li_recognizer.c

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

/*
 *  li_recognizer.c
 *
 *	Copyright 2000 Compaq Computer Corporation.
 *	Copying or modifying this code for any purpose is permitted,
 *	provided that this copyright notice is preserved in its entirety
 *	in all copies or modifications.
 *	COMPAQ COMPUTER CORPORATION MAKES NO WARRANTIES, EXPRESSED OR
 *	IMPLIED, AS TO THE USEFULNESS OR CORRECTNESS OF THIS CODE OR
 *
 *
 *  Adapted from cmu_recognizer.c by Jay Kistler.
 *  
 *  Where is the CMU copyright???? Gotta track it down - Jim Gettys
 *
 *  Credit to Dean Rubine, Jim Kempf, and Ari Rapkin.
 */

#include <u.h>
#include <libc.h>
#include <stdio.h>
#include <draw.h>
#include <scribble.h>
#include "scribbleimpl.h"

#include "hre_internal.h"
#include "li_recognizer_internal.h"

int lidebug = 0;

#define LI_MAGIC 0xACCBADDD

#define CHECK_LI_MAGIC(_a) \
  ((_a) != nil && ((li_recognizer*)(_a))->li_magic == LI_MAGIC)


static void lialg_initialize(rClassifier *);
static int lialg_read_classifier_digest(rClassifier *);
static int lialg_canonicalize_examples(rClassifier *);
static char *lialg_recognize_stroke(rClassifier *, point_list *);
static void lialg_compute_lpf_parameters(void);


char* li_err_msg = nil;

#define bcopy(s1,s2,n) memmove(s2,s1,n)

/*Freeing classifier*/

static void
free_rClassifier(rClassifier* rc);

/*
 * Point List Support
*/

static point_list*
add_example(point_list* l,int npts,pen_point* pts)
{
	pen_point* lpts = mallocz(npts*sizeof(pen_point), 1);
	point_list *p = malloc(sizeof(point_list));

	p->npts = npts;
	p->pts = lpts;
	p->next = l;       /*Order doesn't matter, so we stick on end.*/

	/*Copy points.*/

	bcopy(pts, lpts, npts * sizeof(pen_point));

	return(p);
}
	

static void
delete_examples(point_list* l)
{
	point_list* p;

	for( ; l != nil; l = p ) {
		p = l->next;
		free(l->pts);
		free(l);
	}
}

/*
 * Local functions
 */

/*
 * recognize_internal-Form Vector, use Classifier to classify, return char.
 */

static char*
recognize_internal(rClassifier* rec, Stroke* str, int*)
{
	char *res;
	point_list *stroke;

	stroke = add_example(nil, str->npts, str->pts);
	if (stroke == nil) return(nil);

	res = lialg_recognize_stroke(rec, stroke);

	delete_examples(stroke);
	return(res);
}

/*
 * file_path-Construct pathname, check for proper extension.
 */

static int
  file_path(char* dir,char* filename,char* pathname)
{
	char* dot;
	
	/*Check for proper extension on file name.*/
	
	dot = strrchr(filename,'.');
	
	if( dot == nil ) {
		return(-1);
	}

	/*Determine whether a gesture or character classifier.*/

	if( strcmp(dot,LI_CLASSIFIER_EXTENSION) != 0 ) {
		return(-1);
	}

	/*Concatenate directory and filename into pathname.*/
	
	strcpy(pathname,dir);
	strcat(pathname,"/");
	strcat(pathname,filename);
	
	return(0);
}

/*read_classifier_points-Read points so classifier can be extended.*/

static int 
read_classifier_points(FILE* fd,int nclss,point_list** ex,char** cnames)
{
	int i,j,k;
	char buf[BUFSIZ];
	int nex = 0;
	char* names[MAXSCLASSES];
	point_list* examples[MAXSCLASSES];
	pen_point* pts;
	int npts;

	/*Initialize*/

		for( i = 0; i < MAXSCLASSES; i++ ) {
				names[i] = nil;
				examples[i] = nil;
		}

		/*Go thru classes.*/

		for( k = 0; k < nclss; k++ ) {

				/*Read class name and number of examples.*/
		
				if( fscanf(fd,"%d %s",&nex,buf) != 2 )
					goto unallocate;
		
				/*Save class name*/
		
				names[k] = strdup(buf);
		
				/*Read examples.*/
				
				for( i = 0; i < nex; i++ ) {
					
					/*Read number of points.*/
					
					if( fscanf(fd,"%d",&npts) != 1 )
								goto unallocate; /*Boy would I like exceptions!*/
					
					/*Allocate array for points.*/
					
					if( (pts = mallocz(npts*sizeof(pen_point), 1)) == nil )
								goto unallocate;
					
