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scuffed-code/icu4c/source/i18n/uniset.cpp

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ICU-34 Add UnicodeSet class to i18n X-SVN-Rev: 83
1999-10-20 22:08:09 +00:00
#include "uniset.h"
/**
* A mutable set of Unicode characters. Objects of this class
* represent <em>character classes</em> used in regular expressions.
* Such classes specify a subset of the set of all Unicode characters,
* which in this implementation is the characters from U+0000 to
* U+FFFF, ignoring surrogates.
*
* <p>This class supports two APIs. The first is modeled after Java 2's
* <code>java.util.Set</code> interface, although this class does not
* implement that interface. All methods of <code>Set</code> are
* supported, with the modification that they take a character range
* or single character instead of an <code>Object</code>, and they
* take a <code>UnicodeSet</code> instead of a <code>Collection</code>.
*
* <p>The second API is the
* <code>applyPattern()</code>/<code>toPattern()</code> API from the
* <code>java.text.Format</code>-derived classes. Unlike the
* methods that add characters, add categories, and control the logic
* of the set, the method <code>applyPattern()</code> sets all
* attributes of a <code>UnicodeSet</code> at once, based on a
* string pattern.
*
* <p>In addition, the set complement operation is supported through
* the <code>complement()</code> method.
*
* <p><b>Pattern syntax</b></p>
*
* Patterns are accepted by the constructors and the
* <code>applyPattern()</code> methods and returned by the
* <code>toPattern()</code> method. These patterns follow a syntax
* similar to that employed by version 8 regular expression character
* classes:
*
* <blockquote><code>
* pattern := ('[' '^'? item* ']') | ('[:' '^'? category ':]')<br>
* item := char | (char '-' char) | pattern-expr<br>
* pattern-expr := pattern | pattern-expr pattern | pattern-expr op pattern<br>
* op := '&' | '-'<br>
* special := '[' | ']' | '-'<br>
* char := <em>any character that is not</em> special |
* ('\' <em>any character</em>) |
* ('\\u' hex hex hex hex)<br>
* hex := <em>any hex digit, as defined by </em>Character.digit(c, 16)
* </code>
*
* <br>Legend:
*
* <table>
* <tr><td width=20%><code>a:=b</code>
* <td><code>a</code> may be replaced by
* <code>b</code>
* <tr><td><code>a?</code>
* <td>zero or one instance of <code>a</code><br>
* <tr><td><code>a*</code>
* <td>one or more instances of <code>a</code><br>
* <tr><td><code>a|b</code>
* <td>either <code>a</code> or <code>b</code><br>
* <tr><td><code>'a'</code>
* <td>the literal string between the quotes
* </table>
* </blockquote>
*
* Patterns specify individual characters, ranges of characters, and
* Unicode character categories. When elements are concatenated, they
* specify their union. To complement a set, place a '^' immediately
* after the opening '[' or '[:'. In any other location, '^' has no
* special meaning.
*
* <p>Ranges are indicated by placing two a '-' between two
* characters, as in "a-z". This specifies the range of all
* characters from the left to the right, in Unicode order. If the
* left and right characters are the same, then the range consists of
* just that character. If the left character is greater than the
* right character it is a syntax error. If a '-' occurs as the first
* character after the opening '[' or '[^', or if it occurs as the
* last character before the closing ']', then it is taken as a
* literal. Thus "[a\-b]", "[-ab]", and "[ab-]" all indicate the same
* set of three characters, 'a', 'b', and '-'.
*
* <p>Sets may be intersected using the '&' operator or the asymmetric
* set difference may be taken using the '-' operator, for example,
* "[[:L:]&[\u0000-\u0FFF]]" indicates the set of all Unicode letters
* with values less than 4096. Operators ('&' and '|') have equal
* precedence and bind left-to-right. Thus
* "[[:L:]-[a-z]-[\u0100-\u01FF]]" is equivalent to
* "[[[:L:]-[a-z]]-[\u0100-\u01FF]]". This only really matters for
* difference; intersection is commutative.
*
* <table>
* <tr valign=top><td nowrap><code>[a]</code><td>The set containing 'a'
* <tr valign=top><td nowrap><code>[a-z]</code><td>The set containing 'a'
* through 'z' and all letters in between, in Unicode order
* <tr valign=top><td nowrap><code>[^a-z]</code><td>The set containing
* all characters but 'a' through 'z',
* that is, U+0000 through 'a'-1 and 'z'+1 through U+FFFF
* <tr valign=top><td nowrap><code>[[<em>pat1</em>][<em>pat2</em>]]</code>
* <td>The union of sets specified by <em>pat1</em> and <em>pat2</em>
* <tr valign=top><td nowrap><code>[[<em>pat1</em>]&[<em>pat2</em>]]</code>
* <td>The intersection of sets specified by <em>pat1</em> and <em>pat2</em>
* <tr valign=top><td nowrap><code>[[<em>pat1</em>]-[<em>pat2</em>]]</code>
* <td>The asymmetric difference of sets specified by <em>pat1</em> and
* <em>pat2</em>
* <tr valign=top><td nowrap><code>[:Lu:]</code>
* <td>The set of characters belonging to the given
* Unicode category, as defined by <code>Character.getType()</code>; in
* this case, Unicode uppercase letters
* <tr valign=top><td nowrap><code>[:L:]</code>
* <td>The set of characters belonging to all Unicode categories
* starting wih 'L', that is, <code>[[:Lu:][:Ll:][:Lt:][:Lm:][:Lo:]]</code>.
