141 lines
3.1 KiB
C
141 lines
3.1 KiB
C
#include <ctype.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <assert.h>
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#define MAX_LINE 512
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void die( char * ) ;
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char buffer[MAX_LINE+1] ;
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char *prog_name ;
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void die( char *message )
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{
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fflush(stdout) ;
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fprintf(stderr, "%s: %s\n", prog_name, message) ;
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exit(1) ;
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}
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int main(int argc, char* argv[])
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{
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int errors ;
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prog_name = *argv ;
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if( argc != 1 )
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die("pure filter, takes no arguments") ;
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errors = 0 ;
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while( fgets(buffer, MAX_LINE, stdin))
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errors += do_line(buffer) ;
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exit(errors ? 1 : 0 ) ;
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}
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int do_line(char *data)
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{
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char *p, *q, *r, *end, *before, *after ;
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// expecting two tab-separated fields
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// point r to 2nd, null terminate 1st
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for( r = data ; *r && *r != '\t' ; r++ )
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;
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if( *r != '\t' )
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return(1) ;
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end = r++ ;
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*end = '\0' ;
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for( q = r ; *q ; q++ )
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if( *q == '\n' )
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*q = '\0' ;
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if( !strlen(r) )
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return(1) ;
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// within 1st, parse as space-separated
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// p will point to current word, q past its end
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// before & after point to rest of text
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// spaces converted to nulls & back as req'd
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before = "" ;
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for( p = data ; p < end ; p = q + 1 ) {
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if( p > data ) {
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before = data ;
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p[-1] = '\0' ;
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}
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// find end of word
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for( q = p ; *q && *q != ' ' ; q++ )
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;
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if( q == end )
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after = "" ;
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else if( q < end ) {
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after = q + 1 ;
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*q = '\0' ;
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}
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else assert(0) ;
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print_line(before, p, after, r) ;
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if( q < end )
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*q = ' ' ;
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if( p > data )
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p[-1] = ' ' ;
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}
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return(0) ;
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}
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// print formatted line for permuted index
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// two tab-separated fields
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// 1st is sort key
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// 2nd is printable line
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// pipe it through something like
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// sort -F | awk -F '\t' '{print $2}'
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// to get final output
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print_line( char *before, char *word, char *after, char *tag)
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{
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int i , x, y, z ;
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/*
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printf("%s\t%s\t%s\t%s\n", before, word, after, tag) ;
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*/
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if( list_word(word) )
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return ;
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x = strlen(before) ;
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y = strlen(word) ;
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z = strlen(after) ;
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// put in sortable field
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// strip out with awk after sorting
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printf("%s %s\t", word, after) ;
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// shorten before string to fit field
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for( ; x > 30 ; x-- )
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before++ ;
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printf("%30s", before) ;
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// print keyword, html tagged
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printf(" %s%s</a> ", tag, word) ;
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// padding, outside tag
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for( ; y < 18 ; y++ )
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putchar(' ') ;
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if( z )
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printf("%s", after) ;
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printf("\n") ;
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}
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// avoid indexing on common English words
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char *list[] = {
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"the", "of", "a", "an", "to", "and", "or", "if", "for", "at",
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"am", "is", "are", "was", "were", "have", "has", "had", "be", "been",
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"on", "some", "with", "any", "into", "as", "by", "in", "out",
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"that", "then", "this", "that", "than", "these", "those",
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"he", "his", "him", "she", "her", "hers", "it", "its",
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"&", "", "+", "-", "=", "--", "<", ">", "<=", ">=",
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"!", "?", "#", "$", "%", "/", "\\", "\"", "\'",
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NULL
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} ;
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// interrogative words like "how" and "where" deliberately left out of
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// above list because users might want to search for "how to..." etc.
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// return 1 if word in list, else 0
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// case-insensitive comparison
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list_word( char *p )
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{
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char **z ;
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for( z = list ; *z != NULL ; z++ )
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if( ! strcasecmp( p, *z ) )
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return 1 ;
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return 0 ;
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}
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