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/* 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.
* License: $(LINK2 https://www.mozilla.org/en-US/MPL/2.0/,
* Mozilla Public License, v. 2.0).
* Authors: Jeff Roberts, $(LINK2 mailto:info@caraus.de, Eugene Wissner)
* Source: $(LINK2 https://github.com/caraus-ecms/tanya/blob/master/source/tanya/format/conv.d,
* tanya/format/conv.d)
*/
module tanya.format.conv;
import tanya.container.string;
import tanya.memory;
import tanya.memory.op;
import tanya.meta.trait;
import tanya.meta.transform;
/**
* 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);
}
}
/**
* 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;
}
}
///
pure nothrow @safe @nogc unittest
{
auto val = 5.to!int();
assert(val == 5);
static assert(is(typeof(val) == int));
}
private pure nothrow @safe @nogc 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;
}
}
private pure nothrow @safe @nogc 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);
}
private 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);
}
private unittest
{
ConvException exception;
try
{
assert(int.min.to!short == int.min);
}
catch (ConvException e)
{
exception = e;
}
assert(exception !is null);
defaultAllocator.dispose(exception);
}
private unittest
{
ConvException exception;
try
{
assert(int.max.to!short == int.max);
}
catch (ConvException e)
{
exception = e;
}
assert(exception !is null);
defaultAllocator.dispose(exception);
}
private unittest
{
ConvException exception;
try
{
assert(uint.max.to!ushort == ushort.max);
}
catch (ConvException e)
{
exception = e;
}
assert(exception !is null);
defaultAllocator.dispose(exception);
}
private unittest
{
ConvException exception;
try
{
assert((-1).to!uint == -1);
}
catch (ConvException e)
{
exception = e;
}
assert(exception !is null);
defaultAllocator.dispose(exception);
}
private @nogc unittest
{
enum Test : int
{
one,
two,
}
assert(Test.one.to!int == 0);
assert(Test.two.to!int == 1);
}
/**
* 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 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);
}
private @nogc unittest
{
ConvException exception;
try
{
assert((-1).to!bool);
}
catch (ConvException e)
{
exception = e;
}
assert(exception !is null);
defaultAllocator.dispose(exception);
}
private @nogc unittest
{
ConvException exception;
try
{
assert(2.to!bool);
}
catch (ConvException e)
{
exception = e;
}
assert(exception !is null);
defaultAllocator.dispose(exception);
}
/// 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 unittest
{
assert("true".to!bool);
assert(!"false".to!bool);
assert(String("true").to!bool);
assert(!String("false").to!bool);
}
private @nogc unittest
{
ConvException exception;
try
{
assert("1".to!bool);
}
catch (ConvException e)
{
exception = e;
}
assert(exception !is null);
defaultAllocator.dispose(exception);
}
/**
* 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)(const From from)
if (is(Unqual!From == bool) && isNumeric!To && !is(Unqual!To == Unqual!From))
{
return from;
}
///
pure nothrow @safe @nogc 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);
}
/// Ditto.
To to(To, From)(const From from)
if (is(Unqual!From == bool) && is(Unqual!To == String))
{
return String(from ? "true" : "false");
}
///
@nogc unittest
{
assert(true.to!String == "true");
assert(false.to!String == "false");
}
private @nogc unittest
{
static assert(is(typeof((const String("true")).to!bool)));
static assert(is(typeof(false.to!(const String) == "false")));
}
/**
* 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 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);
}
private @nogc unittest
{
ConvException exception;
try
{
assert(2147483647.5.to!int == 2147483647);
}
catch (ConvException e)
{
exception = e;
}
assert(exception !is null);
defaultAllocator.dispose(exception);
}
private @nogc unittest
{
ConvException exception;
try
{
assert((-2147483648.5).to!int == -2147483648);
}
catch (ConvException e)
{
exception = e;
}
assert(exception !is null);
defaultAllocator.dispose(exception);
}
private @nogc unittest
{
ConvException exception;
try
{
assert((-21474.5).to!uint == -21474);
}
catch (ConvException e)
{
exception = e;
}
assert(exception !is null);
defaultAllocator.dispose(exception);
}
/**
* 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
* $(D_PSYMBOL To).
*/
To to(To, From)(From from)
if (isIntegral!From && is(To == enum))
{
foreach (m; EnumMembers!To)
{
if (from == m)
{
return m;
}
}
throw make!ConvException(defaultAllocator,
"Value not found in enum '" ~ To.stringof ~ "'");
}
///
@nogc unittest
{
enum Test : int
{
one,
two,
}
static assert(is(typeof(1.to!Test) == Test));
assert(0.to!Test == Test.one);
assert(1.to!Test == Test.two);
}
private @nogc unittest
{
enum Test : uint
{
one,
two,
}
ConvException exception;
try
{
assert(5.to!Test == Test.one);
}
catch (ConvException e)
{
exception = e;
}
assert(exception !is null);
defaultAllocator.dispose(exception);
}
// Returns the last part of buffer with converted number.
package char[] number2String(T)(const T number, out char[20] buffer)
{
// abs the integer.
ulong n64 = number < 0 ? -cast(long) number : number;
char* start = buffer.ptr + buffer.sizeof;
while (true)
{
// Do in 32-bit chunks (avoid lots of 64-bit divides even with constant
// denominators).
char* o = start - 8;
uint n;
if (n64 >= 100000000)
{
n = n64 % 100000000;
n64 /= 100000000;
}
else
{
n = cast(uint) n64;
n64 = 0;
}
while (n)
{
*--start = cast(char) (n % 10) + '0';
n /= 10;
}
// Ignore the leading zero if it was the last part of the integer.
if (n64 == 0)
{
if ((start[0] == '0') && (start != (buffer.ptr + buffer.sizeof)))
{
++start;
}
break;
}
// Copy leading zeros if it wasn't the most significant part of the
// integer.
while (start != o)
{
*--start = '0';
}
}
// Get the length that we have copied.
uint l = cast(uint) ((buffer.ptr + buffer.sizeof) - start);
if (l == 0)
{
*--start = '0';
l = 1;
}
else if (number < 0) // Set the sign.
{
*--start = '-';
++l;
}
return buffer[$ - l .. $];
}
private pure nothrow @system @nogc unittest
{
char[20] buf;
assert(number2String(80, buf) == "80");
assert(number2String(-80, buf) == "-80");
assert(number2String(0, buf) == "0");
assert(number2String(uint.max, buf) == "4294967295");
assert(number2String(int.min, buf) == "-2147483648");
}