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
22 #include "FixedBlockReader.h"
23
24
FixedBlockReader(FixedBlockProcessor & fixedBlockProcessor)25 FixedBlockReader::FixedBlockReader(FixedBlockProcessor &fixedBlockProcessor)
26 : FixedBlockAdapter(fixedBlockProcessor) {
27 mPosition = mSize;
28 }
29
open(int32_t bytesPerFixedBlock)30 int32_t FixedBlockReader::open(int32_t bytesPerFixedBlock) {
31 int32_t result = FixedBlockAdapter::open(bytesPerFixedBlock);
32 mPosition = mSize; // Indicate no data in storage.
33 return result;
34 }
35
readFromStorage(uint8_t * buffer,int32_t numBytes)36 int32_t FixedBlockReader::readFromStorage(uint8_t *buffer, int32_t numBytes) {
37 int32_t bytesToRead = numBytes;
38 int32_t dataAvailable = mSize - mPosition;
39 if (bytesToRead > dataAvailable) {
40 bytesToRead = dataAvailable;
41 }
42 memcpy(buffer, &mStorage[mPosition], bytesToRead);
43 mPosition += bytesToRead;
44 return bytesToRead;
45 }
46
processVariableBlock(uint8_t * buffer,int32_t numBytes)47 AdapterProcessResult FixedBlockReader::processVariableBlock(uint8_t *buffer, int32_t numBytes) {
48 int32_t result = 0;
49 int32_t bytesLeft = numBytes;
50 int32_t bytesProcessed = 0;
51 while(bytesLeft > 0 && result == 0) {
52 if (mPosition < mSize) {
53 // Use up bytes currently in storage.
54 int32_t bytesRead = readFromStorage(buffer, bytesLeft);
55 buffer += bytesRead;
56 bytesLeft -= bytesRead;
57 bytesProcessed += bytesRead;
58 } else if (bytesLeft >= mSize) {
59 // Read through if enough for a complete block.
60 result = mFixedBlockProcessor.onProcessFixedBlock(buffer, mSize);
61 if (result != 0) {
62 break;
63 }
64 buffer += mSize;
65 bytesLeft -= mSize;
66 bytesProcessed += mSize;
67 } else {
68 // Just need a partial block so we have to use storage.
69 result = mFixedBlockProcessor.onProcessFixedBlock(mStorage.get(), mSize);
70 mPosition = 0;
71 }
72 }
73 return {result, bytesProcessed};
74 }
75
76