StreamBuffer.cc

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00001 /*
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00004  * this license. If you do not agree to this license, do not download,
00005  * install, copy or use the software.
00006  * 
00007  * Intel Open Source License 
00008  * 
00009  * Copyright (c) 2004 Intel Corporation. All rights reserved. 
00010  * 
00011  * Redistribution and use in source and binary forms, with or without
00012  * modification, are permitted provided that the following conditions are
00013  * met:
00014  * 
00015  *   Redistributions of source code must retain the above copyright
00016  *   notice, this list of conditions and the following disclaimer.
00017  * 
00018  *   Redistributions in binary form must reproduce the above copyright
00019  *   notice, this list of conditions and the following disclaimer in the
00020  *   documentation and/or other materials provided with the distribution.
00021  * 
00022  *   Neither the name of the Intel Corporation nor the names of its
00023  *   contributors may be used to endorse or promote products derived from
00024  *   this software without specific prior written permission.
00025  *  
00026  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
00027  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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00036  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
00037  */
00038 
00039 #include <string.h>
00040 #include "debug/DebugUtils.h"
00041 #include "debug/Log.h"
00042 #include "StreamBuffer.h"
00043 
00044 namespace oasys {
00045 
00046 /***************************************************************************
00047  *
00048  * StreamBuffer
00049  *
00050  **************************************************************************/
00051 StreamBuffer::StreamBuffer(size_t size) : 
00052     start_(0), end_(0), size_(size)
00053 {
00054     if(size_ == 0)
00055         size_ = 4;
00056 
00057     buf_ = static_cast<char*>(malloc(size_));
00058     ASSERT(buf_);
00059 }
00060 
00061 StreamBuffer::~StreamBuffer()
00062 {
00063     if(buf_) 
00064     {
00065         free(buf_);
00066         buf_ = 0;
00067     }
00068 }
00069 
00070 void
00071 StreamBuffer::set_size(size_t size)
00072 {
00073     ASSERT(fullbytes() <= size);
00074     moveup();
00075     
00076     realloc(size);
00077 }
00078 
00079 char*
00080 StreamBuffer::start()
00081 {
00082     return &buf_[start_];
00083 }
00084 
00085 char*
00086 StreamBuffer::end()
00087 {
00088     return &buf_[end_];
00089 }
00090 
00091 void
00092 StreamBuffer::reserve(size_t amount)
00093 {
00094     if (amount <= tailbytes())
00095     {
00096         // do nothing
00097     } 
00098     else if(amount <= start_) 
00099     {
00100         moveup();
00101     } 
00102     else
00103     {
00104         moveup();
00105         realloc(((amount + fullbytes())> size_*2) ? 
00106                 (amount + fullbytes()): (size_*2));
00107     }
00108 }
00109 
00110 void
00111 StreamBuffer::fill(size_t amount)
00112 {
00113     ASSERT(amount <= tailbytes());
00114     
00115     end_ += amount;
00116 }
00117 
00118 void
00119 StreamBuffer::consume(size_t amount)
00120 {
00121     ASSERT(amount <= fullbytes());
00122 
00123     start_ += amount;
00124     if(start_ == end_)
00125     {
00126         start_ = end_ = 0;
00127     }
00128 }
00129 
00130 void
00131 StreamBuffer::clear()
00132 {
00133     start_ = end_ = 0;
00134 }
00135 
00136 size_t
00137 StreamBuffer::fullbytes() 
00138 {
00139     return end_ - start_;
00140 }
00141 
00142 size_t
00143 StreamBuffer::tailbytes() 
00144 {
00145     return size_ - end_;
00146 }
00147 
00148 void
00149 StreamBuffer::realloc(size_t size)
00150 {
00151     buf_ = (char*)::realloc(buf_, size);
00152     if(buf_ == 0)
00153     {
00154         logf("/StreamBuffer", LOG_CRIT, "Out of memory");
00155         ASSERT(0);
00156     }
00157     
00158     size_ = size;
00159 }
00160 
00161 void
00162 StreamBuffer::moveup()
00163 {
00164     memmove(&buf_[0], &buf_[start_], end_ - start_);
00165     end_   = end_ - start_;
00166     start_ = 0;
00167 }
00168 
00169 } // namespace oasys

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