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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 19:33:14 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 19:33:14 +0000
commit36d22d82aa202bb199967e9512281e9a53db42c9 (patch)
tree105e8c98ddea1c1e4784a60a5a6410fa416be2de /intl/icu/source/i18n/rbt_rule.h
parentInitial commit. (diff)
downloadfirefox-esr-upstream.tar.xz
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Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+// © 2016 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
+/*
+* Copyright (C) {1999-2001}, International Business Machines Corporation and others. All Rights Reserved.
+**********************************************************************
+* Date Name Description
+* 11/17/99 aliu Creation.
+**********************************************************************
+*/
+#ifndef RBT_RULE_H
+#define RBT_RULE_H
+
+#include "unicode/utypes.h"
+
+#if !UCONFIG_NO_TRANSLITERATION
+
+#include "unicode/uobject.h"
+#include "unicode/unistr.h"
+#include "unicode/utrans.h"
+#include "unicode/unimatch.h"
+
+U_NAMESPACE_BEGIN
+
+class Replaceable;
+class TransliterationRuleData;
+class StringMatcher;
+class UnicodeFunctor;
+
+/**
+ * A transliteration rule used by
+ * <code>RuleBasedTransliterator</code>.
+ * <code>TransliterationRule</code> is an immutable object.
+ *
+ * <p>A rule consists of an input pattern and an output string. When
+ * the input pattern is matched, the output string is emitted. The
+ * input pattern consists of zero or more characters which are matched
+ * exactly (the key) and optional context. Context must match if it
+ * is specified. Context may be specified before the key, after the
+ * key, or both. The key, preceding context, and following context
+ * may contain variables. Variables represent a set of Unicode
+ * characters, such as the letters <i>a</i> through <i>z</i>.
+ * Variables are detected by looking up each character in a supplied
+ * variable list to see if it has been so defined.
+ *
+ * <p>A rule may contain segments in its input string and segment
+ * references in its output string. A segment is a substring of the
+ * input pattern, indicated by an offset and limit. The segment may
+ * be in the preceding or following context. It may not span a
+ * context boundary. A segment reference is a special character in
+ * the output string that causes a segment of the input string (not
+ * the input pattern) to be copied to the output string. The range of
+ * special characters that represent segment references is defined by
+ * RuleBasedTransliterator.Data.
+ *
+ * @author Alan Liu
+ */
+class TransliterationRule : public UMemory {
+
+private:
+
+ // TODO Eliminate the pattern and keyLength data members. They
+ // are used only by masks() and getIndexValue() which are called
+ // only during build time, not during run-time. Perhaps these
+ // methods and pattern/keyLength can be isolated into a separate
+ // object.
+
+ /**
+ * The match that must occur before the key, or null if there is no
+ * preceding context.
+ */
+ StringMatcher *anteContext;
+
+ /**
+ * The matcher object for the key. If null, then the key is empty.
+ */
+ StringMatcher *key;
+
+ /**
+ * The match that must occur after the key, or null if there is no
+ * following context.
+ */
+ StringMatcher *postContext;
+
+ /**
+ * The object that performs the replacement if the key,
+ * anteContext, and postContext are matched. Never null.
+ */
+ UnicodeFunctor* output;
+
+ /**
+ * The string that must be matched, consisting of the anteContext, key,
+ * and postContext, concatenated together, in that order. Some components
+ * may be empty (zero length).
+ * @see anteContextLength
+ * @see keyLength
+ */
+ UnicodeString pattern;
+
+ /**
+ * An array of matcher objects corresponding to the input pattern
+ * segments. If there are no segments this is null. N.B. This is
+ * a UnicodeMatcher for generality, but in practice it is always a
+ * StringMatcher. In the future we may generalize this, but for
+ * now we sometimes cast down to StringMatcher.
+ *
+ * The array is owned, but the pointers within it are not.
+ */
+ UnicodeFunctor** segments;
+
+ /**
+ * The number of elements in segments[] or zero if segments is nullptr.
+ */
+ int32_t segmentsCount;
+
+ /**
+ * The length of the string that must match before the key. If
+ * zero, then there is no matching requirement before the key.
+ * Substring [0,anteContextLength) of pattern is the anteContext.
+ */
+ int32_t anteContextLength;
+
+ /**
+ * The length of the key. Substring [anteContextLength,
+ * anteContextLength + keyLength) is the key.
+
+ */
+ int32_t keyLength;
+
+ /**
+ * Miscellaneous attributes.
+ */
+ int8_t flags;
+
+ /**
+ * Flag attributes.
+ */
+ enum {
+ ANCHOR_START = 1,
+ ANCHOR_END = 2
+ };
+
+ /**
+ * An alias pointer to the data for this rule. The data provides
+ * lookup services for matchers and segments.
+ */
+ const TransliterationRuleData* data;
+
+public:
+
+ /**
+ * Construct a new rule with the given input, output text, and other
+ * attributes. A cursor position may be specified for the output text.
+ * @param input input string, including key and optional ante and
+ * post context.
+ * @param anteContextPos offset into input to end of ante context, or -1 if
+ * none. Must be <= input.length() if not -1.
+ * @param postContextPos offset into input to start of post context, or -1
+ * if none. Must be <= input.length() if not -1, and must be >=
+ * anteContextPos.
+ * @param outputStr output string.
+ * @param cursorPosition offset into output at which cursor is located, or -1 if
+ * none. If less than zero, then the cursor is placed after the
+ * <code>output</code>; that is, -1 is equivalent to
+ * <code>output.length()</code>. If greater than
+ * <code>output.length()</code> then an exception is thrown.
