to!int == short.max - 1);
assert(short.max.to!int == short.max);
assert((cast(int) short.min).to!short == short.min);
assert((cast(int) short.min + 1).to!short == short.min + 1);
assert((cast(int) -1).to!short == -1);
assert((cast(int) 0).to!short == 0);
assert((cast(int) 1).to!short == 1);
assert((cast(int) short.max - 1).to!short == short.max - 1);
assert((cast(int) short.max).to!short == short.max);
// uint <-> int
assert((cast(uint) 0).to!int == 0);
assert((cast(uint) 1).to!int == 1);
assert((cast(uint) (int.max - 1)).to!int == int.max - 1);
assert((cast(uint) int.max).to!int == int.max);
assert((cast(int) 0).to!uint == 0);
assert((cast(int) 1).to!uint == 1);
assert((cast(int) (int.max - 1)).to!uint == int.max - 1);
assert((cast(int) int.max).to!uint == int.max);
}
@nogc pure @safe unittest
{
assertThrown!ConvException(&to!(short, int), int.min);
assertThrown!ConvException(&to!(short, int), int.max);
assertThrown!ConvException(&to!(ushort, uint), uint.max);
assertThrown!ConvException(&to!(uint, int), -1);
}
@nogc nothrow pure @safe unittest
{
enum Test : int
{
one,
two,
}
assert(Test.one.to!int == 0);
assert(Test.two.to!int == 1);
}
/**
* Converts a floating point number to an integral type.
*
* Params:
* From = Source type.
* To = Target type.
* from = Source value.
*
* Returns: Truncated $(D_PARAM from) (everything after the decimal point is
* dropped).
*
* Throws: $(D_PSYMBOL ConvException) if
* $(D_INLINECODE from < To.min || from > To.max).
*/
To to(To, From)(From from)
if (isFloatingPoint!From
&& isIntegral!To
&& !is(Unqual!To == Unqual!From)
&& !is(To == enum))
{
if (from > To.max)
{
throw make!ConvException(defaultAllocator,
"Positive number overflow");
}
else if (from < To.min)
{
throw make!ConvException(defaultAllocator,
"Negative number overflow");
}
return cast(To) from;
}
///
@nogc pure @safe unittest
{
assert(1.5.to!int == 1);
assert(2147483646.5.to!int == 2147483646);
assert((-2147483647.5).to!int == -2147483647);
assert(2147483646.5.to!uint == 2147483646);
}
@nogc pure @safe unittest
{
assertThrown!ConvException(&to!(int, double), 2147483647.5);
assertThrown!ConvException(&to!(int, double), -2147483648.5);
assertThrown!ConvException(&to!(uint, double), -21474.5);
}
/**
* Performs checked conversion from an integral type $(D_PARAM From) to an
* $(D_KEYWORD enum).
*
* Params:
* From = Source type.
* To = Target type.
* from = Source value.
*
* Returns: $(D_KEYWORD enum) value.
*
* Throws: $(D_PSYMBOL ConvException) if $(D_PARAM from) is not a member of
* $(D_PSYMBOL To).
*/
To to(To, From)(From from)
if (isIntegral!From && is(To == enum))
{
foreach (m; EnumMembers!To)
{
if (from == m)
{
return m;
}
}
throw make!ConvException(defaultAllocator,
"Value not found in enum '" ~ To.stringof ~ "'");
}
///
@nogc pure @safe unittest
{
enum Test : int
{
one,
two,
}
static assert(is(typeof(1.to!Test) == Test));
assert(0.to!Test == Test.one);
assert(1.to!Test == Test.two);
}
@nogc pure @safe unittest
{
enum Test : uint
{
one,
two,
}
assertThrown!ConvException(&to!(Test, int), 5);
}
/**
* Converts $(D_PARAM from) to a boolean.
*
* If $(D_PARAM From) is a numeric type, then `1` becomes $(D_KEYWORD true),
* `0` $(D_KEYWORD false). Otherwise $(D_PSYMBOL ConvException) is thrown.
