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authorbruvzg <7645683+bruvzg@users.noreply.github.com>2020-08-11 12:10:23 +0300
committerbruvzg <7645683+bruvzg@users.noreply.github.com>2020-11-26 13:55:27 +0200
commitb9f441e81e89728f284f61991e14748208817efd (patch)
treea3729bf0b71f11b324d2dff8838e914780917701 /thirdparty/icu4c/common/unicode/ubiditransform.h
parent493da99269b3a111cf58e0352495e25ee49c5f84 (diff)
[Complex Text Layouts] Add third-party TextServer dependencies (ICU, HarfBuzz, Graphite).
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+/*
+******************************************************************************
+*
+* © 2016 and later: Unicode, Inc. and others.
+* License & terms of use: http://www.unicode.org/copyright.html
+*
+******************************************************************************
+* file name: ubiditransform.h
+* encoding: UTF-8
+* tab size: 8 (not used)
+* indentation:4
+*
+* created on: 2016jul24
+* created by: Lina Kemmel
+*
+*/
+
+#ifndef UBIDITRANSFORM_H
+#define UBIDITRANSFORM_H
+
+#include "unicode/utypes.h"
+#include "unicode/ubidi.h"
+#include "unicode/uchar.h"
+
+#if U_SHOW_CPLUSPLUS_API
+#include "unicode/localpointer.h"
+#endif // U_SHOW_CPLUSPLUS_API
+
+/**
+ * \file
+ * \brief Bidi Transformations
+ */
+
+/**
+ * `UBiDiOrder` indicates the order of text.
+ *
+ * This bidi transformation engine supports all possible combinations (4 in
+ * total) of input and output text order:
+ *
+ * - <logical input, visual output>: unless the output direction is RTL, this
+ * corresponds to a normal operation of the Bidi algorithm as described in the
+ * Unicode Technical Report and implemented by `UBiDi` when the
+ * reordering mode is set to `UBIDI_REORDER_DEFAULT`. Visual RTL
+ * mode is not supported by `UBiDi` and is accomplished through
+ * reversing a visual LTR string,
+ *
+ * - <visual input, logical output>: unless the input direction is RTL, this
+ * corresponds to an "inverse bidi algorithm" in `UBiDi` with the
+ * reordering mode set to `UBIDI_REORDER_INVERSE_LIKE_DIRECT`.
+ * Visual RTL mode is not not supported by `UBiDi` and is
+ * accomplished through reversing a visual LTR string,
+ *
+ * - <logical input, logical output>: if the input and output base directions
+ * mismatch, this corresponds to the `UBiDi` implementation with the
+ * reordering mode set to `UBIDI_REORDER_RUNS_ONLY`; and if the
+ * input and output base directions are identical, the transformation engine
+ * will only handle character mirroring and Arabic shaping operations without
+ * reordering,
+ *
+ * - <visual input, visual output>: this reordering mode is not supported by
+ * the `UBiDi` engine; it implies character mirroring, Arabic
+ * shaping, and - if the input/output base directions mismatch - string
+ * reverse operations.
+ * @see ubidi_setInverse
+ * @see ubidi_setReorderingMode
+ * @see UBIDI_REORDER_DEFAULT
+ * @see UBIDI_REORDER_INVERSE_LIKE_DIRECT
+ * @see UBIDI_REORDER_RUNS_ONLY
+ * @stable ICU 58
+ */
+typedef enum {
+ /** 0: Constant indicating a logical order.
+ * This is the default for input text.
+ * @stable ICU 58
+ */
+ UBIDI_LOGICAL = 0,
+ /** 1: Constant indicating a visual order.
+ * This is a default for output text.
+ * @stable ICU 58
+ */
+ UBIDI_VISUAL
+} UBiDiOrder;
+
+/**
+ * <code>UBiDiMirroring</code> indicates whether or not characters with the
+ * "mirrored" property in RTL runs should be replaced with their mirror-image
+ * counterparts.
