| /* |
| * Copyright © {1999}, International Business Machines Corporation and others. All Rights Reserved. |
| ********************************************************************** |
| * Date Name Description |
| * 10/22/99 alan Creation. |
| * 11/11/99 rgillam Complete port from Java. |
| ********************************************************************** |
| */ |
| |
| #ifndef RBBI_H |
| #define RBBI_H |
| |
| #include "unicode/utypes.h" |
| #include "unicode/brkiter.h" |
| |
| class RuleBasedBreakIteratorTables; |
| class BreakIterator; |
| |
| /** |
| * <p>A subclass of BreakIterator whose behavior is specified using a list of rules.</p> |
| * |
| * <p>There are two kinds of rules, which are separated by semicolons: <i>substitutions</i> |
| * and <i>regular expressions.</i></p> |
| * |
| * <p>A substitution rule defines a name that can be used in place of an expression. It |
| * consists of a name, which is a string of characters contained in angle brackets, an equals |
| * sign, and an expression. (There can be no whitespace on either side of the equals sign.) |
| * To keep its syntactic meaning intact, the expression must be enclosed in parentheses or |
| * square brackets. A substitution is visible after its definition, and is filled in using |
| * simple textual substitution. Substitution definitions can contain other substitutions, as |
| * long as those substitutions have been defined first. Substitutions are generally used to |
| * make the regular expressions (which can get quite complex) shorted and easier to read. |
| * They typically define either character categories or commonly-used subexpressions.</p> |
| * |
| * <p>There is one special substitution. If the description defines a substitution |
| * called "<ignore>", the expression must be a [] expression, and the |
| * expression defines a set of characters (the "<em>ignore characters</em>") that |
| * will be transparent to the BreakIterator. A sequence of characters will break the |
| * same way it would if any ignore characters it contains are taken out. Break |
| * positions never occur befoer ignore characters.</p> |
| * |
| * <p>A regular expression uses a subset of the normal Unix regular-expression syntax, and |
| * defines a sequence of characters to be kept together. With one significant exception, the |
| * iterator uses a longest-possible-match algorithm when matching text to regular |
| * expressions. The iterator also treats descriptions containing multiple regular expressions |
| * as if they were ORed together (i.e., as if they were separated by |).</p> |
| * |
| * <p>The special characters recognized by the regular-expression parser are as follows:</p> |
| * |
| * <blockquote> |
| * <table border="1" width="100%"> |
| * <tr> |
| * <td width="6%">*</td> |
| * <td width="94%">Specifies that the expression preceding the asterisk may occur any number |
| * of times (including not at all).</td> |
| * </tr> |
| * <tr> |
| * <td width="6%">{}</td> |
| * <td width="94%">Encloses a sequence of characters that is optional.</td> |
| * </tr> |
| * <tr> |
| * <td width="6%">()</td> |
| * <td width="94%">Encloses a sequence of characters. If followed by *, the sequence |
| * repeats. Otherwise, the parentheses are just a grouping device and a way to delimit |
| * the ends of expressions containing |.</td> |
| * </tr> |
| * <tr> |
| * <td width="6%">|</td> |
| * <td width="94%">Separates two alternative sequences of characters. Either one |
| * sequence or the other, but not both, matches this expression. The | character can |
| * only occur inside ().</td> |
| * </tr> |
| * <tr> |
| * <td width="6%">.</td> |
| * <td width="94%">Matches any character.</td> |
| * </tr> |
| * <tr> |
| * <td width="6%">*?</td> |
| * <td width="94%">Specifies a non-greedy asterisk. *? works the same way as *, except |
| * when there is overlap between the last group of characters in the expression preceding the |
| * * and the first group of characters following the *. When there is this kind of |
| * overlap, * will match the longest sequence of characters that match the expression before |
| * the *, and *? will match the shortest sequence of characters matching the expression |
| * before the *?. For example, if you have "xxyxyyyxyxyxxyxyxyy" in the text, |
| * "x[xy]*x" will match through to the last x (i.e., "<strong>xxyxyyyxyxyxxyxyx</strong>yy", |
| * but "x[xy]*?x" will only match the first two xes ("<strong>xx</strong>yxyyyxyxyxxyxyxyy").</td> |
| * </tr> |
| * <tr> |
| * <td width="6%">[]</td> |
| * <td width="94%">Specifies a group of alternative characters. A [] expression will |
| * match any single character that is specified in the [] expression. For more on the |
| * syntax of [] expressions, see below.</td> |
| * </tr> |
| * <tr> |
| * <td width="6%">/</td> |
| * <td width="94%">Specifies where the break position should go if text matches this |
| * expression. (e.g., "[a-z]*/[:Zs:]*1" will match if the iterator sees a run |
