ts_tags_print.c

// prints the tag tree 'self' into an sds string 'printed'
// recursive function, 'node_addr' should start at 0
sds _ts_tags_print_node(ts_tags * self, size_t node_addr, sds padding, sds printed) {
    
    /*
        return value should resemble this structure:
            . 
            |── 0
            │   |── abc123
            |   +── abc124
            +── 1
    */

   // get a reference to the current node
    ts_tag_node * current = self->data + node_addr;

    // if we're at a leaf node, print the value of the node
    if(current->type == TS_TAG_NODE_LEAF) {
        sds id_str = ts_id_nbit_string(&(current->value.leaf), sdsempty(), 8);
        printed = sdscatprintf(printed, "%s+-- %s\n", padding, id_str);
        sdsfree(id_str);
    }

    // if we're at an inner node...
    if(current->type == TS_TAG_NODE_INNER) {
        
        // the indentation before the next layer of the tree may or may not need a '|' before it,
        // so prepare both indentations
        sds extendedpadding = sdscatprintf(sdsempty(), "%s|   ", padding);
        sds emptypadding = sdscatprintf(sdsempty(), "%s    ", padding);

        // print first branch
        if(current->value.inner[0] != 0) {
            char * tee = "|";
            sds currentpadding = extendedpadding;
            
            // if there is no second branch, print a cap after the first branch
            if(current->value.inner[1] == 0) {
                tee = "+";
                currentpadding = emptypadding;
            }
            
            // recurse to follow the branch
            printed = sdscatprintf(printed, "%s%s-- 0\n", padding, tee);
            printed = _ts_tags_print_node(self, current->value.inner[0], currentpadding, printed);
            
        }

        // print second branch
        if(current->value.inner[1] != 0) {
            // recurse to follow the branch
            printed = sdscatprintf(printed, "%s+-- 1\n", padding);
            printed = _ts_tags_print_node(self, current->value.inner[1], emptypadding, printed);
        }

        sdsfree(extendedpadding);
        sdsfree(emptypadding);
    }

    return printed;
}