*
* If $(D_PARAM To) is a string (built-in string or $(D_PSYMBOL String)),
* then `"true"` or `"false"` are converted to the appropriate boolean value.
* Otherwise $(D_PSYMBOL ConvException) is thrown.
*
* Params:
* From = Source type.
* To = Target type.
* from = Source value.
*
* Returns: $(D_KEYWORD from) converted to a boolean.
*
* Throws: $(D_PSYMBOL ConvException) if $(D_PARAM from) isn't convertible.
*/
To to(To, From)(From from)
if (isNumeric!From && is(Unqual!To == bool) && !is(Unqual!To == Unqual!From))
{
if (from == 0)
{
return false;
}
else if (from < 0)
{
throw make!ConvException(defaultAllocator,
"Negative number overflow");
}
else if (from <= 1)
{
return true;
}
throw make!ConvException(defaultAllocator,
"Positive number overflow");
}
///
@nogc pure @safe unittest
{
assert(!0.0.to!bool);
assert(0.2.to!bool);
assert(0.5.to!bool);
assert(1.0.to!bool);
assert(!0.to!bool);
assert(1.to!bool);
}
@nogc pure @safe unittest
{
assertThrown!ConvException(&to!(bool, int), -1);
assertThrown!ConvException(&to!(bool, int), 2);
}
/// ditto
To to(To, From)(auto ref const From from)
if ((is(From == String) || isSomeString!From) && is(Unqual!To == bool))
{
if (from == "true")
{
return true;
}
else if (from == "false")
{
return false;
}
throw make!ConvException(defaultAllocator,
"String doesn't contain a boolean value");
}
///
@nogc pure @safe unittest
{
assert("true".to!bool);
assert(!"false".to!bool);
assert(String("true").to!bool);
assert(!String("false").to!bool);
}
@nogc pure @safe unittest
{
assertThrown!ConvException(() => "1".to!bool);
}
/**
* Converts a boolean to $(D_PARAM To).
*
* If $(D_PARAM To) is a numeric type, then $(D_KEYWORD true) becomes `1`,
* $(D_KEYWORD false) `0`.
*
* If $(D_PARAM To) is a $(D_PSYMBOL String), then `"true"` or `"false"`
* is returned.
*
* Params:
* From = Source type.
* To = Target type.
* from = Source value.
*
* Returns: $(D_PARAM from) converted to $(D_PARAM To).
*/
To to(To, From)(From from)
if (is(Unqual!From == bool) && isNumeric!To && !is(Unqual!To == Unqual!From))
{
return from;
}
///
@nogc nothrow pure @safe unittest
{
assert(true.to!float == 1.0);
assert(true.to!double == 1.0);
assert(true.to!ubyte == 1);
assert(true.to!byte == 1);
assert(true.to!ushort == 1);
assert(true.to!short == 1);
assert(true.to!uint == 1);
assert(true.to!int == 1);
assert(false.to!float == 0);
assert(false.to!double == 0);
assert(false.to!ubyte == 0);
assert(false.to!byte == 0);
assert(false.to!ushort == 0);
assert(false.to!short == 0);
assert(false.to!uint == 0);
assert(false.to!int == 0);
}
/**
* Converts $(D_PARAM From) to a $(D_PSYMBOL String).
*
* Params:
* From = Source type.
* To = Target type.
* from = Source value.
*
* Returns: $(D_PARAM from) converted to $(D_PSYMBOL String).
*/
To to(To, From)(auto ref From from)
if (is(Unqual!To == String))
{
return format!"{}"(from);
}
///
@nogc nothrow pure @safe unittest
{
assert(true.to!String == "true");
assert(false.to!String == "false");
}
@nogc nothrow pure @safe unittest
{
static assert(is(typeof((const String("true")).to!bool)));
static assert(is(typeof(false.to!(const String) == "false")));
}