cmd/look/look.c

/*
 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*  Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/*    All Rights Reserved   */

/*
 * Copyright (c) 1980 Regents of the University of California.
 * All rights reserved. The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <stdio.h>
#include <ctype.h>
#include <string.h>

FILE *dfile;
char *filenam  = "/usr/share/lib/dict/words";

int fold;
int dict;
int tab;
#define WORDSIZE 257
char entry[WORDSIZE];
char word[WORDSIZE];
char key[WORDSIZE];

int compare(char *, char *);
void    canon(char *, char *);
int getword(char *);

int
main(int argc, char **argv)
{
    int c;
    long top,bot,mid;
    char *wstring, *ptr;

    while(argc>=2 && *argv[1]=='-') {
        for(;;) {
            switch(*++argv[1]) {
            case 'd':
                dict++;
                continue;
            case 'f':
                fold++;
                continue;
            case 't':
                tab = argv[1][1];
                if(tab)
                    ++argv[1];
                continue;
            case 0:
                break;
            default:
                continue;
            }
            break;
        }
        argc --;
        argv++;
    }
    if(argc<=1)
        return (1);
    if(argc==2) {
        fold++;
        dict++;
    } else
        filenam = argv[2];
    dfile = fopen(filenam,"r");
    if(dfile==NULL) {
        fprintf(stderr,"look: can't open %s\n",filenam);
        exit(2);
    }
    wstring = strdup(argv[1]);
    if (tab != NULL) {
        if ((ptr = strchr(wstring, tab)) != NULL) {
            *++ptr = '\0';
        }
    }
    canon(wstring,key);
    bot = 0;
    fseek(dfile,0L,2);
    top = ftell(dfile);
    for(;;) {
        mid = (top+bot)/2;
        fseek(dfile,mid,0);
        do {
            c = getc(dfile);
            mid++;
        } while(c!=EOF && c!='\n');
        if(!getword(entry))
            break;
        canon(entry,word);
        switch(compare(key,word)) {
        case -2:
        case -1:
        case 0:
            if(top<=mid)
                break;
            top = mid;
            continue;
        case 1:
        case 2:
            bot = mid;
            continue;
        }
        break;
    }
    fseek(dfile,bot,0);
    while(ftell(dfile)<top) {
        if(!getword(entry))
            return (0);
        canon(entry,word);
        switch(compare(key,word)) {
        case -2:
            return (0);
        case -1:
        case 0:
            puts(entry);
            break;
        case 1:
        case 2:
            continue;
        }
        break;
    }
    while(getword(entry)) {
        canon(entry,word);
        switch(compare(key,word)) {
        case -1:
        case 0:
            puts(entry);
            continue;
        }
        break;
    }
    return (0);
}

int
compare(char *s, char *t)
{
    for(;*s==*t;s++,t++)
        if(*s==0)
            return(0);
    return(*s==0? -1:
        *t==0? 1:
        *s<*t? -2:
        2);
}

int
getword(char *w)
{
    int c;
    int avail = WORDSIZE - 1;

    while(avail--) {
        c = getc(dfile);
        if(c==EOF)
            return(0);
        if(c=='\n')
            break;
        *w++ = c;
    }
    while (c != '\n')
        c = getc(dfile);
    *w = 0;
    return(1);
}

void
canon(char *old, char *new)
{
    int c;
    int avail = WORDSIZE - 1;

    for(;;) {
        *new = c = *old++;
        if(c==0) {
            *new = 0;
            break;
        }
        if(dict) {
            if(!isalnum(c))
                continue;
        }
        if(fold) {
            if(isupper(c))
                *new += 'a' - 'A';
        }
        new++;
        avail--;
        if (avail <= 0) {
            *new = 0;
            break;
        }
    }
}