chromium/third_party/icu/source/common/ubidiwrt.cpp

// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
******************************************************************************
*
*   Copyright (C) 2000-2015, International Business Machines
*   Corporation and others.  All Rights Reserved.
*
******************************************************************************
*   file name:  ubidiwrt.c
*   encoding:   UTF-8
*   tab size:   8 (not used)
*   indentation:4
*
*   created on: 1999aug06
*   created by: Markus W. Scherer, updated by Matitiahu Allouche
*
* This file contains implementations for BiDi functions that use
* the core algorithm and core API to write reordered text.
*/

#include "unicode/utypes.h"
#include "unicode/ustring.h"
#include "unicode/uchar.h"
#include "unicode/ubidi.h"
#include "unicode/utf16.h"
#include "cmemory.h"
#include "ustr_imp.h"
#include "ubidiimp.h"

/*
 * The function implementations in this file are designed
 * for UTF-16 and UTF-32, not for UTF-8.
 *
 * Assumptions that are not true for UTF-8:
 * - Any code point always needs the same number of code units
 *   ("minimum-length-problem" of UTF-8)
 * - The BiDi control characters need only one code unit each
 *
 * Further assumptions for all UTFs:
 * - u_charMirror(c) needs the same number of code units as c
 */
#if defined(UTF_SIZE) && UTF_SIZE==8
# error reimplement ubidi_writeReordered() for UTF-8, see comment above
#endif

#define IS_COMBINING(type) …

/*
 * When we have UBIDI_OUTPUT_REVERSE set on ubidi_writeReordered(), then we
 * semantically write RTL runs in reverse and later reverse them again.
 * Instead, we actually write them in forward order to begin with.
 * However, if the RTL run was to be mirrored, we need to mirror here now
 * since the implicit second reversal must not do it.
 * It looks strange to do mirroring in LTR output, but it is only because
 * we are writing RTL output in reverse.
 */
static int32_t
doWriteForward(const char16_t *src, int32_t srcLength,
               char16_t *dest, int32_t destSize,
               uint16_t options,
               UErrorCode *pErrorCode) { … }

static int32_t
doWriteReverse(const char16_t *src, int32_t srcLength,
               char16_t *dest, int32_t destSize,
               uint16_t options,
               UErrorCode *pErrorCode) { … }

U_CAPI int32_t U_EXPORT2
ubidi_writeReverse(const char16_t *src, int32_t srcLength,
                   char16_t *dest, int32_t destSize,
                   uint16_t options,
                   UErrorCode *pErrorCode) { … }

// Ticket 20907 - The optimizer in MSVC/Visual Studio versions below 16.4 has trouble with this
// function on Windows ARM64. As a work-around, we disable optimizations for this function.
// This work-around could/should be removed once the following versions of Visual Studio are no
// longer supported: All versions of VS2017, and versions of VS2019 below 16.4.
#if (defined(_MSC_VER) && (defined(_M_ARM64)) && (_MSC_VER < 1924))
#pragma optimize( "", off )
#endif
U_CAPI int32_t U_EXPORT2
ubidi_writeReordered(UBiDi *pBiDi,
                     char16_t *dest, int32_t destSize,
                     uint16_t options,
                     UErrorCode *pErrorCode) { … }
#if (defined(_MSC_VER) && (defined(_M_ARM64)) && (_MSC_VER < 1924))
#pragma optimize( "", on )
#endif