implemented some functions h2-io-file.

renamed h2-sysapi to h2-os

cmd/scheme.adb

@@ -9,8 +9,9 @@ with Ada.Text_IO;
 with Ada.Unchecked_Deallocation;
 
 
-with H2.Sysapi;
+with H2.OS;
 with H2.IO;
+use type H2.System_Length;
 
 with Interfaces.C;
 
@@ -44,27 +45,27 @@ begin
 	--h2init;
 
 declare
-	package Sysapi is new H2.Sysapi (
+	package OS is new H2.OS (
 		H2.Slim.Character,
 		H2.Wide.Character,
 		H2.Slim.String,
 		H2.Wide.String,
 		H2.Wide.Utf8.To_Unicode_String,
 		H2.Wide.Utf8.From_Unicode_String);
-	package File renames Sysapi.File;
+	package File renames OS.File;
 
 	F: File.File_Pointer;
 	FL: File.Flag_Record;
-	Last: H2.System_Length;
+	Length: H2.System_Length;
 	Buffer: H2.System_Byte_Array (50 .. 100);
 begin
-	--Sysapi.File.Set_Flag_Bits (FL, Sysapi.File.FLAG_WRITE); 
+	--OS.File.Set_Flag_Bits (FL, OS.File.FLAG_WRITE); 
 	File.Set_Flag_Bits (FL, File.FLAG_READ);
 	File.Open (F, H2.Wide.String'("/etc/passwd"), FL);
-	File.Read (F, Buffer, Last);
+	File.Read (F, Buffer, Length);
 	File.Close (F);
 
-	File.Write (Sysapi.File.Get_Stdout, Buffer(Buffer'First .. Last), Last);
+	File.Write (OS.File.Get_Stdout, Buffer(Buffer'First .. Buffer'First + Length - 1), Length);
 end;
 
 declare
@@ -74,14 +75,35 @@ declare
 		H2.Slim.String,
 		H2.Wide.String,
 		H2.Wide.Utf8.To_Unicode_String,
-		H2.Wide.Utf8.From_Unicode_String);
+		H2.Wide.Utf8.From_Unicode_String,
+		H2.Wide.Utf8.Sequence_Length);
 
 	package File renames IO.File;
 
 	F: File.File_Record;
 	FL: File.Flag_Record;
+	Buffer: H2.Slim.String (1 .. 10);
+	Length: H2.System_Length;
 begin
-	File.Open (F, H2.Slim.String'("/tmp/qq"), FL);
+	--File.Open (F, H2.Slim.String'("/etc/passwd"), FL);
+	--File.Read (F, Buffer, Length);
+	--Ada.Text_IO.PUt_Line (Standard.String(Buffer(Buffer'First .. Buffer'First + Length - 1)));
+
+	--File.Read (F, Buffer, Length);
+	--Ada.Text_IO.PUt_Line (Standard.String(Buffer(Buffer'First .. Buffer'First + Length - 1)));
+	--File.Close (F);
+
+ada.text_io.put_line ("------------------");
+
+	File.Open (F, H2.Slim.String'("/etc/passwd"), FL);
+	loop
+		File.Read_Line (F, Buffer, Length);
+		if Length <= 0 then
+			exit;
+		end if;
+		Ada.Text_IO.PUt_Line (Standard.String(Buffer(Buffer'First .. Buffer'First + Length - 1)));
+	end loop;
+
 	File.Close (F);
 end;
 

lib/Makefile.am

@@ -8,9 +8,9 @@ EXTRA_DIST =  \
 	h2-ascii.ads  \
 	h2-utf8.ads \
 	h2-utf8.adb  \
-	h2-sysapi.ads \
+	h2-os.ads \
-	h2-sysapi.adb \
+	h2-os.adb \
-	posix/h2-sysapi-file.adb \
+	posix/h2-os-file.adb \
 	h2-io.ads \
 	h2-io.adb \
 	h2-io-file.adb \

lib/Makefile.in

@@ -178,9 +178,9 @@ EXTRA_DIST = \
 	h2-ascii.ads  \
 	h2-utf8.ads \
 	h2-utf8.adb  \
-	h2-sysapi.ads \
+	h2-os.ads \
-	h2-sysapi.adb \
+	h2-os.adb \
-	posix/h2-sysapi-file.adb \
+	posix/h2-os-file.adb \
 	h2-io.ads \
 	h2-io.adb \
 	h2-io-file.adb \

lib/h2-io-file.adb

@@ -1,3 +1,5 @@
+with H2.Ascii;
+
 separate (H2.IO)
 
