1 files changed, 57 insertions, 0 deletions
diff --git a/v_windows/v/vlib/io/custom_string_reading_test.v b/v_windows/v/vlib/io/custom_string_reading_test.v
new file mode 100644
index 0000000..76e3307
--- /dev/null
+++ b/v_windows/v/vlib/io/custom_string_reading_test.v
@@ -0,0 +1,57 @@
+import io
+
+struct StringReader {
+	text string
+mut:
+	place int
+}
+
+fn imin(a int, b int) int {
+	return if a < b { a } else { b }
+}
+
+fn (mut s StringReader) read(mut buf []byte) ?int {
+	$if debug {
+		eprintln('>>>> StringReader.read output buf.len: $buf.len')
+	}
+	if s.place > s.text.len + 1 {
+		return none
+	}
+	mut howmany := imin(buf.len, s.text.len - s.place)
+	xxx := s.text[s.place..s.place + howmany].bytes()
+	read := copy(buf, xxx)
+	s.place += read
+	return read
+}
+
+fn read_from_string(text string, capacity int) []byte {
+	mut str := StringReader{
+		text: text
+	}
+	mut stream := io.new_buffered_reader(reader: str, cap: capacity)
+	//
+	mut buf := []byte{len: 1}
+	mut res := []byte{}
+	mut i := 0
+	for {
+		z := stream.read(mut buf) or { break }
+		res << buf
+		$if debug {
+			println('capacity: $capacity, i: $i, buf: $buf | z: $z')
+		}
+		i++
+	}
+	return res
+}
+
+pub fn test_reading_from_a_string() {
+	for capacity in 1 .. 1000 {
+		assert read_from_string('a', capacity) == [byte(`a`)]
+		assert read_from_string('ab', capacity) == [byte(`a`), `b`]
+		assert read_from_string('abc', capacity) == [byte(`a`), `b`, `c`]
+		assert read_from_string('abcde', capacity) == [byte(`a`), `b`, `c`, `d`, `e`]
+		large_string_bytes := []byte{len: 1000, init: `x`}
+		large_string := large_string_bytes.bytestr()
+		assert read_from_string(large_string, capacity) == large_string_bytes
+	}
+}