intl/icu/source/i18n/rbt_rule.h

Wed, 31 Dec 2014 06:09:35 +0100

author
Michael Schloh von Bennewitz <michael@schloh.com>
date
Wed, 31 Dec 2014 06:09:35 +0100
changeset 0
6474c204b198
permissions
-rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

michael@0 1 /*
michael@0 2 * Copyright (C) {1999-2001}, International Business Machines Corporation and others. All Rights Reserved.
michael@0 3 **********************************************************************
michael@0 4 * Date Name Description
michael@0 5 * 11/17/99 aliu Creation.
michael@0 6 **********************************************************************
michael@0 7 */
michael@0 8 #ifndef RBT_RULE_H
michael@0 9 #define RBT_RULE_H
michael@0 10
michael@0 11 #include "unicode/utypes.h"
michael@0 12
michael@0 13 #if !UCONFIG_NO_TRANSLITERATION
michael@0 14
michael@0 15 #include "unicode/uobject.h"
michael@0 16 #include "unicode/unistr.h"
michael@0 17 #include "unicode/utrans.h"
michael@0 18 #include "unicode/unimatch.h"
michael@0 19
michael@0 20 U_NAMESPACE_BEGIN
michael@0 21
michael@0 22 class Replaceable;
michael@0 23 class TransliterationRuleData;
michael@0 24 class StringMatcher;
michael@0 25 class UnicodeFunctor;
michael@0 26
michael@0 27 /**
michael@0 28 * A transliteration rule used by
michael@0 29 * <code>RuleBasedTransliterator</code>.
michael@0 30 * <code>TransliterationRule</code> is an immutable object.
michael@0 31 *
michael@0 32 * <p>A rule consists of an input pattern and an output string. When
michael@0 33 * the input pattern is matched, the output string is emitted. The
michael@0 34 * input pattern consists of zero or more characters which are matched
michael@0 35 * exactly (the key) and optional context. Context must match if it
michael@0 36 * is specified. Context may be specified before the key, after the
michael@0 37 * key, or both. The key, preceding context, and following context
michael@0 38 * may contain variables. Variables represent a set of Unicode
michael@0 39 * characters, such as the letters <i>a</i> through <i>z</i>.
michael@0 40 * Variables are detected by looking up each character in a supplied
michael@0 41 * variable list to see if it has been so defined.
michael@0 42 *
michael@0 43 * <p>A rule may contain segments in its input string and segment
michael@0 44 * references in its output string. A segment is a substring of the
michael@0 45 * input pattern, indicated by an offset and limit. The segment may
michael@0 46 * be in the preceding or following context. It may not span a
michael@0 47 * context boundary. A segment reference is a special character in
michael@0 48 * the output string that causes a segment of the input string (not
michael@0 49 * the input pattern) to be copied to the output string. The range of
michael@0 50 * special characters that represent segment references is defined by
michael@0 51 * RuleBasedTransliterator.Data.
michael@0 52 *
michael@0 53 * @author Alan Liu
michael@0 54 */
michael@0 55 class TransliterationRule : public UMemory {
michael@0 56
michael@0 57 private:
michael@0 58
michael@0 59 // TODO Eliminate the pattern and keyLength data members. They
michael@0 60 // are used only by masks() and getIndexValue() which are called
michael@0 61 // only during build time, not during run-time. Perhaps these
michael@0 62 // methods and pattern/keyLength can be isolated into a separate
michael@0 63 // object.
michael@0 64
michael@0 65 /**
michael@0 66 * The match that must occur before the key, or null if there is no
michael@0 67 * preceding context.
michael@0 68 */
michael@0 69 StringMatcher *anteContext;
michael@0 70
michael@0 71 /**
michael@0 72 * The matcher object for the key. If null, then the key is empty.
michael@0 73 */
michael@0 74 StringMatcher *key;
michael@0 75
michael@0 76 /**
michael@0 77 * The match that must occur after the key, or null if there is no
michael@0 78 * following context.
michael@0 79 */
michael@0 80 StringMatcher *postContext;
michael@0 81
michael@0 82 /**
michael@0 83 * The object that performs the replacement if the key,
michael@0 84 * anteContext, and postContext are matched. Never null.
michael@0 85 */
michael@0 86 UnicodeFunctor* output;
michael@0 87
michael@0 88 /**
michael@0 89 * The string that must be matched, consisting of the anteContext, key,
michael@0 90 * and postContext, concatenated together, in that order. Some components
michael@0 91 * may be empty (zero length).
michael@0 92 * @see anteContextLength
michael@0 93 * @see keyLength
michael@0 94 */
michael@0 95 UnicodeString pattern;
michael@0 96
michael@0 97 /**
michael@0 98 * An array of matcher objects corresponding to the input pattern
michael@0 99 * segments. If there are no segments this is null. N.B. This is
michael@0 100 * a UnicodeMatcher for generality, but in practice it is always a
michael@0 101 * StringMatcher. In the future we may generalize this, but for
michael@0 102 * now we sometimes cast down to StringMatcher.
