/* alw1.c RAP Version 2.1 28/11/07 */

#include <stdio.h>
#include <stdlib.h>
#include "alw1.h"

void alwcons (ALW * a, int maxword)
{
    int good;
    a->maxword=maxword;
    good=1;
    a->nex = (int *) malloc(sizeof(int)*maxword);
    if(a->nex == NULL) good=0;
    a->prev = (int *) malloc(sizeof(int)*maxword);
    if(a->prev == NULL) good=0;
    a->len = (int *) malloc(sizeof(int)*maxword);
    if(a->len == NULL) good=0;
    a->word = (int **) malloc(sizeof(int*)*maxword);
    if(a->nex == NULL) good=0;
    if(good==0)
    {
        printf("malloc failed in alwcons\n");
        exit(21);
    }
}

void alwstart (ALW * a)
{
    int i;
    for(i=3;i<(a->maxword);i++)  a->nex[i]=i+1;
    a->nex[a->maxword-1]=0;
    a->nex[1]=2;
    a->prev[2]=1;
    a->freechain=3;
}

int alwfind (ALW *a, int * word, int len)
{
    int i,ml,j;
    int * pt;
    i=1;
    while(1)
    {
        i=a->nex[i];
        if(i==2) break;
        pt=a->word[i];
        ml=a->len[i];
        if(ml>len) ml=len;
        for(j=0;j<ml;j++)
        {
            if(pt[j]>word[j]) 
                return -(a->prev[i]);  
            if(word[j]>pt[j]) 
                break;
        }
        if(j<ml) continue;
        if(len==a->len[i]) return i;
        if(len<a->len[i]) return -(a->prev[i]);
    }
    return -(a->prev[i]);
}

int alwinsert (ALW *a, int * word, int len, int han)
{
    int i,j;
    j=a->freechain;
    if(j==0)
    {
        printf("Run out of words in the store adin arrays\n");
        exit(22);
    }
    a->freechain=a->nex[j];
    a->len[j]=len;
    a->word[j]=word;
    i=a->nex[han];
/*                han  (j)   i       */
    a->nex[han]=j;
    a->prev[j]=han;
    a->nex[j]=i;
    a->prev[i]=j;
    return j;
}

void alwdelete (ALW *a, int han)
{
    int i,j;
    i=a->prev[han];
    j=a->nex[han];
/*                i  (han)   j      */
    a->nex[i]=j;
    a->prev[j]=i;
    a->nex[han]=a->freechain;
    a->freechain=han;
}


/* end of alw1.c */