Textbox with Word Wrap for KickC

/*

Textbox routine with unsigned int wrap for KickC by Scan/Desire

Use KickC 0.8 or newer to compile

*/
#include "c64.h"

const char* screen = $0400;
const char text[] = "this is a small test with word wrap, if a word is too long it moves it to the next line. isn't that supercalifragilisticexpialidocious? i think it's cool!@";
const char text2[] = "textbox by scan of desire@";

void main() {
    for (char x = 0; x < 15; x += 1) {
        textbox(x,x,x+x+1,x+10,text2);
        for (unsigned int wait = 0; wait < 15000; wait++) {}
    }
    textbox(30,8,39,24,text);
    textbox(1,3,38,9,text);
    textbox(0,12,20,24,text);
    do {} while (true);
}

void textbox(char x1, char y1, char x2, char y2, char* text) {
    draw_window(x1, y1, x2, y2);
    char y = y1+1;
    char x = x1+1;
    unsigned int z = y * 40;
    unsigned int i = 0;
    if (x == x2 || y == y2) {
        // no room to draw text, simply return
        return;
    }
    do {
        char character = text[i];
        screen[z+x] = character;
        if (character == $20) {
            // scan ahead to determine next unsigned int length
            char c = 0;
            unsigned int ls = i+1;
            while (text[ls] != $20 && text[ls] != $00) {
                ls++;
                c++;
            }
            // if it's too big to fit but not bigger than the whole box width, move to next line
            if (c+x >= x2 && c < x2-x1) {
              x = x1;
              y++;
              if (y == y2) {
                  // text too long for textbox
                  return;
              }
              z = y * 40;
            }
        }
        i++;
        // only move x if the the character was not a space and not at the beginning of a box
        if (character == $20 && x == x1+1) {} else {
            x++;
        }

        // this is in case the unsigned int is too long for one line and needs to be cut
        if (x == x2) {
            x = x1+1;
            y++;
            if (y == y2) {
                // text too long for textbox
                return;
            }
            z = y * 40;
        }
    } while (text[i] != 0);
}

void draw_window(char x1, char y1, char x2, char y2) {
    unsigned int z = y1 * 40;
    unsigned int q = y2 * 40;

    // draw horizontal lines
    for (char x = x1+1; x < x2; x++) {
        screen[z+x] = 64;
        screen[q+x] = 64;
    }

    // draw upper corners
    screen[z+x1] = 112;
    screen[z+x2] = 110;

    // draw vertical lines
    for (char y = y1+1; y < y2; y++) {
        z = y * 40;
        screen[z+x1] = 93;
        screen[z+x2] = 93;
    }

    // draw lower corners
    screen[q+x1] = 109;
    screen[q+x2] = 125;

    // window big enough to have an inside?
    if (x2-x1 > 1 && y2-y1 > 1) {
        // blank inside
        for(char y = y1+1; y < y2; y++) {
            z = y * 40;
            for(char x = x1+1; x < x2; x++) {
                screen[z+x] = $20;
           }
        }
    }
}