* </table>
*
* <p><b>Character categories.</b>
*
* Character categories are specified using the POSIX-like syntax
* '[:Lu:]'. The complement of a category is specified by inserting
* '^' after the opening '[:'. The following category names are
* recognized. Actual determination of category data uses
* <code>Character.getType()</code>, so it reflects the underlying
* implmementation used by <code>Character</code>. As of Java 2 and
* JDK 1.1.8, this is Unicode <b>2.x.x - fill in version here</b>.
*
* <pre>
* Normative
* Mn = Mark, Non-Spacing
* Mc = Mark, Spacing Combining
* Me = Mark, Enclosing
*
* Nd = Number, Decimal Digit
* Nl = Number, Letter
* No = Number, Other
*
* Zs = Separator, Space
* Zl = Separator, Line
* Zp = Separator, Paragraph
*
* Cc = Other, Control
* Cf = Other, Format
* Cs = Other, Surrogate
* Co = Other, Private Use
* Cn = Other, Not Assigned
*
* Informative
* Lu = Letter, Uppercase
* Ll = Letter, Lowercase
* Lt = Letter, Titlecase
* Lm = Letter, Modifier
* Lo = Letter, Other
*
* Pc = Punctuation, Connector
* Pd = Punctuation, Dash
* Ps = Punctuation, Open
* Pe = Punctuation, Close
* Pi = Punctuation, Initial quote
* Pf = Punctuation, Final quote
* Po = Punctuation, Other
*
* Sm = Symbol, Math
* Sc = Symbol, Currency
* Sk = Symbol, Modifier
* So = Symbol, Other
* </pre>
* *Unsupported by Java (and hence unsupported by UnicodeSet).
*
* @author Alan Liu
* @version $RCSfile: uniset.cpp,v $ $Revision: 1.1 $ $Date: 1999/10/20 22:06:52 $
*/
// Note: This mapping is different in ICU and Java
const UnicodeString UnicodeSet::CATEGORY_NAMES(
"CnLuLlLtLmLoMnMeMcNdNlNoZsZlZpCcCfCoCsPdPsPePcPoSmScSkSoPiPf");
/**
* A cache mapping character category integers, as returned by
* Character.getType(), to pairs strings. Entries are initially
* null and are created on demand.
*/
UnicodeString* UnicodeSet::CATEGORY_PAIRS_CACHE =
new UnicodeString[Unicode::GENERAL_TYPES_COUNT];
//----------------------------------------------------------------
// Debugging and testing
//----------------------------------------------------------------
/**
* Return the representation of this set as a list of character
* ranges. Ranges are listed in ascending Unicode order. For
* example, the set [a-zA-M3] is represented as "33AMaz".
*/
const UnicodeString& UnicodeSet::getPairs() const {
return pairs;
}
//----------------------------------------------------------------
// Public API
//----------------------------------------------------------------
/**
* Constructs an empty set.
*/
UnicodeSet::UnicodeSet() {}
/**
* Constructs a set from the given pattern, optionally ignoring
* white space. See the class description for the syntax of the
* pattern language.
* @param pattern a string specifying what characters are in the set
* @param ignoreSpaces if <code>true</code>, all spaces in the
* pattern are ignored, except those preceded by '\\'. Spaces are
* those characters for which <code>Character.isSpaceChar()</code>
* is <code>true</code>.
* @exception <code>IllegalArgumentException</code> if the pattern
* contains a syntax error.
*/
UnicodeSet::UnicodeSet(const UnicodeString& pattern, bool_t ignoreSpaces,
UErrorCode& status) {
applyPattern(pattern, ignoreSpaces, status);
}
UnicodeSet::UnicodeSet(const UnicodeString& pattern,
UErrorCode& status) {
applyPattern(pattern, status);
}
/**
* Constructs a set from the given Unicode character category.
* @param category an integer indicating the character category as
* returned by <code>Character.getType()</code>.
* @exception <code>IllegalArgumentException</code> if the given
* category is invalid.
*/
UnicodeSet::UnicodeSet(int8_t category, UErrorCode& status) {
if (U_SUCCESS(status)) {
if (category < 0 || category >= Unicode::GENERAL_TYPES_COUNT) {
status = U_ILLEGAL_ARGUMENT_ERROR;
} else {
pairs = getCategoryPairs(category);
}
}
}
/**
* Modifies this set to represent the set specified by the given
* pattern, optionally ignoring white space. See the class
* description for the syntax of the pattern language.
* @param pattern a string specifying what characters are in the set
* @param ignoreSpaces if <code>true</code>, all spaces in the
* pattern are ignored. Spaces are those characters for which
* <code>Character.isSpaceChar()</code> is <code>true</code>.
* Characters preceded by '\\' are escaped, losing any special
* meaning they otherwise have. Spaces may be included by
* escaping them.
* @exception <code>IllegalArgumentException</code> if the pattern
* contains a syntax error.