michael@0 103 *
michael@0 104 * The array is owned, but the pointers within it are not.
michael@0 105 */
michael@0 106 UnicodeFunctor** segments;
michael@0 107
michael@0 108 /**
michael@0 109 * The number of elements in segments[] or zero if segments is NULL.
michael@0 110 */
michael@0 111 int32_t segmentsCount;
michael@0 112
michael@0 113 /**
michael@0 114 * The length of the string that must match before the key. If
michael@0 115 * zero, then there is no matching requirement before the key.
michael@0 116 * Substring [0,anteContextLength) of pattern is the anteContext.
michael@0 117 */
michael@0 118 int32_t anteContextLength;
michael@0 119
michael@0 120 /**
michael@0 121 * The length of the key. Substring [anteContextLength,
michael@0 122 * anteContextLength + keyLength) is the key.
michael@0 123
michael@0 124 */
michael@0 125 int32_t keyLength;
michael@0 126
michael@0 127 /**
michael@0 128 * Miscellaneous attributes.
michael@0 129 */
michael@0 130 int8_t flags;
michael@0 131
michael@0 132 /**
michael@0 133 * Flag attributes.
michael@0 134 */
michael@0 135 enum {
michael@0 136 ANCHOR_START = 1,
michael@0 137 ANCHOR_END = 2
michael@0 138 };
michael@0 139
michael@0 140 /**
michael@0 141 * An alias pointer to the data for this rule. The data provides
michael@0 142 * lookup services for matchers and segments.
michael@0 143 */
michael@0 144 const TransliterationRuleData* data;
michael@0 145
michael@0 146 public:
michael@0 147
michael@0 148 /**
michael@0 149 * Construct a new rule with the given input, output text, and other
michael@0 150 * attributes. A cursor position may be specified for the output text.
michael@0 151 * @param input input string, including key and optional ante and
michael@0 152 * post context.
michael@0 153 * @param anteContextPos offset into input to end of ante context, or -1 if
michael@0 154 * none. Must be <= input.length() if not -1.
michael@0 155 * @param postContextPos offset into input to start of post context, or -1
michael@0 156 * if none. Must be <= input.length() if not -1, and must be >=
michael@0 157 * anteContextPos.
michael@0 158 * @param outputStr output string.
michael@0 159 * @param cursorPosition offset into output at which cursor is located, or -1 if
michael@0 160 * none. If less than zero, then the cursor is placed after the
michael@0 161 * <code>output</code>; that is, -1 is equivalent to
michael@0 162 * <code>output.length()</code>. If greater than
michael@0 163 * <code>output.length()</code> then an exception is thrown.
michael@0 164 * @param cursorOffset an offset to be added to cursorPos to position the
michael@0 165 * cursor either in the ante context, if < 0, or in the post context, if >
michael@0 166 * 0. For example, the rule "abc{def} > | @@@ xyz;" changes "def" to
michael@0 167 * "xyz" and moves the cursor to before "a". It would have a cursorOffset
michael@0 168 * of -3.
michael@0 169 * @param segs array of UnicodeMatcher corresponding to input pattern
michael@0 170 * segments, or null if there are none. The array itself is adopted,
michael@0 171 * but the pointers within it are not.
michael@0 172 * @param segsCount number of elements in segs[].
michael@0 173 * @param anchorStart TRUE if the the rule is anchored on the left to
michael@0 174 * the context start.
michael@0 175 * @param anchorEnd TRUE if the rule is anchored on the right to the
michael@0 176 * context limit.
michael@0 177 * @param data the rule data.
michael@0 178 * @param status Output parameter filled in with success or failure status.
michael@0 179 */
michael@0 180 TransliterationRule(const UnicodeString& input,
michael@0 181 int32_t anteContextPos, int32_t postContextPos,
michael@0 182 const UnicodeString& outputStr,
michael@0 183 int32_t cursorPosition, int32_t cursorOffset,
michael@0 184 UnicodeFunctor** segs,
michael@0 185 int32_t segsCount,
michael@0 186 UBool anchorStart, UBool anchorEnd,
michael@0 187 const TransliterationRuleData* data,
michael@0 188 UErrorCode& status);
michael@0 189
michael@0 190 /**
michael@0 191 * Copy constructor.
michael@0 192 * @param other the object to be copied.
michael@0 193 */
michael@0 194 TransliterationRule(TransliterationRule& other);
michael@0 195
michael@0 196 /**
michael@0 197 * Destructor.
michael@0 198 */
michael@0 199 virtual ~TransliterationRule();
michael@0 200
michael@0 201 /**
michael@0 202 * Change the data object that this rule belongs to. Used
michael@0 203 * internally by the TransliterationRuleData copy constructor.
michael@0 204 * @param data the new data value to be set.
