/*

*******************************************************************************

*

*   Copyright (C) 1999-2004, International Business Machines

*   Corporation and others.  All Rights Reserved.

*

*******************************************************************************

*   file name:  utf.h

*   encoding:   US-ASCII

*   tab size:   8 (not used)

*   indentation:4

*

*   created on: 1999sep09

*   created by: Markus W. Scherer

*/

/**

 * \file

 * \brief C API: Code point macros

 *

 * This file defines macros for checking whether a code point is

 * a surrogate or a non-character etc.

 *

 * The UChar and UChar32 data types for Unicode code units and code points

 * are defined in umachines.h because they can be machine-dependent.

 *

 * utf.h is included by utypes.h and itself includes utf8.h and utf16.h after some

 * common definitions. Those files define macros for efficiently getting code points

 * in and out of UTF-8/16 strings.

 * utf16.h macros have "U16_" prefixes.

 * utf8.h defines similar macros with "U8_" prefixes for UTF-8 string handling.

 *

 * ICU processes 16-bit Unicode strings.

 * Most of the time, such strings are well-formed UTF-16.

 * Single, unpaired surrogates must be handled as well, and are treated in ICU

 * like regular code points where possible.

 * (Pairs of surrogate code points are indistinguishable from supplementary

 * code points encoded as pairs of supplementary code units.)

 *

 * In fact, almost all Unicode code points in normal text (>99%)

 * are on the BMP (<=U+ffff) and even <=U+d7ff.

 * ICU functions handle supplementary code points (U+10000..U+10ffff)

 * but are optimized for the much more frequently occurring BMP code points.

 *

 * utf.h defines UChar to be an unsigned 16-bit integer. If this matches wchar_t, then

 * UChar is defined to be exactly wchar_t, otherwise uint16_t.

 *

 * UChar32 is defined to be a signed 32-bit integer (int32_t), large enough for a 21-bit

 * Unicode code point (Unicode scalar value, 0..0x10ffff).

 * Before ICU 2.4, the definition of UChar32 was similarly platform-dependent as

 * the definition of UChar. For details see the documentation for UChar32 itself.

 *

 * utf.h also defines a small number of C macros for single Unicode code points.

 * These are simple checks for surrogates and non-characters.

 * For actual Unicode character properties see uchar.h.

 *

 * By default, string operations must be done with error checking in case

 * a string is not well-formed UTF-16.

 * The macros will detect if a surrogate code unit is unpaired

 * (lead unit without trail unit or vice versa) and just return the unit itself

 * as the code point.

 * (It is an accidental property of Unicode and UTF-16 that all

 * malformed sequences can be expressed unambiguously with a distinct subrange

 * of Unicode code points.)

 *

 * When it is safe to assume that text is well-formed UTF-16

 * (does not contain single, unpaired surrogates), then one can use

 * U16_..._UNSAFE macros.

 * These do not check for proper code unit sequences or truncated text and may

 * yield wrong results or even cause a crash if they are used with "malformed"

 * text.

 * In practice, U16_..._UNSAFE macros will produce slightly less code but

 * should not be faster because the processing is only different when a

 * surrogate code unit is detected, which will be rare.

 *

 * Similarly for UTF-8, there are "safe" macros without a suffix,

 * and U8_..._UNSAFE versions.

 * The performance differences are much larger here because UTF-8 provides so

 * many opportunities for malformed sequences.

 * The unsafe UTF-8 macros are entirely implemented inside the macro definitions

 * and are fast, while the safe UTF-8 macros call functions for all but the

 * trivial (ASCII) cases.

 *

 * Unlike with UTF-16, malformed sequences cannot be expressed with distinct

 * code point values (0..U+10ffff). They are indicated with negative values instead.

 *

 * For more information see the ICU User Guide Strings chapter

 * (http://oss.software.ibm.com/icu/userguide/).

 *

 * <em>Usage:</em>

 * ICU coding guidelines for if() statements should be followed when using these macros.

 * Compound statements (curly braces {}) must be used  for if-else-while... 

 * bodies and all macro statements should be terminated with semicolon.