+ * @see UBIDI_DO_MIRRORING
+ * @see ubidi_setReorderingOptions
+ * @see ubidi_writeReordered
+ * @see ubidi_writeReverse
+ * @stable ICU 58
+ */
+typedef enum {
+ /** 0: Constant indicating that character mirroring should not be
+ * performed.
+ * This is the default.
+ * @stable ICU 58
+ */
+ UBIDI_MIRRORING_OFF = 0,
+ /** 1: Constant indicating that character mirroring should be performed.
+ * This corresponds to calling <code>ubidi_writeReordered</code> or
+ * <code>ubidi_writeReverse</code> with the
+ * <code>UBIDI_DO_MIRRORING</code> option bit set.
+ * @stable ICU 58
+ */
+ UBIDI_MIRRORING_ON
+} UBiDiMirroring;
+
+/**
+ * Forward declaration of the <code>UBiDiTransform</code> structure that stores
+ * information used by the layout transformation engine.
+ * @stable ICU 58
+ */
+typedef struct UBiDiTransform UBiDiTransform;
+
+/**
+ * Performs transformation of text from the bidi layout defined by the input
+ * ordering scheme to the bidi layout defined by the output ordering scheme,
+ * and applies character mirroring and Arabic shaping operations.<p>
+ * In terms of <code>UBiDi</code>, such a transformation implies:
+ * <ul>
+ * <li>calling <code>ubidi_setReorderingMode</code> as needed (when the
+ * reordering mode is other than normal),</li>
+ * <li>calling <code>ubidi_setInverse</code> as needed (when text should be
+ * transformed from a visual to a logical form),</li>
+ * <li>resolving embedding levels of each character in the input text by
+ * calling <code>ubidi_setPara</code>,</li>
+ * <li>reordering the characters based on the computed embedding levels, also
+ * performing character mirroring as needed, and streaming the result to the
+ * output, by calling <code>ubidi_writeReordered</code>,</li>
+ * <li>performing Arabic digit and letter shaping on the output text by calling
+ * <code>u_shapeArabic</code>.</li>
+ * </ul>
+ * An "ordering scheme" encompasses the base direction and the order of text,
+ * and these characteristics must be defined by the caller for both input and
+ * output explicitly .<p>
+ * There are 36 possible combinations of <input, output> ordering schemes,
+ * which are partially supported by <code>UBiDi</code> already. Examples of the
+ * currently supported combinations:
+ * <ul>
+ * <li><Logical LTR, Visual LTR>: this is equivalent to calling
+ * <code>ubidi_setPara</code> with <code>paraLevel == UBIDI_LTR</code>,</li>
+ * <li><Logical RTL, Visual LTR>: this is equivalent to calling
+ * <code>ubidi_setPara</code> with <code>paraLevel == UBIDI_RTL</code>,</li>
+ * <li><Logical Default ("Auto") LTR, Visual LTR>: this is equivalent to
+ * calling <code>ubidi_setPara</code> with
+ * <code>paraLevel == UBIDI_DEFAULT_LTR</code>,</li>
+ * <li><Logical Default ("Auto") RTL, Visual LTR>: this is equivalent to
+ * calling <code>ubidi_setPara</code> with
+ * <code>paraLevel == UBIDI_DEFAULT_RTL</code>,</li>
+ * <li><Visual LTR, Logical LTR>: this is equivalent to
+ * calling <code>ubidi_setInverse(UBiDi*, true)</code> and then
+ * <code>ubidi_setPara</code> with <code>paraLevel == UBIDI_LTR</code>,</li>
+ * <li><Visual LTR, Logical RTL>: this is equivalent to
+ * calling <code>ubidi_setInverse(UBiDi*, true)</code> and then
+ * <code>ubidi_setPara</code> with <code>paraLevel == UBIDI_RTL</code>.</li>
+ * </ul>
+ * All combinations that involve the Visual RTL scheme are unsupported by
+ * <code>UBiDi</code>, for instance:
+ * <ul>
+ * <li><Logical LTR, Visual RTL>,</li>
+ * <li><Visual RTL, Logical RTL>.</li>
+ * </ul>
+ * <p>Example of usage of the transformation engine:<br>
+ * <pre>
+ * \code
+ * UChar text1[] = {'a', 'b', 'c', 0x0625, '1', 0};
+ * UChar text2[] = {'a', 'b', 'c', 0x0625, '1', 0};
+ * UErrorCode errorCode = U_ZERO_ERROR;
+ * // Run a transformation.
