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tesseract/dict/dawg.h

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/* -*-C-*-
********************************************************************************
*
* File: dawg.h (Formerly dawg.h)
* Description: Definition of a class that represents Directed Accyclic Word
* Graph (DAWG), functions to build and manipulate the DAWG.
* Author: Mark Seaman, SW Productivity
* Created: Fri Oct 16 14:37:00 1987
* Modified: Wed Jun 19 16:50:24 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.
*
*********************************************************************************/
#ifndef DICT_DAWG_H_
#define DICT_DAWG_H_
/*----------------------------------------------------------------------
I n c l u d e s
----------------------------------------------------------------------*/
#include "elst.h"
#include "ratngs.h"
#include "params.h"
#include "tesscallback.h"
#ifndef __GNUC__
#ifdef _WIN32
#define NO_EDGE (inT64) 0xffffffffffffffffi64
#endif /*_WIN32*/
#else
#define NO_EDGE (inT64) 0xffffffffffffffffll
#endif /*__GNUC__*/
/*----------------------------------------------------------------------
T y p e s
----------------------------------------------------------------------*/
class UNICHARSET;
typedef uinT64 EDGE_RECORD;
typedef EDGE_RECORD *EDGE_ARRAY;
typedef inT64 EDGE_REF;
typedef inT64 NODE_REF;
typedef EDGE_REF *NODE_MAP;
namespace tesseract {
struct NodeChild {
UNICHAR_ID unichar_id;
EDGE_REF edge_ref;
NodeChild(UNICHAR_ID id, EDGE_REF ref): unichar_id(id), edge_ref(ref) {}
NodeChild(): unichar_id(INVALID_UNICHAR_ID), edge_ref(NO_EDGE) {}
};
typedef GenericVector<NodeChild> NodeChildVector;
typedef GenericVector<int> SuccessorList;
typedef GenericVector<SuccessorList *> SuccessorListsVector;
enum DawgType {
DAWG_TYPE_PUNCTUATION,
DAWG_TYPE_WORD,
DAWG_TYPE_NUMBER,
DAWG_TYPE_PATTERN,
DAWG_TYPE_COUNT // number of enum entries
};
/*----------------------------------------------------------------------
C o n s t a n t s
----------------------------------------------------------------------*/
#define FORWARD_EDGE (inT32) 0
#define BACKWARD_EDGE (inT32) 1
#define MAX_NODE_EDGES_DISPLAY (inT64) 100
#define MARKER_FLAG (inT64) 1
#define DIRECTION_FLAG (inT64) 2
#define WERD_END_FLAG (inT64) 4
#define LETTER_START_BIT 0
#define NUM_FLAG_BITS 3
#define REFFORMAT "%lld"
static const bool kDawgSuccessors[DAWG_TYPE_COUNT][DAWG_TYPE_COUNT] = {
{ 0, 1, 1, 0 }, // for DAWG_TYPE_PUNCTUATION
{ 1, 0, 0, 0 }, // for DAWG_TYPE_WORD
{ 1, 0, 0, 0 }, // for DAWG_TYPE_NUMBER
{ 0, 0, 0, 0 }, // for DAWG_TYPE_PATTERN
};
static const char kWildcard[] = "*";
/*----------------------------------------------------------------------
C l a s s e s a n d S t r u c t s
----------------------------------------------------------------------*/
//
/// Abstract class (an interface) that declares methods needed by the
/// various tesseract classes to operate on SquishedDawg and Trie objects.
///
/// This class initializes all the edge masks (since their usage by
/// SquishedDawg and Trie is identical) and implements simple accessors
/// for each of the fields encoded in an EDGE_RECORD.
/// This class also implements word_in_dawg() and check_for_words()
/// (since they use only the public methods of SquishedDawg and Trie
/// classes that are inherited from the Dawg base class).
//
class Dawg {
public:
/// Magic number to determine endianness when reading the Dawg from file.
static const inT16 kDawgMagicNumber = 42;
/// A special unichar id that indicates that any appropriate pattern
/// (e.g.dicitonary word, 0-9 digit, etc) can be inserted instead
/// Used for expressing patterns in punctuation and number Dawgs.
static const UNICHAR_ID kPatternUnicharID = 0;
inline DawgType type() const { return type_; }
inline const STRING &lang() const { return lang_; }
inline PermuterType permuter() const { return perm_; }
virtual ~Dawg() {};
/// Returns true if the given word is in the Dawg.
bool word_in_dawg(const WERD_CHOICE &word) const;
// Returns true if the given word prefix is not contraindicated by the dawg.
