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 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 31 ReadBuffer::~ReadBuffer() 32 { 33 free(m_buf); 34 } 35 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 68 void ReadBuffer::consume(size_t amount) 69 { 70 assert(amount <= m_validData); 71 m_validData -= amount; 72 m_readPtr += amount; 73 } 74
