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[bytebuffer] Rework ByteBuffer using templates (#7638)
This commit is contained in:
Clyde Stubbs
GitHub
5
esphome/components/bytebuffer/__init__.py
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5
esphome/components/bytebuffer/__init__.py
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@@ -0,0 +1,5 @@
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CODEOWNERS = ["@clydebarrow"]
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# Allows bytebuffer to be configured in yaml, to allow use of the C++ api.
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CONFIG_SCHEMA = {}
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421
esphome/components/bytebuffer/bytebuffer.h
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421
esphome/components/bytebuffer/bytebuffer.h
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@@ -0,0 +1,421 @@
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#pragma once
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#include <utility>
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#include <vector>
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#include <cinttypes>
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#include <cstddef>
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#include "esphome/core/helpers.h"
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namespace esphome {
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namespace bytebuffer {
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enum Endian { LITTLE, BIG };
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/**
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* A class modelled on the Java ByteBuffer class. It wraps a vector of bytes and permits putting and getting
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* items of various sizes, with an automatically incremented position.
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*
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* There are three variables maintained pointing into the buffer:
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*
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* capacity: the maximum amount of data that can be stored - set on construction and cannot be changed
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* limit: the limit of the data currently available to get or put
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* position: the current insert or extract position
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*
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* 0 <= position <= limit <= capacity
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*
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* In addition a mark can be set to the current position with mark(). A subsequent call to reset() will restore
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* the position to the mark.
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*
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* The buffer can be marked to be little-endian (default) or big-endian. All subsequent operations will use that order.
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*
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* The flip() operation will reset the position to 0 and limit to the current position. This is useful for reading
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* data from a buffer after it has been written.
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*
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* The code is defined here in the header file rather than in a .cpp file, so that it does not get compiled if not used.
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* The templated functions ensure that only those typed functions actually used are compiled. The functions
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* are implicitly inline-able which will aid performance.
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*/
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class ByteBuffer {
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public:
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// Default constructor (compatibility with TEMPLATABLE_VALUE)
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// Creates a zero-length ByteBuffer which is little use to anybody.
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ByteBuffer() : ByteBuffer(std::vector<uint8_t>()) {}
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/**
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* Create a new Bytebuffer with the given capacity
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*/
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ByteBuffer(size_t capacity, Endian endianness = LITTLE)
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: data_(std::vector<uint8_t>(capacity)), endianness_(endianness), limit_(capacity){};
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// templated functions to implement putting and getting data of various types. There are two flavours of all
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// functions - one that uses the position as the offset, and updates the position accordingly, and one that
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// takes an explicit offset and does not update the position.
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// Separate temnplates are provided for types that fit into 32 bits and those that are bigger. These delegate
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// the actual put/get to common code based around those sizes.
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// This reduces the code size and execution time for smaller types. A similar structure for e.g. 16 bits is unlikely
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// to provide any further benefit given that all target platforms are native 32 bit.
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template<typename T>
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T get(typename std::enable_if<std::is_integral<T>::value, T>::type * = 0,
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typename std::enable_if<(sizeof(T) <= sizeof(uint32_t)), T>::type * = 0) {
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// integral types that fit into 32 bit
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return static_cast<T>(this->get_uint32_(sizeof(T)));
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}
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template<typename T>
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T get(size_t offset, typename std::enable_if<std::is_integral<T>::value, T>::type * = 0,
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typename std::enable_if<(sizeof(T) <= sizeof(uint32_t)), T>::type * = 0) {
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return static_cast<T>(this->get_uint32_(offset, sizeof(T)));
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}
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template<typename T>
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void put(const T &value, typename std::enable_if<std::is_integral<T>::value, T>::type * = 0,
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typename std::enable_if<(sizeof(T) <= sizeof(uint32_t)), T>::type * = 0) {
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this->put_uint32_(static_cast<uint32_t>(value), sizeof(T));
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}
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template<typename T>
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void put(const T &value, size_t offset, typename std::enable_if<std::is_integral<T>::value, T>::type * = 0,
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typename std::enable_if<(sizeof(T) <= sizeof(uint32_t)), T>::type * = 0) {
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this->put_uint32_(static_cast<uint32_t>(value), offset, sizeof(T));
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}
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// integral types that do not fit into 32 bit (basically only 64 bit types)
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template<typename T>
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T get(typename std::enable_if<std::is_integral<T>::value, T>::type * = 0,
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typename std::enable_if<(sizeof(T) == sizeof(uint64_t)), T>::type * = 0) {
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return static_cast<T>(this->get_uint64_(sizeof(T)));
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}
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template<typename T>
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T get(size_t offset, typename std::enable_if<std::is_integral<T>::value, T>::type * = 0,
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typename std::enable_if<(sizeof(T) == sizeof(uint64_t)), T>::type * = 0) {
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return static_cast<T>(this->get_uint64_(offset, sizeof(T)));
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}
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template<typename T>
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void put(const T &value, typename std::enable_if<std::is_integral<T>::value, T>::type * = 0,
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typename std::enable_if<(sizeof(T) == sizeof(uint64_t)), T>::type * = 0) {
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this->put_uint64_(value, sizeof(T));
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}
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template<typename T>
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void put(const T &value, size_t offset, typename std::enable_if<std::is_integral<T>::value, T>::type * = 0,
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typename std::enable_if<(sizeof(T) == sizeof(uint64_t)), T>::type * = 0) {
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this->put_uint64_(static_cast<uint64_t>(value), offset, sizeof(T));
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}
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// floating point types. Caters for 32 and 64 bit floating point.