+ * ubiditransform_transform(pBidiTransform,
+ * text1, -1, text2, -1,
+ * UBIDI_LTR, UBIDI_VISUAL,
+ * UBIDI_RTL, UBIDI_LOGICAL,
+ * UBIDI_MIRRORING_OFF,
+ * U_SHAPE_DIGITS_AN2EN | U_SHAPE_DIGIT_TYPE_AN_EXTENDED,
+ * &errorCode);
+ * // Do something with text2.
+ * text2[4] = '2';
+ * // Run a reverse transformation.
+ * ubiditransform_transform(pBidiTransform,
+ * text2, -1, text1, -1,
+ * UBIDI_RTL, UBIDI_LOGICAL,
+ * UBIDI_LTR, UBIDI_VISUAL,
+ * UBIDI_MIRRORING_OFF,
+ * U_SHAPE_DIGITS_EN2AN | U_SHAPE_DIGIT_TYPE_AN_EXTENDED,
+ * &errorCode);
+ *\endcode
+ * </pre>
+ * </p>
+ *
+ * @param pBiDiTransform A pointer to a <code>UBiDiTransform</code> object
+ * allocated with <code>ubiditransform_open()</code> or
+ * <code>NULL</code>.<p>
+ * This object serves for one-time setup to amortize initialization
+ * overheads. Use of this object is not thread-safe. All other threads
+ * should allocate a new <code>UBiDiTransform</code> object by calling
+ * <code>ubiditransform_open()</code> before using it. Alternatively,
+ * a caller can set this parameter to <code>NULL</code>, in which case
+ * the object will be allocated by the engine on the fly.</p>
+ * @param src A pointer to the text that the Bidi layout transformations will
+ * be performed on.
+ * <p><strong>Note:</strong> the text must be (at least)
+ * <code>srcLength</code> long.</p>
+ * @param srcLength The length of the text, in number of UChars. If
+ * <code>length == -1</code> then the text must be zero-terminated.
+ * @param dest A pointer to where the processed text is to be copied.
+ * @param destSize The size of the <code>dest</code> buffer, in number of
+ * UChars. If the <code>U_SHAPE_LETTERS_UNSHAPE</code> option is set,
+ * then the destination length could be as large as
+ * <code>srcLength * 2</code>. Otherwise, the destination length will
+ * not exceed <code>srcLength</code>. If the caller reserves the last
+ * position for zero-termination, it should be excluded from
+ * <code>destSize</code>.
+ * <p><code>destSize == -1</code> is allowed and makes sense when
+ * <code>dest</code> was holds some meaningful value, e.g. that of
+ * <code>src</code>. In this case <code>dest</code> must be
+ * zero-terminated.</p>
+ * @param inParaLevel A base embedding level of the input as defined in
+ * <code>ubidi_setPara</code> documentation for the
+ * <code>paraLevel</code> parameter.
+ * @param inOrder An order of the input, which can be one of the
+ * <code>UBiDiOrder</code> values.
+ * @param outParaLevel A base embedding level of the output as defined in
+ * <code>ubidi_setPara</code> documentation for the
+ * <code>paraLevel</code> parameter.
+ * @param outOrder An order of the output, which can be one of the
+ * <code>UBiDiOrder</code> values.
+ * @param doMirroring Indicates whether or not to perform character mirroring,
+ * and can accept one of the <code>UBiDiMirroring</code> values.
