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With inspiration from other libraries
// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html#License
/*
******************************************************************************
*
* Copyright (C) 2009-2015, International Business Machines
* Corporation and others. All Rights Reserved.
*
******************************************************************************
*/
package com.ibm.icu.impl;
import com.ibm.icu.text.UnicodeSet.SpanCondition;
import com.ibm.icu.util.OutputInt;
/**
* Helper class for frozen UnicodeSets, implements contains() and span() optimized for BMP code points.
*
* Latin-1: Look up bytes.
* 2-byte characters: Bits organized vertically.
* 3-byte characters: Use zero/one/mixed data per 64-block in U+0000..U+FFFF, with mixed for illegal ranges.
* Supplementary characters: Binary search over
* the supplementary part of the parent set's inversion list.
*/
public final class BMPSet {
public static int U16_SURROGATE_OFFSET = ((0xd800 << 10) + 0xdc00 - 0x10000);
/**
* One boolean ('true' or 'false') per Latin-1 character.
*/
private boolean[] latin1Contains;
/**
* One bit per code point from U+0000..U+07FF. The bits are organized vertically; consecutive code points
* correspond to the same bit positions in consecutive table words. With code point parts lead=c{10..6}
* trail=c{5..0} it is set.contains(c)==(table7FF[trail] bit lead)
*
* Bits for 0..FF are unused (0).
*/
private int[] table7FF;
/**
* One bit per 64 BMP code points. The bits are organized vertically; consecutive 64-code point blocks
* correspond to the same bit position in consecutive table words. With code point parts lead=c{15..12}
* t1=c{11..6} test bits (lead+16) and lead in bmpBlockBits[t1]. If the upper bit is 0, then the lower bit
* indicates if contains(c) for all code points in the 64-block. If the upper bit is 1, then the block is mixed
* and set.contains(c) must be called.
*
* Bits for 0..7FF are unused (0).
*/
private int[] bmpBlockBits;
/**
* Inversion list indexes for restricted binary searches in findCodePoint(), from findCodePoint(U+0800, U+1000,
* U+2000, .., U+F000, U+10000). U+0800 is the first 3-byte-UTF-8 code point. Code points below U+0800 are
* always looked up in the bit tables. The last pair of indexes is for finding supplementary code points.
*/
private int[] list4kStarts;
/**
* The inversion list of the parent set, for the slower contains() implementation for mixed BMP blocks and for
* supplementary code points. The list is terminated with list[listLength-1]=0x110000.
*/
private final int[] list;
private final int listLength; // length used; list may be longer to minimize reallocs
public BMPSet(final int[] parentList, int parentListLength) {
list = parentList;
listLength = parentListLength;
latin1Contains = new boolean[0x100];
table7FF = new int[64];
bmpBlockBits = new int[64];
list4kStarts = new int[18];
/*
* Set the list indexes for binary searches for U+0800, U+1000, U+2000, .., U+F000, U+10000. U+0800 is the
* first 3-byte-UTF-8 code point. Lower code points are looked up in the bit tables. The last pair of
* indexes is for finding supplementary code points.
*/
list4kStarts[0] = findCodePoint(0x800, 0, listLength - 1);
int i;
for (i = 1; i <= 0x10; ++i) {
list4kStarts[i] = findCodePoint(i << 12, list4kStarts[i - 1], listLength - 1);
}
list4kStarts[0x11] = listLength - 1;
initBits();
}
public BMPSet(final BMPSet otherBMPSet, final int[] newParentList, int newParentListLength) {
list = newParentList;
listLength = newParentListLength;
latin1Contains = otherBMPSet.latin1Contains.clone();
table7FF = otherBMPSet.table7FF.clone();
bmpBlockBits = otherBMPSet.bmpBlockBits.clone();
list4kStarts = otherBMPSet.list4kStarts.clone();
}
public boolean contains(int c) {
if (c <= 0xff) {
return (latin1Contains[c]);
} else if (c <= 0x7ff) {
return ((table7FF[c & 0x3f] & (1 << (c >> 6))) != 0);
} else if (c < 0xd800 || (c >= 0xe000 && c <= 0xffff)) {
int lead = c >> 12;
int twoBits = (bmpBlockBits[(c >> 6) & 0x3f] >> lead) & 0x10001;
if (twoBits <= 1) {
// All 64 code points with the same bits 15..6
// are either in the set or not.
return (0 != twoBits);
} else {
// Look up the code point in its 4k block of code points.
return containsSlow(c, list4kStarts[lead], list4kStarts[lead + 1]);
}
} else if (c <= 0x10ffff) {
// surrogate or supplementary code point
return containsSlow(c, list4kStarts[0xd], list4kStarts[0x11]);
} else {
// Out-of-range code points get false, consistent with long-standing
// behavior of UnicodeSet.contains(c).
return false;
}
}
/**
* Span the initial substring for which each character c has spanCondition==contains(c). It must be
* spanCondition==0 or 1.