| * of letters, followed by a run of whitespace, followed by a digit, but the break position |
| * will actually go before the whitespace). Expressions that don't contain / put the |
| * break position at the end of the matching text.</td> |
| * </tr> |
| * <tr> |
| * <td width="6%">\</td> |
| * <td width="94%">Escape character. The \ itself is ignored, but causes the next |
| * character to be treated as literal character. This has no effect for many |
| * characters, but for the characters listed above, this deprives them of their special |
| * meaning. (There are no special escape sequences for Unicode characters, or tabs and |
| * newlines; these are all handled by a higher-level protocol. In a Java string, |
| * "\n" will be converted to a literal newline character by the time the |
| * regular-expression parser sees it. Of course, this means that \ sequences that are |
| * visible to the regexp parser must be written as \\ when inside a Java string.) All |
| * characters in the ASCII range except for letters, digits, and control characters are |
| * reserved characters to the parser and must be preceded by \ even if they currently don't |
| * mean anything.</td> |
| * </tr> |
| * <tr> |
| * <td width="6%">!</td> |
| * <td width="94%">If ! appears at the beginning of a regular expression, it tells the regexp |
| * parser that this expression specifies the backwards-iteration behavior of the iterator, |
| * and not its normal iteration behavior. This is generally only used in situations |
| * where the automatically-generated backwards-iteration brhavior doesn't produce |
| * satisfactory results and must be supplemented with extra client-specified rules.</td> |
| * </tr> |
| * <tr> |
| * <td width="6%"><em>(all others)</em></td> |
| * <td width="94%">All other characters are treated as literal characters, which must match |
| * the corresponding character(s) in the text exactly.</td> |
| * </tr> |
| * </table> |
| * </blockquote> |
| * |
| * <p>Within a [] expression, a number of other special characters can be used to specify |
| * groups of characters:</p> |
| * |
| * <blockquote> |
| * <table border="1" width="100%"> |
| * <tr> |
| * <td width="6%">-</td> |
| * <td width="94%">Specifies a range of matching characters. For example |
| * "[a-p]" matches all lowercase Latin letters from a to p (inclusive). The - |
| * sign specifies ranges of continuous Unicode numeric values, not ranges of characters in a |
| * language's alphabetical order: "[a-z]" doesn't include capital letters, nor does |
| * it include accented letters such as a-umlaut.</td> |
| * </tr> |
| * <tr> |
| * <td width="6%">::</td> |
| * <td width="94%">A pair of colons containing a one- or two-letter code matches all |
| * characters in the corresponding Unicode category. The two-letter codes are the same |
| * as the two-letter codes in the Unicode database (for example, "[:Sc::Sm:]" |
| * matches all currency symbols and all math symbols). Specifying a one-letter code is |
| * the same as specifying all two-letter codes that begin with that letter (for example, |
| * "[:L:]" matches all letters, and is equivalent to |
| * "[:Lu::Ll::Lo::Lm::Lt:]"). Anything other than a valid two-letter Unicode |
| * category code or a single letter that begins a Unicode category code is illegal within |
| * colons.</td> |
| * </tr> |
| * <tr> |
| * <td width="6%">[]</td> |
| * <td width="94%">[] expressions can nest. This has no effect, except when used in |
| * conjunction with the ^ token.</td> |
| * </tr> |
| * <tr> |
| * <td width="6%">^</td> |
| * <td width="94%">Excludes the character (or the characters in the [] expression) following |
| * it from the group of characters. For example, "[a-z^p]" matches all Latin |
| * lowercase letters except p. "[:L:^[\u4e00-\u9fff]]" matches all letters |
| * except the Han ideographs.</td> |
| * </tr> |
| * <tr> |
| * <td width="6%"><em>(all others)</em></td> |
| * <td width="94%">All other characters are treated as literal characters. (For |
| * example, "[aeiou]" specifies just the letters a, e, i, o, and u.)</td> |
| * </tr> |
| * </table> |
| * </blockquote> |
| * |
| * <p>For a more complete explanation, see <a |
| * href="http://www.ibm.com/java/education/boundaries/boundaries.html">http://www.ibm.com/java/education/boundaries/boundaries.html</a>. |
| * For examples, see the resource data (which is annotated).</p> |
| * |
| * @author Richard Gillam |
| */ |
| class U_I18N_API RuleBasedBreakIterator : public BreakIterator { |
| |
| public: |
| /** |
| * A token used as a character-category value to identify ignore characters |
| */ |
| static int8_t IGNORE; |
| |
| private: |
| /** |
| * The state number of the starting state |
| */ |
| static int16_t START_STATE; |
| |
| /** |
| * The state-transition value indicating "stop" |
| */ |
| static int16_t STOP_STATE; |
| |
| protected: |
| /** |
