ScratchBuffer.h

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00038 #ifndef __STATIC_SCRATCH_BUFFER__
00039 #define __STATIC_SCRATCH_BUFFER__
00040 
00041 #include <cstdlib>
00042 #include <cstring>
00043 
00044 #include "../debug/DebugUtils.h"
00045 #include "../util/ExpandableBuffer.h"
00046 
00047 namespace oasys {
00048 
00059 template<typename _memory_t = void*, size_t _static_size = 0>
00060 class ScratchBuffer;
00061 
00065 template<typename _memory_t>
00066 class ScratchBuffer<_memory_t, 0> : public ExpandableBuffer {
00067 public:
00068     ScratchBuffer(size_t size = 0) : ExpandableBuffer(size) {}
00069     
00071     _memory_t buf(size_t size = 0) {
00072         if (size > buf_len_) {
00073             reserve(size);
00074         }
00075         return reinterpret_cast<_memory_t>(buf_);
00076     }
00077 };
00078 
00083 template<typename _memory_t, size_t _static_size>
00084 class ScratchBuffer : public ExpandableBuffer {
00085 public:
00086     ScratchBuffer() {
00087         buf_     = static_buf_; 
00088         buf_len_ = _static_size;        
00089     }
00090 
00091     ScratchBuffer(size_t size) {
00092         buf_     = static_buf_;
00093         buf_len_ = _static_size;
00094 
00095         if (size > buf_len_) {
00096             reserve(size);
00097         }
00098     }
00099 
00100     virtual ~ScratchBuffer() {
00101         if (! using_malloc()) {
00102             buf_ = 0;
00103         }
00104     }
00105 
00107     _memory_t buf(size_t size = 0) {
00108         if (size != 0) {
00109             reserve(size);
00110         }
00111         return reinterpret_cast<_memory_t>(buf_);
00112     }
00113 
00115     virtual void reserve(size_t size = 0) {
00116         if (size == 0) {
00117             size = (buf_len_ == 0) ? 1 : (buf_len_ * 2);
00118         }     
00119 
00120         if (size <= buf_len_) {
00121             return;
00122         }
00123 
00124         if (! using_malloc()) 
00125         {
00126             ASSERT(size > _static_size);
00127             buf_ = 0;
00128             size_t old_buf_len = buf_len_;
00129 
00130             ExpandableBuffer::reserve(size);
00131             memcpy(buf_, static_buf_, old_buf_len);
00132         } 
00133         else 
00134         {
00135             ExpandableBuffer::reserve(size);
00136         }
00137     }
00138 
00139 private:
00140     char static_buf_[_static_size];
00141     bool using_malloc() { 
00142         return buf_ != static_buf_;
00143     }
00144 };
00145 
00146 } // namespace oasys
00147 
00148 #endif //__STATIC_SCRATCH_BUFFER_H__

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