*
* @param start The start index
* @param outCount If not null: Receives the number of code points in the span.
* @return the limit (exclusive end) of the span
*
* NOTE: to reduce the overhead of function call to contains(c), it is manually inlined here. Check for
* sufficient length for trail unit for each surrogate pair. Handle single surrogates as surrogate code points
* as usual in ICU.
*/
public final int span(CharSequence s, int start, SpanCondition spanCondition,
OutputInt outCount) {
char c, c2;
int i = start;
int limit = s.length();
int numSupplementary = 0;
if (SpanCondition.NOT_CONTAINED != spanCondition) {
// span
while (i < limit) {
c = s.charAt(i);
if (c <= 0xff) {
if (!latin1Contains[c]) {
break;
}
} else if (c <= 0x7ff) {
if ((table7FF[c & 0x3f] & (1 << (c >> 6))) == 0) {
break;
}
} else if (c < 0xd800 ||
c >= 0xdc00 || (i + 1) == limit || (c2 = s.charAt(i + 1)) < 0xdc00 || c2 >= 0xe000) {
int lead = c >> 12;
int twoBits = (bmpBlockBits[(c >> 6) & 0x3f] >> lead) & 0x10001;
if (twoBits <= 1) {
// All 64 code points with the same bits 15..6
// are either in the set or not.
if (twoBits == 0) {
break;
}
} else {
// Look up the code point in its 4k block of code points.
if (!containsSlow(c, list4kStarts[lead], list4kStarts[lead + 1])) {
break;
}
}
} else {
// surrogate pair
int supplementary = Character.toCodePoint(c, c2);
if (!containsSlow(supplementary, list4kStarts[0x10], list4kStarts[0x11])) {
break;
}
++numSupplementary;
++i;
}
++i;
}
} else {
// span not
while (i < limit) {
c = s.charAt(i);
if (c <= 0xff) {
if (latin1Contains[c]) {
break;
}
} else if (c <= 0x7ff) {
if ((table7FF[c & 0x3f] & (1 << (c >> 6))) != 0) {
break;
}
} else if (c < 0xd800 ||
c >= 0xdc00 || (i + 1) == limit || (c2 = s.charAt(i + 1)) < 0xdc00 || c2 >= 0xe000) {
int lead = c >> 12;
int twoBits = (bmpBlockBits[(c >> 6) & 0x3f] >> lead) & 0x10001;
if (twoBits <= 1) {
// All 64 code points with the same bits 15..6
// are either in the set or not.
if (twoBits != 0) {
break;
}
} else {
// Look up the code point in its 4k block of code points.
if (containsSlow(c, list4kStarts[lead], list4kStarts[lead + 1])) {
break;
}
}
} else {
// surrogate pair
int supplementary = Character.toCodePoint(c, c2);
if (containsSlow(supplementary, list4kStarts[0x10], list4kStarts[0x11])) {
break;
}
++numSupplementary;
++i;
}
++i;
}
}
if (outCount != null) {
int spanLength = i - start;
outCount.value = spanLength - numSupplementary; // number of code points
}
return i;
}
/**
* Symmetrical with span().
* Span the trailing substring for which each character c has spanCondition==contains(c). It must be s.length >=
* limit and spanCondition==0 or 1.
*
* @return The string index which starts the span (i.e. inclusive).
*/
public final int spanBack(CharSequence s, int limit, SpanCondition spanCondition) {
char c, c2;
if (SpanCondition.NOT_CONTAINED != spanCondition) {
// span
for (;;) {
c = s.charAt(--limit);
if (c <= 0xff) {
if (!latin1Contains[c]) {
break;
}
} else if (c <= 0x7ff) {
if ((table7FF[c & 0x3f] & (1 << (c >> 6))) == 0) {
break;
}
} else if (c < 0xd800 ||
c < 0xdc00 || 0 == limit || (c2 = s.charAt(limit - 1)) < 0xd800 || c2 >= 0xdc00) {
int lead = c >> 12;
int twoBits = (bmpBlockBits[(c >> 6) & 0x3f] >> lead) & 0x10001;
if (twoBits <= 1) {
// All 64 code points with the same bits 15..6
// are either in the set or not.
if (twoBits == 0) {
break;
}
} else {
// Look up the code point in its 4k block of code points.
