| /* |
| ********************************************************************** |
| * Copyright (C) 1999, International Business Machines |
| * Corporation and others. All Rights Reserved. |
| ********************************************************************** |
| * Date Name Description |
| * 11/17/99 aliu Creation. |
| ********************************************************************** |
| */ |
| #include "rbt_set.h" |
| #include "rbt_rule.h" |
| #include "unicode/unistr.h" |
| |
| /* Note: There was an old implementation that indexed by first letter of |
| * key. Problem with this is that key may not have a meaningful first |
| * letter; e.g., {Lu}>*. One solution is to keep a separate vector of all |
| * rules whose intial key letter is a category variable. However, the |
| * problem is that they must be kept in order with respect to other rules. |
| * One solution -- add a sequence number to each rule. Do the usual |
| * first-letter lookup, and also a lookup from the spare bin with rules like |
| * {Lu}>*. Take the lower sequence number. This seems complex and not |
| * worth the trouble, but we may revisit this later. For documentation (or |
| * possible resurrection) the old code is included below, commented out |
| * with the remark "// OLD INDEXED IMPLEMENTATION". Under the old |
| * implementation, <code>rules</code> is a Hashtable, not a Vector. |
| */ |
| |
| /** |
| * Construct a new empty rule set. |
| */ |
| TransliterationRuleSet::TransliterationRuleSet() { |
| maxContextLength = 0; |
| ruleVector = new UVector(); |
| rules = NULL; |
| } |
| |
| /** |
| * Destructor. |
| */ |
| TransliterationRuleSet::~TransliterationRuleSet() { |
| delete ruleVector; |
| delete[] rules; |
| } |
| |
| /** |
| * Return the maximum context length. |
| * @return the length of the longest preceding context. |
| */ |
| int32_t TransliterationRuleSet::getMaximumContextLength(void) const { |
| return maxContextLength; |
| } |
| |
| /** |
| * Add a rule to this set. Rules are added in order, and order is |
| * significant. |
| * |
| * <p>Once freeze() is called, this method must not be called. |
| * @param adoptedRule the rule to add |
| */ |
| void TransliterationRuleSet::addRule(TransliterationRule* adoptedRule, |
| UErrorCode& status) { |
| if (U_FAILURE(status)) { |
| delete adoptedRule; |
| return; |
| } |
| if (ruleVector == NULL) { |
| // throw new IllegalArgumentException("Cannot add rules after freezing"); |
| status = U_ILLEGAL_ARGUMENT_ERROR; |
| delete adoptedRule; |
| return; |
| } |
| ruleVector->addElement(adoptedRule); |
| |
| int32_t len; |
| if ((len = adoptedRule->getAnteContextLength()) > maxContextLength) { |
| maxContextLength = len; |
| } |
| } |
| |
| /** |
| * Close this rule set to further additions, check it for masked rules, |
| * and index it to optimize performance. Once this method is called, |
| * addRule() can no longer be called. |
| * @exception IllegalArgumentException if some rules are masked |
| */ |
| void TransliterationRuleSet::freeze(const TransliterationRuleData& data, |
| UErrorCode& status) { |
| if (U_FAILURE(status)) { |
| return; |
| } |
| |
| /* Construct the rule array and index table. We reorder the |
| * rules by sorting them into 256 bins. Each bin contains all |
| * rules matching the index value for that bin. A rule |
| * matches an index value if string whose first key character |
| * has a low byte equal to the index value can match the rule. |
| * |
| * Each bin contains zero or more rules, in the same order |
| * they were found originally. However, the total rules in |
| * the bins may exceed the number in the original vector, |
| * since rules that have a variable as their first key |
| * character will generally fall into more than one bin. |
| * |
| * That is, each bin contains all rules that either have that |
| * first index value as their first key character, or have |
| * a set containing the index value as their first character. |
| */ |
| int32_t n = ruleVector->size(); |
| int32_t j; |
| int16_t x; |
| UVector v(2*n); // heuristic; adjust as needed |
| |
| /* Precompute the index values. This saves a LOT of time. |
| */ |
| int16_t* indexValue = new int16_t[n]; |
| for (j=0; j<n; ++j) { |
| TransliterationRule* r = (TransliterationRule*) ruleVector->elementAt(j); |
| indexValue[j] = r->getIndexValue(data); |
| } |
| for (x=0; x<256; ++x) { |
| index[x] = v.size(); |
| for (j=0; j<n; ++j) { |
| if (indexValue[j] >= 0) { |
| if (indexValue[j] == x) { |
| v.addElement(ruleVector->elementAt(j)); |
| } |
| } else { |
| // If the indexValue is < 0, then the first key character is |
| // a set, and we must use the more time-consuming |
| // matchesIndexValue check. In practice this happens |
| // rarely, so we seldom tread this code path. |
| TransliterationRule* r = (TransliterationRule*) ruleVector->elementAt(j); |
| if (r->matchesIndexValue((uint8_t)x, data)) { |
| v.addElement(r); |
| } |
| } |
| } |
| } |
| delete[] indexValue; |
| index[256] = v.size(); |
| |
| /* Freeze things into an array. |
| */ |