*/
void UnicodeSet::applyPattern(const UnicodeString& pattern,
bool_t ignoreSpaces,
UErrorCode& status) {
if (U_FAILURE(status)) {
return;
}
ParsePosition pos(0);
UnicodeString* pat = (UnicodeString*) &pattern;
// To ignore spaces, create a new pattern without spaces. We
// have to process all '\' escapes. If '\' is encountered,
// insert it and the following character (if any -- let parse
// deal with any syntax errors) in the pattern. This allows
// escaped spaces.
if (ignoreSpaces) {
pat = new UnicodeString();
for (int32_t i=0; i<pattern.length(); ++i) {
UChar c = pattern.charAt(i);
if (Unicode::isSpaceChar(c)) {
continue;
}
if (c == '\\' && (i+1) < pattern.length()) {
pat->append(c);
c = pattern.charAt(++i);
// Fall through and append the following char
}
pat->append(c);
}
}
parse(pairs, *pat, pos, status);
if (pos.getIndex() != pat->length()) {
status = U_ILLEGAL_ARGUMENT_ERROR;
}
if (pat != &pattern) {
delete pat;
}
}
/**
* Returns a string representation of this set. If the result of
* calling this function is passed to a UnicodeSet constructor, it
* will produce another set that is equal to this one.
*/
UnicodeString& UnicodeSet::toPattern(UnicodeString& result) const {
result.remove().append((UChar)'[');
// iterate through the ranges in the CharSet
for (int32_t i=0; i<pairs.length(); i+=2) {
// for a range with the same beginning and ending point,
// output that character, otherwise, output the start and
// end points of the range separated by a dash
result.append(pairs.charAt(i));
if (pairs.charAt(i) != pairs.charAt(i+1)) {
result.append((UChar)'-').append(pairs.charAt(i+1));
}
}
return result.append((UChar)']');
}
/**
* Returns the number of elements in this set (its cardinality). If this
* set contains more than <tt>Integer.MAX_VALUE</tt> elements, returns
* <tt>Integer.MAX_VALUE</tt>.
*
* @return the number of elements in this set (its cardinality).
*/
int32_t UnicodeSet::size() const {
int32_t n = 0;
for (int32_t i=0; i<pairs.length(); i+=2) {
n += pairs.charAt(i+1) - pairs.charAt(i) + 1;
}
return n;
}
/**
* Returns <tt>true</tt> if this set contains no elements.
*
* @return <tt>true</tt> if this set contains no elements.
*/
bool_t UnicodeSet::isEmpty() const {
return pairs.length() == 0;
}
/**
* Returns <tt>true</tt> if this set contains the specified range
* of chars.
*
* @return <tt>true</tt> if this set contains the specified range
* of chars.
*/
bool_t UnicodeSet::contains(UChar first, UChar last) const {
// Set i to the end of the smallest range such that its end
// point >= last, or pairs.length() if no such range exists.
int32_t i = 1;
while (i<pairs.length() && last>pairs.charAt(i)) i+=2;
return i<pairs.length() && first>=pairs.charAt(i-1);
}
/**
* Returns <tt>true</tt> if this set contains the specified char.
*
* @return <tt>true</tt> if this set contains the specified char.
*/
bool_t UnicodeSet::contains(UChar c) const {
return contains(c, c);
}
/**
* Adds the specified range to this set if it is not already
* present. If this set already contains the specified range,
* the call leaves this set unchanged. If <code>last > first</code>
* then an empty range is added, leaving the set unchanged.
*
* @param first first character, inclusive, of range to be added
* to this set.
* @param last last character, inclusive, of range to be added
* to this set.
*/
void UnicodeSet::add(UChar first, UChar last) {
if (first <= last) {
addPair(pairs, first, last);
}
}
/**
* Adds the specified character to this set if it is not already
* present. If this set already contains the specified character,
* the call leaves this set unchanged.
*/
void UnicodeSet::add(UChar c) {
add(c, c);
}
/**
* Removes the specified range from this set if it is present.
* The set will not contain the specified range once the call
* returns. If <code>last > first</code> then an empty range is
* removed, leaving the set unchanged.
*
* @param first first character, inclusive, of range to be removed
* from this set.
* @param last last character, inclusive, of range to be removed
* from this set.
*/
void UnicodeSet::remove(UChar first, UChar last) {
if (first <= last) {
removePair(pairs, first, last);
}
}
/**
* Removes the specified character from this set if it is present.
* The set will not contain the specified range once the call
* returns.
*/
void UnicodeSet::remove(UChar c) {
remove(c, c);
}
/**
* Returns <tt>true</tt> if the specified set is a <i>subset</i>
* of this set.
*
* @param c set to be checked for containment in this set.
* @return <tt>true</tt> if this set contains all of the elements of the
* specified set.
*/
bool_t UnicodeSet::containsAll(const UnicodeSet& c) const {
// The specified set is a subset if all of its pairs are contained
// in this set.
int32_t i = 1;
for (int32_t j=0; j<c.pairs.length(); j+=2) {
UChar last = c.pairs.charAt(j+1);
// Set i to the end of the smallest range such that its
// end point >= last, or pairs.length() if no such range
// exists.
while (i<pairs.length() && last>pairs.charAt(i)) i+=2;
if (i>pairs.length() || c.pairs.charAt(j) < pairs.charAt(i-1)) {
return FALSE;
}
}
return TRUE;
}
/**
* Adds all of the elements in the specified set to this set if
* they're not already present. This operation effectively
* modifies this set so that its value is the <i>union</i> of the two
* sets. The behavior of this operation is unspecified if the specified
* collection is modified while the operation is in progress.