					/*Read in points.*/
					
					for( j = 0; j < npts; j++ ) {
								int x,y;
								if( fscanf(fd,"%d %d",&x,&y) != 2 ) {
									delete_pen_point_array(pts);
									goto unallocate;
								}
								pts[j].Point = Pt(x, y);
					}
					
					/*Add example*/
					
					if( (examples[k] = add_example(examples[k],npts,pts)) == nil ) {
								delete_pen_point_array(pts);
								goto unallocate;
					}
					
					delete_pen_point_array(pts);
			
				}
		}

/* ari -- end of list of classes */
/* fprint(2, "]\n"); */

		/*Transfer to recognizer.*/

		bcopy(examples,ex,sizeof(examples));
		bcopy(names,cnames,sizeof(names));

		return(0);

		/*Error. Deallocate memory and return.*/

unallocate:
		for( ; k >= 0; k-- ) {
				delete_examples(examples[k]);
				free(names[k]);
		}

		return(-1);
}

/*read_classifier-Read a classifier file.*/

static int read_classifier(FILE* fd,rClassifier* rc)
{
	
	li_err_msg = nil;

	/*Read in classifier file.*/

	if(fscanf(fd, "%d", &rc->nclasses) != 1)
		return -1;

	/*Read in the example points, so classifier can be extended.*/

	if( read_classifier_points(fd,rc->nclasses,rc->ex,rc->cnames) != 0 )
		return -1;

	return(0);
}

/*
 * Extension Functions
*/

/* getClasses and clearState are by Ari */

static int
recognizer_getClasses (recognizer r, char ***list, int *nc)
{
	int i, nclasses;
	li_recognizer* rec;
	char **ret;

		rec = (li_recognizer*)r->recognizer_specific;

		/*Check for LI recognizer.*/

		if( !CHECK_LI_MAGIC(rec) ) {
				li_err_msg = "Not a LI recognizer";
				return(-1);
	}
	
	*nc = nclasses = rec->li_rc.nclasses;
	ret = malloc(nclasses*sizeof(char*));

	for (i = 0; i < nclasses; i++)
				ret[i] = rec->li_rc.cnames[i];   /* only the 1st char of the cname */
	*list = ret;
		return 0;
}

static int
recognizer_clearState (recognizer)
{
  /*This operation isn't supported by the LI recognizer.*/

  li_err_msg = "Clearing state is not supported by the LI recognizer";

  return(-1);
}

static bool isa_li(recognizer r)
{ return(CHECK_LI_MAGIC(r)); }

static int
recognizer_train(recognizer, rc*, uint, Stroke*, rec_element*, bool)
{
  /*This operation isn't supported by the LI recognizer.*/

  li_err_msg = "Training is not supported by the LI recognizer";

  return(-1);
}

int
li_recognizer_get_example (recognizer r,
						   int		class, 
						   int		instance,
						   char		**name, 
						   pen_point	**points,
						   int		*npts)
{
	li_recognizer   *rec = (li_recognizer*)r->recognizer_specific;
	int nclasses = rec->li_rc.nclasses;
	point_list	    *pl;
	
		if( !CHECK_LI_MAGIC(rec) ) {
				li_err_msg = "Not a LI recognizer";
				return(-1);
		}
		if (class > nclasses)
				return -1;
		pl = rec->li_rc.canonex[class];
		while (instance && pl)
		{
				pl = pl->next;
				instance--;
		}
		if (!pl)
				return -1;
		*name = rec->li_rc.cnames[class];
		*points = pl->pts;
		*npts = pl->npts;
		return pl->npts; /* I hope [sjm] */
}

/*
 * API Functions
 */


/*li_recognizer_load-Load a classifier file.*/

static int li_recognizer_load(recognizer r, char* dir, char* filename)
{
		FILE *fd;
		char* pathname;
		li_recognizer* rec;
		rClassifier* rc;
		
		rec = (li_recognizer*)r->recognizer_specific;

		/*Make sure recognizer's OK*/

		if( !CHECK_LI_MAGIC(rec) ) {
				li_err_msg = "Not a LI recognizer";
				return(-1);
		}

		rc = &(rec->li_rc);

		/*Check parameters.*/

		if( filename == nil ) {
				li_err_msg = "Invalid parameters";
				return(-1);
		}

		/*We let the directory be null.*/

		if( dir == nil || (int)strlen(dir) <= 0 ) {
				dir = ".";
		}

		if(0)fprint(2, "dir = %s, filename = %s\n",
				dir, filename);

		/*Make full pathname and check filename*/

		pathname = malloc((strlen(dir) + strlen(filename) + 2)*sizeof(char));
		if( file_path(dir, filename, pathname) == -1 ) {
				free(pathname);
				li_err_msg = "Not a LI recognizer classifier file";
				return -1;
		}

