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#ifndef DISFLUID_TRIE_INCLUDED
# define DISFLUID_TRIE_INCLUDED
# include <config.h>
# include "string-desc.h"
MAYBE_UNUSED static int
ao_trie_read (int fd, size_t offset, size_t *n_keys, uint8_t * keys,
size_t *offsets);
MAYBE_UNUSED static int
ao_trie_push (int fd, size_t *offset, size_t n_keys, const uint8_t * keys,
const size_t *offsets);
MAYBE_UNUSED static int
ao_trie_fold (int fd, size_t offset,
int (*down) (void *context, char key, size_t offset,
bool *explore),
int (*up) (void *context), void *context);
# include "disfluid-append-only-file.h"
# include "safe-alloc.h"
static int
ao_trie_read (int fd,
size_t offset, size_t *n_keys, uint8_t * keys, size_t *offsets)
{
uint8_t n_keys_data[8] = { 0 };
string_desc_t n_keys_desc = {
._nbytes = sizeof (n_keys_data),
._data = n_keys_data
};
int error = 0;
if (ao_file_read (fd, offset, n_keys_desc) < 0)
{
error = -1;
goto cleanup;
}
*n_keys = 0;
for (size_t i = 0; i < sizeof (n_keys_data); i++)
{
*n_keys *= 256;
*n_keys += n_keys_data[i];
}
offset -= sizeof (n_keys_data);
for (size_t i = 0; i < *n_keys; i++)
{
uint8_t entry_data[9] = { 0 };
string_desc_t entry_desc = {
._nbytes = sizeof (entry_data),
._data = entry_data
};
if (ao_file_read (fd, offset, entry_desc) < 0)
{
error = -1;
goto cleanup;
}
keys[i] = entry_data[0];
offsets[i] = 0;
for (size_t j = 1; j < sizeof (entry_data); j++)
{
offsets[i] *= 256;
offsets[i] += entry_data[j];
}
offset -= sizeof (entry_data);
}
cleanup:
return error;
}
struct entry
{
bool used;
uint8_t key;
size_t offset;
};
static int
ao_trie_push (int fd,
size_t *offset,
size_t n_keys, const uint8_t * keys, const size_t *offsets)
{
struct entry entries[256];
for (size_t i = 0; i < sizeof (entries) / sizeof (entries[0]); i++)
{
entries[i].used = false;
}
for (size_t i = 0; i < n_keys; i++)
{
if (entries[keys[i]].used)
{
return -1;
}
entries[keys[i]].used = true;
entries[keys[i]].key = keys[i];
entries[keys[i]].offset = offsets[i];
}
for (size_t i = 256; i-- > 0;)
{
if (entries[i].used)
{
uint8_t entry_data[9] = { entries[i].key, 0 };
size_t branch_offset = entries[i].offset;
for (size_t j = sizeof (entry_data); j-- > 1;)
{
entry_data[j] = branch_offset % 256;
branch_offset /= 256;
}
string_desc_t entry_desc = {
._nbytes = sizeof (entry_data),
._data = entry_data
};
if (ao_file_push_data (fd, entry_desc, offset) < 0)
{
return -1;
}
}
}
size_t n_branches = n_keys;
uint8_t count_data[8] = { 0 };
for (size_t j = sizeof (count_data); j-- > 0;)
{
count_data[j] = n_branches % 256;
n_branches /= 256;
}
string_desc_t count_desc = {
._nbytes = sizeof (count_data),
._data = count_data
};
if (ao_file_push_data (fd, count_desc, offset) < 0)
{
return -1;
}
return 0;
}
struct ao_trie_path
{
struct ao_trie_path *parent;
size_t n_keys;
uint8_t keys[256];
size_t suboffsets[256];
size_t n_explored;
};
static int ao_trie_path_skip (struct ao_trie_path **path);
static int ao_trie_path_down (struct ao_trie_path **path, int fd);
static int ao_trie_path_up (struct ao_trie_path **path);
static int
ao_trie_fold (int fd, size_t offset,
int (*down) (void *context, char key, size_t offset,
bool *explore),
int (*up) (void *context), void *context)
{
struct ao_trie_path root = {.parent = NULL,.n_keys = 0,.n_explored = 0 };
if (ao_trie_read (fd, offset, &(root.n_keys), root.keys, root.suboffsets)
< 0)
{
return -1;
}
struct ao_trie_path *path = &root;
int error = 0;
while (path->parent != NULL || path->n_explored < path->n_keys)
{
if (path->n_explored == path->n_keys)
{
if (up (context) != 0)
{
error = -1;
goto cleanup;
}
if (ao_trie_path_up (&path) < 0)
{
error = -1;
goto cleanup;
}
}
else
{
bool explore = false;
if (down
(context, path->keys[path->n_explored],
path->suboffsets[path->n_explored], &explore) != 0)
{
error = -1;
goto cleanup;
}
if (explore)
{
if (ao_trie_path_down (&path, fd) < 0)
{
error = -2;
goto cleanup;
}
}
else
{
if (up (context) != 0)
{
error = -1;
goto cleanup;
}
if (ao_trie_path_skip (&path) < 0)
{
error = -2;
goto cleanup;
}
}
}
}
cleanup:
return error;
}
static int
ao_trie_path_skip (struct ao_trie_path **path)
{
struct ao_trie_path *old_path = *path;
old_path->n_explored++;
return 0;
}
static int
ao_trie_path_down (struct ao_trie_path **path, int fd)
{
struct ao_trie_path *old_path = *path;
struct ao_trie_path *new_path;
if (ALLOC (new_path) < 0)
{
return -2;
}
new_path->parent = old_path;
new_path->n_keys = 0;
new_path->n_explored = 0;
if (ao_trie_read
(fd, old_path->suboffsets[old_path->n_explored], &(new_path->n_keys),
new_path->keys, new_path->suboffsets) < 0)
{
FREE (new_path);
return -1;
}
*path = new_path;
return 0;
}
static int
ao_trie_path_up (struct ao_trie_path **path)
{
struct ao_trie_path *current = *path;
*path = current->parent;
(*path)->n_explored++;
FREE (current);
return 0;
}
#endif /* not DISFLUID_TRIE_INCLUDED */
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