 *

 * @stable ICU 2.4

 */

#ifndef __UTF_H__

#define __UTF_H__

#include "unicode/utypes.h"

/* include the utfXX.h after the following definitions */

/* single-code point definitions -------------------------------------------- */

/**

 * This value is intended for sentinel values for APIs that

 * (take or) return single code points (UChar32).

 * It is outside of the Unicode code point range 0..0x10ffff.

 * 

 * For example, a "done" or "error" value in a new API

 * could be indicated with U_SENTINEL.

 *

 * ICU APIs designed before ICU 2.4 usually define service-specific "done"

 * values, mostly 0xffff.

 * Those may need to be distinguished from

 * actual U+ffff text contents by calling functions like

 * CharacterIterator::hasNext() or UnicodeString::length().

 *

 * @return -1

 * @see UChar32

 * @stable ICU 2.4

 */

#define U_SENTINEL (-1)

/**

 * Is this code point a Unicode noncharacter?

 * @param c 32-bit code point

 * @return TRUE or FALSE

 * @stable ICU 2.4

 */

#define U_IS_UNICODE_NONCHAR(c) \

    ((c)>=0xfdd0 && \

     ((uint32_t)(c)<=0xfdef || ((c)&0xfffe)==0xfffe) && \

     (uint32_t)(c)<=0x10ffff)

/**

 * Is c a Unicode code point value (0..U+10ffff)

 * that can be assigned a character?

 *

 * Code points that are not characters include:

 * - single surrogate code points (U+d800..U+dfff, 2048 code points)

 * - the last two code points on each plane (U+__fffe and U+__ffff, 34 code points)

 * - U+fdd0..U+fdef (new with Unicode 3.1, 32 code points)

 * - the highest Unicode code point value is U+10ffff

 *

 * This means that all code points below U+d800 are character code points,

 * and that boundary is tested first for performance.

 *

 * @param c 32-bit code point

 * @return TRUE or FALSE

 * @stable ICU 2.4

 */

#define U_IS_UNICODE_CHAR(c) \

    ((uint32_t)(c)<0xd800 || \

        ((uint32_t)(c)>0xdfff && \

         (uint32_t)(c)<=0x10ffff && \

         !U_IS_UNICODE_NONCHAR(c)))

#ifndef U_HIDE_DRAFT_API

/**

 * Is this code point a BMP code point (U+0000..U+ffff)?

 * @param c 32-bit code point

 * @return TRUE or FALSE

 * @draft ICU 2.8

 */

#define U_IS_BMP(c) ((uint32_t)(c)<=0xffff)

/**

 * Is this code point a supplementary code point (U+10000..U+10ffff)?

 * @param c 32-bit code point

 * @return TRUE or FALSE

 * @draft ICU 2.8

 */

#define U_IS_SUPPLEMENTARY(c) ((uint32_t)((c)-0x10000)<=0xfffff)

#endif /*U_HIDE_DRAFT_API*/

/**

 * Is this code point a lead surrogate (U+d800..U+dbff)?

 * @param c 32-bit code point

 * @return TRUE or FALSE

 * @stable ICU 2.4

 */

#define U_IS_LEAD(c) (((c)&0xfffffc00)==0xd800)

/**

 * Is this code point a trail surrogate (U+dc00..U+dfff)?

 * @param c 32-bit code point

 * @return TRUE or FALSE

 * @stable ICU 2.4

 */

#define U_IS_TRAIL(c) (((c)&0xfffffc00)==0xdc00)

/**

 * Is this code point a surrogate (U+d800..U+dfff)?

 * @param c 32-bit code point

 * @return TRUE or FALSE

 * @stable ICU 2.4

 */

#define U_IS_SURROGATE(c) (((c)&0xfffff800)==0xd800)

/**

 * Assuming c is a surrogate code point (U_IS_SURROGATE(c)),

 * is it a lead surrogate?

 * @param c 32-bit code point

 * @return TRUE or FALSE

 * @stable ICU 2.4

 */

#define U_IS_SURROGATE_LEAD(c) (((c)&0x400)==0)

/* include the utfXX.h ------------------------------------------------------ */

#include "unicode/utf8.h"

#include "unicode/utf16.h"

/* utf_old.h contains deprecated, pre-ICU 2.4 definitions */

#include "unicode/utf_old.h"

#endif