Paul Greenwood | 31a5488 | 2019-08-01 17:05:09 -0500 | [diff] [blame] | 1 | #pragma once |
| 2 | |
| 3 | /** |
| 4 | @file hei_chip_data_stream.hpp |
| 5 | @brief Description: The ChipDataStream class |
| 6 | |
| 7 | ChipDataStream makes it possible to read a buffer of binary data using the stream operators, ">>". |
| 8 | |
| 9 | Instantiate ChipDataStream class with a pointer to a data buffer |
| 10 | and its size in bytes as below: |
| 11 | |
| 12 | ChipDataStream cds(streamData,552); |
| 13 | |
| 14 | Use the ">>" stream operator then to read the basic integral types |
| 15 | (bool, char, uint8_t, int8_t, uint16_t, int16_t, uint32_t, |
| 16 | int32_t, uint64_t, and int64_t). |
| 17 | |
| 18 | Endian issues are taken care of by template specialization. |
| 19 | **/ |
| 20 | |
| 21 | #include <endian.h> |
| 22 | #include <hei_includes.hpp> |
| 23 | #include <string.h> |
| 24 | |
| 25 | namespace libhei |
| 26 | { |
| 27 | |
| 28 | /** |
| 29 | * ChipDataStream |
| 30 | * ChipDataStream offers convenient stream operator access to binary data. |
| 31 | **/ |
| 32 | class ChipDataStream |
| 33 | { |
| 34 | |
| 35 | private: |
| 36 | |
| 37 | /** iv_buffer points to the first address of the Chip Data File |
| 38 | buffer. **/ |
| 39 | const void * const iv_buffer; |
| 40 | /** iv_bufferSize is the size of the data buffer. It is |
| 41 | initialized when the ChipDataStream class is instantiated. **/ |
| 42 | const size_t iv_bufferSize; |
| 43 | /** iv_asyncOffset keeps an offset into the buffer. This |
| 44 | offset is incremented appropriately as data is read. **/ |
| 45 | size_t iv_asyncOffset; |
| 46 | |
| 47 | public: |
| 48 | |
| 49 | /* Constructors */ |
| 50 | |
| 51 | /** |
| 52 | When instantiating the ChipDataStream object a pointer to a |
| 53 | data buffer containing all the data and its size is passed |
| 54 | into the class. |
| 55 | **/ |
| 56 | ChipDataStream(void * i_buffer, size_t i_bufferSize) : |
| 57 | iv_asyncOffset(0), iv_buffer(i_buffer), iv_bufferSize(i_bufferSize) {} |
| 58 | |
| 59 | /** Eliminate copy and assignment operator constructors **/ |
| 60 | ChipDataStream ( const ChipDataStream & ) = delete; |
| 61 | ChipDataStream & operator=( const ChipDataStream & ) = delete; |
| 62 | |
| 63 | /** Destructor **/ |
| 64 | |
| 65 | ~ChipDataStream() = default; |
| 66 | |
| 67 | /** Functions **/ |
| 68 | |
| 69 | /** |
| 70 | *@brief Default case for "operator>>" template. |
| 71 | *@param D: A type |
| 72 | *@param o_right: A pointer to where the data is stored |
| 73 | *@return *this: A pointer to "this" object |
| 74 | **/ |
| 75 | template <class D> |
| 76 | ChipDataStream & operator>>( D & o_right ) |
| 77 | { |
| 78 | read( &o_right, sizeof(D) ); |
| 79 | return *this; |
| 80 | } |
| 81 | |
| 82 | private: |
| 83 | |
| 84 | /** |
| 85 | *@brief Read does the copy from the buffer |
| 86 | *@param o_buf a pointer to the location to copy to |
| 87 | *@param i_size the size (in bytes) to copy |
| 88 | *@return None\n\n |
| 89 | **/ |
| 90 | void read( void * o_buf, size_t i_size ) |
| 91 | { |
| 92 | /* Ensure memory is not accessed outside i_buffer */ |
| 93 | HEI_ASSERT((iv_asyncOffset + i_size) <= iv_bufferSize); |
