esp-idf/components/fatfs/vfs/vfs_fat_internal.h

// Copyright 2018 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#pragma once

#include "esp_vfs_fat.h"
#include <sys/param.h>
#include <stddef.h>

static inline size_t esp_vfs_fat_get_allocation_unit_size(
        size_t sector_size, size_t requested_size)
{
    size_t alloc_unit_size = requested_size;
    const size_t max_sectors_per_cylinder = 128;
    const size_t max_size = sector_size * max_sectors_per_cylinder;
    alloc_unit_size = MAX(alloc_unit_size, sector_size);
    alloc_unit_size = MIN(alloc_unit_size, max_size);
    return alloc_unit_size;
}