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#ifndef DISFLUID_DISFLUID_CACHE_GROUP_INCLUDED
# define DISFLUID_DISFLUID_CACHE_GROUP_INCLUDED
# include <config.h>
# include "string-desc.h"
# include <stdbool.h>
MAYBE_UNUSED static int
ao_cache_group_read (int fd, size_t offset,
size_t *n_entries, size_t **entry_offsets);
MAYBE_UNUSED static int
ao_cache_group_push (int fd, size_t *offset,
size_t n_entries, const size_t *entry_offsets);
MAYBE_UNUSED static int
ao_cache_group_invalidate (int fd, size_t offset, size_t *invalidated_offset);
# include "disfluid-append-only-file.h"
# include "safe-alloc.h"
/* The cache group is organized as follows:
- on 8 bytes, the number of entries,
- on 8 bytes, the offset of the entry array.
*/
static int
ao_cache_group_read (int fd,
size_t offset, size_t *n_entries, size_t **entry_offsets)
{
uint8_t header[16];
string_desc_t header_desc = {
._nbytes = sizeof (header),
._data = header
};
*n_entries = 0;
*entry_offsets = NULL;
size_t array_offset = 0;
if (ao_file_read (fd, offset, header_desc) < 0)
{
return -1;
}
for (size_t i = 0; i < 8; i++)
{
*n_entries *= 256;
*n_entries += header[i];
}
for (size_t i = 8; i < 16; i++)
{
array_offset *= 256;
array_offset += header[i];
}
uint8_t *array_data = NULL;
if (ALLOC_N (array_data, *n_entries * 8) < 0
|| ALLOC_N (*entry_offsets, *n_entries) < 0)
{
FREE (array_data);
FREE (*entry_offsets);
return -1;
}
string_desc_t array_desc = {
._nbytes = *n_entries * 8,
._data = array_data
};
if (ao_file_read (fd, array_offset, array_desc) < 0)
{
FREE (array_data);
FREE (*entry_offsets);
return -1;
}
for (size_t i = 0; i < *n_entries; i++)
{
(*entry_offsets)[i] = 0;
for (size_t j = i * 8; j < (i + 1) * 8; j++)
{
(*entry_offsets)[i] *= 256;
(*entry_offsets)[i] += array_data[j];
}
}
FREE (array_data);
return 0;
}
static int
ao_cache_group_push (int fd,
size_t *offset,
size_t n_entries, const size_t *entry_offsets)
{
uint8_t *array_data = NULL;
if (ALLOC_N (array_data, n_entries * 8) < 0)
{
return -1;
}
for (size_t i = 0; i < n_entries; i++)
{
size_t offset = entry_offsets[i];
for (size_t j = 8 * (i + 1); j-- > 8 * i;)
{
array_data[j] = offset % 256;
offset /= 256;
}
}
string_desc_t array_desc = {
._nbytes = n_entries * 8,
._data = array_data
};
size_t array_offset;
if (ao_file_push_data (fd, array_desc, &array_offset) < 0)
{
FREE (array_data);
return -1;
}
FREE (array_data);
uint8_t header_data[16] = { 0 };
for (size_t i = 8; i-- > 0;)
{
header_data[i] = n_entries % 256;
n_entries /= 256;
}
for (size_t i = 16; i-- > 8;)
{
header_data[i] = array_offset % 256;
array_offset /= 256;
}
string_desc_t header_desc = {
._nbytes = 16,
._data = header_data
};
return ao_file_push_data (fd, header_desc, offset);
}
MAYBE_UNUSED static int
ao_cache_group_invalidate (int fd, size_t offset, size_t *invalidated_offset)
{
size_t n_entries = 42;
size_t *offsets = NULL;
int error = ao_cache_group_read (fd, offset, &n_entries, &offsets);
if (error != 0)
{
FREE (offsets);
return -1;
}
bool changed = false;
for (size_t i = 0; i < n_entries; i++)
{
size_t old_offset = offsets[i];
size_t new_offset = 42;
if (ao_cache_entry_invalidate (fd, old_offset, &new_offset) < 0)
{
FREE (offsets);
return -1;
}
if (old_offset != new_offset)
{
changed = true;
}
offsets[i] = new_offset;
}
if (changed)
{
if (ao_cache_group_push (fd, invalidated_offset, n_entries, offsets) <
0)
{
FREE (offsets);
return -1;
}
}
else
{
*invalidated_offset = offset;
}
FREE (offsets);
return 0;
}
#endif /* DISFLUID_DISFLUID_CACHE_GROUP_INCLUDED */
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