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| 1 | +/*! |
| 2 | + * Copyright (c) 2019 by Contributors |
| 3 | + * \file allocator_stream.h |
| 4 | + * \brief allocator stream utility |
| 5 | + */ |
| 6 | +#ifndef TVM_RUNTIME_MICRO_ALLOCATOR_STREAM_H_ |
| 7 | +#define TVM_RUNTIME_MICRO_ALLOCATOR_STREAM_H_ |
| 8 | + |
| 9 | +#include <cstring> |
| 10 | +#include <string> |
| 11 | +#include <algorithm> |
| 12 | +#include <vector> |
| 13 | +#include <dmlc/memory_io.h> |
| 14 | + |
| 15 | +namespace tvm { |
| 16 | +namespace runtime { |
| 17 | +/*! |
| 18 | + * \brief allocation-based stream with bounded buffer size for uTVM args allocation |
| 19 | + * \note based on dmlc::MemoryStringStream |
| 20 | + */ |
| 21 | +struct AllocatorStream : public dmlc::SeekStream { |
| 22 | + public: |
| 23 | + /*! |
| 24 | + * \brief constructor |
| 25 | + * \param p_buffer the pointer to the string. |
| 26 | + */ |
| 27 | + explicit AllocatorStream(std::string *p_buffer) |
| 28 | + : p_buffer_(p_buffer) { |
| 29 | + curr_ptr_ = 0; |
| 30 | + max_ptr_ = 0; |
| 31 | + } |
| 32 | + |
| 33 | + /*! |
| 34 | + * \brief reads size bytes of data starting at ptr |
| 35 | + * \param ptr address to begin read |
| 36 | + * \param size number of bytes to be read |
| 37 | + * \return number of bytes read |
| 38 | + */ |
| 39 | + size_t Read(void *ptr, size_t size) { |
| 40 | + CHECK(curr_ptr_ <= p_buffer_->length()); |
| 41 | + CHECK(curr_ptr_ + size <= max_ptr_); |
| 42 | + size_t nread = std::min(p_buffer_->length() - curr_ptr_, size); |
| 43 | + if (nread != 0) std::memcpy(ptr, &(*p_buffer_)[0] + curr_ptr_, nread); |
| 44 | + curr_ptr_ += nread; |
| 45 | + return nread; |
| 46 | + } |
| 47 | + |
| 48 | + /*! |
| 49 | + * \brief writes size bytes of data starting at ptr |
| 50 | + * \param ptr address of the buffer to be written |
| 51 | + * \param size number of bytes to be written |
| 52 | + */ |
| 53 | + void Write(const void *ptr, size_t size) { |
| 54 | + if (size == 0) return; |
| 55 | + CHECK(curr_ptr_ + size <= max_ptr_); |
| 56 | + if (curr_ptr_ + size > p_buffer_->length()) { |
| 57 | + p_buffer_->resize(curr_ptr_+size); |
| 58 | + } |
| 59 | + std::memcpy(&(*p_buffer_)[0] + curr_ptr_, ptr, size); |
| 60 | + curr_ptr_ += size; |
| 61 | + } |
| 62 | + |
| 63 | + /*! |
| 64 | + * \brief seek to specified location within internal buffer |
| 65 | + * \param pos seek position from start in bytes |
| 66 | + */ |
| 67 | + void Seek(size_t pos) { |
| 68 | + curr_ptr_ = static_cast<size_t>(pos); |
| 69 | + } |
| 70 | + |
| 71 | + /*! |
| 72 | + * \brief get seek pointer location |
| 73 | + * \return current seek pointer location from start in bytes |
| 74 | + */ |
| 75 | + size_t Tell(void) { |
| 76 | + return curr_ptr_; |
| 77 | + } |
| 78 | + |
| 79 | + /*! |
| 80 | + * \brief allocates an empty region within the stream buffer |
| 81 | + * \param size size of the allocated region |
| 82 | + * \return offset bytes of the allocated region from start of the buffer |
| 83 | + */ |
| 84 | + size_t Allocate(size_t size) { |
| 85 | + size_t ret = max_ptr_; |
| 86 | + max_ptr_ += size; |
| 87 | + return ret; |
| 88 | + } |
| 89 | + |
| 90 | + /*! |
| 91 | + * \brief returns current size of the stream buffer |
| 92 | + * \return buffer size |
| 93 | + */ |
| 94 | + size_t GetBufferSize() { |
| 95 | + return max_ptr_; |
| 96 | + } |
| 97 | + |
| 98 | + private: |
| 99 | + /*! \brief in memory buffer */ |
| 100 | + std::string *p_buffer_; |
| 101 | + /*! \brief current pointer */ |
| 102 | + size_t curr_ptr_; |
| 103 | + /*! \brief maximum pointer */ |
| 104 | + size_t max_ptr_; |
| 105 | +}; |
| 106 | +} // namespace runtime |
| 107 | +} // namespace tvm |
| 108 | +#endif // TVM_RUNTIME_MICRO_ALLOCATOR_STREAM_H_ |
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