1 /*
2 * Copyright (C) 2011 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 #include "ReadBuffer.h"
17 #include <string.h>
18 #include <assert.h>
19 #include <limits.h>
20 #include "ErrorLog.h"
21
ReadBuffer(IOStream * stream,size_t bufsize)22 ReadBuffer::ReadBuffer(IOStream *stream, size_t bufsize)
23 {
24 m_size = bufsize;
25 m_stream = stream;
26 m_buf = (unsigned char*)malloc(m_size*sizeof(unsigned char));
27 m_validData = 0;
28 m_readPtr = m_buf;
29 }
30
~ReadBuffer()31 ReadBuffer::~ReadBuffer()
32 {
33 free(m_buf);
34 }
35
getData()36 int ReadBuffer::getData()
37 {
38 if ((m_validData > 0) && (m_readPtr > m_buf)) {
39 memmove(m_buf, m_readPtr, m_validData);
40 }
41 // get fresh data into the buffer;
42 size_t len = m_size - m_validData;
43 if (len==0) {
44 //we need to inc our buffer
45 size_t new_size = m_size*2;
46 unsigned char* new_buf;
47 if (new_size < m_size) { // overflow check
48 new_size = INT_MAX;
49 }
50
51 new_buf = (unsigned char*)realloc(m_buf, new_size);
52 if (!new_buf) {
53 ERR("Failed to alloc %zu bytes for ReadBuffer\n", new_size);
54 return -1;
55 }
56 m_size = new_size;
57 m_buf = new_buf;
58 len = m_size - m_validData;
59 }
60 m_readPtr = m_buf;
61 if (NULL != m_stream->read(m_buf + m_validData, &len)) {
62 m_validData += len;
63 return len;
64 }
65 return -1;
66 }
67
consume(size_t amount)68 void ReadBuffer::consume(size_t amount)
69 {
70 assert(amount <= m_validData);
71 m_validData -= amount;
72 m_readPtr += amount;
73 }
74