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template<typename T>
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T get(typename std::enable_if<std::is_floating_point<T>::value, T>::type * = 0,
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typename std::enable_if<(sizeof(T) == sizeof(uint32_t)), T>::type * = 0) {
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return bit_cast<T>(this->get_uint32_(sizeof(T)));
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}
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template<typename T>
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T get(typename std::enable_if<std::is_floating_point<T>::value, T>::type * = 0,
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typename std::enable_if<(sizeof(T) == sizeof(uint64_t)), T>::type * = 0) {
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return bit_cast<T>(this->get_uint64_(sizeof(T)));
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}
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template<typename T>
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T get(size_t offset, typename std::enable_if<std::is_floating_point<T>::value, T>::type * = 0,
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typename std::enable_if<(sizeof(T) == sizeof(uint32_t)), T>::type * = 0) {
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return bit_cast<T>(this->get_uint32_(offset, sizeof(T)));
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}
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template<typename T>
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T get(size_t offset, typename std::enable_if<std::is_floating_point<T>::value, T>::type * = 0,
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typename std::enable_if<(sizeof(T) == sizeof(uint64_t)), T>::type * = 0) {
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return bit_cast<T>(this->get_uint64_(offset, sizeof(T)));
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}
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template<typename T>
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void put(const T &value, typename std::enable_if<std::is_floating_point<T>::value, T>::type * = 0,
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typename std::enable_if<(sizeof(T) <= sizeof(uint32_t)), T>::type * = 0) {
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this->put_uint32_(bit_cast<uint32_t>(value), sizeof(T));
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}
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template<typename T>
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void put(const T &value, typename std::enable_if<std::is_floating_point<T>::value, T>::type * = 0,
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typename std::enable_if<(sizeof(T) == sizeof(uint64_t)), T>::type * = 0) {
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this->put_uint64_(bit_cast<uint64_t>(value), sizeof(T));
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}
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template<typename T>
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void put(const T &value, size_t offset, typename std::enable_if<std::is_floating_point<T>::value, T>::type * = 0,
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typename std::enable_if<(sizeof(T) <= sizeof(uint32_t)), T>::type * = 0) {
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this->put_uint32_(bit_cast<uint32_t>(value), offset, sizeof(T));
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}
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template<typename T>
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void put(const T &value, size_t offset, typename std::enable_if<std::is_floating_point<T>::value, T>::type * = 0,
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typename std::enable_if<(sizeof(T) == sizeof(uint64_t)), T>::type * = 0) {
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this->put_uint64_(bit_cast<uint64_t>(value), offset, sizeof(T));
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}
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template<typename T> static ByteBuffer wrap(T value, Endian endianness = LITTLE) {
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ByteBuffer buffer = ByteBuffer(sizeof(T), endianness);
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buffer.put(value);
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buffer.flip();
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return buffer;
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}
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static ByteBuffer wrap(std::vector<uint8_t> const &data, Endian endianness = LITTLE) {
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ByteBuffer buffer = {data};
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buffer.endianness_ = endianness;
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return buffer;
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}
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static ByteBuffer wrap(const uint8_t *ptr, size_t len, Endian endianness = LITTLE) {
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return wrap(std::vector<uint8_t>(ptr, ptr + len), endianness);
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}
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// convenience functions with explicit types named..
