scuffed-code/icu4c/source/i18n/unirange.cpp
2001-08-23 01:06:08 +00:00

112 lines
3.1 KiB
C++

/*
**********************************************************************
* Copyright (C) 1999, International Business Machines
* Corporation and others. All Rights Reserved.
**********************************************************************
* Date Name Description
* 11/17/99 aliu Creation.
**********************************************************************
*/
#include "unirange.h"
#include "uvector.h"
#include "unicode/unistr.h"
UnicodeRange::UnicodeRange(UChar theStart, int32_t theLength) {
start = theStart;
length = theLength;
}
UnicodeRange* UnicodeRange::clone() const {
return new UnicodeRange(start, length);
}
/**
* CALLER OWNS RESULT.
*/
UBool UnicodeRange::contains(UChar c) const {
return c >= start && (c - start) < length;
}
/**
* Assume that contains(c) is true. Split this range into two new
* ranges around the character c. Make this range one of the new ranges
* (modify it in place) and return the other new range. The character
* itself is not included in either range. If the split results in an
* empty range (that is, if c == start or c == start + length - 1) then
* return null.
*
* MODIFIES THIS RANGE IN PLACE.
*
* CALLER OWNS RESULT.
*/
UnicodeRange* UnicodeRange::split(UChar c) {
if (c == start) {
++start;
--length;
return 0;
} else if (c - start == length - 1) {
--length;
return 0;
} else {
++c;
UnicodeRange* r = new UnicodeRange(c, start + length - c);
length = --c - start;
return r;
}
}
/**
* Finds the largest unused subrange by the given string. A
* subrange is unused by a string if the string contains no
* characters in that range. If the given string contains no
* characters in this range, then this range itself is
* returned.
*
* CALLER OWNS RESULT.
*/
UnicodeRange*
UnicodeRange::largestUnusedSubrange(const UnicodeString& str, UErrorCode &status) const {
int32_t n = str.length();
UVector v(status);
if (U_FAILURE(status)) {
return NULL;
}
v.setDeleter(UnicodeRange::deleter);
v.addElement(clone(), status);
for (int32_t i=0; i<n; ++i) {
UChar c = str.charAt(i);
if (contains(c)) {
for (int32_t j=0; j<v.size(); ++j) {
UnicodeRange* r = (UnicodeRange*) v.elementAt(j);
if (r->contains(c)) {
r = r->split(c);
if (r != 0) {
v.addElement(r, status);
}
break;
}
}
}
}
UnicodeRange* bestRange = 0;
int32_t ibest = -1;
for (int32_t j=0; j<v.size(); ++j) {
UnicodeRange* r = (UnicodeRange*) v.elementAt(j);
if (bestRange == 0 || r->length > bestRange->length) {
bestRange = r;
ibest = j;
}
}
v.orphanElementAt(ibest); // So bestRange doesn't get deleted
return bestRange;
}
// For UVector of UnicodeRange* objects
void U_CALLCONV UnicodeRange::deleter(void* e) {
delete (UnicodeRange*) e;
}