// SPDX-License-Identifier: BSD-2-Clause
// author: Max Kellermann <max.kellermann@gmail.com>

#ifndef CHAR_UTIL_HXX
#define CHAR_UTIL_HXX

#ifdef _UNICODE
#include "WCharUtil.hxx"
#endif

constexpr bool
IsASCII(const unsigned char ch) noexcept
{
	return ch < 0x80;
}

constexpr bool
IsASCII(const char ch) noexcept
{
	return IsASCII((unsigned char)ch);
}

constexpr bool
IsWhitespaceOrNull(const char ch) noexcept
{
	return (unsigned char)ch <= 0x20;
}

constexpr bool
IsWhitespaceNotNull(const char ch) noexcept
{
	return ch > 0 && ch <= 0x20;
}

/**
 * Is the given character whitespace?  This calls the faster one of
 * IsWhitespaceOrNull() or IsWhitespaceNotNull().  Use this if you
 * want the fastest implementation, and you don't care if a null byte
 * matches.
 */
constexpr bool
IsWhitespaceFast(const char ch) noexcept
{
	return IsWhitespaceOrNull(ch);
}

/**
 * Is this a non-printable ASCII character?  Returns false for
 * non-ASCII characters.
 *
 * Note that this is not the opposite of IsNonPrintableASCII().
 */
constexpr bool
IsPrintableASCII(char ch) noexcept
{
	return (signed char)ch >= 0x20;
}

/**
 * Is this a non-printable character?  Returns false for non-ASCII characters.
 *
 * Note that this is not the opposite of IsPrintableASCII()
 */
constexpr bool
IsNonPrintableASCII(char ch) noexcept
{
	return (unsigned char)ch < 0x20;
}

constexpr bool
IsDigitASCII(char ch) noexcept
{
	return ch >= '0' && ch <= '9';
}

constexpr bool
IsUpperAlphaASCII(char ch) noexcept
{
	return ch >= 'A' && ch <= 'Z';
}

constexpr bool
IsLowerAlphaASCII(char ch) noexcept
{
	return ch >= 'a' && ch <= 'z';
}

constexpr bool
IsAlphaASCII(char ch) noexcept
{
	return IsUpperAlphaASCII(ch) || IsLowerAlphaASCII(ch);
}

constexpr bool
IsAlphaNumericASCII(char ch) noexcept
{
	return IsAlphaASCII(ch) || IsDigitASCII(ch);
}

constexpr bool
IsLowerAlphaNumericASCII(char ch) noexcept
{
	return IsLowerAlphaASCII(ch) || IsDigitASCII(ch);
}

/**
 * Convert the specified ASCII character (0x00..0x7f) to upper case.
 * Unlike toupper(), it ignores the system locale.
 */
constexpr char
ToUpperASCII(char ch) noexcept
{
	return ch >= 'a' && ch <= 'z'
		? (ch - ('a' - 'A'))
		: ch;
}

/**
 * Convert the specified ASCII character (0x00..0x7f) to lower case.
 * Unlike tolower(), it ignores the system locale.
 */
constexpr char
ToLowerASCII(char ch) noexcept
{
	return ch >= 'A' && ch <= 'Z'
		? (ch + ('a' - 'A'))
		: ch;
}

constexpr bool
IsHexDigit(char ch) noexcept
{
	return IsDigitASCII(ch) ||
		(ch >= 'a' && ch <= 'f') ||
		(ch >= 'A' && ch <= 'F');
}

#endif