openharmony/third_party_qrcodegen
1
0
Fork 0
mirror of https://github.com/openharmony/third_party_qrcodegen.git synced 2026-07-01 23:34:05 -04:00
Code Issues Packages Projects Releases Wiki Activity

Refactored logic in QrTemplate and ReedSolomonGenerator into new Memozier class.

Browse Source
This commit is contained in:
Project Nayuki
2019-07-20 19:12:00 +00:00
parent df55fd6504
commit f8f01c4d4e
4 changed files with 94 additions and 102 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/io/nayuki/fastqrcodegen/Memoizer.java
+88
View File
@@ -0,0 +1,88 @@
/*
* Fast QR Code generator library
*
* Copyright (c) Project Nayuki. (MIT License)
* https://www.nayuki.io/page/fast-qr-code-generator-library
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
* - The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
* - The Software is provided "as is", without warranty of any kind, express or
* implied, including but not limited to the warranties of merchantability,
* fitness for a particular purpose and noninfringement. In no event shall the
* authors or copyright holders be liable for any claim, damages or other
* liability, whether in an action of contract, tort or otherwise, arising from,
* out of or in connection with the Software or the use or other dealings in the
* Software.
*/
package io.nayuki.fastqrcodegen;
import java.lang.ref.SoftReference;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.function.Function;
// A thread-safe cache based on soft references.
final class Memoizer<T,R> {
private final Function<T,R> function;
private Map<T,SoftReference<R>> cache = new HashMap<>();
private Set<T> pending = new HashSet<>();
// Creates a memoizer based on the given function that takes one input to compute an output.
public Memoizer(Function<T,R> func) {
function = func;
}
// Computes function.apply(arg) or returns a cached copy of a previous call.
public R get(T arg) {
while (true) {
synchronized(this) {
if (cache.containsKey(arg)) {
SoftReference<R> ref = cache.get(arg);
R result = ref.get();
if (result != null)
return result;
cache.remove(arg);
}
// Now cache.containsKey(arg) == false
if (!pending.contains(arg)) {
pending.add(arg);
break;
}
try {
this.wait();
} catch (InterruptedException e) {
throw new RuntimeException(e);
}
}
}
try {
R result = function.apply(arg);
synchronized(this) {
cache.put(arg, new SoftReference<>(result));
}
return result;
} finally {
synchronized(this) {
pending.remove(arg);
this.notifyAll();
}
}
}
}
src/io/nayuki/fastqrcodegen/QrCode.java
+2 -2
View File
@@ -248,7 +248,7 @@ public final class QrCode {
errorCorrectionLevel = Objects.requireNonNull(ecl);
Objects.requireNonNull(dataCodewords);
QrTemplate tpl = QrTemplate.getInstance(ver);
QrTemplate tpl = QrTemplate.MEMOIZER.get(ver);
modules = tpl.template.clone();
// Compute ECC, draw modules, do masking
@@ -407,7 +407,7 @@ public final class QrCode {
// Split data into blocks, calculate ECC, and interleave
// (not concatenate) the bytes into a single sequence
byte[] result = new byte[rawCodewords];
ReedSolomonGenerator rs = ReedSolomonGenerator.getInstance(blockEccLen);
ReedSolomonGenerator rs = ReedSolomonGenerator.MEMOIZER.get(blockEccLen);
byte[] ecc = new byte[blockEccLen]; // Temporary storage per iteration
for (int i = 0, k = 0; i < numBlocks; i++) {
int datLen = shortBlockDataLen + (i < numShortBlocks ? 0 : 1);
src/io/nayuki/fastqrcodegen/QrTemplate.java
+2 -49
View File
@@ -25,59 +25,12 @@ package io.nayuki.fastqrcodegen;
import static io.nayuki.fastqrcodegen.QrCode.MAX_VERSION;
import static io.nayuki.fastqrcodegen.QrCode.MIN_VERSION;
import java.lang.ref.SoftReference;
final class QrTemplate {
/*---- Factory members ----*/
public static QrTemplate getInstance(int version) {
if (version < MIN_VERSION || version > MAX_VERSION)
throw new IllegalArgumentException("Version out of range");
while (true) {
synchronized(cache) {
SoftReference<QrTemplate> ref = cache[version];
if (ref != null) {
QrTemplate result = ref.get();
if (result != null)
return result;
cache[version] = null;
}
if (!isPending[version]) {
isPending[version] = true;
break;
}
try {
cache.wait();
} catch (InterruptedException e) {
throw new RuntimeException(e);
}
}
}
try {
QrTemplate tpl = new QrTemplate(version);
synchronized(cache) {
cache[version] = new SoftReference<>(tpl);
}
return tpl;
} finally {
synchronized(cache) {
isPending[version] = false;
cache.notifyAll();
}
}
}
@SuppressWarnings("unchecked")
private static final SoftReference<QrTemplate>[] cache = new SoftReference[MAX_VERSION + 1];
private static final boolean[] isPending = new boolean[MAX_VERSION + 1];
public static final Memoizer<Integer,QrTemplate> MEMOIZER
= new Memoizer<>(QrTemplate::new);
src/io/nayuki/fastqrcodegen/ReedSolomonGenerator.java
+2 -51
View File
@@ -23,63 +23,14 @@
package io.nayuki.fastqrcodegen;
import java.lang.ref.SoftReference;
import java.util.Arrays;
import java.util.Objects;
final class ReedSolomonGenerator {
/*---- Factory members ----*/
public static ReedSolomonGenerator getInstance(int degree) {
if (degree < 1 || degree > MAX_DEGREE)
throw new IllegalArgumentException("Degree out of range");
while (true) {
synchronized(cache) {
SoftReference<ReedSolomonGenerator> ref = cache[degree];
if (ref != null) {
ReedSolomonGenerator result = ref.get();
if (result != null)
return result;
cache[degree] = null;
}
if (!isPending[degree]) {
isPending[degree] = true;
break;
}
try {
cache.wait();
} catch (InterruptedException e) {
throw new RuntimeException(e);
}
}
}
try {
ReedSolomonGenerator rs = new ReedSolomonGenerator(degree);
synchronized(cache) {
cache[degree] = new SoftReference<>(rs);
}
return rs;
} finally {
synchronized(cache) {
isPending[degree] = false;
cache.notifyAll();
}
}
}
private static final int MAX_DEGREE = 30;
@SuppressWarnings("unchecked")
private static final SoftReference<ReedSolomonGenerator>[] cache = new SoftReference[MAX_DEGREE + 1];
private static final boolean[] isPending = new boolean[MAX_DEGREE + 1];
public static final Memoizer<Integer,ReedSolomonGenerator> MEMOIZER
= new Memoizer<>(ReedSolomonGenerator::new);