michael@0 205 */
michael@0 206 void setData(const TransliterationRuleData* data);
michael@0 207
michael@0 208 /**
michael@0 209 * Return the preceding context length. This method is needed to
michael@0 210 * support the <code>Transliterator</code> method
michael@0 211 * <code>getMaximumContextLength()</code>. Internally, this is
michael@0 212 * implemented as the anteContextLength, optionally plus one if
michael@0 213 * there is a start anchor. The one character anchor gap is
michael@0 214 * needed to make repeated incremental transliteration with
michael@0 215 * anchors work.
michael@0 216 * @return the preceding context length.
michael@0 217 */
michael@0 218 virtual int32_t getContextLength(void) const;
michael@0 219
michael@0 220 /**
michael@0 221 * Internal method. Returns 8-bit index value for this rule.
michael@0 222 * This is the low byte of the first character of the key,
michael@0 223 * unless the first character of the key is a set. If it's a
michael@0 224 * set, or otherwise can match multiple keys, the index value is -1.
michael@0 225 * @return 8-bit index value for this rule.
michael@0 226 */
michael@0 227 int16_t getIndexValue() const;
michael@0 228
michael@0 229 /**
michael@0 230 * Internal method. Returns true if this rule matches the given
michael@0 231 * index value. The index value is an 8-bit integer, 0..255,
michael@0 232 * representing the low byte of the first character of the key.
michael@0 233 * It matches this rule if it matches the first character of the
michael@0 234 * key, or if the first character of the key is a set, and the set
michael@0 235 * contains any character with a low byte equal to the index
michael@0 236 * value. If the rule contains only ante context, as in foo)>bar,
michael@0 237 * then it will match any key.
michael@0 238 * @param v the given index value.
michael@0 239 * @return true if this rule matches the given index value.
michael@0 240 */
michael@0 241 UBool matchesIndexValue(uint8_t v) const;
michael@0 242
michael@0 243 /**
michael@0 244 * Return true if this rule masks another rule. If r1 masks r2 then
michael@0 245 * r1 matches any input string that r2 matches. If r1 masks r2 and r2 masks
michael@0 246 * r1 then r1 == r2. Examples: "a>x" masks "ab>y". "a>x" masks "a[b]>y".
michael@0 247 * "[c]a>x" masks "[dc]a>y".
michael@0 248 * @param r2 the given rule to be compared with.
michael@0 249 * @return true if this rule masks 'r2'
michael@0 250 */
michael@0 251 virtual UBool masks(const TransliterationRule& r2) const;
michael@0 252
michael@0 253 /**
michael@0 254 * Attempt a match and replacement at the given position. Return
michael@0 255 * the degree of match between this rule and the given text. The
michael@0 256 * degree of match may be mismatch, a partial match, or a full
michael@0 257 * match. A mismatch means at least one character of the text
michael@0 258 * does not match the context or key. A partial match means some
michael@0 259 * context and key characters match, but the text is not long
michael@0 260 * enough to match all of them. A full match means all context
michael@0 261 * and key characters match.
michael@0 262 *
michael@0 263 * If a full match is obtained, perform a replacement, update pos,
michael@0 264 * and return U_MATCH. Otherwise both text and pos are unchanged.
michael@0 265 *
michael@0 266 * @param text the text
michael@0 267 * @param pos the position indices
michael@0 268 * @param incremental if TRUE, test for partial matches that may
michael@0 269 * be completed by additional text inserted at pos.limit.
michael@0 270 * @return one of <code>U_MISMATCH</code>,
michael@0 271 * <code>U_PARTIAL_MATCH</code>, or <code>U_MATCH</code>. If
michael@0 272 * incremental is FALSE then U_PARTIAL_MATCH will not be returned.
michael@0 273 */
michael@0 274 UMatchDegree matchAndReplace(Replaceable& text,
michael@0 275 UTransPosition& pos,
michael@0 276 UBool incremental) const;
michael@0 277
michael@0 278 /**
michael@0 279 * Create a rule string that represents this rule object. Append
michael@0 280 * it to the given string.
michael@0 281 */
michael@0 282 virtual UnicodeString& toRule(UnicodeString& pat,
michael@0 283 UBool escapeUnprintable) const;
michael@0 284
michael@0 285 /**
michael@0 286 * Union the set of all characters that may be modified by this rule
michael@0 287 * into the given set.
michael@0 288 */
michael@0 289 void addSourceSetTo(UnicodeSet& toUnionTo) const;
michael@0 290
michael@0 291 /**
michael@0 292 * Union the set of all characters that may be emitted by this rule
michael@0 293 * into the given set.
michael@0 294 */
michael@0 295 void addTargetSetTo(UnicodeSet& toUnionTo) const;
michael@0 296
michael@0 297 private:
michael@0 298
michael@0 299 friend class StringMatcher;
michael@0 300
michael@0 301 TransliterationRule &operator=(const TransliterationRule &other); // forbid copying of this class
michael@0 302 };
michael@0 303
michael@0 304 U_NAMESPACE_END
michael@0 305
michael@0 306 #endif /* #if !UCONFIG_NO_TRANSLITERATION */
michael@0 307
michael@0 308 #endif

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