//ww:run-exit 47
// Migrated from 778_bufio_vstream_run row stream_read_unread.
package main;
import bufio;
import memio;
import io;
export fn main() i32 = {
    let raw: [8]u8;
    raw[0] = 65u8; raw[1] = 66u8; raw[2] = 67u8; raw[3] = 68u8;
    raw[4] = 69u8; raw[5] = 70u8; raw[6] = 71u8; raw[7] = 72u8;
    let mst: memio.stream = memio.fixed(raw[0:8]);
    let msrc: io.stream = &mst.vt;
    let rbuf: [8]u8;
    let wbuf: [4]u8;
    let b: bufio.stream = bufio.newstream(msrc, rbuf[0:8], wbuf[0:4]);
    let vs: io.stream = &b.vt;
    let out: [4]u8;
    let rd1 = io.read(vs, out[0:3]);
    let n1: size = 0;
    if (rd1 is size) { n1 = rd1 as size; };
    if (n1 != 3: size) { return 91; };
    if (out[0] != 65u8 || out[2] != 67u8) { return 92; };
    let rd2 = io.read(vs, out[0:4]);
    let n2: size = 0;
    if (rd2 is size) { n2 = rd2 as size; };
    if (n2 != 4: size) { return 93; };
    if (out[0] != 68u8 || out[3] != 71u8) { return 94; };
    return 47;
};