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tesseract/dict/trie.cpp
theraysmith 2a678305c6 Major internationalization improvements 
git-svn-id: https://tesseract-ocr.googlecode.com/svn/trunk@133 d0cd1f9f-072b-0410-8dd7-cf729c803f20
2008-02-01 00:21:49 +00:00

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/* -*-C-*-
********************************************************************************
*
* File: trie.c (Formerly trie.c)
* Description: Functions to build a trie data structure.
* Author: Mark Seaman, OCR Technology
* Created: Fri Oct 16 14:37:00 1987
* Modified: Fri Jul 26 12:18:10 1991 (Mark Seaman) marks@hpgrlt
* Language: C
* Package: N/A
* Status: Reusable Software Component
*
* (c) Copyright 1987, Hewlett-Packard Company.
** 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.
*
*********************************************************************************/
/*----------------------------------------------------------------------
I n c l u d e s
----------------------------------------------------------------------*/
#include "trie.h"
#include "callcpp.h"
#ifdef __UNIX__
#include <assert.h>
#endif
#include <stdio.h>
/*----------------------------------------------------------------------
V a r i a b l e s
----------------------------------------------------------------------*/
static INT32 move_counter = 0;
static INT32 new_counter = 0;
static INT32 edge_counter = 0;
INT32 max_new_attempts = 0;
/*----------------------------------------------------------------------
F u n c t i o n s
----------------------------------------------------------------------*/
/**********************************************************************
* add_edge_linkage
*
* Add a single edge linkage to between the two nodes. This function
* can be used to add either forward or backward links.
**********************************************************************/
void add_edge_linkage(EDGE_ARRAY dawg,
NODE_REF node1,
NODE_REF node2,
EDGE_RECORD direction,
char character,
EDGE_RECORD word_end) {
EDGE_REF edge1 = node1;
EDGE_REF edge2;
INT32 num_edges = edges_in_node (dawg, node1);
INT32 last_one;
word_end = (word_end ? WERD_END_FLAG : 0);
if (num_edges == 0) { /* No edges yet */
direction = ((direction == FORWARD_EDGE) ? DIRECTION_FLAG : 0);
link_edge (dawg, edge1, node2, character,
LAST_FLAG | direction | word_end);
}
else {
/* Forward links */
if (direction == FORWARD_EDGE) {
last_one = (forward_edge (dawg, edge1) ? 0 : LAST_FLAG);
if (debug)
cprintf ("moving edges (nodes = " REFFORMAT ", " REFFORMAT \
", num = %d)\n",
edge1, edge1+1, num_edges);
copy_edges (dawg, edge1, edge1+1, num_edges);
link_edge (dawg, edge1, node2, character,
last_one | DIRECTION_FLAG | word_end);
}
else { /* Backward links */
if (forward_edge (dawg, edge1))
edge_loop(dawg, edge1);
/* Existing back edges */
if (backward_edge (dawg,edge1)) {
num_edges = 0;
edge2 = edge1;
do { num_edges++; }
edge_loop(dawg, edge2);
if (debug)
cprintf ("moving edges (nodes = " REFFORMAT ", " REFFORMAT \
", num = %d)\n",
edge1, edge1+1, num_edges);
copy_edges (dawg, edge1, edge1+1, num_edges);
link_edge(dawg, edge1, node2, character, word_end);
}
else { /* First back edge */
link_edge (dawg, edge1, node2, character,
LAST_FLAG | word_end);
}
}
}
}
/**********************************************************************
* add_new_edge
*
* Add an edge between two nodes in the DAWG. Link the nodes both ways.
**********************************************************************/
bool add_new_edge(EDGE_ARRAY dawg,
NODE_REF *node1,
NODE_REF *node2,
char character,
EDGE_RECORD word_end,
INT32 max_num_edges,
INT32 reserved_edges) {
int direction;
if (debug)
cprintf ("add_new_edge (nodes = " REFFORMAT ", " REFFORMAT \
", ch = '%c', end = %d)\n",
*node1, *node2, character, word_end);
edge_counter++;
if (!move_node_if_needed(dawg, node1, max_num_edges, reserved_edges))
return false;
if (!move_node_if_needed(dawg, node2, max_num_edges, reserved_edges))
return false;
direction = (int) FORWARD_EDGE;
add_edge_linkage(dawg, *node1, *node2, direction, character, word_end);
direction = (int) BACKWARD_EDGE;
add_edge_linkage(dawg, *node2, *node1, direction, character, word_end);
return true;
}
/**********************************************************************
* add_word_to_dawg
*
* Add in a word by creating the necessary nodes and edges.