// If requires_complete is true, then the exact complete word must be present.
bool prefix_in_dawg(const WERD_CHOICE &prefix, bool requires_complete) const;
/// Checks the Dawg for the words that are listed in the requested file.
/// Returns the number of words in the given file missing from the Dawg.
int check_for_words(const char *filename,
const UNICHARSET &unicharset,
bool enable_wildcard) const;
// For each word in the Dawg, call the given (permanent) callback with the
// text (UTF-8) version of the word.
void iterate_words(const UNICHARSET &unicharset,
TessCallback1<const WERD_CHOICE *> *cb) const;
// For each word in the Dawg, call the given (permanent) callback with the
// text (UTF-8) version of the word.
void iterate_words(const UNICHARSET &unicharset,
TessCallback1<const char *> *cb) const;
// Pure virtual function that should be implemented by the derived classes.
/// Returns the edge that corresponds to the letter out of this node.
virtual EDGE_REF edge_char_of(NODE_REF node, UNICHAR_ID unichar_id,
bool word_end) const = 0;
/// Fills the given NodeChildVector with all the unichar ids (and the
/// corresponding EDGE_REFs) for which there is an edge out of this node.
virtual void unichar_ids_of(NODE_REF node, NodeChildVector *vec,
bool word_end) const = 0;
/// Returns the next node visited by following the edge
/// indicated by the given EDGE_REF.
virtual NODE_REF next_node(EDGE_REF edge_ref) const = 0;
/// Returns true if the edge indicated by the given EDGE_REF
/// marks the end of a word.
virtual bool end_of_word(EDGE_REF edge_ref) const = 0;
/// Returns UNICHAR_ID stored in the edge indicated by the given EDGE_REF.
virtual UNICHAR_ID edge_letter(EDGE_REF edge_ref) const = 0;
/// Prints the contents of the node indicated by the given NODE_REF.
/// At most max_num_edges will be printed.
virtual void print_node(NODE_REF node, int max_num_edges) const = 0;
/// Fills vec with unichar ids that represent the character classes
/// of the given unichar_id.
virtual void unichar_id_to_patterns(UNICHAR_ID unichar_id,
const UNICHARSET &unicharset,
GenericVector<UNICHAR_ID> *vec) const {};
/// Returns the given EDGE_REF if the EDGE_RECORD that it points to has
/// a self loop and the given unichar_id matches the unichar_id stored in the
/// EDGE_RECORD, returns NO_EDGE otherwise.
virtual EDGE_REF pattern_loop_edge(
EDGE_REF edge_ref, UNICHAR_ID unichar_id, bool word_end) const {
return false;
}
protected:
Dawg() {}
/// Returns the next node visited by following this edge.
inline NODE_REF next_node_from_edge_rec(const EDGE_RECORD &edge_rec) const {
return ((edge_rec & next_node_mask_) >> next_node_start_bit_);
}
/// Returns the marker flag of this edge.
inline bool marker_flag_from_edge_rec(const EDGE_RECORD &edge_rec) const {
return (edge_rec & (MARKER_FLAG << flag_start_bit_)) != 0;
}
/// Returns the direction flag of this edge.
inline int direction_from_edge_rec(const EDGE_RECORD &edge_rec) const {
return ((edge_rec & (DIRECTION_FLAG << flag_start_bit_))) ?
BACKWARD_EDGE : FORWARD_EDGE;
}
/// Returns true if this edge marks the end of a word.
inline bool end_of_word_from_edge_rec(const EDGE_RECORD &edge_rec) const {
return (edge_rec & (WERD_END_FLAG << flag_start_bit_)) != 0;
}
/// Returns UNICHAR_ID recorded in this edge.
inline UNICHAR_ID unichar_id_from_edge_rec(
const EDGE_RECORD &edge_rec) const {
return ((edge_rec & letter_mask_) >> LETTER_START_BIT);
}
/// Sets the next node link for this edge in the Dawg.
inline void set_next_node_in_edge_rec(
EDGE_RECORD *edge_rec, EDGE_REF value) {
*edge_rec &= (~next_node_mask_);
*edge_rec |= ((value << next_node_start_bit_) & next_node_mask_);
}
/// Sets this edge record to be the last one in a sequence of edges.
inline void set_marker_flag_in_edge_rec(EDGE_RECORD *edge_rec) {
*edge_rec |= (MARKER_FLAG << flag_start_bit_);
}
/// Sequentially compares the given values of unichar ID, next node
/// and word end marker with the values in the given EDGE_RECORD.