+ * @param shapingOptions Arabic digit and letter shaping options defined in the
+ * ushape.h documentation.
+ * <p><strong>Note:</strong> Direction indicator options are computed by
+ * the transformation engine based on the effective ordering schemes, so
+ * user-defined direction indicators will be ignored.</p>
+ * @param pErrorCode A pointer to an error code value.
+ *
+ * @return The destination length, i.e. the number of UChars written to
+ * <code>dest</code>. If the transformation fails, the return value
+ * will be 0 (and the error code will be written to
+ * <code>pErrorCode</code>).
+ *
+ * @see UBiDiLevel
+ * @see UBiDiOrder
+ * @see UBiDiMirroring
+ * @see ubidi_setPara
+ * @see u_shapeArabic
+ * @stable ICU 58
+ */
+U_CAPI uint32_t U_EXPORT2
+ubiditransform_transform(UBiDiTransform *pBiDiTransform,
+ const UChar *src, int32_t srcLength,
+ UChar *dest, int32_t destSize,
+ UBiDiLevel inParaLevel, UBiDiOrder inOrder,
+ UBiDiLevel outParaLevel, UBiDiOrder outOrder,
+ UBiDiMirroring doMirroring, uint32_t shapingOptions,
+ UErrorCode *pErrorCode);
+
+/**
+ * Allocates a <code>UBiDiTransform</code> object. This object can be reused,
+ * e.g. with different ordering schemes, mirroring or shaping options.<p>
+ * <strong>Note:</strong>The object can only be reused in the same thread.
+ * All other threads should allocate a new <code>UBiDiTransform</code> object
+ * before using it.<p>
+ * Example of usage:<p>
+ * <pre>
+ * \code
+ * UErrorCode errorCode = U_ZERO_ERROR;
+ * // Open a new UBiDiTransform.
+ * UBiDiTransform* transform = ubiditransform_open(&errorCode);
+ * // Run a transformation.
+ * ubiditransform_transform(transform,
+ * text1, -1, text2, -1,
+ * UBIDI_RTL, UBIDI_LOGICAL,
+ * UBIDI_LTR, UBIDI_VISUAL,
+ * UBIDI_MIRRORING_ON,
+ * U_SHAPE_DIGITS_EN2AN,
+ * &errorCode);
+ * // Do something with the output text and invoke another transformation using
+ * // that text as input.
+ * ubiditransform_transform(transform,
+ * text2, -1, text3, -1,
+ * UBIDI_LTR, UBIDI_VISUAL,
+ * UBIDI_RTL, UBIDI_VISUAL,
+ * UBIDI_MIRRORING_ON,
+ * 0, &errorCode);
+ *\endcode
+ * </pre>
+ * <p>
+ * The <code>UBiDiTransform</code> object must be deallocated by calling
+ * <code>ubiditransform_close()</code>.
+ *
+ * @return An empty <code>UBiDiTransform</code> object.
+ * @stable ICU 58
+ */
+U_CAPI UBiDiTransform* U_EXPORT2
+ubiditransform_open(UErrorCode *pErrorCode);
+
+/**
+ * Deallocates the given <code>UBiDiTransform</code> object.
+ * @stable ICU 58
+ */
+U_CAPI void U_EXPORT2
+ubiditransform_close(UBiDiTransform *pBidiTransform);
+
+#if U_SHOW_CPLUSPLUS_API
+
+U_NAMESPACE_BEGIN
+
+/**
+ * \class LocalUBiDiTransformPointer
+ * "Smart pointer" class, closes a UBiDiTransform via ubiditransform_close().
+ * For most methods see the LocalPointerBase base class.
+ *
+ * @see LocalPointerBase
+ * @see LocalPointer
+ * @stable ICU 58
+ */
+U_DEFINE_LOCAL_OPEN_POINTER(LocalUBiDiTransformPointer, UBiDiTransform, ubiditransform_close);
+
+U_NAMESPACE_END
+
+#endif
+
+#endif