| * The character iterator through which this BreakIterator accesses the text |
| */ |
| CharacterIterator* text; |
| |
| /** |
| * The data tables this iterator uses to determine the break positions |
| */ |
| RuleBasedBreakIteratorTables* tables; |
| |
| private: |
| /** |
| * Class ID |
| */ |
| static char fgClassID; |
| /* |
| * HSYS: To be revisited, once the ctor are made public. |
| */ |
| protected: |
| //======================================================================= |
| // constructors |
| //======================================================================= |
| |
| // This constructor uses the udata interface to create a BreakIterator whose |
| // internal tables live in a memory-mapped file. "image" is a pointer to the |
| // beginning of that file. |
| RuleBasedBreakIterator(const void* image); |
| |
| public: |
| /** |
| * Copy constructor. Will produce a collator with the same behavior, |
| * and which iterates over the same text, as the one passed in. |
| */ |
| RuleBasedBreakIterator(const RuleBasedBreakIterator& that); |
| |
| //======================================================================= |
| // boilerplate |
| //======================================================================= |
| |
| /** |
| * Destructor |
| */ |
| virtual ~RuleBasedBreakIterator(); |
| |
| /** |
| * Assignment operator. Sets this iterator to have the same behavior, |
| * and iterate over the same text, as the one passed in. |
| */ |
| RuleBasedBreakIterator& operator=(const RuleBasedBreakIterator& that); |
| |
| /** |
| * Equality operator. Returns TRUE if both BreakIterators are of the |
| * same class, have the same behavior, and iterate over the same text. |
| */ |
| virtual UBool operator==(const BreakIterator& that) const; |
| |
| /** |
| * Not-equal operator. If operator== returns TRUE, this returns FALSE, |
| * and vice versa. |
| */ |
| UBool operator!=(const BreakIterator& that) const; |
| |
| /** |
| * Returns a newly-constructed RuleBasedBreakIterator with the same |
| * behavior, and iterating over the same text, as this one. |
| */ |
| virtual BreakIterator* clone(void) const; |
| |
| /** |
| * Compute a hash code for this BreakIterator |
| * @return A hash code |
| */ |
| virtual int32_t hashCode(void) const; |
| |
| /** |
| * Returns the description used to create this iterator |
| */ |
| virtual const UnicodeString& getRules(void) const; |
| |
| //======================================================================= |
| // BreakIterator overrides |
| //======================================================================= |
| |
| /** |
| * Return a CharacterIterator over the text being analyzed. This version |
| * of this method returns the actual CharacterIterator we're using internally. |
| * Changing the state of this iterator can have undefined consequences. If |
| * you need to change it, clone it first. |
| * @return An iterator over the text being analyzed. |
| */ |
| virtual const CharacterIterator& getText(void) const; |
| |
| /** |
| * Returns a newly-created CharacterIterator that the caller is to take |
| * ownership of. |
| * THIS FUNCTION SHOULD NOT BE HERE. IT'S HERE BECAUSE BreakIterator DEFINES |
| * IT AS PURE VIRTUAL, FORCING RBBI TO IMPLEMENT IT. IT SHOULD BE REMOVED |
| * FROM *BOTH* CLASSES. |
| */ |
| virtual CharacterIterator* createText(void) const; |
| |
| /** |
| * Set the iterator to analyze a new piece of text. This function resets |
| * the current iteration position to the beginning of the text. |
| * @param newText An iterator over the text to analyze. The BreakIterator |
| * takes ownership of the character iterator. The caller MUST NOT delete it! |
| */ |
| virtual void adoptText(CharacterIterator* newText); |
| |
| /** |
| * Set the iterator to analyze a new piece of text. This function resets |
| * the current iteration position to the beginning of the text. |
| * @param newText The text to analyze. |
| */ |
| virtual void setText(const UnicodeString& newText); |
| |
| /** |
| * Set the iterator to analyze a new piece of text. This function resets |
| * the current iteration position to the beginning of the text. |
| * @param newText The text to analyze. |
| * THIS FUNCTION SHOULD NOT BE HERE. IT'S HERE BECAUSE BreakIterator DEFINES |
| * IT AS PURE VIRTUAL, FORCING RBBI TO IMPLEMENT IT. IT SHOULD BE REMOVED |
| * FROM *BOTH* CLASSES. |
| */ |
| virtual void setText(const UnicodeString* newText); |
| |
| /** |
| * Sets the current iteration position to the beginning of the text. |
| * (i.e., the CharacterIterator's starting offset). |
| * @return The offset of the beginning of the text. |
| */ |
| virtual int32_t first(void); |
| |
| /** |
| * Sets the current iteration position to the end of the text. |
| * (i.e., the CharacterIterator's ending offset). |
| * @return The text's past-the-end offset. |
| */ |
| virtual int32_t last(void); |
| |
| /** |
| * Advances the iterator either forward or backward the specified number of steps. |
