The Tor Browser: comparison intl/icu/source/common/unicode/utf.h

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+/*
+*******************************************************************************
+*
+*   Copyright (C) 1999-2011, 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 umachine.h because they can be machine-dependent.
+*
+* If U_NO_DEFAULT_INCLUDE_UTF_HEADERS is 0 then utf.h is included by utypes.h
+* and itself includes utf8.h and utf16.h after some
+* common definitions.
+* If U_NO_DEFAULT_INCLUDE_UTF_HEADERS is 1 then each of these headers must be
+* included explicitly if their definitions are used.
+*
+* utf8.h and utf16.h 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 mostly 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.
+*
+* umachine.h defines UChar to be an unsigned 16-bit integer.
+* Where available, UChar is defined to be a char16_t
+* or a wchar_t (if that is an unsigned 16-bit type), 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 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.
+*
+* The regular "safe" macros require that the initial, passed-in string index
+* is within bounds. They only check the index when they read more than one
+* code unit. This is usually done with code similar to the following loop:
+* <pre>while(i<length) {
+*   U16_NEXT(s, i, length, c);
+*   // use c
+* }</pre>
+*
+* 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.
+* (ICU 3.6 optimizes U8_NEXT() and U8_APPEND() to handle most other common
+* characters inline as well.)
+*
+* 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://userguide.icu-project.org/strings).
+*
+* <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/umachine.h"
+/* include the utfXX.h after the following definitions */
+/* single-code point definitions -------------------------------------------- */
+/**
+* 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)))
+/**
+* Is this code point a BMP code point (U+0000..U+ffff)?
+* @param c 32-bit code point
+* @return TRUE or FALSE
+* @stable 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
+* @stable ICU 2.8
+*/
+#define U_IS_SUPPLEMENTARY(c) ((uint32_t)((c)-0x10000)<=0xfffff)
+/**
+* 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)
+/**
+* Assuming c is a surrogate code point (U_IS_SURROGATE(c)),
+* is it a trail surrogate?
+* @param c 32-bit code point
+* @return TRUE or FALSE
+* @stable ICU 4.2
+*/
+#define U_IS_SURROGATE_TRAIL(c) (((c)&0x400)!=0)
+/* include the utfXX.h ------------------------------------------------------ */
+#if !U_NO_DEFAULT_INCLUDE_UTF_HEADERS
+#include "unicode/utf8.h"
+#include "unicode/utf16.h"
+/* utf_old.h contains deprecated, pre-ICU 2.4 definitions */
+#include "unicode/utf_old.h"
+#endif  /* !U_NO_DEFAULT_INCLUDE_UTF_HEADERS */
+#endif  /* __UTF_H__ */

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comparison: intl/icu/source/common/unicode/utf.h

intl/icu/source/common/unicode/utf.h