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void put_float(float value) { this->put(value); }
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void put_double(double value) { this->put(value); }
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uint8_t get_uint8() { return this->data_[this->position_++]; }
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// Get a 16 bit unsigned value, increment by 2
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uint16_t get_uint16() { return this->get<uint16_t>(); }
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// Get a 24 bit unsigned value, increment by 3
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uint32_t get_uint24() { return this->get_uint32_(3); };
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// Get a 32 bit unsigned value, increment by 4
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uint32_t get_uint32() { return this->get<uint32_t>(); };
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// Get a 64 bit unsigned value, increment by 8
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uint64_t get_uint64() { return this->get<uint64_t>(); };
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// Signed versions of the get functions
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uint8_t get_int8() { return static_cast<int8_t>(this->get_uint8()); };
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int16_t get_int16() { return this->get<uint16_t>(); }
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int32_t get_int32() { return this->get<int32_t>(); }
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int64_t get_int64() { return this->get<int64_t>(); }
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// Get a float value, increment by 4
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float get_float() { return this->get<float>(); }
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// Get a double value, increment by 8
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double get_double() { return this->get<double>(); }
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// Get a bool value, increment by 1
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bool get_bool() { return static_cast<bool>(this->get_uint8()); }
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uint32_t get_int24(size_t offset) {
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auto value = this->get_uint24(offset);
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uint32_t mask = (~static_cast<uint32_t>(0)) << 23;
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if ((value & mask) != 0)
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value |= mask;
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return value;
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}
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uint32_t get_int24() {
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auto value = this->get_uint24();
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uint32_t mask = (~static_cast<uint32_t>(0)) << 23;
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if ((value & mask) != 0)
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value |= mask;
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return value;
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}
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std::vector<uint8_t> get_vector(size_t length, size_t offset) {
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auto start = this->data_.begin() + offset;
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return {start, start + length};
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}
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std::vector<uint8_t> get_vector(size_t length) {
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auto result = this->get_vector(length, this->position_);
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this->position_ += length;
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return result;
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}
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// Convenience named functions
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void put_uint8(uint8_t value) { this->data_[this->position_++] = value; }
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void put_uint16(uint16_t value) { this->put(value); }
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void put_uint24(uint32_t value) { this->put_uint32_(value, 3); }
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void put_uint32(uint32_t value) { this->put(value); }
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void put_uint64(uint64_t value) { this->put(value); }
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// Signed versions of the put functions
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void put_int8(int8_t value) { this->put_uint8(static_cast<uint8_t>(value)); }
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void put_int16(int16_t value) { this->put(value); }
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void put_int24(int32_t value) { this->put_uint32_(value, 3); }
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void put_int32(int32_t value) { this->put(value); }
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void put_int64(int64_t value) { this->put(value); }
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// Extra put functions
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void put_bool(bool value) { this->put_uint8(value); }
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// versions of the above with an offset, these do not update the position
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uint64_t get_uint64(size_t offset) { return this->get<uint64_t>(offset); }
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uint32_t get_uint24(size_t offset) { return this->get_uint32_(offset, 3); };
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double get_double(size_t offset) { return get<double>(offset); }
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// Get one byte from the buffer, increment position by 1
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uint8_t get_uint8(size_t offset) { return this->data_[offset]; }
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// Get a 16 bit unsigned value, increment by 2
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uint16_t get_uint16(size_t offset) { return get<uint16_t>(offset); }
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// Get a 24 bit unsigned value, increment by 3
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uint32_t get_uint32(size_t offset) { return this->get<uint32_t>(offset); };
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// Get a 64 bit unsigned value, increment by 8
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uint8_t get_int8(size_t offset) { return get<int8_t>(offset); }
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int16_t get_int16(size_t offset) { return get<int16_t>(offset); }
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int32_t get_int32(size_t offset) { return get<int32_t>(offset); }
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int64_t get_int64(size_t offset) { return get<int64_t>(offset); }
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// Get a float value, increment by 4
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float get_float(size_t offset) { return get<float>(offset); }
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// Get a double value, increment by 8
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// Get a bool value, increment by 1
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bool get_bool(size_t offset) { return this->get_uint8(offset); }
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void put_uint8(uint8_t value, size_t offset) { this->data_[offset] = value; }
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void put_uint16(uint16_t value, size_t offset) { this->put(value, offset); }
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void put_uint24(uint32_t value, size_t offset) { this->put(value, offset); }
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void put_uint32(uint32_t value, size_t offset) { this->put(value, offset); }
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void put_uint64(uint64_t value, size_t offset) { this->put(value, offset); }
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// Signed versions of the put functions
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void put_int8(int8_t value, size_t offset) { this->put_uint8(static_cast<uint8_t>(value), offset); }
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void put_int16(int16_t value, size_t offset) { this->put(value, offset); }
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void put_int24(int32_t value, size_t offset) { this->put_uint32_(value, offset, 3); }
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void put_int32(int32_t value, size_t offset) { this->put(value, offset); }
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void put_int64(int64_t value, size_t offset) { this->put(value, offset); }
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// Extra put functions
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void put_float(float value, size_t offset) { this->put(value, offset); }
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void put_double(double value, size_t offset) { this->put(value, offset); }
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void put_bool(bool value, size_t offset) { this->put_uint8(value, offset); }
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void put(const std::vector<uint8_t> &value, size_t offset) {
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std::copy(value.begin(), value.end(), this->data_.begin() + offset);
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}
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void put_vector(const std::vector<uint8_t> &value, size_t offset) { this->put(value, offset); }
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void put(const std::vector<uint8_t> &value) {
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this->put_vector(value, this->position_);
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this->position_ += value.size();
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}
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void put_vector(const std::vector<uint8_t> &value) { this->put(value); }
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// Getters
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inline size_t get_capacity() const { return this->data_.size(); }
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inline size_t get_position() const { return this->position_; }
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inline size_t get_limit() const { return this->limit_; }
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inline size_t get_remaining() const { return this->get_limit() - this->get_position(); }
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inline Endian get_endianness() const { return this->endianness_; }
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inline void mark() { this->mark_ = this->position_; }
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inline void big_endian() { this->endianness_ = BIG; }
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inline void little_endian() { this->endianness_ = LITTLE; }
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// retrieve a pointer to the underlying data.
