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/* ########################################################### */
/* This Software is licensed under the GPL licensed Version 2, */
/* please read http://www.gnu.org/copyleft/gpl.html. */
/* ########################################################### */
/* Ternary Search Tree and sorted array creation functions. */
/* Inspired by a code described in "Ternary Search Trees" by Jon */
/* Bentley and Robert Sedgewick in the April, 1998, Dr. Dobb's Journal. */
/* Links: */
/* https://www.drdobbs.com/database/ternary-search-trees/184410528?pgno=1 */
/* https://www.cs.princeton.edu/~rs/strings/tstdemo.c. */
/* ************************************************************************ */
#include <stdlib.h>
#include <stdint.h>
#include <unistd.h>
#include <wchar.h>
#include <string.h>
#include "xmalloc.h"
#include "list.h"
#include "utils.h"
#include "index.h"
/* List of words matching the current search. */
/* """""""""""""""""""""""""""""""""""""""""" */
ll_t * tst_search_list; /* Must be initialized by ll_new() before use. */
/* ======================================= */
/* Ternary search tree insertion function. */
/* ======================================= */
tst_node_t *
tst_insert(tst_node_t * p, wchar_t * w, void * data)
{
if (p == NULL)
{
p = (tst_node_t *)xmalloc(sizeof(tst_node_t));
p->splitchar = *w;
p->lokid = p->eqkid = p->hikid = NULL;
p->data = NULL;
}
if (*w < p->splitchar)
p->lokid = tst_insert(p->lokid, w, data);
else if (*w == p->splitchar)
{
if (*w == L'\0')
{
p->data = data;
p->eqkid = NULL;
}
else
p->eqkid = tst_insert(p->eqkid, ++w, data);
}
else
p->hikid = tst_insert(p->hikid, w, data);
return (p);
}
/* ====================================== */
/* Ternary search tree deletion function. */
/* User data area not cleaned. */
/* ====================================== */
void
tst_cleanup(tst_node_t * p)
{
if (p)
{
tst_cleanup(p->lokid);
if (p->splitchar)
tst_cleanup(p->eqkid);
tst_cleanup(p->hikid);
free(p);
}
}
/* ========================================================== */
/* Recursive traversal of a ternary tree. A callback function */
/* is also called when a complete string is found. */
/* Returns 1 if the callback function succeed (returned 1) at */
/* least once. */
/* The first_call argument is for initializing the static */
/* variable. */
/* ========================================================== */
int
tst_traverse(tst_node_t * p, int (*callback)(void *), int first_call)
{
static int rc;
if (first_call)
rc = 0;
if (!p)
return 0;
tst_traverse(p->lokid, callback, 0);
if (p->splitchar != L'\0')
tst_traverse(p->eqkid, callback, 0);
else
rc += (*callback)(p->data);
tst_traverse(p->hikid, callback, 0);
return !!rc;
}
/* ======================================================================= */
/* Traverses the word tst looking for a wchar and build a list of pointers */
/* containing all the sub-tst potentially leading to words containing the */
/* next wchar os the search string. */
/* ======================================================================= */
int
tst_substring_traverse(tst_node_t * p, int (*callback)(void *), int first_call,
wchar_t w)
{
static int rc;
if (first_call)
rc = 0;
if (!p)
return 0;
if (p->splitchar == w)
{
ll_node_t * node;
sub_tst_t * sub_tst_data;
node = tst_search_list->tail;
sub_tst_data = (sub_tst_t *)(node->data);
if (p->eqkid)
insert_sorted_ptr(&(sub_tst_data->array), &(sub_tst_data->size),
&(sub_tst_data->count), p->eqkid);
rc = 1;
}
tst_substring_traverse(p->lokid, callback, 0, w);
if (p->splitchar != L'\0')
tst_substring_traverse(p->eqkid, callback, 0, w);
else if (callback != NULL)
rc += (*callback)(p->data);
tst_substring_traverse(p->hikid, callback, 0, w);
return !!rc;
}
/* ======================================================================== */
/* Traverses the word tst looking for a wchar and build a list of pointers */
/* containing all the sub-tst nodes potentially leading to words containing */
/* the next wchar os the search string. */
/* ======================================================================== */
int
tst_fuzzy_traverse(tst_node_t * p, int (*callback)(void *), int first_call,
wchar_t w)
{
static int rc;
wchar_t w1s[2];
wchar_t w2s[2];
w1s[1] = w2s[1] = L'\0';
if (first_call)
rc = 0;
if (!p)
return 0;
w1s[0] = p->splitchar;
w2s[0] = w;
if (xwcscasecmp(w1s, w2s) == 0)
{
ll_node_t * node;
sub_tst_t * sub_tst_data;
node = tst_search_list->tail;
sub_tst_data = (sub_tst_t *)(node->data);
if (p->eqkid != NULL)
insert_sorted_ptr(&(sub_tst_data->array), &(sub_tst_data->size),
&(sub_tst_data->count), p->eqkid);
rc += 1;
}
tst_fuzzy_traverse(p->lokid, callback, 0, w);
if (p->splitchar != L'\0')
tst_fuzzy_traverse(p->eqkid, callback, 0, w);
else if (callback != NULL)
rc += (*callback)(p->data);
tst_fuzzy_traverse(p->hikid, callback, 0, w);
return !!rc;
}
/* ======================================================================= */
/* Searches a complete string in a ternary tree starting from a root node. */
/* ======================================================================= */
void *
tst_search(tst_node_t * root, wchar_t * w)
{
tst_node_t * p;
p = root;
while (p)
{
if (*w < p->splitchar)
p = p->lokid;
else if (*w == p->splitchar)
{
if (*w++ == L'\0')
return p->data;
p = p->eqkid;
}
else
p = p->hikid;
}
return NULL;
}
/* ================================================================= */
/* Searches all strings beginning with the same prefix. */
/* the callback function will be applied to each of theses strings */
/* returns NULL if no string matched the prefix. */
/* ================================================================= */
void *
tst_prefix_search(tst_node_t * root, wchar_t * w, int (*callback)(void *))
{
tst_node_t * p = root;
size_t len = wcslen(w);
size_t rc;
while (p)
{
if (*w < p->splitchar)
p = p->lokid;
else if (*w == p->splitchar)
{
len--;
if (*w++ == L'\0')
return p->data;
if (len == 0)
{
rc = tst_traverse(p->eqkid, callback, 1);
return (void *)(long)rc;
}
p = p->eqkid;
}
else
p = p->hikid;
}
return NULL;
}
/* ========================================================= */
/* Insertion of an integer in a already sorted integer array */
/* without duplications. */
/* ========================================================= */
void
insert_sorted_index(long ** array, long * size, long * nb, long value)
{
long pos = *nb;
long left = 0, right = *nb, middle;
if (*nb > 0)
{
/* Bisection search. */
/* """"""""""""""""" */
while (left < right)
{
middle = (left + right) / 2;
if ((*array)[middle] == value)
return; /* Value already in array. */
if (value < (*array)[middle])
right = middle;
else
left = middle + 1;
}
pos = left;
}
if (*nb == *size)
{
*size += 64;
*array = xrealloc(*array, *size
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