*
* @param c set whose elements are to be added to this set.
* @see #add(char, char)
*/
void UnicodeSet::addAll(const UnicodeSet& c) {
doUnion(pairs, c.pairs);
}
/**
* Retains only the elements in this set that are contained in the
* specified set. In other words, removes from this set all of
* its elements that are not contained in the specified set. This
* operation effectively modifies this set so that its value is
* the <i>intersection</i> of the two sets.
*
* @param c set that defines which elements this set will retain.
*/
void UnicodeSet::retainAll(const UnicodeSet& c) {
doIntersection(pairs, c.pairs);
}
/**
* Removes from this set all of its elements that are contained in the
* specified set. This operation effectively modifies this
* set so that its value is the <i>asymmetric set difference</i> of
* the two sets.
*
* @param c set that defines which elements will be removed from
* this set.
*/
void UnicodeSet::removeAll(const UnicodeSet& c) {
doDifference(pairs, c.pairs);
}
/**
* Inverts this set. This operation modifies this set so that
* its value is its complement. This is equivalent to the pseudo code:
* <code>this = new CharSet("[\u0000-\uFFFF]").removeAll(this)</code>.
*/
void UnicodeSet::complement() {
doComplement(pairs);
}
/**
* Removes all of the elements from this set. This set will be
* empty after this call returns.
*/
void UnicodeSet::clear() {
pairs.remove();
}
/**
* Compares the specified object with this set for equality. Returns
* <tt>true</tt> if the specified object is also a set, the two sets
* have the same size, and every member of the specified set is
* contained in this set (or equivalently, every member of this set is
* contained in the specified set).
*
* @param o Object to be compared for equality with this set.
* @return <tt>true</tt> if the specified Object is equal to this set.
*/
bool_t UnicodeSet::operator==(const UnicodeSet& o) const {
return pairs == o.pairs;
}
/**
* Returns the hash code value for this set.
*
* @return the hash code value for this set.
* @see Object#hashCode()
*/
int32_t UnicodeSet::hashCode() const {
return pairs.hashCode();
}
//----------------------------------------------------------------
// Implementation: Pattern parsing
//----------------------------------------------------------------
/**
* Parses the given pattern, starting at the given position. The
* character at pattern.charAt(pos.getIndex()) must be '[', or the
* parse fails. Parsing continues until the corresponding closing
* ']'. If a syntax error is encountered between the opening and
* closing brace, the parse fails. Upon return from a U_SUCCESSful
* parse, the ParsePosition is updated to point to the character
* following the closing ']', and a StringBuffer containing a
* pairs list for the parsed pattern is returned. This method calls
* itself recursively to parse embedded subpatterns.
*
* @param pattern the string containing the pattern to be parsed.
* The portion of the string from pos.getIndex(), which must be a
* '[', to the corresponding closing ']', is parsed.
* @param pos upon entry, the position at which to being parsing.
* The character at pattern.charAt(pos.getIndex()) must be a '['.
* Upon return from a U_SUCCESSful parse, pos.getIndex() is either
* the character after the closing ']' of the parsed pattern, or
* pattern.length() if the closing ']' is the last character of
* the pattern string.
* @return a StringBuffer containing a pairs list for the parsed
* substring of <code>pattern</code>
* @exception IllegalArgumentException if the parse fails.
*/
UnicodeString& UnicodeSet::parse(UnicodeString& pairsBuf /*result*/,
const UnicodeString& pattern,
ParsePosition& pos,
UErrorCode& status) {
if (U_FAILURE(status)) {
return pairsBuf;
}
bool_t invert = FALSE;
pairsBuf.remove();
/**
* Nodes: 0 - idle, waiting for '['
* 10 - like 11, but immediately after "[" or "[^"
* 11 - awaiting x, "]", "[...]", or "[:...:]"
* 21 - after x
* 23 - after x-
*
* The parsing state machine moves from node 0 through zero or more
* other nodes back to node 0, in a U_SUCCESSful parse.
*/
int32_t node = 0;
UChar first = 0;
int32_t i;
/**
* This loop iterates over the characters in the pattern. We
* start at the position specified by pos. We exit the loop
* when either a matching closing ']' is seen, or we read all
* characters of the pattern.
*/
for (i=pos.getIndex(); i<pattern.length(); ++i) {
UChar c = pattern.charAt(i); /**
* Handle escapes here. If a character is escaped, then
* it assumes its literal value. This is true for all
* characters, both special characters and characters with
* no special meaning. We also interpret '\\uxxxx' Unicode
* escapes here.