		/* Try to short-circuit the full classifier-file processing. */
		rc->file_name = pathname;
		if (lialg_read_classifier_digest(rc) == 0)
				return(0);
		rc->file_name = nil;

		/*Open the file*/

		if( (fd = fopen(pathname,"r")) == nil ) {
				li_err_msg = "Can't open classifier file";
				if(0)fprint(2, "Can't open %s.\n", pathname);
				free(pathname);
				return(-1);
		}

		/*If rClassifier is OK, then delete it first.*/

		if( rc->file_name != nil ) {
				free_rClassifier(rc);
		}

		/*Read classifier.*/
		
		if( read_classifier(fd,rc) < 0 ) {
				free(pathname);
				return(-1);
		}

		/*Close file.*/

		fclose(fd);

		/*Add classifier name.*/

		rc->file_name = pathname;

		/* Canonicalize examples. */
		if (lialg_canonicalize_examples(rc) != 0) {
				free(pathname);
				rc->file_name = nil;
				return -1;
		}

		return(0);
}

/*li_recognizer_save-Save a classifier file.*/

static int li_recognizer_save(recognizer, char*, char*)
{ 
		/*This operation isn't supported by the LI recognizer.*/

		li_err_msg = "Saving is not supported by the LI recognizer";
		return -1;
}

static wordset
li_recognizer_load_dictionary(recognizer, char*, char*)
{
		/*This operation isn't supported by the LI recognizer.*/

		li_err_msg = "Dictionaries are not supported by the LI recognizer";
		return nil;
}

static int
li_recognizer_save_dictionary(recognizer, char*, char*, wordset)
{
		/*This operation isn't supported by the LI recognizer.*/
		li_err_msg = "Dictionaries are not supported by the LI recognizer";
		return -1;
}

static int
li_recognizer_free_dictionary(recognizer, wordset)
{
  /*This operation isn't supported by the LI recognizer.*/

  li_err_msg = "Dictionaries are not supported by the LI recognizer";

  return -1;

}

static int
li_recognizer_add_to_dictionary(recognizer, letterset*, wordset)
{
		/*This operation isn't supported by the LI recognizer.*/
		li_err_msg = "Dictionaries are not supported by the LI recognizer";
		return -1;
}

static int
li_recognizer_delete_from_dictionary(recognizer, letterset*, wordset)
{
		/*This operation isn't supported by the LI recognizer.*/
		li_err_msg = "Dictionaries are not supported by the LI recognizer";
		return -1;
}

static char*
li_recognizer_error(recognizer rec)
{
	char* ret = li_err_msg;

	/*Check for LI recognizer.*/

	if( !CHECK_LI_MAGIC(rec->recognizer_specific) ) {
				li_err_msg = "Not a LI recognizer";
				return nil;
	}
	li_err_msg = nil;
	return ret;
}

static int 
li_recognizer_clear(recognizer r, bool)
{
		li_recognizer* rec; 

		rec = (li_recognizer*)r->recognizer_specific;
		/*Check for LI recognizer.*/
		if( !CHECK_LI_MAGIC(rec) ) {
				li_err_msg = "Not a LI recognizer";
				return 0;
		}
		return 0;
}

static int 
li_recognizer_set_context(recognizer, rc*)
{
		/*This operation isn't supported by the LI recognizer.*/
		li_err_msg = "Contexts are not supported by the LI recognizer";
		return -1;
}

static rc*
li_recognizer_get_context(recognizer)
{
		/*This operation isn't supported by the LI recognizer.*/
		li_err_msg = "Contexts are not supported by the LI recognizer";
		return nil;
}

static int 
li_recognizer_get_buffer(recognizer, uint*, Stroke**)
{
		/*This operation isn't supported by the LI recognizer.*/
		li_err_msg = "Buffer get/set are not supported by the LI recognizer";
		return -1;
}

static int 
li_recognizer_set_buffer(recognizer, uint, Stroke*)
{
		/*This operation isn't supported by the LI recognizer.*/
		li_err_msg = "Buffer get/set are not supported by the LI recognizer";
		return -1;
}

static int
li_recognizer_translate(recognizer r, uint ncs, Stroke* tps, bool, int* nret, rec_alternative** ret)
{
	char* clss;
	li_recognizer* rec; 
	int conf;
	rClassifier* rc;
	  
	rec = (li_recognizer*)r->recognizer_specific;

	*nret = 0;
	*ret = nil;

	/*Check for LI recognizer.*/

	if( !CHECK_LI_MAGIC(rec) ) {
				li_err_msg = "Not a LI recognizer";
				return(-1);
	}

		rc = &(rec->li_rc);

	/*Check for valid parameters.*/
	if (ncs < 1) {
				li_err_msg = "Invalid parameters: ncs";
				return(-1);
	}
	if( tps == nil) {
				li_err_msg = "Invalid parameters: tps";
				return(-1);