**********************************************************************/
void add_word_to_dawg(EDGE_ARRAY dawg,
char *string,
INT32 max_num_edges,
INT32 reserved_edges) {
EDGE_REF edge;
NODE_REF last_node = 0;
NODE_REF the_next_node;
INT32 i;
INT32 still_finding_chars = TRUE;
INT32 word_end = FALSE;
bool add_failed = false;
if (debug) cprintf("Adding word %s\n", string);
for (i=0; i<strlen(string)-1; i++) {
if (still_finding_chars) {
edge = edge_char_of (dawg, last_node, string[i], word_end);
if (debug) cprintf ("exploring edge = " REFFORMAT "\n", edge);
if (edge == NO_EDGE)
still_finding_chars = FALSE;
else
if (next_node (dawg, edge) == 0) {
word_end = TRUE;
still_finding_chars = FALSE;
if (! case_sensative) string[i] = tolower (string[i]);
remove_edge (dawg, last_node, 0, string[i], word_end);
}
else {
last_node = next_node (dawg, edge);
}
}
if (! still_finding_chars) {
the_next_node = new_dawg_node (dawg, DEFAULT_NODE_SIZE,
max_num_edges, reserved_edges);
if (the_next_node == 0) {
add_failed = true;
break;
}
if (edges_in_node (dawg, last_node) + last_node == the_next_node) {
//cprintf ("Node collision at %d\n", the_next_node);
the_next_node = new_dawg_node (dawg, DEFAULT_NODE_SIZE,
max_num_edges, reserved_edges);
if (the_next_node == 0) {
add_failed = true;
break;
}
}
if (! case_sensative) string[i] = tolower (string[i]);
if (!add_new_edge (dawg, &last_node, &the_next_node,
string[i], word_end, max_num_edges, reserved_edges)) {
add_failed = true;
break;
}
word_end = FALSE;
if (debug)
cprintf ("adding node = %ld\n", the_next_node);
last_node = the_next_node;
}
}
the_next_node = 0;
if (! case_sensative) string[i] = tolower (string[i]);
if (!add_failed &&
!add_new_edge(dawg, &last_node, &the_next_node,
string[i], TRUE, max_num_edges, reserved_edges))
add_failed = true;
if (edges_in_node (dawg, 0) > reserved_edges) {
cprintf ("error: Not enough room in root node, %d\n",
edges_in_node (dawg, 0));
add_failed = true;
}
if (add_failed) {
cprintf ("Re-initializing document dictionary...\n");
initialize_dawg(dawg,max_num_edges);
}
}
/**********************************************************************
* initialize_dawg
*
* Initialize the DAWG data structure for further used. Reset each of
* the edge cells to NO_EDGE.
**********************************************************************/
void initialize_dawg(EDGE_ARRAY dawg, INT32 max_num_edges) {
INT32 x;
//changed by jetsoft
// these values were not getting changes.
move_counter = 0;
new_counter = 0;
edge_counter = 0;
// end jetsoft
clear_all_edges(dawg, x, max_num_edges);
}
/**********************************************************************
* move_node_if_needed
*
* Move the node location if there is a need to do it because there is
* not enough room to add the new edges.
**********************************************************************/
bool move_node_if_needed(EDGE_ARRAY dawg,
NODE_REF* node,
INT32 max_num_edges,
INT32 reserved_edges) {
if (room_in_node(dawg, *node))
return true;
NODE_REF this_new_node;
EDGE_REF edge;
INT32 num_edges = edges_in_node (dawg, *node);
if (debug)
print_dawg_node(dawg, *node);
this_new_node = new_dawg_node (dawg, num_edges + EDGE_NUM_MARGIN,
max_num_edges, reserved_edges);
if (this_new_node == 0)
return false;
if (debug)
cprintf ("move_node (from = " REFFORMAT ", to = " REFFORMAT
", num = %d)\n",
*node, this_new_node, num_edges);
move_edges(dawg, *node, this_new_node, num_edges);
if (debug)
print_dawg_node(dawg, this_new_node);
edge = this_new_node;
if (forward_edge (dawg, edge)) {
do {
relocate_edge (dawg, next_node (dawg, edge), *node, this_new_node);
} edge_loop (dawg, edge);
}
if (backward_edge (dawg, edge)) {
do {
relocate_edge (dawg, next_node (dawg, edge), *node, this_new_node);
} edge_loop (dawg, edge);
}
move_counter++;
*node = this_new_node;
return true;
}
/**********************************************************************
* new_dawg_node
*
* Create a space within the DAWG data structure to house a node that
* consists of the requested number of edges.