*/
bool_t isLiteral = FALSE;
if (c == '\\') {
++i;
if (i < pattern.length()) {
c = pattern.charAt(i);
isLiteral = TRUE;
if (c == 'u') {
if ((i+4) >= pattern.length()) {
status = U_ILLEGAL_ARGUMENT_ERROR;
return pairsBuf;
}
c = (UChar)0x0000;
for (int32_t j=(++i)+4; i<j; ++i) { // [sic]
// TO DO: Change this to use Unicode::digit()
// when that method exists.
int32_t digit = /*Unicode::*/UnicodeSet::digit(pattern.charAt(i), 16);
if (digit<0) {
status = U_ILLEGAL_ARGUMENT_ERROR;
return pairsBuf;
}
c = (UChar) ((c << 4) | digit);
}
--i; // Move i back to last parsed character
}
} else {
status = U_ILLEGAL_ARGUMENT_ERROR;
return pairsBuf;
}
}
/**
* Within this loop, we handle each of the four
* conditions: '[', ']', '-', other. The first three
* characters must not be escaped.
*/
/**
* An opening bracket indicates either the first bracket
* of the entire subpattern we are parsing, in which case
* we are in node 0 and move into node 10. We also check
* for an immediately following '^', indicating the
* complement of the following pattern. ('^' is any other
* position has no special meaning.) If we are not in
* node 0, '[' represents a nested subpattern that must be
* recursively parsed and checked for following operators
* ('&' or '|'). If two nested subpatterns follow one
* another with no operator, their union is formed, just
* as with any other elements that follow one another
* without intervening operator. The other thing we
* handle here is the syntax "[:Xx:]" or "[:X:]" that
* indicates a Unicode category or supercategory.
*/
if (!isLiteral && c == '[') {
bool_t parseOp = FALSE;
UChar d = charAfter(pattern, i);
// "[:...:]" represents a character category
if (d == ':') {
if (node == 23) {
status = U_ILLEGAL_ARGUMENT_ERROR;
return pairsBuf;
}
if (node == 21) {
addPair(pairsBuf, first, first);
node = 11;
}
i += 2;
int32_t j = pattern.indexOf(":]", i);
if (j < 0) {
status = U_ILLEGAL_ARGUMENT_ERROR;
return pairsBuf;
}
UnicodeString categoryName;
pattern.extract(i, j-i, categoryName);
UnicodeString temp;
doUnion(pairsBuf,
getCategoryPairs(temp, categoryName, status));
if (U_FAILURE(status)) {
return pairsBuf;
}
i = j+1;
if (node == 10) {
node = 11;
parseOp = TRUE;
} else if (node == 0) {
break;
}
} else {
if (node == 0) {
node = 10;
if (d == '^') {
invert = TRUE;
++i;
}
} else {
// Nested '['
pos.setIndex(i);
UnicodeString subPairs; // Pairs for the nested []
doUnion(pairsBuf, parse(subPairs, pattern, pos, status));
if (U_FAILURE(status)) {
return pairsBuf;
}
i = pos.getIndex() - 1; // Subtract 1 to point at ']'
parseOp = TRUE;
}
}
/**
* parseOp is true after "[:...:]" or a nested
* "[...]". It is false only after the final closing
* ']'. If parseOp is true, we look past the closing
* ']' to see if we have an operator character. If
* so, we parse the subsequent "[...]" recursively,
* then perform the operation. We do this in a loop
* until there are no more operators. Note that this
* means the operators have equal precedence and are
* bound left-to-right.
*/
if (parseOp) {
for (;;) {
// Is the next character an operator?
UChar op = charAfter(pattern, i);
if (op == '-' || op == '&') {
pos.setIndex(i+2); // Add 2 to point AFTER op
UnicodeString rhs;
parse(rhs, pattern, pos, status);
if (U_FAILURE(status)) {
return pairsBuf;
}
if (op == '-') {
doDifference(pairsBuf, rhs);
} else if (op == '&') {
doIntersection(pairsBuf, rhs);
}
i = pos.getIndex() - 1; // - 1 to point at ']'
} else {
break;
}
}
}
}
/**
* A closing bracket can only be a closing bracket for
* "[...]", since the closing bracket for "[:...:]" is
* taken care of when the initial "[:" is seen. When we
* see a closing bracket, we then know, if we were in node
* 21 (after x) or 23 (after x-) that nothing more is
* coming, and we add the last character(s) we saw to the
* set. Note that a trailing '-' assumes its literal
* meaning, just as a leading '-' after "[" or "[^".
*/
else if (!isLiteral && c == ']') {
if (node == 0) {
status = U_ILLEGAL_ARGUMENT_ERROR;
return pairsBuf;
}
if (node == 21 || node == 23) {
addPair(pairsBuf, first, first);
if (node == 23) {
addPair(pairsBuf, '-', '-');
}
}
node = 0;
break;
}
/**
* '-' has the following interpretations: 1. Within
* "[...]", between two letters, it indicates a range.
* 2. Between two nested bracket patterns, "[[...]-[...]",
* it indicates asymmetric difference. 3. At the start of
* a bracket pattern, "[-...]", "[^-...]", it indicates
* the literal character '-'. 4. At the end of a bracket
* pattern, "[...-]", it indicates the literal character
* '-'.
*
* We handle cases 1 and 3 here. Cases 2 and 4 are
* handled in the ']' parsing code.
*/
else if (!isLiteral && c == '-') {
if (node == 10) {
addPair(pairsBuf, c, c); // Handle "[-...]", "[^-...]"
} else if (node == 21) {
node = 23;
} else {
status = U_ILLEGAL_ARGUMENT_ERROR;
return pairsBuf;
}
}
/**
* If we fall through to this point, we have a literal
* character, either one that has been escaped with a
* backslash, escaped with a backslash u, or that isn't
* a special '[', ']', or '-'.
