Add read_at/write_at to missing platforms

core/os/errors.odin

@@ -156,4 +156,12 @@ _error_string :: proc "contextless" (e: Platform_Error) -> string where intrinsi
 		return ti.names[idx]
 	}
 	return "<unknown platform error>"
-}
+}
+
+@(private, require_results)
+error_to_io_error :: proc(ferr: Error) -> io.Error {
+	if ferr == nil {
+		return .None
+	}
+	return ferr.(io.Error) or_else .Unknown
+}

core/os/os_freebsd.odin

@@ -472,6 +472,26 @@ write :: proc(fd: Handle, data: []byte) -> (int, Error) {
 	return int(bytes_written), nil
 }
 
+read_at :: proc(fd: Handle, data: []byte, offset: i64) -> (n: int, err: Error) {
+	curr := seek(fd, offset, SEEK_CUR) or_return
+	n, err = read(fd, data)
+	_, err1 := seek(fd, curr, SEEK_SET)
+	if err1 != nil && err == nil {
+		err = err1
+	}
+	return
+}
+
+write_at :: proc(fd: Handle, data: []byte, offset: i64) -> (n: int, err: Error) {
+	curr := seek(fd, offset, SEEK_CUR) or_return
+	n, err = write(fd, data)
+	_, err1 := seek(fd, curr, SEEK_SET)
+	if err1 != nil && err == nil {
+		err = err1
+	}
+	return
+}
+
 seek :: proc(fd: Handle, offset: i64, whence: int) -> (i64, Error) {
 	res := _unix_seek(fd, offset, c.int(whence))
 	if res == -1 {

core/os/os_haiku.odin

@@ -241,6 +241,26 @@ write :: proc(fd: Handle, data: []byte) -> (int, Error) {
 	return int(bytes_written), nil
 }
 
+read_at :: proc(fd: Handle, data: []byte, offset: i64) -> (n: int, err: Error) {
+	curr := seek(fd, offset, SEEK_CUR) or_return
+	n, err = read(fd, data)
+	_, err1 := seek(fd, curr, SEEK_SET)
+	if err1 != nil && err == nil {
+		err = err1
+	}
+	return
+}
+
+write_at :: proc(fd: Handle, data: []byte, offset: i64) -> (n: int, err: Error) {
+	curr := seek(fd, offset, SEEK_CUR) or_return
+	n, err = write(fd, data)
+	_, err1 := seek(fd, curr, SEEK_SET)
+	if err1 != nil && err == nil {
+		err = err1
+	}
+	return
+}
+
 seek :: proc(fd: Handle, offset: i64, whence: int) -> (i64, Error) {
 	res := _unix_seek(fd, offset, c.int(whence))
 	if res == -1 {

core/os/os_netbsd.odin

@@ -528,6 +528,26 @@ write :: proc(fd: Handle, data: []byte) -> (int, Error) {
 	return int(bytes_written), nil
 }
 
+read_at :: proc(fd: Handle, data: []byte, offset: i64) -> (n: int, err: Error) {
+	curr := seek(fd, offset, SEEK_CUR) or_return
+	n, err = read(fd, data)
+	_, err1 := seek(fd, curr, SEEK_SET)
+	if err1 != nil && err == nil {
+		err = err1
+	}
+	return
+}
+
+write_at :: proc(fd: Handle, data: []byte, offset: i64) -> (n: int, err: Error) {
+	curr := seek(fd, offset, SEEK_CUR) or_return
+	n, err = write(fd, data)
+	_, err1 := seek(fd, curr, SEEK_SET)
+	if err1 != nil && err == nil {
+		err = err1
+	}
+	return
+}
+
 seek :: proc(fd: Handle, offset: i64, whence: int) -> (i64, Error) {
 	res := _unix_seek(fd, offset, c.int(whence))
 	if res == -1 {

core/os/os_openbsd.odin

@@ -456,6 +456,26 @@ write :: proc(fd: Handle, data: []byte) -> (int, Error) {
 	return int(bytes_written), nil
 }
 
+read_at :: proc(fd: Handle, data: []byte, offset: i64) -> (n: int, err: Error) {
+	curr := seek(fd, offset, SEEK_CUR) or_return
+	n, err = read(fd, data)
+	_, err1 := seek(fd, curr, SEEK_SET)
+	if err1 != nil && err == nil {
+		err = err1
+	}
+	return
+}
+
+write_at :: proc(fd: Handle, data: []byte, offset: i64) -> (n: int, err: Error) {
+	curr := seek(fd, offset, SEEK_CUR) or_return
+	n, err = write(fd, data)
+	_, err1 := seek(fd, curr, SEEK_SET)
+	if err1 != nil && err == nil {
+		err = err1
+	}
+	return
+}
+
 seek :: proc(fd: Handle, offset: i64, whence: int) -> (i64, Error) {
 	res := _unix_seek(fd, offset, c.int(whence))
 	if res == -1 {

core/os/stream.odin

@@ -32,12 +32,10 @@ _file_stream_proc :: proc(stream_data: rawptr, mode: io.Stream_Mode, p: []byte,
 		}
 
 	case .Read_At:
-		when !(ODIN_OS == .FreeBSD || ODIN_OS == .OpenBSD || ODIN_OS == .NetBSD || ODIN_OS == .Haiku) {
-			n_int, os_err = read_at(fd, p, offset)
-			n = i64(n_int)
-			if n == 0 && os_err == nil {
-				err = .EOF
-			}
+		n_int, os_err = read_at(fd, p, offset)
+		n = i64(n_int)
+		if n == 0 && os_err == nil {
+			err = .EOF
 		}
 	case .Write:
 		n_int, os_err = write(fd, p)
@@ -46,12 +44,10 @@ _file_stream_proc :: proc(stream_data: rawptr, mode: io.Stream_Mode, p: []byte,
 			err = .EOF
 		}
 	case .Write_At:
-		when !(ODIN_OS == .FreeBSD || ODIN_OS == .OpenBSD || ODIN_OS == .NetBSD || ODIN_OS == .Haiku) {
-			n_int, os_err = write_at(fd, p, offset)
-			n = i64(n_int)
-			if n == 0 && os_err == nil {
-				err = .EOF
-			}
+		n_int, os_err = write_at(fd, p, offset)
+		n = i64(n_int)
+		if n == 0 && os_err == nil {
+			err = .EOF
 		}
 	case .Seek:
 		n, os_err = seek(fd, offset, int(whence))
@@ -60,11 +56,7 @@ _file_stream_proc :: proc(stream_data: rawptr, mode: io.Stream_Mode, p: []byte,
 	case .Destroy:
 		err = .Empty
 	case .Query:
-		when ODIN_OS == .FreeBSD || ODIN_OS == .OpenBSD || ODIN_OS == .NetBSD || ODIN_OS == .Haiku {
-			return io.query_utility({.Close, .Flush, .Read, .Write, .Seek, .Size, .Query})
-		} else {
-			return io.query_utility({.Close, .Flush, .Read, .Read_At, .Write, .Write_At, .Seek, .Size, .Query})
-		}
+		return io.query_utility({.Close, .Flush, .Read, .Read_At, .Write, .Write_At, .Seek, .Size, .Query})
 	}
 
 	if err == nil && os_err != nil {
@@ -73,7 +65,7 @@ _file_stream_proc :: proc(stream_data: rawptr, mode: io.Stream_Mode, p: []byte,
 				return n, .EOF
 			}
 		}
-		err = .Unknown
+		err = error_to_io_error(os_err)
 	}
 	return
 }