**********************************************************************/
NODE_REF new_dawg_node(EDGE_ARRAY dawg,
INT32 num_edges,
INT32 max_num_edges,
INT32 reserved_edges) {
INT32 i;
INT32 n;
INT32 edge_index;
INT32 edge_collision;
/* Try several times */
for (i=0; i<NUM_PLACEMENT_ATTEMPTS; i++) {
edge_index = reserved_edges +
long_rand (max_num_edges - MAX_WERD_LENGTH - reserved_edges);
edge_collision = FALSE;
/* Find N adjacent slots */
for (n=0; n<num_edges && !edge_collision; n++) {
if (edge_occupied (dawg, edge_index + n))
edge_collision = TRUE;
}
if (! edge_collision) {
new_counter++;
//? max_new_attempts = max (max_new_attempts, i);
return (edge_index);
}
}
cprintf ("DAWG Table is too full, nodes = %d, edges = %d, moves %d\n",
new_counter, edge_counter, move_counter);
return 0;
}
/**********************************************************************
* print_dawg_map
*
* Print the contents of one of the nodes in the DAWG.
**********************************************************************/
void print_dawg_map (EDGE_ARRAY dawg, INT32 max_num_edges) {
EDGE_REF edge = 0;
INT32 counter = 0;
do {
if (edge_occupied (dawg, edge))
printf (".");
else
printf (" ");
if (counter % 100 == 0) fflush (stdout);
} while (edge++ < max_num_edges);
}
/**********************************************************************
* read_full_dawg
*
* Read this DAWG in from a file. The nodes in this DAWG contain both
* forward and backward edges. There are gaps in between the nodes.
**********************************************************************/
void read_full_dawg (const char *filename,
EDGE_ARRAY dawg,
INT32 max_num_edges) {
FILE *file;
EDGE_REF node_index;
INT32 num_edges;
INT32 node_count;
INT32 error_occured = FALSE;
if (debug) print_string ("read_dawg");
clear_all_edges (dawg, node_index, max_num_edges);
file = open_file (filename, "rb");
fread (&node_count, sizeof (INT32), 1, file);
while (node_count-- > 0) {
fread (&node_index, sizeof (EDGE_REF), 1, file);
fread (&num_edges, sizeof (INT32), 1, file);
assert (node_index + num_edges < max_num_edges);
fread (&dawg[node_index], sizeof (EDGE_RECORD), num_edges, file);
if (debug > 2) {
print_dawg_node (dawg, node_index);
new_line ();
}
}
fclose (file);
if (error_occured) exit (1);
}
/**********************************************************************
* read_word_list
*
* Read the requested file (containing a list of words) and add all
* the words to the DAWG.
**********************************************************************/
void read_word_list(const char *filename,
EDGE_ARRAY dawg,
INT32 max_num_edges,
INT32 reserved_edges) {
FILE *word_file;
char string [CHARS_PER_LINE];
int word_count = 0;
int old_debug = debug;
if (debug > 0 && debug < 3)
debug = 0;
word_file = open_file (filename, "r");
initialize_dawg(dawg, max_num_edges);
while (fgets (string, CHARS_PER_LINE, word_file) != NULL) {
string [strlen (string) - 1] = (char) 0;
++word_count;
if (debug && word_count % 10000 == 0)
cprintf("Read %d words so far\n", word_count);
if (string[0] != '\0' /* strlen (string) */) {
add_word_to_dawg(dawg, string, max_num_edges, reserved_edges);
if (! word_in_dawg (dawg, string)) {
cprintf ("error: word not in DAWG after adding it '%s'\n", string);
return;
}
}
}
debug = old_debug;
if (debug)
cprintf("Read %d words total.\n", word_count);
fclose(word_file);
}
/**********************************************************************
* relocate_edge
*
* The location of a node has moved, so an edge entry in another node
* must be changed. Change the value of this edge entry to match the
* new location of the node.
**********************************************************************/
void relocate_edge(EDGE_ARRAY dawg,
NODE_REF node,
NODE_REF old_node,
NODE_REF new_node) {
EDGE_REF edge;
if (debug) cprintf ("relocate (" REFFORMAT ", " REFFORMAT " ==> " \
REFFORMAT ")\n", node, old_node, new_node);
edge = node;
if (forward_edge (dawg, edge)) {
do {
if (next_node (dawg, edge) == old_node) {
if (debug)
cprintf ("forward assign (" REFFORMAT ", " REFFORMAT " ==> " \
REFFORMAT ")\n", edge, old_node, new_node);
set_next_edge(dawg, edge, new_node);
}
} edge_loop (dawg, edge);
}
if (backward_edge (dawg, edge)) {
do {
if (next_node (dawg, edge) == old_node) {
if (debug)
cprintf ("backward assign (" REFFORMAT ", " REFFORMAT " ==> " \
REFFORMAT ")\n", edge, old_node, new_node);
set_next_edge(dawg, edge, new_node);
}
}
edge_loop(dawg, edge);
}
}
/**********************************************************************
* remove_edge
*
* Add a single edge linkage to between the two nodes. This function
* can be used to add either forward or backward links.
