ardupilot/libraries/AP_Common/AP_ExpandingArray.cpp

67 lines
2.1 KiB
C++

/*
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "AP_ExpandingArray.h"
AP_ExpandingArrayGeneric::~AP_ExpandingArrayGeneric(void)
{
// free chunks
for (uint16_t i=0; i<chunk_count; i++) {
free(chunk_ptrs[i]);
}
// free chunks_ptrs array
free(chunk_ptrs);
}
// expand the array by specified number of chunks, returns true on success
bool AP_ExpandingArrayGeneric::expand(uint16_t num_chunks)
{
// expand chunk_ptrs array if necessary
if (chunk_count + num_chunks >= chunk_count_max) {
uint16_t chunk_ptr_size = chunk_count + num_chunks + chunk_ptr_increment;
chunk_ptr_t *chunk_ptrs_new = (chunk_ptr_t*)realloc(chunk_ptrs, chunk_ptr_size * sizeof(chunk_ptr_t));
if (chunk_ptrs_new == nullptr) {
return false;
}
// use new pointers array
chunk_ptrs = chunk_ptrs_new;
chunk_count_max = chunk_ptr_size;
}
// allocate new chunks
for (uint16_t i = 0; i < num_chunks; i++) {
uint8_t *new_chunk = (uint8_t *)calloc(chunk_size, elem_size);
if (new_chunk == nullptr) {
// failed to allocate new chunk
return false;
}
chunk_ptrs[chunk_count] = new_chunk;
chunk_count++;
}
return true;
}
// expand to hold at least num_items
bool AP_ExpandingArrayGeneric::expand_to_hold(uint16_t num_items)
{
// check if already big enough
if (num_items <= max_items()) {
return true;
}
uint16_t chunks_required = ((num_items - max_items()) / chunk_size) + 1;
return expand(chunks_required);
}