*
* Literals can either start a range "x-...", end a range,
* "...-x", or indicate a single character "x".
*/
else {
if (node == 10 || node == 11) {
first = c;
node = 21;
} else if (node == 21) {
addPair(pairsBuf, first, first);
first = c;
node = 21;
} else if (node == 23) {
if (c < first) {
status = U_ILLEGAL_ARGUMENT_ERROR;
return pairsBuf;
}
addPair(pairsBuf, first, c);
node = 11;
} else {
status = U_ILLEGAL_ARGUMENT_ERROR;
return pairsBuf;
}
}
}
if (node != 0) {
status = U_ILLEGAL_ARGUMENT_ERROR;
return pairsBuf;
}
/**
* i indexes the last character we parsed or is
* pattern.length(). In the latter case, the node will not be
* zero, since we have run off the end without finding a
* closing ']'. Therefore, the above statement will have
* thrown an exception, and we'll never get here. If we get
* here, we know i < pattern.length(), and we set the
* ParsePosition to the next character to be parsed.
*/
pos.setIndex(i+1);
/**
* If we saw a '^' after the initial '[' of this pattern, then
* perform the complement. (Inversion after '[:' is handled
* elsewhere.)
*/
if (invert) {
doComplement(pairsBuf);
}
return pairsBuf;
}
//----------------------------------------------------------------
// Implementation: Efficient in-place union & difference
//----------------------------------------------------------------
/**
* Performs a union operation: adds the range 'c'-'d' to the given
* pairs list. The pairs list is modified in place. The result
* is normalized (in order and as short as possible). For
* example, addPair("am", 'l', 'q') => "aq". addPair("ampz", 'n',
* 'o') => "az".
*/
void UnicodeSet::addPair(UnicodeString& pairs, UChar c, UChar d) {
UChar a = 0;
UChar b = 0;
for (int32_t i=0; i<pairs.length(); i+=2) {
UChar e = pairs.charAt(i);
UChar f = pairs.charAt(i+1);
if (e <= (d+1) && c <= (f+1)) {
// Merge with this range
f = (UChar) icu_max(d, f);
// Check to see if we need to merge with the
// subsequent range also. This happens if we have
// "abdf" and are merging in "cc". We only need to
// check on the right side -- never on the left.
if ((i+2) < pairs.length() &&
pairs.charAt(i+2) == (f+1)) {
f = pairs.charAt(i+3);
pairs.remove(i+2, 2);
}
pairs.setCharAt(i, (UChar) icu_min(c, e));
pairs.setCharAt(i+1, f);
return;
} else if ((b+1) < c && (d+1) < e) {
// Insert before this range c, then d
pairs.insert(i, d); // d gets moved to i+1 by next insert
pairs.insert(i, c);
return;
}
a = e;
b = f;
}
// If nothing else, fall through and append this new range to
// the end.
pairs.append(c).append(d);
}
/**
* Performs an asymmetric difference: removes the range 'c'-'d'
* from the pairs list. The pairs list is modified in place. The
* result is normalized (in order and as short as possible). For
* example, removePair("am", 'l', 'q') => "ak".
* removePair("ampz", 'l', 'q') => "akrz".
*/
void UnicodeSet::removePair(UnicodeString& pairs, UChar c, UChar d) {
// Iterate over pairs until we find a pair that overlaps
// with the given range.
for (int32_t i=0; i<pairs.length(); i+=2) {
UChar b = pairs.charAt(i+1);
if (b < c) {
// Range at i is entirely before the given range,
// since we have a-b < c-d. No overlap yet...keep
// iterating.
continue;
}
UChar a = pairs.charAt(i);
if (d < a) {
// Range at i is entirely after the given range; c-d <
// a-b. Since ranges are in order, nothing else will
// overlap.
break;
}
// Once we get here, we know c <= b and d >= a.
// rangeEdited is set to true if we have modified the
// range a-b (the range at i) in place.
bool_t rangeEdited = FALSE;
if (c > a) {
// If c is after a and before b, then we have overlap
// of this sort: a--c==b--d or a--c==d--b, where a-b
// and c-d are the ranges of interest. We need to
// add the range a,c-1.
pairs.setCharAt(i+1, (UChar)(c-1));
// i is already a
rangeEdited = TRUE;
}
if (d < b) {
// If d is after a and before b, we overlap like this:
// c--a==d--b or a--c==d--b, where a-b is the range at
// i and c-d is the range being removed. We need to
// add the range d+1,b.
if (rangeEdited) {
// Insert {d+1, b}
pairs.insert(i+2, b); // b moves to i+3 by next insert:
pairs.insert(i+2, (UChar)(d+1));
i += 2;
} else {
pairs.setCharAt(i, (UChar)(d+1));
// i+1 is already b
rangeEdited = TRUE;
}
}
if (!rangeEdited) {
// If we didn't add any ranges, that means the entire
// range a-b must be deleted, since we have
// c--a==b--d.
pairs.remove(i, 2);
i -= 2;
}
}
}
//----------------------------------------------------------------
// Implementation: Fundamental operators
//----------------------------------------------------------------
/**
* Changes the pairs list to represent the complement of the set it
* currently represents. The pairs list will be normalized (in
* order and in shortest possible form) if the original pairs list
* was normalized.
