Return `0, nil` in all `io` cases where an empty slice is provided

6 files changed, 44 insertions, 1 deletions

diff --git a/core/bytes/buffer.odin b/core/bytes/buffer.odin
index a61f8f00d..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
@@ -246,6 +249,9 @@ 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) {
diff --git a/core/bytes/reader.odin b/core/bytes/reader.odin
index d85e4fe13..2e1c5ed42 100644
--- a/core/bytes/reader.odin
+++ b/core/bytes/reader.odin
@@ -34,6 +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
 	}
@@ -43,6 +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
 	}
diff --git a/core/io/util.odin b/core/io/util.odin
index 27c344890..e65a69fb3 100644
--- a/core/io/util.odin
+++ b/core/io/util.odin
@@ -340,6 +340,9 @@ _limited_reader_proc :: proc(stream_data: rawptr, mode: Stream_Mode, p: []byte,
 	l := (^Limited_Reader)(stream_data)
 	#partial switch mode {
 	case .Read:
+		if len(p) == 0 {
+			return 0, nil
+		}
 		if l.n <= 0 {
 			return 0, .EOF
 		}
@@ -394,6 +397,9 @@ _section_reader_proc :: proc(stream_data: rawptr, mode: Stream_Mode, p: []byte,
 	s := (^Section_Reader)(stream_data)
 	#partial switch mode {
 	case .Read:
+		if len(p) == 0 {
+			return 0, nil
+		}
 		if s.off >= s.limit {
 			return 0, .EOF
 		}
@@ -405,6 +411,9 @@ _section_reader_proc :: proc(stream_data: rawptr, mode: Stream_Mode, p: []byte,
 		s.off += i64(n)
 		return
 	case .Read_At:
+		if len(p) == 0 {
+			return 0, nil
+		}
 		p, off := p, offset
 
 		if off < 0 || off >= s.limit - s.base {
diff --git a/core/os/os2/file_linux.odin b/core/os/os2/file_linux.odin
index 11be64741..ad6ddbf17 100644
--- a/core/os/os2/file_linux.odin
+++ b/core/os/os2/file_linux.odin
@@ -201,6 +201,9 @@ _read :: proc(f: ^File_Impl, p: []byte) -> (i64, Error) {
 }
 
 _read_at :: proc(f: ^File_Impl, p: []byte, offset: i64) -> (i64, Error) {
+	if len(p) == 0 {
+		return 0, nil
+	}
 	if offset < 0 {
 		return 0, .Invalid_Offset
 	}
@@ -226,6 +229,9 @@ _write :: proc(f: ^File_Impl, p: []byte) -> (i64, Error) {
 }
 
 _write_at :: proc(f: ^File_Impl, p: []byte, offset: i64) -> (i64, Error) {
+	if len(p) == 0 {
+		return 0, nil
+	}
 	if offset < 0 {
 		return 0, .Invalid_Offset
 	}
diff --git a/core/os/os2/file_windows.odin b/core/os/os2/file_windows.odin
index 56ac7aaae..47e5f0cf2 100644
--- a/core/os/os2/file_windows.odin
+++ b/core/os/os2/file_windows.odin
@@ -266,6 +266,11 @@ _read :: proc(f: ^File_Impl, p: []byte) -> (n: i64, err: Error) {
 }
 
 _read_internal :: proc(f: ^File_Impl, p: []byte) -> (n: i64, err: Error) {
+	length := len(p)
+	if length == 0 {
+		return
+	}
+
 	read_console :: proc(handle: win32.HANDLE, b: []byte) -> (n: int, err: Error) {
 		if len(b) == 0 {
 			return 0, nil
@@ -320,7 +325,6 @@ _read_internal :: proc(f: ^File_Impl, p: []byte) -> (n: i64, err: Error) {
 
 	single_read_length: win32.DWORD
 	total_read: int
-	length := len(p)
 
 	sync.shared_guard(&f.rw_mutex) // multiple readers
 
diff --git a/core/os/stream.odin b/core/os/stream.odin
index ad8c2461c..39edc9cd5 100644
--- a/core/os/stream.odin
+++ b/core/os/stream.odin
@@ -21,6 +21,9 @@ _file_stream_proc :: proc(stream_data: rawptr, mode: io.Stream_Mode, p: []byte,
 	case .Flush:
 		os_err = flush(fd)
 	case .Read:
+		if len(p) == 0 {
+			return 0, nil
+		}
 		n_int, os_err = read(fd, p)
 		n = i64(n_int)
 		if n == 0 && os_err == nil {
@@ -28,18 +31,27 @@ _file_stream_proc :: proc(stream_data: rawptr, mode: io.Stream_Mode, p: []byte,
 		}
 
 	case .Read_At:
+		if len(p) == 0 {
+			return 0, nil
+		}
 		n_int, os_err = read_at(fd, p, offset)
 		n = i64(n_int)
 		if n == 0 && os_err == nil {
 			err = .EOF
 		}
 	case .Write:
+		if len(p) == 0 {
+			return 0, nil
+		}
 		n_int, os_err = write(fd, p)
 		n = i64(n_int)
 		if n == 0 && os_err == nil {
 			err = .EOF
 		}
 	case .Write_At:
+		if len(p) == 0 {
+			return 0, nil
+		}
 		n_int, os_err = write_at(fd, p, offset)
 		n = i64(n_int)
 		if n == 0 && os_err == nil {