/// Returns: 1 if at any step the given input value exceeds
/// that of edge_rec (and all the values already
/// checked are the same)
/// 0 if edge_rec_match() returns true
/// -1 otherwise
inline int given_greater_than_edge_rec(NODE_REF next_node,
bool word_end,
UNICHAR_ID unichar_id,
const EDGE_RECORD &edge_rec) const {
UNICHAR_ID curr_unichar_id = unichar_id_from_edge_rec(edge_rec);
NODE_REF curr_next_node = next_node_from_edge_rec(edge_rec);
bool curr_word_end = end_of_word_from_edge_rec(edge_rec);
if (edge_rec_match(next_node, word_end, unichar_id, curr_next_node,
curr_word_end, curr_unichar_id)) return 0;
if (unichar_id > curr_unichar_id) return 1;
if (unichar_id == curr_unichar_id) {
if (next_node > curr_next_node) return 1;
if (next_node == curr_next_node) {
if (word_end > curr_word_end) return 1;
}
}
return -1;
}
/// Returns true if all the values are equal (any value matches
/// next_node if next_node == NO_EDGE, any value matches word_end
/// if word_end is false).
inline bool edge_rec_match(NODE_REF next_node,
bool word_end,
UNICHAR_ID unichar_id,
NODE_REF other_next_node,
bool other_word_end,
UNICHAR_ID other_unichar_id) const {
return ((unichar_id == other_unichar_id) &&
(next_node == NO_EDGE || next_node == other_next_node) &&
(!word_end || (word_end == other_word_end)));
}
/// Sets type_, lang_, perm_, unicharset_size_.
/// Initializes the values of various masks from unicharset_size_.
void init(DawgType type, const STRING &lang,
PermuterType perm, int unicharset_size, int debug_level);
/// Matches all of the words that are represented by this string.
/// If wilcard is set to something other than INVALID_UNICHAR_ID,
/// the *'s in this string are interpreted as wildcards.
/// WERD_CHOICE param is not passed by const so that wildcard searches
/// can modify it and work without having to copy WERD_CHOICEs.
bool match_words(WERD_CHOICE *word, inT32 index,
NODE_REF node, UNICHAR_ID wildcard) const;
// Recursively iterate over all words in a dawg (see public iterate_words).
void iterate_words_rec(const WERD_CHOICE &word_so_far,
NODE_REF to_explore,
TessCallback1<const WERD_CHOICE *> *cb) const;
// Member Variables.
DawgType type_;
STRING lang_;
/// Permuter code that should be used if the word is found in this Dawg.
PermuterType perm_;
// Variables to construct various edge masks. Formerly:
// #define NEXT_EDGE_MASK (inT64) 0xfffffff800000000i64
// #define FLAGS_MASK (inT64) 0x0000000700000000i64
// #define LETTER_MASK (inT64) 0x00000000ffffffffi64
int unicharset_size_;
int flag_start_bit_;
int next_node_start_bit_;
uinT64 next_node_mask_;
uinT64 flags_mask_;
uinT64 letter_mask_;
// Level of debug statements to print to stdout.
int debug_level_;
};
//
// DawgPosition keeps track of where we are in the primary dawg we're searching
// as well as where we may be in the "punctuation dawg" which may provide
// surrounding context.
//
// Example:
// punctuation dawg -- space is the "pattern character"
// " " // no punctuation
// "' '" // leading and trailing apostrophes
// " '" // trailing apostrophe
// word dawg:
// "cat"
// "cab"
// "cat's"
//
// DawgPosition(dawg_index, dawg_ref, punc_index, punc_ref, rtp)
//
// DawgPosition(-1, NO_EDGE, p, pe, false)
// We're in the punctuation dawg, no other dawg has been started.
// (1) If there's a pattern edge as a punc dawg child of us,
// for each punc-following dawg starting with ch, produce:
// Result: DawgPosition(k, w, p', false)
// (2) If there's a valid continuation in the punc dawg, produce:
// Result: DawgPosition(-k, NO_EDGE, p', false)
//
// DawgPosition(k, w, -1, NO_EDGE, false)
// We're in dawg k. Going back to punctuation dawg is not an option.
