drgn/libdrgn/vector.c
Omar Sandoval 8d52536271 libdrgn: add common vector implementation
drgn has enough open-coded dynamic arrays at this point to warrant a
common implementation. Add one inspired by hash_table.h. The API is
pretty minimal. I'll add more to it as the need arises.
2019-07-15 12:27:15 -07:00

63 lines
1.3 KiB
C

// Copyright 2019 - Omar Sandoval
// SPDX-License-Identifier: GPL-3.0+
#include "vector.h"
bool vector_do_reserve(size_t new_capacity, size_t entry_size, void **data,
size_t *capacity)
{
size_t bytes;
void *new_data;
if (new_capacity <= *capacity || new_capacity == 0)
return true;
if (__builtin_mul_overflow(new_capacity, entry_size, &bytes))
return false;
new_data = realloc(*data, bytes);
if (!new_data)
return false;
*data = new_data;
*capacity = new_capacity;
return true;
}
void vector_do_shrink_to_fit(size_t size, size_t entry_size, void **data,
size_t *capacity)
{
void *new_data;
if (*capacity > size) {
/*
* We already have at least size * entry_size bytes allocated,
* so we don't need to worry about overflow.
*/
new_data = realloc(*data, size * entry_size);
if (new_data) {
*data = new_data;
*capacity = size;
}
}
}
bool vector_reserve_for_append(size_t size, size_t entry_size, void **data,
size_t *capacity)
{
size_t new_capacity, bytes;
void *new_data;
if (size < *capacity)
return true;
if (*capacity == 0)
new_capacity = 1;
else
new_capacity = 2 * *capacity;
if (__builtin_mul_overflow(new_capacity, entry_size, &bytes))
return false;
new_data = realloc(*data, bytes);
if (!new_data)
return false;
*data = new_data;
*capacity = new_capacity;
return true;
}