_ALGORITHM ALLEY_
written by Dean Clark
edited by Bruce Schneier

Example 1

/****************************************************************************
** AddColorToList
** Adds a color to the list of most popular colors in the image, if necessary
*****************************************************************************/
void AddColorToList(COLOR_NODE **popcolors, int npal, int *currentcount, COLOR_NODE *color)
{
    COLOR_NODE  *temp;
    int         i;

    /* If table is empty then insert this color */
    if (*currentcount < 0) {
        *currentcount = 0;
        popcolors[*currentcount] = color;
        return;
    }
    /* Search the table for the same color */
    for (i = 0; i <= *currentcount; i++) {
        if (popcolors[i] == color) break;
    }
    if (popcolors[i] == color) {
        /* Found it. Since the color is already in the table, adjust it
        ** to its proper position */
        while (i && (popcolors[i-1]->count < popcolors[i]->count)) {
            temp = popcolors[i-1];
            popcolors[i-1] = popcolors[i];
            popcolors[i] = temp;
            i--;
        }
        return;
    }
    /* This color isn't in the list.  See if it belongs there.  First of all,
    ** if the list isn't full, this color must have a count of 1 and can be
    ** simply added to the end */
    if (*currentcount < npal-1) {
        (*currentcount)++;
        popcolors[*currentcount] = color;
    }
    else {
        /* Otherwise the list is full and this color may belong in the list.
        ** Start at the low end (if the color had a high count it would
        ** already be in the list) */
        if (color->count > popcolors[npal-1]->count) {
            i = npal - 1;
            popcolors[i] = color;
            i--;
            while ((i >= 0) && (popcolors[i]->count < popcolors[i+1]->count)) {
                temp = popcolors[i+1];
                popcolors[i+1] = popcolors[i];
                popcolors[i] = temp;
                i--;
            }
        }
    }
}