*/
void UnicodeSet::doComplement(UnicodeString& pairs) {
if (pairs.length() == 0) {
pairs.append((UChar)0x0000).append((UChar)0xffff);
return;
}
// Change each end to a start and each start to an end of the
// gaps between the ranges. That is, 3-7 9-12 becomes x-2 8-8
// 13-x, where 'x' represents a range that must now be fixed
// up.
for (int32_t i=0; i<pairs.length(); i+=2) {
pairs.setCharAt(i, (UChar) (pairs.charAt(i) - 1));
pairs.setCharAt(i+1, (UChar) (pairs.charAt(i+1) + 1));
}
// Fix up the initial range, either by adding a start point of
// U+0000, or by deleting the range altogether, if the
// original range was U+0000 - x.
if (pairs.charAt(0) == (UChar)0xFFFF) {
pairs.remove(0, 1);
} else {
pairs.insert(0, (UChar)0x0000);
}
// Fix up the final range, either by adding an end point of
// U+FFFF, or by deleting the range altogether, if the
// original range was x - U+FFFF.
if (pairs.charAt(pairs.length() - 1) == (UChar)0x0000) {
pairs.remove(pairs.length() - 1);
} else {
pairs.append((UChar)0xFFFF);
}
}
/**
* Given two pairs lists, changes the first in place to represent
* the union of the two sets.
*/
void UnicodeSet::doUnion(UnicodeString& c1, const UnicodeString& c2) {
UnicodeString result;
int32_t i = 0;
int32_t j = 0;
// consider all the characters in both strings
while (i < c1.length() && j < c2.length()) {
UChar ub;
// the first character in the result is the lower of the
// starting characters of the two strings, and "ub" gets
// set to the upper bound of that range
if (c1.charAt(i) < c2.charAt(j)) {
result.append(c1.charAt(i));
ub = c1.charAt(++i);
}
else {
result.append(c2.charAt(j));
ub = c2.charAt(++j);
}
// for as long as one of our two pointers is pointing to a range's
// end point, or i is pointing to a character that is less than
// "ub" plus one (the "plus one" stitches touching ranges together)...
while (i % 2 == 1 || j % 2 == 1 || (i < c1.length() && c1.charAt(i)
<= ub + 1)) {
// advance i to the first character that is greater than
// "ub" plus one
while (i < c1.length() && c1.charAt(i) <= ub + 1)
++i;
// if i points to the endpoint of a range, update "ub"
// to that character, or if i points to the start of
// a range and the endpoint of the preceding range is
// greater than "ub", update "up" to _that_ character
if (i % 2 == 1)
ub = c1.charAt(i);
else if (i > 0 && c1.charAt(i - 1) > ub)
ub = c1.charAt(i - 1);
// now advance j to the first character that is greater
// that "ub" plus one
while (j < c2.length() && c2.charAt(j) <= ub + 1)
++j;
// if j points to the endpoint of a range, update "ub"
// to that character, or if j points to the start of
// a range and the endpoint of the preceding range is
// greater than "ub", update "up" to _that_ character
if (j % 2 == 1)
ub = c2.charAt(j);
else if (j > 0 && c2.charAt(j - 1) > ub)
ub = c2.charAt(j - 1);
}
// when we finally fall out of this loop, we will have stitched
// together a series of ranges that overlap or touch, i and j
// will both point to starting points of ranges, and "ub" will
// be the endpoint of the range we're working on. Write "ub"
// to the result
result.append(ub);
// loop back around to create the next range in the result
}
// we fall out to here when we've exhausted all the characters in
// one of the operands. We can append all of the remaining characters
// in the other operand without doing any extra work.
if (i < c1.length())
result.append(c1, i, LONG_MAX);
if (j < c2.length())
result.append(c2, j, LONG_MAX);
c1 = result;
}
/**
* Given two pairs lists, changes the first in place to represent
* the asymmetric difference of the two sets.
*/
void UnicodeSet::doDifference(UnicodeString& pairs, const UnicodeString& pairs2) {
UnicodeString p2(pairs2);
doComplement(p2);
doIntersection(pairs, p2);
}
/**
* Given two pairs lists, changes the first in place to represent
* the intersection of the two sets.