if (!containsSlow(c, list4kStarts[lead], list4kStarts[lead + 1])) {
break;
}
}
} else {
// surrogate pair
int supplementary = Character.toCodePoint(c2, c);
if (!containsSlow(supplementary, list4kStarts[0x10], list4kStarts[0x11])) {
break;
}
--limit;
}
if (0 == limit) {
return 0;
}
}
} else {
// span not
for (;;) {
c = s.charAt(--limit);
if (c <= 0xff) {
if (latin1Contains[c]) {
break;
}
} else if (c <= 0x7ff) {
if ((table7FF[c & 0x3f] & (1 << (c >> 6))) != 0) {
break;
}
} else if (c < 0xd800 ||
c < 0xdc00 || 0 == limit || (c2 = s.charAt(limit - 1)) < 0xd800 || c2 >= 0xdc00) {
int lead = c >> 12;
int twoBits = (bmpBlockBits[(c >> 6) & 0x3f] >> lead) & 0x10001;
if (twoBits <= 1) {
// All 64 code points with the same bits 15..6
// are either in the set or not.
if (twoBits != 0) {
break;
}
} else {
// Look up the code point in its 4k block of code points.
if (containsSlow(c, list4kStarts[lead], list4kStarts[lead + 1])) {
break;
}
}
} else {
// surrogate pair
int supplementary = Character.toCodePoint(c2, c);
if (containsSlow(supplementary, list4kStarts[0x10], list4kStarts[0x11])) {
break;
}
--limit;
}
if (0 == limit) {
return 0;
}
}
}
return limit + 1;
}
/**
* Set bits in a bit rectangle in "vertical" bit organization. start> 6; // Named for UTF-8 2-byte lead byte with upper 5 bits.
int trail = start & 0x3f; // Named for UTF-8 2-byte trail byte with lower 6 bits.
// Set one bit indicating an all-one block.
int bits = 1 << lead;
if ((start + 1) == limit) { // Single-character shortcut.
table[trail] |= bits;
return;
}
int limitLead = limit >> 6;
int limitTrail = limit & 0x3f;
if (lead == limitLead) {
// Partial vertical bit column.
while (trail < limitTrail) {
table[trail++] |= bits;
}
} else {
// Partial vertical bit column,
// followed by a bit rectangle,
// followed by another partial vertical bit column.
if (trail > 0) {
do {
table[trail++] |= bits;
} while (trail < 64);
++lead;
}
if (lead < limitLead) {
bits = ~((1 << lead) - 1);
if (limitLead < 0x20) {
bits &= (1 << limitLead) - 1;
}
for (trail = 0; trail < 64; ++trail) {
table[trail] |= bits;
}
}
// limit<=0x800. If limit==0x800 then limitLead=32 and limitTrail=0.
// In that case, bits=1<= 0x100) {
break;
}
do {
latin1Contains[start++] = true;
} while (start < limit && start < 0x100);
} while (limit <= 0x100);
// Set table7FF[].
while (start < 0x800) {
set32x64Bits(table7FF, start, limit <= 0x800 ? limit : 0x800);
if (limit > 0x800) {
start = 0x800;
break;
}
start = list[listIndex++];
if (listIndex < listLength) {
limit = list[listIndex++];
} else {
limit = 0x110000;
}
}
// Set bmpBlockBits[].
int minStart = 0x800;
while (start < 0x10000) {
if (limit > 0x10000) {
limit = 0x10000;
}
if (start < minStart) {
start = minStart;
}
if (start < limit) { // Else: Another range entirely in a known mixed-value block.
if (0 != (start & 0x3f)) {
// Mixed-value block of 64 code points.
start >>= 6;
bmpBlockBits[start & 0x3f] |= 0x10001 << (start >> 6);
start = (start + 1) << 6; // Round up to the next block boundary.
minStart = start; // Ignore further ranges in this block.
}
if (start < limit) {
if (start < (limit & ~0x3f)) {
// Multiple all-ones blocks of 64 code points each.
set32x64Bits(bmpBlockBits, start >> 6, limit >> 6);
}
if (0 != (limit & 0x3f)) {
// Mixed-value block of 64 code points.
limit >>= 6;
bmpBlockBits[limit & 0x3f] |= 0x10001 << (limit >> 6);
limit = (limit + 1) << 6; // Round up to the next block boundary.
minStart = limit; // Ignore further ranges in this block.
}
}
}
if (limit == 0x10000) {
break;
}
start = list[listIndex++];
if (listIndex < listLength) {
limit = list[listIndex++];
} else {
limit = 0x110000;
}
}
}
/**
* Same as UnicodeSet.findCodePoint(int c) except that the binary search is restricted for finding code
* points in a certain range.
*
* For restricting the search for finding in the range start..end, pass in lo=findCodePoint(start) and
* hi=findCodePoint(end) with 0<=lo<=hi= hi || c >= list[hi - 1])
return hi;
// invariant: c >= list[lo]
// invariant: c < list[hi]
for (;;) {
int i = (lo + hi) >>> 1;
if (i == lo) {
break; // Found!
} else if (c < list[i]) {
hi = i;
} else {
lo = i;
}
}
return hi;
}
private final boolean containsSlow(int c, int lo, int hi) {
return (0 != (findCodePoint(c, lo, hi) & 1));
}
}