LSR.java
// © 2017 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
package com.ibm.icu.impl.locale;
import com.ibm.icu.lang.UCharacter;
import com.ibm.icu.lang.UProperty;
import com.ibm.icu.lang.UScript;
import java.util.HashMap;
import java.util.List;
import java.util.Objects;
public final class LSR {
public static final int REGION_INDEX_LIMIT = 1001 + 26 * 26;
public static final int EXPLICIT_LSR = 7;
public static final int EXPLICIT_LANGUAGE = 4;
public static final int EXPLICIT_SCRIPT = 2;
public static final int EXPLICIT_REGION = 1;
public static final int IMPLICIT_LSR = 0;
public static final int DONT_CARE_FLAGS = 0;
public static final boolean DEBUG_OUTPUT = false;
public final String language;
public final String script;
public final String region;
/** Index for region, negative if ill-formed. @see indexForRegion */
final int regionIndex;
public final int flags;
public LSR(String language, String script, String region, int flags) {
this.language = language;
this.script = script;
this.region = region;
regionIndex = indexForRegion(region);
this.flags = flags;
}
/**
* Returns a positive index (>0) for a well-formed region code. Do not rely on a particular
* region->index mapping; it may change. Returns 0 for ill-formed strings.
*/
public static final int indexForRegion(String region) {
if (region.length() == 2) {
int a = region.charAt(0) - 'A';
if (a < 0 || 25 < a) {
return 0;
}
int b = region.charAt(1) - 'A';
if (b < 0 || 25 < b) {
return 0;
}
return 26 * a + b + 1001;
} else if (region.length() == 3) {
int a = region.charAt(0) - '0';
if (a < 0 || 9 < a) {
return 0;
}
int b = region.charAt(1) - '0';
if (b < 0 || 9 < b) {
return 0;
}
int c = region.charAt(2) - '0';
if (c < 0 || 9 < c) {
return 0;
}
return (10 * a + b) * 10 + c + 1;
}
return 0;
}
@Override
public String toString() {
StringBuilder result = new StringBuilder(language);
if (!script.isEmpty()) {
result.append('-').append(script);
}
if (!region.isEmpty()) {
result.append('-').append(region);
}
return result.toString();
}
public boolean isEquivalentTo(LSR other) {
return language.equals(other.language)
&& script.equals(other.script)
&& region.equals(other.region);
}
@Override
public boolean equals(Object obj) {
LSR other;
return this == obj
|| (obj != null
&& obj.getClass() == this.getClass()
&& language.equals((other = (LSR) obj).language)
&& script.equals(other.script)
&& region.equals(other.region)
&& flags == other.flags);
}
@Override
public int hashCode() {
return Objects.hash(language, script, region, flags);
}
// This method is added only to support encodeToIntForResource()
// It only support [a-z]{2,3} and will not work for other cases.
private int encodeLanguageToInt() {
assert language.length() >= 2;
assert language.length() <= 3;
assert language.charAt(0) >= 'a';
assert language.charAt(0) <= 'z';
assert language.charAt(1) >= 'a';
assert language.charAt(1) <= 'z';
assert language.length() == 2 || language.charAt(2) >= 'a';
assert language.length() == 2 || language.charAt(2) <= 'z';
return language.charAt(0)
- 'a'
+ 1
+ 27 * (language.charAt(1) - 'a' + 1)
+ ((language.length() == 2) ? 0 : 27 * 27 * (language.charAt(2) - 'a' + 1));
}
// This method is added only to support encodeToIntForResource()
// It only support [A-Z][a-z]{3} which defined in UScript and does not work for other cases.
private int encodeScriptToInt() {
int ret = UScript.getCodeFromName(script);
assert ret != UScript.INVALID_CODE;
return ret;
}
// This method is added only to support encodeToIntForResource()
// It only support [A-Z]{2} and the code in m49 but does not work for other cases.
private int encodeRegionToInt(List<String> m49) {
assert region.length() >= 2;
assert region.length() <= 3;
if (region.length() == 3) {
int index = m49.indexOf(region);
assert index >= 0;
if (index < 0) {
throw new IllegalStateException(
"Please add '" + region + "' to M49 in LocaleDistanceMapper.java");
}
return index;
}
assert region.charAt(0) >= 'A';
assert region.charAt(0) <= 'Z';
assert region.charAt(1) >= 'A';
assert region.charAt(1) <= 'Z';
// 'AA' => 1+27*1 = 28
// ...
