void LSQ_ShiftPosition(LSQ_IteratorT iterator, LSQ_IntegerIndexT shift){
if(NULL == iterator || !shift) return;
TreeIteratorPtr it = iterator;
if(it->state == IT_PAST_REAR && shift > 0 || it->state == IT_BEFORE_FIRST && shift < 0)
return;
if(it->state == IT_BEFORE_FIRST){
LSQ_SetPosition(it, 0);
shift--;
} else if(it->state == IT_PAST_REAR){
LSQ_SetPosition(it, it->tree->size - 1);
shift++;
}
if(shift > 0) shiftForward(it, shift);
else shiftBackward(it, -shift);
}
// Queries the use to find out what actions they want to perform.
// Runs continuously until the user selects 'Quit'. Contains basic
// operations for manipulating a doubly linked list, except adding
// a new node.
int query(ring *r) {
printf("What would you like to do?\n");
printf("1 - View previous website\n");
printf("2 - View next website\n");
printf("3 - View latest website\n");
printf("4 - View first website\n");
printf("5 - Open current website\n");
printf("6 - Remove from history\n");
printf("7 - Print number of links stored\n");
printf("8 - Print all links (from last to first)\n");
printf("9 - Quit\n");
char option, nl;
char link[120] = "open ";
scanf("%c%c", &option, &nl);
switch(option) {
case '1':
shiftForward(r);
printf("Previous:\n%s\n", getCurrent(r));
return 1;
break;
case '2':
shiftBackward(r);
printf("Next:\n%s\n", getCurrent(r));
return 1;
break;
case '3':
setFirst(r);
printf("Latest:\n%s\n", getCurrent(r));
return 1;
break;
case '4':
setLast(r);
printf("First:\n%s\n", getCurrent(r));
return 1;
break;
case '5':
printf("Opening:\n%s\n", getCurrent(r));
strcat(link, getCurrent(r));
system(link);
return 1;
break;
case '6':
deleteCurrent(r);
printf("Previous:\n%s\n", getCurrent(r));
return 1;
break;
case '7':
printf("There are %d links stored.\n", getLength(r));
printf("Current: \n%s\n", getCurrent(r));
return 1;
break;
case '8':
printAll(r);
printf("\nCurrent: \n%s\n", getCurrent(r));
return 1;
break;
case '9':
return 0;
break;
default:
printf("Please enter a valid option!\n");
return 1;
}
}
// Loads ring with nodes containing a fake web-history. Demonstrates
// both types of insert, and a backward shift. Ordered so that the most
// recently visited webpage is 'first' in the linked list (but was
// entered last in this).
void loadRing(ring *r) {
insertAfter(r, "http://www.google.com");
insertBefore(r, "https://www.google.co.uk/?gfe_rd=cr&ei=58RkVqCSEITP0wWvzrPQDg#q=what%20is%20computer%20science");
shiftBackward(r);
insertBefore(r, "http://www.bbc.co.uk/guides/zxgdwmn");
shiftBackward(r);
insertBefore(r, "https://www.google.co.uk/?gfe_rd=cr&ei=58RkVqCSEITP0wWvzrPQDg#q=what%20is%20computer%20science");
shiftBackward(r);
insertBefore(r, "https://www.google.co.uk/?gfe_rd=cr&ei=58RkVqCSEITP0wWvzrPQDg#q=university+of+bristol+computer+science");
shiftBackward(r);
insertBefore(r, "https://www.cs.bris.ac.uk/Teaching/");
shiftBackward(r);
insertBefore(r, "https://www.cs.bris.ac.uk/Teaching/yearpage.jsp?stage=1");
shiftBackward(r);
insertBefore(r, "https://www.cs.bris.ac.uk/Teaching/");
shiftBackward(r);
insertBefore(r, "https://www.google.co.uk/?gfe_rd=cr&ei=58RkVqCSEITP0wWvzrPQDg#q=university+of+bristol+computer+science");
shiftBackward(r);
insertBefore(r, "http://www.cs.bris.ac.uk/");
shiftBackward(r);
insertBefore(r, "https://www.cs.bris.ac.uk/ugadmissions/");
shiftBackward(r);
insertBefore(r, "https://www.cs.bris.ac.uk/ugadmissions/whyBristol/");
shiftBackward(r);
insertBefore(r, "https://www.cs.bris.ac.uk/ugadmissions/howToApply/");
shiftBackward(r);
insertBefore(r, "https://www.cs.bris.ac.uk/People/");
shiftBackward(r);
insertBefore(r, "https://www.cs.bris.ac.uk/People/staff.jsp");
shiftBackward(r);
insertBefore(r, "https://www.cs.bris.ac.uk/People/personal.jsp?key=4196");
shiftBackward(r);
insertBefore(r, "http://www.cs.bris.ac.uk/~ian/");
shiftBackward(r);
insertBefore(r, "http://pastebin.com/SusF2063");
setFirst(r);
}