**********************************************************************/
void remove_edge(EDGE_ARRAY dawg,
NODE_REF node1,
NODE_REF node2,
char character,
EDGE_RECORD word_end) {
remove_edge_linkage(dawg, node1, node2, FORWARD_EDGE, character, word_end);
remove_edge_linkage(dawg, node2, node1, BACKWARD_EDGE, character, word_end);
}
/**********************************************************************
* remove_edge_linkage
*
* Remove this edge reference from this node. Move the edge entries in
* this node to fill the gap.
**********************************************************************/
void remove_edge_linkage(EDGE_ARRAY dawg,
NODE_REF node,
NODE_REF next,
EDGE_RECORD direction,
char character,
EDGE_RECORD word_end) {
INT32 forward_edges;
INT32 num_edges;
NODE_REF e = node;
INT32 last_flag;
forward_edges = num_forward_edges (dawg, node);
num_edges = edges_in_node (dawg, node);
for (e=node; e<node+num_edges; e++) {
/* Is this the edge*/
if ((edge_letter (dawg, e) == character) &&
((direction == FORWARD_EDGE) ?
forward_edge(dawg,e) : backward_edge(dawg,e)) &&
(next_node (dawg, e) == next) &&
(word_end ? end_of_word(dawg,e) : (! end_of_word(dawg,e)))) {
if (debug)
cprintf ("remove (edge = " REFFORMAT ", character is '%c')\n",
e, edge_letter (dawg, e));
/* Delete the slot */
last_flag = last_edge (dawg, e);
set_empty_edge(dawg, e);
move_edges (dawg, e+1, e, num_edges+node-e-1);
/* Restore 'last' flag */
if (direction == FORWARD_EDGE) {
if ((forward_edges - 1) &&
(forward_edges - 1 == e - node)) {
set_last_flag (dawg, e - 1);
}
}
else {
if ((num_edges - forward_edges - 1) &&
(num_edges - 1 == e - node)) {
set_last_flag (dawg, e - 1);
}
}
if (debug)
print_dawg_node(dawg, node);
return;
}
}
cprintf ("error: Could not find the edge to remove, %d char = '%c'\n",
next, character);
print_dawg_node(dawg, node);
exit (1);
}
/**********************************************************************
* room_in_node
*
* Check to see if there is enough room left in this node for one more
* edge link. This may be a forward or backward link.
**********************************************************************/
INT32 room_in_node(EDGE_ARRAY dawg, NODE_REF node) {
EDGE_REF edge = node;
if (edge_occupied (dawg, edge + edges_in_node (dawg, node))) {
return (FALSE);
}
else {
return (TRUE);
}
}
/**********************************************************************
* write_full_dawg
*
* Write the DAWG out to a file
**********************************************************************/
void write_full_dawg (const char *filename, EDGE_ARRAY dawg,
INT32 max_num_edges) {
FILE *file;
EDGE_REF edge;
INT32 num_edges;
INT32 node_count = 0;
NODE_REF node;
if (debug) print_string ("write_full_dawg");
for (edge=0; edge<max_num_edges; edge++) {
/* Count nodes links */
if (forward_edge (dawg, edge)) {
node_count++;
if (forward_edge (dawg, edge)) edge_loop (dawg, edge);
if (backward_edge (dawg, edge)) edge_loop (dawg, edge);
edge--;
}
}
file = open_file (filename, "wb");
fwrite (&node_count, sizeof (INT32), 1, file);
node_count = 0;
for (edge=0; edge<max_num_edges; edge++) {
/* Write all edges */
if (forward_edge (dawg, edge)) {
node = edge;
num_edges = edges_in_node (dawg, edge);
assert ((node + num_edges < max_num_edges) && (num_edges > 0));
fwrite (&edge, sizeof (EDGE_REF), 1, file);
fwrite (&num_edges, sizeof (INT32), 1, file);
fwrite (&edge_of (dawg,edge), sizeof (EDGE_RECORD), num_edges, file);
node_count++;
if (debug) {
printf ("Writing node index=" REFFORMAT
", node_count=%d, edges=%d\n",
node, node_count, num_edges);
for (edge = node; edge < node + num_edges; edge++) {
printf ("Writing index=" REFFORMAT ", old_node=" REFFORMAT \
", letter=%c, flags=%d\n",
node, next_node (dawg,edge),
(char) edge_letter(dawg,edge),
(char) edge_flags (dawg,edge));
}
}
edge = node + num_edges - 1;
}
}
fclose (file);
}
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