X-Git-Url: http://source.jalview.org/gitweb/?a=blobdiff_plain;f=src%2Fjalview%2Fext%2Fandroid%2FSparseDoubleArray.java;fp=src%2Fjalview%2Fext%2Fandroid%2FSparseDoubleArray.java;h=eaf059c27e163d3660f60c1d562e9320d9dea5d2;hb=2595e9d4ee0dbbd3406a98c4e49a61ccde806479;hp=0000000000000000000000000000000000000000;hpb=e20075ba805d744d7cc4976e2b8d5e5840fb0a8d;p=jalview.git diff --git a/src/jalview/ext/android/SparseDoubleArray.java b/src/jalview/ext/android/SparseDoubleArray.java new file mode 100644 index 0000000..eaf059c --- /dev/null +++ b/src/jalview/ext/android/SparseDoubleArray.java @@ -0,0 +1,443 @@ +package jalview.ext.android; + +/* + * Copyright (C) 2006 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +/** + * SparseDoubleArray map integers to doubles. Unlike a normal array of integers, + * there can be gaps in the indices. It is intended to be more memory efficient + * than using a HashMap to map Integer to Double, both because it avoids + * auto-boxing keys and values and its data structure doesn't rely on an extra + * entry object for each mapping. + * + *
+ * Note that this container keeps its mappings in an array data structure, using + * a binary search to find keys. The implementation is not intended to be + * appropriate for data structures that may contain large numbers of items. It + * is generally slower than a traditional HashMap, since lookups require a + * binary search and adds and removes require inserting and deleting entries in + * the array. For containers holding up to hundreds of items, the performance + * difference is not significant, less than 50%. + *
+ * + *
+ * It is possible to iterate over the items in this container using
+ * {@link #keyAt(int)} and {@link #valueAt(int)}. Iterating over the keys using
+ * keyAt(int)
with ascending values of the index will return the
+ * keys in ascending order, or the values corresponding to the keys in ascending
+ * order in the case of valueAt(int)
.
+ *
0
if no such
+ * mapping has been made.
+ */
+ public double get(int key)
+ {
+ return get(key, 0d);
+ }
+
+ /**
+ * Gets the int mapped from the specified key, or the specified value if no
+ * such mapping has been made.
+ */
+ public double get(int key, double valueIfKeyNotFound)
+ {
+ int i = ContainerHelpers.binarySearch(mKeys, mSize, key);
+ if (i < 0)
+ {
+ return valueIfKeyNotFound;
+ }
+ else
+ {
+ return mValues[i];
+ }
+ }
+
+ /**
+ * Removes the mapping from the specified key, if there was any.
+ */
+ public void delete(int key)
+ {
+ int i = ContainerHelpers.binarySearch(mKeys, mSize, key);
+ if (i >= 0)
+ {
+ removeAt(i);
+ }
+ }
+
+ /**
+ * Removes the mapping at the given index.
+ */
+ public void removeAt(int index)
+ {
+ System.arraycopy(mKeys, index + 1, mKeys, index, mSize - (index + 1));
+ System.arraycopy(mValues, index + 1, mValues, index, mSize
+ - (index + 1));
+ mSize--;
+ }
+
+ /**
+ * Adds a mapping from the specified key to the specified value, replacing the
+ * previous mapping from the specified key if there was one.
+ */
+ public void put(int key, double value)
+ {
+ int i = ContainerHelpers.binarySearch(mKeys, mSize, key);
+ if (i >= 0)
+ {
+ mValues[i] = value;
+ }
+ else
+ {
+ i = ~i;
+ if (mSize >= mKeys.length)
+ {
+ int n = idealDoubleArraySize(mSize + 1);
+ int[] nkeys = new int[n];
+ double[] nvalues = new double[n];
+ // Log.e("SparseDoubleArray", "grow " + mKeys.length + " to " + n);
+ System.arraycopy(mKeys, 0, nkeys, 0, mKeys.length);
+ System.arraycopy(mValues, 0, nvalues, 0, mValues.length);
+ mKeys = nkeys;
+ mValues = nvalues;
+ }
+ if (mSize - i != 0)
+ {
+ // Log.e("SparseDoubleArray", "move " + (mSize - i));
+ System.arraycopy(mKeys, i, mKeys, i + 1, mSize - i);
+ System.arraycopy(mValues, i, mValues, i + 1, mSize - i);
+ }
+ mKeys[i] = key;
+ mValues[i] = value;
+ mSize++;
+ }
+ }
+
+ /**
+ * Returns the number of key-value mappings that this SparseDoubleArray
+ * currently stores.
+ */
+ public int size()
+ {
+ return mSize;
+ }
+
+ /**
+ * Given an index in the range 0...size()-1
, returns the key from
+ * the index
th key-value mapping that this SparseDoubleArray
+ * stores.
+ *
+ *
+ * The keys corresponding to indices in ascending order are guaranteed to be
+ * in ascending order, e.g., keyAt(0)
will return the smallest
+ * key and keyAt(size()-1)
will return the largest key.
+ *
0...size()-1
, returns the value
+ * from the index
th key-value mapping that this SparseDoubleArray
+ * stores.
+ *
+ *
+ * The values corresponding to indices in ascending order are guaranteed to be
+ * associated with keys in ascending order, e.g., valueAt(0)
will
+ * return the value associated with the smallest key and
+ * valueAt(size()-1)
will return the value associated with the
+ * largest key.
+ *
+ * This implementation composes a string by iterating over its mappings. + */ + @Override + public String toString() + { + if (size() <= 0) + { + return "{}"; + } + StringBuilder buffer = new StringBuilder(mSize * 28); + buffer.append('{'); + for (int i = 0; i < mSize; i++) + { + if (i > 0) + { + buffer.append(", "); + } + int key = keyAt(i); + buffer.append(key); + buffer.append('='); + double value = valueAt(i); + buffer.append(value); + } + buffer.append('}'); + return buffer.toString(); + } + + /** + * Method (copied from put) added for Jalview to efficiently increment a key's + * value if present, else add it with the given value. This avoids a double + * binary search (once to get the value, again to put the updated value). + * + * @param key + * @oparam toAdd + * @return the new value for the key + */ + public double add(int key, double toAdd) + { + double newValue = toAdd; + int i = ContainerHelpers.binarySearch(mKeys, mSize, key); + if (i >= 0) + { + mValues[i] += toAdd; + newValue = mValues[i]; + } + else + { + i = ~i; + if (mSize >= mKeys.length) + { + int n = idealDoubleArraySize(mSize + 1); + int[] nkeys = new int[n]; + double[] nvalues = new double[n]; + System.arraycopy(mKeys, 0, nkeys, 0, mKeys.length); + System.arraycopy(mValues, 0, nvalues, 0, mValues.length); + mKeys = nkeys; + mValues = nvalues; + } + if (mSize - i != 0) + { + System.arraycopy(mKeys, i, mKeys, i + 1, mSize - i); + System.arraycopy(mValues, i, mValues, i + 1, mSize - i); + } + mKeys[i] = key; + mValues[i] = toAdd; + mSize++; + } + return newValue; + } + + /** + * Method added for Jalview to efficiently multiply a key's value if present, + * else do nothing. This avoids a double binary search (once to get the value, + * again to put the updated value). + * + * @param key + * @oparam toAdd + * @return the new value for the key + */ + public double divide(int key, double divisor) + { + double newValue = 0d; + if (divisor == 0d) + { + return newValue; + } + int i = ContainerHelpers.binarySearch(mKeys, mSize, key); + if (i >= 0) + { + mValues[i] /= divisor; + newValue = mValues[i]; + } + return newValue; + } +}