helloworld.c

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/* File: helloworld.c
 *
 * Time-stamp: <Wed 03 Aug 2005-- 14:15:43 Paolo Frasconi>
 * $Id: helloworld.c,v 1.1 2006/05/31 09:21:19 andrea Exp $
 *
 * Author: Alessio Ceroni and Paolo Frasconi
 *
 * Description: Very simple data type and associated kernel
 *              The purpose is just to demonstrate how to program
 *              a plugin
 */
# include <stdio.h>
# include <stdlib.h>
# include <ctype.h>
# include "helloworld.h"

# include "svector.h"

# define MULTK 0
# define MINK 1

int min_or_mult=0;

int space_or_null(int c) {
  if (c==0)
    return 1;
  return isspace(c);
}

void* plugin_null(void) 
{
  DATUM* nulldatum = (DATUM *)malloc(sizeof(DATUM));
  nulldatum->x = 0;
  return nulldatum;
}


void* plugin_copy_constructor(void* _words)
{

  DATUM* words = (DATUM *)malloc(sizeof(DATUM));
  words->x = ((DATUM*)_words)->x;
  return(words);
}


double plugin_kernel(void *_a, void *_b) 
{
  SVECTOR* va = (SVECTOR*) _a; 
  SVECTOR* vb = (SVECTOR*) _b; 
  double a = ((DATUM*)va->words)->x;
  double b = ((DATUM*)vb->words)->x;
  /* printf("Calculating kernel between %f and %f\n",a, b); */
  if (min_or_mult==MULTK)
    return a * b;
  else
    return a<b? a:b;
}



void* 
plugin_parse_document(char *line, double *label,
                      long *queryid, long *slackid, double *costfactor,
                      long int *highest_feature, 
                      long int max_words_doc,
                      char **comment)
{
  DATUM* words = (DATUM *)malloc(sizeof(DATUM));

  register long pos;
  char buffer[1024];

  (*queryid)=0;
  (*slackid)=0;
  (*costfactor)=1;
  (*highest_feature) = 1;

  pos=0;
  (*comment)=NULL;
  while(line[pos] ) {      /* cut off comments */
    if((line[pos] == '#') && (!(*comment))) {
      line[pos]=0;
      (*comment)=&(line[pos+1]);
    }
    if(line[pos] == '\n') { /* strip the CR */
      line[pos]=0;
    }
    pos++;
  }
  if(!(*comment)) (*comment)=&(line[pos]);
  /* printf("Comment: '%s'\n",(*comment)); */


  if(sscanf(line,"%s",buffer) == EOF) return(NULL);
  pos=0;
  while((buffer[pos] != ':') && buffer[pos]) pos++;
  if(buffer[pos] == ':') {
        perror ("Line must start with label or 0!!!\n"); 
        printf("LINE: %s\n",line);
        exit (1); 
  }
  /* read the target value */
  if(sscanf(line,"%lf",label) == EOF) return(NULL);
  /* printf("label: '%f'\n",(float)(*label)); */
  pos=0;
  while(space_or_null((int)line[pos])) pos++;
  while((!space_or_null((int)line[pos])) && line[pos]) pos++;
  if (sscanf(line+pos,"%s",buffer) != 1) {
        perror ("x value expected\n"); 
        printf("LINE: %s\n",line);
        exit (1); 
  }
  words->x = atof(buffer);
  /* printf("x: '%f'\n",(float)words->x); */
  return(words);
}


void   
plugin_write(FILE* os, void* _words) 
{
  fprintf(os,"%.8g ", (double)((DATUM*)_words)->x);
}


void
plugin_destructor(void* _words)
{
  free(_words);
}


void
plugin_clip(void* _words, int totwords)
{

}

void
plugin_kernel_setparm(char* kernel_parm)
{
  if (strcmp(kernel_parm,"empty")==0 || strcmp(kernel_parm,"multk")==0)
    min_or_mult = MULTK;
  else if (strcmp(kernel_parm,"mink")==0)
    min_or_mult = MINK;
  else {
    fprintf(stderr,"invalid argument to -u: %s\n", kernel_parm); exit(1);
  }
}

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