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std::vector<uint8_t> get_data() { return this->data_; };
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void get_bytes(void *dest, size_t length) {
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std::copy(this->data_.begin() + this->position_, this->data_.begin() + this->position_ + length, (uint8_t *) dest);
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this->position_ += length;
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}
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void get_bytes(void *dest, size_t length, size_t offset) {
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std::copy(this->data_.begin() + offset, this->data_.begin() + offset + length, (uint8_t *) dest);
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}
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void rewind() { this->position_ = 0; }
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void reset() { this->position_ = this->mark_; }
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void set_limit(size_t limit) { this->limit_ = limit; }
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void set_position(size_t position) { this->position_ = position; }
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void clear() {
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this->limit_ = this->get_capacity();
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this->position_ = 0;
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}
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void flip() {
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this->limit_ = this->position_;
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this->position_ = 0;
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}
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protected:
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uint64_t get_uint64_(size_t offset, size_t length) const {
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uint64_t value = 0;
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if (this->endianness_ == LITTLE) {
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offset += length;
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while (length-- != 0) {
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value <<= 8;
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value |= this->data_[--offset];
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}
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} else {
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while (length-- != 0) {
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value <<= 8;
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value |= this->data_[offset++];
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}
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}
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return value;
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}
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uint64_t get_uint64_(size_t length) {
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auto result = this->get_uint64_(this->position_, length);
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this->position_ += length;
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return result;
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}
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uint32_t get_uint32_(size_t offset, size_t length) const {
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uint32_t value = 0;
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if (this->endianness_ == LITTLE) {
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offset += length;
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while (length-- != 0) {
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value <<= 8;
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value |= this->data_[--offset];
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}
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} else {
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while (length-- != 0) {
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value <<= 8;
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value |= this->data_[offset++];
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}
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}
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return value;
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}
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uint32_t get_uint32_(size_t length) {
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auto result = this->get_uint32_(this->position_, length);
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this->position_ += length;
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return result;
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}
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/// Putters
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void put_uint64_(uint64_t value, size_t length) {
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this->put_uint64_(value, this->position_, length);
|
||||
this->position_ += length;
|
||||
}
|
||||
void put_uint32_(uint32_t value, size_t length) {
|
||||
this->put_uint32_(value, this->position_, length);
|
||||
this->position_ += length;
|
||||
}
|
||||
|
||||
void put_uint64_(uint64_t value, size_t offset, size_t length) {
|
||||
if (this->endianness_ == LITTLE) {
|
||||
while (length-- != 0) {
|
||||
this->data_[offset++] = static_cast<uint8_t>(value);
|
||||
value >>= 8;
|
||||
}
|
||||
} else {
|
||||
offset += length;
|
||||
while (length-- != 0) {
|
||||
this->data_[--offset] = static_cast<uint8_t>(value);
|
||||
value >>= 8;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
void put_uint32_(uint32_t value, size_t offset, size_t length) {
|
||||
if (this->endianness_ == LITTLE) {
|
||||
while (length-- != 0) {
|
||||
this->data_[offset++] = static_cast<uint8_t>(value);
|
||||
value >>= 8;
|
||||
}
|
||||
} else {
|
||||
offset += length;
|
||||
while (length-- != 0) {
|
||||
this->data_[--offset] = static_cast<uint8_t>(value);
|
||||
value >>= 8;
|
||||
}
|
||||
}
|
||||
}
|
||||
ByteBuffer(std::vector<uint8_t> const &data) : data_(data), limit_(data.size()) {}
|
||||
|
||||
std::vector<uint8_t> data_;
|
||||
Endian endianness_{LITTLE};
|
||||
size_t position_{0};
|
||||
size_t mark_{0};
|
||||
size_t limit_{0};
|
||||
};
|
||||
|
||||
} // namespace bytebuffer
|
||||
} // namespace esphome
|
||||
Reference in New Issue
Block a user