Merge pull request #4112 from Feoramund/fix-test-io-issues

Add `core:io` test suite

2 files changed, 42 insertions, 5 deletions

diff --git a/core/bytes/buffer.odin b/core/bytes/buffer.odin
index a7e9b1c64..f4d883353 100644
--- a/core/bytes/buffer.odin
+++ b/core/bytes/buffer.odin
@@ -144,6 +144,9 @@ buffer_grow :: proc(b: ^Buffer, n: int, loc := #caller_location) {
 }
 
 buffer_write_at :: proc(b: ^Buffer, p: []byte, offset: int, loc := #caller_location) -> (n: int, err: io.Error) {
+	if len(p) == 0 {
+		return 0, nil
+	}
 	b.last_read = .Invalid
 	if offset < 0 {
 		err = .Invalid_Offset
@@ -246,10 +249,13 @@ buffer_read_ptr :: proc(b: ^Buffer, ptr: rawptr, size: int) -> (n: int, err: io.
 }
 
 buffer_read_at :: proc(b: ^Buffer, p: []byte, offset: int) -> (n: int, err: io.Error) {
+	if len(p) == 0 {
+		return 0, nil
+	}
 	b.last_read = .Invalid
 
 	if uint(offset) >= len(b.buf) {
-		err = .Invalid_Offset
+		err = .EOF
 		return
 	}
 	n = copy(p, b.buf[offset:])
@@ -310,6 +316,27 @@ buffer_unread_rune :: proc(b: ^Buffer) -> io.Error {
 	return nil
 }
 
+buffer_seek :: proc(b: ^Buffer, offset: i64, whence: io.Seek_From) -> (i64, io.Error) {
+	abs: i64
+	switch whence {
+	case .Start:
+		abs = offset
+	case .Current:
+		abs = i64(b.off) + offset
+	case .End:
+		abs = i64(len(b.buf)) + offset
+	case:
+		return 0, .Invalid_Whence
+	}
+
+	abs_int := int(abs)
+	if abs_int < 0 {
+		return 0, .Invalid_Offset
+	}
+	b.last_read = .Invalid
+	b.off = abs_int
+	return abs, nil
+}
 
 buffer_read_bytes :: proc(b: ^Buffer, delim: byte) -> (line: []byte, err: io.Error) {
 	i := index_byte(b.buf[b.off:], delim)
@@ -395,14 +422,17 @@ _buffer_proc :: proc(stream_data: rawptr, mode: io.Stream_Mode, p: []byte, offse
 		return io._i64_err(buffer_write(b, p))
 	case .Write_At:
 		return io._i64_err(buffer_write_at(b, p, int(offset)))
+	case .Seek:
+		n, err = buffer_seek(b, offset, whence)
+		return
 	case .Size:
-		n = i64(buffer_capacity(b))
+		n = i64(buffer_length(b))
 		return
 	case .Destroy:
 		buffer_destroy(b)
 		return
 	case .Query:
-		return io.query_utility({.Read, .Read_At, .Write, .Write_At, .Size, .Destroy})
+		return io.query_utility({.Read, .Read_At, .Write, .Write_At, .Seek, .Size, .Destroy, .Query})
 	}
 	return 0, .Empty
 }
diff --git a/core/bytes/reader.odin b/core/bytes/reader.odin
index 4b18345ba..2e1c5ed42 100644
--- a/core/bytes/reader.odin
+++ b/core/bytes/reader.odin
@@ -9,10 +9,11 @@ Reader :: struct {
 	prev_rune: int,    // previous reading index of rune or < 0
 }
 
-reader_init :: proc(r: ^Reader, s: []byte) {
+reader_init :: proc(r: ^Reader, s: []byte) -> io.Stream {
 	r.s = s
 	r.i = 0
 	r.prev_rune = -1
+	return reader_to_stream(r)
 }
 
 reader_to_stream :: proc(r: ^Reader) -> (s: io.Stream) {
@@ -33,6 +34,9 @@ reader_size :: proc(r: ^Reader) -> i64 {
 }
 
 reader_read :: proc(r: ^Reader, p: []byte) -> (n: int, err: io.Error) {
+	if len(p) == 0 {
+		return 0, nil
+	}
 	if r.i >= i64(len(r.s)) {
 		return 0, .EOF
 	}
@@ -42,6 +46,9 @@ reader_read :: proc(r: ^Reader, p: []byte) -> (n: int, err: io.Error) {
 	return
 }
 reader_read_at :: proc(r: ^Reader, p: []byte, off: i64) -> (n: int, err: io.Error) {
+	if len(p) == 0 {
+		return 0, nil
+	}
 	if off < 0 {
 		return 0, .Invalid_Offset
 	}
@@ -97,7 +104,6 @@ reader_unread_rune :: proc(r: ^Reader) -> io.Error {
 	return nil
 }
 reader_seek :: proc(r: ^Reader, offset: i64, whence: io.Seek_From) -> (i64, io.Error) {
-	r.prev_rune = -1
 	abs: i64
 	switch whence {
 	case .Start:
@@ -114,6 +120,7 @@ reader_seek :: proc(r: ^Reader, offset: i64, whence: io.Seek_From) -> (i64, io.E
 		return 0, .Invalid_Offset
 	}
 	r.i = abs
+	r.prev_rune = -1
 	return abs, nil
 }
 reader_write_to :: proc(r: ^Reader, w: io.Writer) -> (n: i64, err: io.Error) {