+ * @param cursorOffset an offset to be added to cursorPos to position the
+ * cursor either in the ante context, if < 0, or in the post context, if >
+ * 0. For example, the rule "abc{def} > | @@@ xyz;" changes "def" to
+ * "xyz" and moves the cursor to before "a". It would have a cursorOffset
+ * of -3.
+ * @param segs array of UnicodeMatcher corresponding to input pattern
+ * segments, or null if there are none. The array itself is adopted,
+ * but the pointers within it are not.
+ * @param segsCount number of elements in segs[].
+ * @param anchorStart true if the the rule is anchored on the left to
+ * the context start.
+ * @param anchorEnd true if the rule is anchored on the right to the
+ * context limit.
+ * @param data the rule data.
+ * @param status Output parameter filled in with success or failure status.
+ */
+ TransliterationRule(const UnicodeString& input,
+ int32_t anteContextPos, int32_t postContextPos,
+ const UnicodeString& outputStr,
+ int32_t cursorPosition, int32_t cursorOffset,
+ UnicodeFunctor** segs,
+ int32_t segsCount,
+ UBool anchorStart, UBool anchorEnd,
+ const TransliterationRuleData* data,
+ UErrorCode& status);
+
+ /**
+ * Copy constructor.
+ * @param other the object to be copied.
+ */
+ TransliterationRule(TransliterationRule& other);
+
+ /**
+ * Destructor.
+ */
+ virtual ~TransliterationRule();
+
+ /**
+ * Change the data object that this rule belongs to. Used
+ * internally by the TransliterationRuleData copy constructor.
+ * @param data the new data value to be set.
+ */
+ void setData(const TransliterationRuleData* data);
+
+ /**
+ * Return the preceding context length. This method is needed to
+ * support the <code>Transliterator</code> method
+ * <code>getMaximumContextLength()</code>. Internally, this is
+ * implemented as the anteContextLength, optionally plus one if
+ * there is a start anchor. The one character anchor gap is
+ * needed to make repeated incremental transliteration with
+ * anchors work.
+ * @return the preceding context length.
+ */
+ virtual int32_t getContextLength() const;
+
+ /**
+ * Internal method. Returns 8-bit index value for this rule.
+ * This is the low byte of the first character of the key,
+ * unless the first character of the key is a set. If it's a
+ * set, or otherwise can match multiple keys, the index value is -1.
+ * @return 8-bit index value for this rule.
+ */
+ int16_t getIndexValue() const;
+
+ /**
+ * Internal method. Returns true if this rule matches the given
+ * index value. The index value is an 8-bit integer, 0..255,
+ * representing the low byte of the first character of the key.
+ * It matches this rule if it matches the first character of the
+ * key, or if the first character of the key is a set, and the set
+ * contains any character with a low byte equal to the index
+ * value. If the rule contains only ante context, as in foo)>bar,
+ * then it will match any key.
+ * @param v the given index value.
+ * @return true if this rule matches the given index value.
+ */
+ UBool matchesIndexValue(uint8_t v) const;
+
+ /**
+ * Return true if this rule masks another rule. If r1 masks r2 then
+ * r1 matches any input string that r2 matches. If r1 masks r2 and r2 masks
+ * r1 then r1 == r2. Examples: "a>x" masks "ab>y". "a>x" masks "a[b]>y".
+ * "[c]a>x" masks "[dc]a>y".
+ * @param r2 the given rule to be compared with.
+ * @return true if this rule masks 'r2'
+ */
+ virtual UBool masks(const TransliterationRule& r2) const;
+
+ /**
+ * Attempt a match and replacement at the given position. Return
+ * the degree of match between this rule and the given text. The
+ * degree of match may be mismatch, a partial match, or a full
+ * match. A mismatch means at least one character of the text
+ * does not match the context or key. A partial match means some
+ * context and key characters match, but the text is not long
+ * enough to match all of them. A full match means all context
+ * and key characters match.
+ *
+ * If a full match is obtained, perform a replacement, update pos,
+ * and return U_MATCH. Otherwise both text and pos are unchanged.
+ *
+ * @param text the text
+ * @param pos the position indices
+ * @param incremental if true, test for partial matches that may
+ * be completed by additional text inserted at pos.limit.
+ * @return one of <code>U_MISMATCH</code>,
+ * <code>U_PARTIAL_MATCH</code>, or <code>U_MATCH</code>. If
+ * incremental is false then U_PARTIAL_MATCH will not be returned.
+ */
+ UMatchDegree matchAndReplace(Replaceable& text,
+ UTransPosition& pos,
+ UBool incremental) const;
+
+ /**
+ * Create a rule string that represents this rule object. Append
+ * it to the given string.
+ */
+ virtual UnicodeString& toRule(UnicodeString& pat,
+ UBool escapeUnprintable) const;
+
+ /**
+ * Union the set of all characters that may be modified by this rule
+ * into the given set.
+ */
+ void addSourceSetTo(UnicodeSet& toUnionTo) const;
+
+ /**
+ * Union the set of all characters that may be emitted by this rule
+ * into the given set.
+ */
+ void addTargetSetTo(UnicodeSet& toUnionTo) const;
+
+ private:
+
+ friend class StringMatcher;
+
+ TransliterationRule &operator=(const TransliterationRule &other); // forbid copying of this class
+};
+
+U_NAMESPACE_END
+
+#endif /* #if !UCONFIG_NO_TRANSLITERATION */
+
+#endif