| using Lucene.Net.Diagnostics; |
| using System; |
| using System.Globalization; |
| |
| namespace Lucene.Net.Util.Packed |
| { |
| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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. |
| */ |
| |
| using DataInput = Lucene.Net.Store.DataInput; |
| |
| /// <summary> |
| /// A <see cref="DataInput"/> wrapper to read unaligned, variable-length packed |
| /// integers. This API is much slower than the <see cref="PackedInt32s"/> fixed-length |
| /// API but can be convenient to save space. |
| /// <para/> |
| /// @lucene.internal |
| /// </summary> |
| /// <seealso cref="PackedDataOutput"/> |
| public sealed class PackedDataInput |
| { |
| internal readonly DataInput @in; |
| internal long current; |
| internal int remainingBits; |
| |
| /// <summary> |
| /// Create a new instance that wraps <paramref name="in"/>. |
| /// </summary> |
| public PackedDataInput(DataInput @in) |
| { |
| this.@in = @in; |
| SkipToNextByte(); |
| } |
| |
| /// <summary> |
| /// Read the next <see cref="long"/> using exactly <paramref name="bitsPerValue"/> bits. |
| /// <para/> |
| /// NOTE: This was readLong() in Lucene. |
| /// </summary> |
| public long ReadInt64(int bitsPerValue) |
| { |
| if (Debugging.AssertsEnabled) Debugging.Assert(bitsPerValue > 0 && bitsPerValue <= 64, "{0}", bitsPerValue); |
| long r = 0; |
| while (bitsPerValue > 0) |
| { |
| if (remainingBits == 0) |
| { |
| current = @in.ReadByte() & 0xFF; |
| remainingBits = 8; |
| } |
| int bits = Math.Min(bitsPerValue, remainingBits); |
| r = (r << bits) | (((long)((ulong)current >> (remainingBits - bits))) & ((1L << bits) - 1)); |
| bitsPerValue -= bits; |
| remainingBits -= bits; |
| } |
| return r; |
| } |
| |
| /// <summary> |
| /// If there are pending bits (at most 7), they will be ignored and the next |
| /// value will be read starting at the next byte. |
| /// </summary> |
| public void SkipToNextByte() |
| { |
| remainingBits = 0; |
| } |
| } |
| } |