// 'AZ' => 1+27*26 = 703
// 'BA' => 2+27*1 = 29
// ...
// 'IN' => 9+27*14 = 387
// 'ZZ' => 26+27*26 = 728
return (region.charAt(0) - 'A' + 1) + 27 * (region.charAt(1) - 'A' + 1);
}
// This is designed to only support encoding some LSR into resources but not for other cases.
public int encodeToIntForResource(List<String> m49) {
return (encodeLanguageToInt() + (27 * 27 * 27) * encodeRegionToInt(m49))
| (encodeScriptToInt() << 24);
}
/**
* CachedDecoder uses string pools to reduce memory needed for creating strings representing
* lang, region and script.
*/
private static class CachedDecoder {
private static final String[] DECODED_ZERO =
new String[] {/* lang= */ "", /* script= */ "", /* region= */ ""};
private static final String[] DECODED_ONE =
new String[] {/* lang= */ "skip", /* script= */ "script", /* region= */ ""};
// Use local string pools instead of String.intern(), because a java runtime may put
// interned
// string into the GC root, and never get released if ICU4J needs to be unloaded.
// String.intern() could also be slower than a simple java.util.HashMap.
private final HashMap<Integer, String> langsCache;
private final HashMap<Integer, String> scriptsCache;
private final HashMap<Integer, String> regionsCache;
private final String[] m49;
CachedDecoder(String[] m49) {
int estLangCacheCapacity = 556; // ~= LocaleIDs._languages.length
langsCache = new HashMap<>(estLangCacheCapacity);
scriptsCache = new HashMap<>(UCharacter.getIntPropertyMaxValue(UProperty.SCRIPT));
int estRegionCacheCapacity = 253; // ~= LocaleIDs._countries.length
regionsCache = new HashMap<>(estRegionCacheCapacity);
this.m49 = m49;
}
/**
* @return a String[3] object where the first element is a language code, the second element
* is a script code, and the third element is a region code.
*/
String[] decode(int encoded) {
if (encoded == 0) {
return DECODED_ZERO;
}
if (encoded == 1) {
return DECODED_ONE;
}
int encodedLang = encoded & 0x00ffffff;
encodedLang %= 27 * 27 * 27;
String lang = langsCache.computeIfAbsent(encodedLang, CachedDecoder::toLanguage);
int encodedScript = (encoded >> 24) & 0x000000ff;
String script = scriptsCache.computeIfAbsent(encodedScript, UScript::getShortName);
int encodedRegion = encoded & 0x00ffffff;
encodedRegion /= 27 * 27 * 27;
encodedRegion %= 27 * 27;
String region;
if (encodedRegion < 27) {
region = m49[encodedRegion];
} else {
region = regionsCache.computeIfAbsent(encodedRegion, CachedDecoder::toRegion);
}
return new String[] {lang, script, region};
}
private static String toLanguage(int encoded) {
StringBuilder res = new StringBuilder(3);
res.append((char) ('a' + ((encoded % 27) - 1)));
res.append((char) ('a' + (((encoded / 27) % 27) - 1)));
if (encoded / (27 * 27) != 0) {
res.append((char) ('a' + ((encoded / (27 * 27)) - 1)));
}
return res.toString();
}
private static String toRegion(int encoded) {
StringBuilder res = new StringBuilder(3);
res.append((char) ('A' + ((encoded % 27) - 1)));
res.append((char) ('A' + (((encoded / 27) % 27) - 1)));
return res.toString();
}
}
public static LSR[] decodeInts(int[] nums, String[] m49) {
LSR[] lsrs = new LSR[nums.length];
// The decoder uses string pools to reduce memory impact.
// At least 7k LSR instances are created from this path.
CachedDecoder decoder = new CachedDecoder(m49);
for (int i = 0; i < nums.length; ++i) {
int encoded = nums[i];
String[] lsrStrings = decoder.decode(encoded);
lsrs[i] = new LSR(lsrStrings[0], lsrStrings[1], lsrStrings[2], LSR.IMPLICIT_LSR);
}
return lsrs;
}
}