| 94 | /* Copy appropriate bytes from i_buffer to o_buff */ |
| 95 | memcpy(o_buf,(char *)iv_buffer+iv_asyncOffset,i_size); |
| 96 | /* Increment asynchronous offset to next piece of data */ |
| 97 | iv_asyncOffset = iv_asyncOffset + i_size; |
| 98 | } |
| 99 | }; |
| 100 | |
| 101 | /* |
| 102 | * Note: The specializations below ensure the big-endian Chip Data File |
| 103 | * format is converted into the host format. |
| 104 | */ |
| 105 | |
| 106 | /** |
| 107 | * @brief This template extracts a uint16_t data type from the data buffer |
| 108 | * @param o_right: A pointer to where the data is stored |
| 109 | * @return *this: A pointer to "this" object |
| 110 | **/ |
| 111 | template <> inline |
| 112 | ChipDataStream & ChipDataStream::operator>>( uint16_t & o_right ) |
| 113 | { |
| 114 | read( &o_right, sizeof(o_right)); |
| 115 | be16toh( o_right ); |
| 116 | return *this; |
| 117 | } |
| 118 | |
| 119 | /**@brief This template extracts an int16_t type from the data buffer |
| 120 | * @param o_right: A pointer to where the data is stored |
| 121 | * @return *this: A pointer to "this" object |
| 122 | **/ |
| 123 | template <> inline |
| 124 | ChipDataStream & ChipDataStream::operator>>( int16_t & o_right ) |
| 125 | { |
| 126 | read( &o_right, sizeof(o_right) ); |
| 127 | be16toh( o_right ); |
| 128 | return *this; |
| 129 | } |
| 130 | |
| 131 | /**@brief This template extracts a uint32_t type from the data buffer |
| 132 | * @param o_right: A pointer to where the data is stored |
| 133 | * @return *this: A pointer to "this" object |
| 134 | **/ |
| 135 | template <> inline |
| 136 | ChipDataStream & ChipDataStream::operator>>( uint32_t & o_right ) |
| 137 | { |
| 138 | read( &o_right, sizeof(o_right) ); |
| 139 | be32toh( o_right ); |
| 140 | return *this; |
| 141 | } |
| 142 | |
| 143 | /**@brief This template extracts an int32_t type from the data buffer |
| 144 | * @param o_right: A pointer to where the data is stored |
| 145 | * @return *this: A pointer to "this" object |
| 146 | **/ |
| 147 | template <> inline |
| 148 | ChipDataStream & ChipDataStream::operator>>( int32_t & o_right ) |
| 149 | { |
| 150 | read( &o_right, sizeof(o_right) ); |
| 151 | be32toh( o_right ); |
| 152 | return *this; |
| 153 | } |
| 154 | |
| 155 | /**@brief This template extracts a uint64_t type from the data buffer |
| 156 | * @param o_right: A pointer to where the data is stored |
| 157 | * @return *this: A pointer to "this" object |
| 158 | **/ |
| 159 | template <> inline |
| 160 | ChipDataStream & ChipDataStream::operator>>( uint64_t & o_right ) |
| 161 | { |
| 162 | read( &o_right, sizeof(o_right) ); |
| 163 | be64toh( o_right ); |
| 164 | return *this; |
| 165 | } |
| 166 | |
| 167 | /**@brief This template extracts an int64_t type from the data buffer |
| 168 | * @param o_right: A pointer to where the data is stored |
| 169 | * @return *this: A pointer to "this" object |
| 170 | **/ |
| 171 | template <> inline |
| 172 | ChipDataStream & ChipDataStream::operator>>( int64_t & o_right ) |
| 173 | { |
| 174 | read( &o_right, sizeof(o_right) ); |
| 175 | be64toh( o_right ); |
| 176 | return *this; |
| 177 | } |
| 178 | |
| 179 | } /** namespace libhei **/ |