| rules = new TransliterationRule*[v.size()]; |
| for (j=0; j<v.size(); ++j) { |
| rules[j] = (TransliterationRule*) v.elementAt(j); |
| } |
| delete ruleVector; |
| ruleVector = NULL; |
| |
| // TODO Add error reporting that indicates the rules that |
| // are being masked. |
| //UnicodeString errors; |
| |
| /* Check for masking. This is MUCH faster than our old check, |
| * which was each rule against each following rule, since we |
| * only have to check for masking within each bin now. It's |
| * 256*O(n2^2) instead of O(n1^2), where n1 is the total rule |
| * count, and n2 is the per-bin rule count. But n2<<n1, so |
| * it's a big win. |
| */ |
| for (x=0; x<256; ++x) { |
| for (j=index[x]; j<index[x+1]-1; ++j) { |
| TransliterationRule* r1 = rules[j]; |
| for (int32_t k=j+1; k<index[x+1]; ++k) { |
| TransliterationRule* r2 = rules[k]; |
| if (r1->masks(*r2)) { |
| //| if (errors == null) { |
| //| errors = new StringBuffer(); |
| //| } else { |
| //| errors.append("\n"); |
| //| } |
| //| errors.append("Rule " + r1 + " masks " + r2); |
| status = U_ILLEGAL_ARGUMENT_ERROR; |
| return; |
| } |
| } |
| } |
| } |
| |
| //if (errors != null) { |
| // throw new IllegalArgumentException(errors.toString()); |
| //} |
| } |
| |
| /** |
| * Attempt to find a matching rule at the specified point in the text. |
| * @param text the text, both translated and untranslated |
| * @param start the beginning index, inclusive; <code>0 <= start |
| * <= limit</code>. |
| * @param limit the ending index, exclusive; <code>start <= limit |
| * <= text.length()</code>. |
| * @param cursor position at which to translate next, representing offset |
| * into text. This value must be between <code>start</code> and |
| * <code>limit</code>. |
| * @param data a dictionary mapping variables to the sets they |
| * represent (maps <code>Character</code> to <code>UnicodeSet</code>) |
| * @param filter the filter. Any character for which |
| * <tt>filter.contains()</tt> returns <tt>false</tt> will not be |
| * altered by this transliterator. If <tt>filter</tt> is |
| * <tt>null</tt> then no filtering is applied. |
| * @return the matching rule, or null if none found. |
| */ |
| TransliterationRule* |
| TransliterationRuleSet::findMatch(const Replaceable& text, |
| const UTransPosition& pos, |
| const TransliterationRuleData& data, |
| const UnicodeFilter* filter) const { |
| /* We only need to check our indexed bin of the rule table, |
| * based on the low byte of the first key character. |
| */ |
| int16_t x = text.charAt(pos.start) & 0xFF; |
| for (int32_t i=index[x]; i<index[x+1]; ++i) { |
| if (rules[i]->matches(text, pos, data, filter)) { |
| return rules[i]; |
| } |
| } |
| return NULL; |
| } |
| |
| /** |
| * Attempt to find a matching rule at the specified point in the text. |
| * Unlike <code>findMatch()</code>, this method does an incremental match. |
| * An incremental match requires that there be no partial matches that might |
| * pre-empt the full match that is found. If there are partial matches, |
| * then null is returned. A non-null result indicates that a full match has |
| * been found, and that it cannot be pre-empted by a partial match |
| * regardless of what additional text is added to the translation buffer. |
| * @param text the text, both translated and untranslated |
| * @param start the beginning index, inclusive; <code>0 <= start |
| * <= limit</code>. |
| * @param limit the ending index, exclusive; <code>start <= limit |
| * <= text.length()</code>. |
| * @param cursor position at which to translate next, representing offset |
| * into text. This value must be between <code>start</code> and |
| * <code>limit</code>. |
| * @param data a dictionary mapping variables to the sets they |
| * represent (maps <code>Character</code> to <code>UnicodeSet</code>) |
| * @param partial output parameter. <code>partial[0]</code> is set to |
| * true if a partial match is returned. |
| * @param filter the filter. Any character for which |
| * <tt>filter.contains()</tt> returns <tt>false</tt> will not be |
| * altered by this transliterator. If <tt>filter</tt> is |
| * <tt>null</tt> then no filtering is applied. |
| * @return the matching rule, or null if none found, or if the text buffer |
| * does not have enough text yet to unambiguously match a rule. |
| */ |
| TransliterationRule* |
| TransliterationRuleSet::findIncrementalMatch(const Replaceable& text, |
| const UTransPosition& pos, |
| const TransliterationRuleData& data, |
| UBool& isPartial, |
| const UnicodeFilter* filter) const { |
| |
| /* We only need to check our indexed bin of the rule table, |
| * based on the low byte of the first key character. |
| */ |
| isPartial = FALSE; |
| int16_t x = text.charAt(pos.start) & 0xFF; |
| for (int32_t i=index[x]; i<index[x+1]; ++i) { |
| int32_t match = rules[i]->getMatchDegree(text, pos, data, filter); |
| switch (match) { |
| case TransliterationRule::FULL_MATCH: |
| return rules[i]; |
| case TransliterationRule::PARTIAL_MATCH: |
| isPartial = TRUE; |
| return NULL; |
| } |
| } |
| return NULL; |
| } |