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#include "kernel/devices/block_device_utils.hpp"
#include "kapi/devices/device.hpp"
#include "kapi/system.hpp"
#include "kernel/devices/block_device.hpp"
#include <kstd/cstring>
#include <kstd/memory>
#include <kstd/vector>
#include <algorithm>
#include <cstddef>
namespace kernel::devices::block_device_utils
{
using block_op = void (*)(size_t idx, size_t off, size_t len, size_t done, devices::block_device * device,
std::byte * scratch, void * buffer);
auto process_blocks(kstd::shared_ptr<kapi::devices::device> const & device, size_t offset, size_t size, void * buffer,
block_op op) -> size_t
{
if (buffer == nullptr)
{
kapi::system::panic("[FILESYSTEM] device_file::process_blocks called with null buffer.");
}
if (size == 0)
{
return 0;
}
auto * block_dev = static_cast<devices::block_device *>(device.get());
if (block_dev == nullptr)
{
kapi::system::panic("[FILESYSTEM] device_file: expected block_device.");
}
size_t const block_size = block_dev->block_size();
size_t const capacity = block_dev->capacity();
if (offset >= capacity)
return 0;
size_t const total_to_process = std::min(size, capacity - offset);
kstd::vector<std::byte> scratch_buffer{block_size};
auto processed = 0uz;
while (processed < total_to_process)
{
size_t const absolute_offset = offset + processed;
size_t const block_index = absolute_offset / block_size;
size_t const in_block_offset = absolute_offset % block_size;
size_t const chunk_size = std::min(total_to_process - processed, block_size - in_block_offset);
op(block_index, in_block_offset, chunk_size, processed, block_dev, scratch_buffer.data(), buffer);
processed += chunk_size;
}
return processed;
}
auto read(kstd::shared_ptr<kapi::devices::device> const & device, void * buffer, size_t offset, size_t size) -> size_t
{
return process_blocks(device, offset, size, buffer,
[](size_t idx, size_t off, size_t len, size_t done, devices::block_device * device,
std::byte * scratch, void * buffer) {
auto * out = static_cast<std::byte *>(buffer);
if (off == 0 && len == device->block_size())
{
device->read_block(idx, out + done);
}
else
{
device->read_block(idx, scratch);
kstd::libc::memcpy(out + done, scratch + off, len);
}
});
}
auto write(kstd::shared_ptr<kapi::devices::device> const & device, void const * buffer, size_t offset, size_t size)
-> size_t
{
return process_blocks(device, offset, size, const_cast<void *>(buffer),
[](size_t idx, size_t off, size_t len, size_t done, devices::block_device * device,
std::byte * scratch, void * buffer) {
auto const * in = static_cast<std::byte const *>(buffer);
if (off == 0 && len == device->block_size())
{
device->write_block(idx, in + done);
}
else
{
device->read_block(idx, scratch);
kstd::libc::memcpy(scratch + off, in + done, len);
device->write_block(idx, scratch);
}
});
}
} // namespace kernel::devices::block_device_utils
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