FixedBlockWriter.cpp revision e4d7bb418df0fdc4c708c334ba3601f5ed8d89b3 
1/*
2 * Copyright (C) 2017 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <stdint.h>
18#include <memory.h>
19
20#include "FixedBlockAdapter.h"
21#include "FixedBlockWriter.h"
22
23FixedBlockWriter::FixedBlockWriter(FixedBlockProcessor &fixedBlockProcessor)
24        : FixedBlockAdapter(fixedBlockProcessor) {}
25
26
27int32_t FixedBlockWriter::writeToStorage(uint8_t *buffer, int32_t numBytes) {
28    int32_t bytesToStore = numBytes;
29    int32_t roomAvailable = mSize - mPosition;
30    if (bytesToStore > roomAvailable) {
31        bytesToStore = roomAvailable;
32    }
33    memcpy(mStorage + mPosition, buffer, bytesToStore);
34    mPosition += bytesToStore;
35    return bytesToStore;
36}
37
38int32_t FixedBlockWriter::processVariableBlock(uint8_t *buffer, int32_t numBytes) {
39    int32_t result = 0;
40    int32_t bytesLeft = numBytes;
41
42    // If we already have data in storage then add to it.
43    if (mPosition > 0) {
44        int32_t bytesWritten = writeToStorage(buffer, bytesLeft);
45        buffer += bytesWritten;
46        bytesLeft -= bytesWritten;
47        // If storage full then flush it out
48        if (mPosition == mSize) {
49            result = mFixedBlockProcessor.onProcessFixedBlock(mStorage, mSize);
50            mPosition = 0;
51        }
52    }
53
54    // Write through if enough for a complete block.
55    while(bytesLeft > mSize && result == 0) {
56        result = mFixedBlockProcessor.onProcessFixedBlock(buffer, mSize);
57        buffer += mSize;
58        bytesLeft -= mSize;
59    }
60
61    // Save any remaining partial block for next time.
62    if (bytesLeft > 0) {
63        writeToStorage(buffer, bytesLeft);
64    }
65
66    return result;
67}
68