// Follow ch in dawg k.
//
// DawgPosition(k, w, p, pe, false)
// We're in dawg k. Continue in dawg k and/or go back to the punc dawg.
// If ending, check that the punctuation dawg is also ok to end here.
//
// DawgPosition(k, w, p, pe true)
// We're back in the punctuation dawg. Continuing there is the only option.
struct DawgPosition {
DawgPosition()
: dawg_index(-1), dawg_ref(NO_EDGE), punc_ref(NO_EDGE),
back_to_punc(false) {}
DawgPosition(int dawg_idx, EDGE_REF dawgref,
int punc_idx, EDGE_REF puncref,
bool backtopunc)
: dawg_index(dawg_idx), dawg_ref(dawgref),
punc_index(punc_idx), punc_ref(puncref),
back_to_punc(backtopunc) {
}
bool operator==(const DawgPosition &other) {
return dawg_index == other.dawg_index &&
dawg_ref == other.dawg_ref &&
punc_index == other.punc_index &&
punc_ref == other.punc_ref &&
back_to_punc == other.back_to_punc;
}
inT8 dawg_index;
EDGE_REF dawg_ref;
inT8 punc_index;
EDGE_REF punc_ref;
// Have we returned to the punc dawg at the end of the word?
bool back_to_punc;
};
class DawgPositionVector : public GenericVector<DawgPosition> {
public:
/// Overload destructor, since clear() does not delete data_[] any more.
~DawgPositionVector() {
if (size_reserved_ > 0) {
delete[] data_;
size_used_ = 0;
size_reserved_ = 0;
}
}
/// Overload clear() in order to avoid allocating/deallocating memory
/// when clearing the vector and re-inserting entries into it later.
void clear() { size_used_ = 0; }
/// Adds an entry for the given dawg_index with the given node to the vec.
/// Returns false if the same entry already exists in the vector,
/// true otherwise.
inline bool add_unique(const DawgPosition &new_pos,
bool debug,
const char *debug_msg) {
for (int i = 0; i < size_used_; ++i) {
if (data_[i] == new_pos) return false;
}
push_back(new_pos);
if (debug) {
tprintf("%s[%d, " REFFORMAT "] [punc: " REFFORMAT "%s]\n",
debug_msg, new_pos.dawg_index, new_pos.dawg_ref,
new_pos.punc_ref, new_pos.back_to_punc ? " returned" : "");
}
return true;
}
};
//
/// Concrete class that can operate on a compacted (squished) Dawg (read,
/// search and write to file). This class is read-only in the sense that
/// new words can not be added to an instance of SquishedDawg.
/// The underlying representation of the nodes and edges in SquishedDawg
/// is stored as a contiguous EDGE_ARRAY (read from file or given as an
/// argument to the constructor).
//
class SquishedDawg : public Dawg {
public:
SquishedDawg(FILE *file, DawgType type, const STRING &lang,
PermuterType perm, int debug_level) {
read_squished_dawg(file, type, lang, perm, debug_level);
num_forward_edges_in_node0 = num_forward_edges(0);
}
SquishedDawg(const char* filename, DawgType type,
const STRING &lang, PermuterType perm, int debug_level) {
FILE *file = fopen(filename, "rb");
if (file == NULL) {
tprintf("Failed to open dawg file %s\n", filename);
exit(1);
}
read_squished_dawg(file, type, lang, perm, debug_level);
num_forward_edges_in_node0 = num_forward_edges(0);
fclose(file);
}
SquishedDawg(EDGE_ARRAY edges, int num_edges, DawgType type,
const STRING &lang, PermuterType perm,
int unicharset_size, int debug_level) :
edges_(edges), num_edges_(num_edges) {
init(type, lang, perm, unicharset_size, debug_level);
num_forward_edges_in_node0 = num_forward_edges(0);
if (debug_level > 3) print_all("SquishedDawg:");
}
~SquishedDawg();
int NumEdges() { return num_edges_; }
/// Returns the edge that corresponds to the letter out of this node.