| * Negative values move backward, and positive values move forward. This is |
| * equivalent to repeatedly calling next() or previous(). |
| * @param n The number of steps to move. The sign indicates the direction |
| * (negative is backwards, and positive is forwards). |
| * @return The character offset of the boundary position n boundaries away from |
| * the current one. |
| */ |
| virtual int32_t next(int32_t n); |
| |
| /** |
| * Advances the iterator to the next boundary position. |
| * @return The position of the first boundary after this one. |
| */ |
| virtual int32_t next(void); |
| |
| /** |
| * Advances the iterator backwards, to the last boundary preceding this one. |
| * @return The position of the last boundary position preceding this one. |
| */ |
| virtual int32_t previous(void); |
| |
| /** |
| * Sets the iterator to refer to the first boundary position following |
| * the specified position. |
| * @offset The position from which to begin searching for a break position. |
| * @return The position of the first break after the current position. |
| */ |
| virtual int32_t following(int32_t offset); |
| |
| /** |
| * Sets the iterator to refer to the last boundary position before the |
| * specified position. |
| * @offset The position to begin searching for a break from. |
| * @return The position of the last boundary before the starting position. |
| */ |
| virtual int32_t preceding(int32_t offset); |
| |
| /** |
| * Returns true if the specfied position is a boundary position. As a side |
| * effect, leaves the iterator pointing to the first boundary position at |
| * or after "offset". |
| * @param offset the offset to check. |
| * @return True if "offset" is a boundary position. |
| */ |
| virtual UBool isBoundary(int32_t offset); |
| |
| /** |
| * Returns the current iteration position. |
| * @return The current iteration position. |
| */ |
| virtual int32_t current(void) const; |
| |
| /** |
| * Returns a unique class ID POLYMORPHICALLY. Pure virtual override. |
| * This method is to implement a simple version of RTTI, since not all |
| * C++ compilers support genuine RTTI. Polymorphic operator==() and |
| * clone() methods call this method. |
| * |
| * @return The class ID for this object. All objects of a |
| * given class have the same class ID. Objects of |
| * other classes have different class IDs. |
| */ |
| inline virtual UClassID getDynamicClassID(void) const; |
| |
| /** |
| * Returns the class ID for this class. This is useful only for |
| * comparing to a return value from getDynamicClassID(). For example: |
| * |
| * Base* polymorphic_pointer = createPolymorphicObject(); |
| * if (polymorphic_pointer->getDynamicClassID() == |
| * Derived::getStaticClassID()) ... |
| * |
| * @return The class ID for all objects of this class. |
| */ |
| inline static UClassID getStaticClassID(void); |
| |
| protected: |
| //======================================================================= |
| // implementation |
| //======================================================================= |
| /** |
| * This method is the actual implementation of the next() method. All iteration |
| * vectors through here. This method initializes the state machine to state 1 |
| * and advances through the text character by character until we reach the end |
| * of the text or the state machine transitions to state 0. We update our return |
| * value every time the state machine passes through a possible end state. |
| */ |
| virtual int32_t handleNext(void); |
| |
| /** |
| * This method backs the iterator back up to a "safe position" in the text. |
| * This is a position that we know, without any context, must be a break position. |
| * The various calling methods then iterate forward from this safe position to |
| * the appropriate position to return. (For more information, see the description |
| * of buildBackwardsStateTable() in RuleBasedBreakIterator.Builder.) |
| */ |
| virtual int32_t handlePrevious(void); |
| |
| /** |
| * Dumps caches and performs other actions associated with a complete change |
| * in text or iteration position. This function is a no-op in RuleBasedBreakIterator, |
| * but subclasses can and do override it. |
| */ |
| virtual void reset(void); |
| |
| private: |
| |
| /** |
| * Constructs a RuleBasedBreakIterator that uses the already-created |
| * tables object that is passed in as a parameter. |
| */ |
| RuleBasedBreakIterator(RuleBasedBreakIteratorTables* tables); |
| |
| friend class BreakIterator; |
| }; |
| |
| inline UBool RuleBasedBreakIterator::operator!=(const BreakIterator& that) const { |
| return !operator==(that); |
| } |
| |
| inline UClassID RuleBasedBreakIterator::getDynamicClassID(void) const { |
| return RuleBasedBreakIterator::getStaticClassID(); |
| } |
| |
| inline UClassID RuleBasedBreakIterator::getStaticClassID(void) { |
| return (UClassID)(&fgClassID); |
| } |
| |
| #endif |
