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// ArduinoJson - arduinojson.org
// Copyright Benoit Blanchon 2014-2018
// MIT License
#pragma once
#include "JsonBufferBase.hpp"
#include <stdlib.h>
#if defined(__clang__)
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wnon-virtual-dtor"
#elif defined(__GNUC__)
#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)
#pragma GCC diagnostic push
#endif
#pragma GCC diagnostic ignored "-Wnon-virtual-dtor"
#endif
namespace ArduinoJson {
namespace Internals {
class DefaultAllocator {
public:
void* allocate(size_t size) {
return malloc(size);
}
void deallocate(void* pointer) {
free(pointer);
}
};
template <typename TAllocator>
class DynamicJsonBufferBase
: public JsonBufferBase<DynamicJsonBufferBase<TAllocator> > {
struct Block;
struct EmptyBlock {
Block* next;
size_t capacity;
size_t size;
};
struct Block : EmptyBlock {
uint8_t data[1];
};
public:
enum { EmptyBlockSize = sizeof(EmptyBlock) };
DynamicJsonBufferBase(size_t initialSize = 256)
: _head(NULL), _nextBlockCapacity(initialSize) {}
~DynamicJsonBufferBase() {
clear();
}
// Gets the number of bytes occupied in the buffer
size_t size() const {
size_t total = 0;
for (const Block* b = _head; b; b = b->next) total += b->size;
return total;
}
// Allocates the specified amount of bytes in the buffer
virtual void* alloc(size_t bytes) {
alignNextAlloc();
return canAllocInHead(bytes) ? allocInHead(bytes) : allocInNewBlock(bytes);
}
// Resets the buffer.
// USE WITH CAUTION: this invalidates all previously allocated data
void clear() {
Block* currentBlock = _head;
while (currentBlock != NULL) {
_nextBlockCapacity = currentBlock->capacity;
Block* nextBlock = currentBlock->next;
_allocator.deallocate(currentBlock);
currentBlock = nextBlock;
}
_head = 0;
}
class String {
public:
String(DynamicJsonBufferBase* parent)
: _parent(parent), _start(NULL), _length(0) {}
void append(char c) {
if (_parent->canAllocInHead(1)) {
char* end = static_cast<char*>(_parent->allocInHead(1));
*end = c;
if (_length == 0) _start = end;
} else {
char* newStart =
static_cast<char*>(_parent->allocInNewBlock(_length + 1));
if (_start && newStart) memcpy(newStart, _start, _length);
if (newStart) newStart[_length] = c;
_start = newStart;
}
_length++;
}
const char* c_str() {
append(0);
return _start;
}
private:
DynamicJsonBufferBase* _parent;
char* _start;
size_t _length;
};
String startString() {
return String(this);
}
private:
void alignNextAlloc() {
if (_head) _head->size = this->round_size_up(_head->size);
}
bool canAllocInHead(size_t bytes) const {
return _head != NULL && _head->size + bytes <= _head->capacity;
}
void* allocInHead(size_t bytes) {
void* p = _head->data + _head->size;
_head->size += bytes;
return p;
}
void* allocInNewBlock(size_t bytes) {
size_t capacity = _nextBlockCapacity;
if (bytes > capacity) capacity = bytes;
if (!addNewBlock(capacity)) return NULL;
_nextBlockCapacity *= 2;
return allocInHead(bytes);
}
bool addNewBlock(size_t capacity) {
size_t bytes = EmptyBlockSize + capacity;
Block* block = static_cast<Block*>(_allocator.allocate(bytes));
if (block == NULL) return false;
block->capacity = capacity;
block->size = 0;
block->next = _head;
_head = block;
return true;
}
TAllocator _allocator;
Block* _head;
size_t _nextBlockCapacity;
};
}
#if defined(__clang__)
#pragma clang diagnostic pop
#elif defined(__GNUC__)
#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)
#pragma GCC diagnostic pop
#endif
#endif
// Implements a JsonBuffer with dynamic memory allocation.
// You are strongly encouraged to consider using StaticJsonBuffer which is much
// more suitable for embedded systems.
typedef Internals::DynamicJsonBufferBase<Internals::DefaultAllocator>
DynamicJsonBuffer;
}
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