*/
void UnicodeSet::doIntersection(UnicodeString& c1, const UnicodeString& c2) {
UnicodeString result;
int32_t i = 0;
int32_t j = 0;
int32_t oldI;
int32_t oldJ;
// iterate until we've exhausted one of the operands
while (i < c1.length() && j < c2.length()) {
// advance j until it points to a character that is larger than
// the one i points to. If this is the beginning of a one-
// character range, advance j to point to the end
if (i < c1.length() && i % 2 == 0) {
while (j < c2.length() && c2.charAt(j) < c1.charAt(i))
++j;
if (j < c2.length() && j % 2 == 0 && c2.charAt(j) == c1.charAt(i))
++j;
}
// if j points to the endpoint of a range, save the current
// value of i, then advance i until it reaches a character
// which is larger than the character pointed at
// by j. All of the characters we've advanced over (except
// the one currently pointed to by i) are added to the result
oldI = i;
while (j % 2 == 1 && i < c1.length() && c1.charAt(i) <= c2.charAt(j))
++i;
result.append(c1, oldI, i-oldI);
// if i points to the endpoint of a range, save the current
// value of j, then advance j until it reaches a character
// which is larger than the character pointed at
// by i. All of the characters we've advanced over (except
// the one currently pointed to by i) are added to the result
oldJ = j;
while (i % 2 == 1 && j < c2.length() && c2.charAt(j) <= c1.charAt(i))
++j;
result.append(c2, oldJ, j-oldJ);
// advance i until it points to a character larger than j
// If it points at the beginning of a one-character range,
// advance it to the end of that range
if (j < c2.length() && j % 2 == 0) {
while (i < c1.length() && c1.charAt(i) < c2.charAt(j))
++i;
if (i < c1.length() && i % 2 == 0 && c2.charAt(j) == c1.charAt(i))
++i;
}
}
c1 = result;
}
//----------------------------------------------------------------
// Implementation: Generation of pairs for Unicode categories
//----------------------------------------------------------------
/**
* Returns a pairs string for the given category, given its name.
* The category name must be either a two-letter name, such as
* "Lu", or a one letter name, such as "L". One-letter names
* indicate the logical union of all two-letter names that start
* with that letter. Case is significant. If the name starts
* with the character '^' then the complement of the given
* character set is returned.
*
* Although individual categories such as "Lu" are cached, we do
* not currently cache single-letter categories such as "L" or
* complements such as "^Lu" or "^L". It would be easy to cache
* these as well in a hashtable should the need arise.
*/
UnicodeString& UnicodeSet::getCategoryPairs(UnicodeString& result,
const UnicodeString& catName,
UErrorCode& status) {
if (U_FAILURE(status)) {
return result;
}
// The temporary cat is only really needed if invert is true.
// TO DO: Allocate cat on the heap only if needed.
UnicodeString cat(catName);
bool_t invert = (catName.length() > 1 &&
catName.charAt(0) == '^');
if (invert) {
cat.remove(0, 1);
}
result.remove();
// if we have two characters, search the category map for that
// code and either construct and return a UnicodeSet from the
// data in the category map or throw an exception
if (cat.length() == 2) {
int32_t i = CATEGORY_NAMES.indexOf(cat);
if (i>=0 && i%2==0) {
i /= 2;
result = getCategoryPairs((int8_t)i);
if (!invert) {
return result;
}
}
} else if (cat.length() == 1) {
// if we have one character, search the category map for
// codes beginning with that letter, and union together
// all of the matching sets that we find (or throw an
// exception if there are no matches)
for (int32_t i=0; i<Unicode::GENERAL_TYPES_COUNT; ++i) {
if (CATEGORY_NAMES.charAt(2*i) == cat.charAt(0)) {
const UnicodeString& pairs = getCategoryPairs((int8_t)i);
if (result.length() == 0) {
result = pairs;
} else {
doUnion(result, pairs);
}
}
}
}
if (result.length() == 0) {
status = U_ILLEGAL_ARGUMENT_ERROR;
return result;
}
if (invert) {
doComplement(result);
}
return result;
}
/**
* Returns a pairs string for the given category. This string is
* cached and returned again if this method is called again with
* the same parameter.
*/
const UnicodeString& UnicodeSet::getCategoryPairs(int8_t cat) {
// In order to tell what cache entries are empty, we assume
// every category specifies at least one character. Thus
// pair lists in the cache that are empty are uninitialized.
if (CATEGORY_PAIRS_CACHE[cat].length() == 0) {
// Walk through all Unicode characters, noting the start
// and end of each range for which Character.getType(c)
// returns the given category integer. Since we are
// iterating in order, we can simply append the resulting
// ranges to the pairs string.
UnicodeString& pairs = CATEGORY_PAIRS_CACHE[cat];
int32_t first = -1;
int32_t last = -2;
for (int32_t i=0; i<=0xFFFF; ++i) {
if (Unicode::getType((UChar)i) == cat) {
if ((last+1) == i) {
last = i;
} else {
if (first >= 0) {
pairs.append((UChar)first).append((UChar)last);
}
first = last = i;
}
}
}
if (first >= 0) {
pairs.append((UChar)first).append((UChar)last);
}
}
return CATEGORY_PAIRS_CACHE[cat];
}
//----------------------------------------------------------------
// Implementation: Utility methods
//----------------------------------------------------------------
/**
* Returns the character after the given position, or '\uFFFF' if
* there is none.
*/
UChar UnicodeSet::charAfter(const UnicodeString& str, int32_t i) {
return ((++i) < str.length()) ? str.charAt(i) : (UChar)0xFFFF;
}
/**
* TEMPORARY WORKAROUND UNTIL Unicode::digit() exists.
* Return the digit value of the given UChar, or -1. The radix
* value is ignored for now and hardcoded as 16.
*/
int8_t UnicodeSet::digit(UChar c, int8_t radix) {
int32_t d = Unicode::digitValue(c);
if (d < 0) {
if (c >= (UChar)'a' && c <= (UChar)'f') {
d = c - (UChar)('a' - 10);
} else if (c >= (UChar)'A' && c <= (UChar)'F') {
d = c - (UChar)('A' - 10);
}
}
return (int8_t)d;
}
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