EDGE_REF edge_char_of(NODE_REF node, UNICHAR_ID unichar_id,
bool word_end) const;
/// Fills the given NodeChildVector with all the unichar ids (and the
/// corresponding EDGE_REFs) for which there is an edge out of this node.
void unichar_ids_of(NODE_REF node, NodeChildVector *vec,
bool word_end) const {
EDGE_REF edge = node;
if (!edge_occupied(edge) || edge == NO_EDGE) return;
assert(forward_edge(edge)); // we don't expect any backward edges to
do { // be present when this funciton is called
if (!word_end || end_of_word_from_edge_rec(edges_[edge])) {
vec->push_back(NodeChild(unichar_id_from_edge_rec(edges_[edge]), edge));
}
} while (!last_edge(edge++));
}
/// Returns the next node visited by following the edge
/// indicated by the given EDGE_REF.
NODE_REF next_node(EDGE_REF edge) const {
return next_node_from_edge_rec((edges_[edge]));
}
/// Returns true if the edge indicated by the given EDGE_REF
/// marks the end of a word.
bool end_of_word(EDGE_REF edge_ref) const {
return end_of_word_from_edge_rec((edges_[edge_ref]));
}
/// Returns UNICHAR_ID stored in the edge indicated by the given EDGE_REF.
UNICHAR_ID edge_letter(EDGE_REF edge_ref) const {
return unichar_id_from_edge_rec((edges_[edge_ref]));
}
/// Prints the contents of the node indicated by the given NODE_REF.
/// At most max_num_edges will be printed.
void print_node(NODE_REF node, int max_num_edges) const;
/// Writes the squished/reduced Dawg to a file.
void write_squished_dawg(FILE *file);
/// Opens the file with the given filename and writes the
/// squished/reduced Dawg to the file.
void write_squished_dawg(const char *filename) {
FILE *file = fopen(filename, "wb");
if (file == NULL) {
tprintf("Error opening %s\n", filename);
exit(1);
}
this->write_squished_dawg(file);
fclose(file);
}
private:
/// Sets the next node link for this edge.
inline void set_next_node(EDGE_REF edge_ref, EDGE_REF value) {
set_next_node_in_edge_rec(&(edges_[edge_ref]), value);
}
/// Sets the edge to be empty.
inline void set_empty_edge(EDGE_REF edge_ref) {
(edges_[edge_ref] = next_node_mask_);
}
/// Goes through all the edges and clears each one out.
inline void clear_all_edges() {
for (int edge = 0; edge < num_edges_; edge++) set_empty_edge(edge);
}
/// Clears the last flag of this edge.
inline void clear_marker_flag(EDGE_REF edge_ref) {
(edges_[edge_ref] &= ~(MARKER_FLAG << flag_start_bit_));
}
/// Returns true if this edge is in the forward direction.
inline bool forward_edge(EDGE_REF edge_ref) const {
return (edge_occupied(edge_ref) &&
(FORWARD_EDGE == direction_from_edge_rec(edges_[edge_ref])));
}
/// Returns true if this edge is in the backward direction.
inline bool backward_edge(EDGE_REF edge_ref) const {
return (edge_occupied(edge_ref) &&
(BACKWARD_EDGE == direction_from_edge_rec(edges_[edge_ref])));
}
/// Returns true if the edge spot in this location is occupied.
inline bool edge_occupied(EDGE_REF edge_ref) const {
return (edges_[edge_ref] != next_node_mask_);
}
/// Returns true if this edge is the last edge in a sequence.
inline bool last_edge(EDGE_REF edge_ref) const {
return (edges_[edge_ref] & (MARKER_FLAG << flag_start_bit_)) != 0;
}
/// Counts and returns the number of forward edges in this node.
inT32 num_forward_edges(NODE_REF node) const;
/// Reads SquishedDawg from a file.
void read_squished_dawg(FILE *file, DawgType type, const STRING &lang,
PermuterType perm, int debug_level);
/// Prints the contents of an edge indicated by the given EDGE_REF.
void print_edge(EDGE_REF edge) const;
/// Prints the contents of the SquishedDawg.
void print_all(const char* msg) {
tprintf("\n__________________________\n%s\n", msg);
for (int i = 0; i < num_edges_; ++i) print_edge(i);
tprintf("__________________________\n");
}
/// Constructs a mapping from the memory node indices to disk node indices.
NODE_MAP build_node_map(inT32 *num_nodes) const;
// Member variables.
EDGE_ARRAY edges_;
int num_edges_;
int num_forward_edges_in_node0;
};
} // namespace tesseract
#endif // DICT_DAWG_H_
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