 package body File is
@@ -7,7 +9,10 @@ package body File is
 	                Flag: in     Flag_Record;
 	                Pool: in     Storage_Pool_Pointer := null) is
 	begin
-		Sysapi.File.Open (File.File, Name, flag, Pool => Pool);
+		OS.File.Open (File.File, Name, Flag, Pool => Pool);
+		File.Rbuf.Length := 0;
+		File.Wbuf.Length := 0;
+		File.EOF := Standard.False;
 	end Open;
 
 	procedure Open (File: in out File_Record;
@@ -15,41 +20,226 @@ package body File is
 	                Flag: in     Flag_Record;
 	                Pool: in     Storage_Pool_Pointer := null) is
 	begin
-		Sysapi.File.Open (File.File, Name, flag, Pool => Pool);
+		OS.File.Open (File.File, Name, Flag, Pool => Pool);
+		File.Rbuf.Length := 0;
+		File.Wbuf.Length := 0;
+		File.EOF := Standard.False;
 	end Open;
 
-
 	procedure Close (File: in out File_Record) is
 	begin
-		Sysapi.File.Close (File.File);
+		OS.File.Close (File.File);
 		File.File := null;
-		File.Last := System_Length'First;
 	end Close;
 
+	procedure OS_Read_File (File:   in out File_Record;
+	                        Buffer: in out System_Byte_Array;
+	                        Length: out    System_Length) is
+	begin
+		OS.File.Read (File.File, Buffer, Length);
+		File.EOF := (Length <= 0);
+	end OS_Read_File;
+
 	procedure Read (File:   in out File_Record; 
 	                Buffer: in out Slim_String;
-	                Last:   out    System_Length) is
+	                Length: out    System_Length) is
+		pragma Assert (Buffer'Length > 0);
+
+		Outbuf: System_Byte_Array (Buffer'Range);
+		for Outbuf'Address use Buffer'Address;
+
+		Rbuf: File_Buffer renames File.Rbuf;
+		L1, L2: System_Length;
 	begin
-		null;
+		if Rbuf.Length <= 0 and then File.EOF then
+			-- raise EOF EXCEPTION. ???
+			Length := 0;
+			return;
+		end if;
+
+		if Outbuf'Length >= Rbuf.Data'Length then
+			-- The output buffer size if greater than the internal buffer size.
+
+			L1 := Rbuf.Length;
+			if L1 < Outbuf'Length then
+				-- Read into the tail of the output buffer if insufficient
+				-- data is available in the internal buffer.
+				OS_Read_File (File, Outbuf(Outbuf'First + L1 .. Outbuf'Last), L2);
+			end if;
+
+			-- Fill the head of the output buffer with the internal buffer contents
+			Outbuf(Outbuf'First .. Outbuf'First + L1 - 1) := Rbuf.Data(Rbuf.Data'First .. Rbuf.Data'First + L1 - 1);
+
+			-- Empty the internal buffer.
+			Rbuf.Length := 0;
+
+			-- Set the output length
+			Length := L1 + L2;
+		else
+			if Rbuf.Length < Rbuf.Data'Length then
+				-- Attempt to fill the internal buffer. It may not get full with a single read.
+				OS_Read_File (File, Rbuf.Data(Rbuf.Data'First + Rbuf.Length .. Rbuf.Data'Last), L1);
+				Rbuf.Length := RBuf.Length + L1;
+			end if;
+
+			-- Determine how much need to be copied to the output buffer.
+			If Outbuf'Length < Rbuf.Length then
+				L2 := Outbuf'Length;
+			else
+				L2 := Rbuf.Length;
+			end if;
+
+			-- Copy the head of the internal buffer to the output buffer
+			Outbuf(Outbuf'First .. Outbuf'First + L2 - 1) := Rbuf.Data(Rbuf.Data'First .. Rbuf.Data'First + L2 - 1);
+
+			-- Move the residue of the internal buffer to the head
+			Rbuf.Length := Rbuf.Length - L2;
+			Rbuf.Data(Rbuf.Data'First .. Rbuf.Data'First + Rbuf.Length - 1) := Rbuf.Data(Rbuf.Data'First + L2 .. Rbuf.Data'First + L2 + Rbuf.Length - 1);
+			
+			-- Set the output length
+			Length := L2;
+		end if;
+
 	end Read;
 
 	procedure Read (File:   in out File_Record; 
 	                Buffer: in out Wide_String;
-	                Last:   out    System_Length) is
+	                Length: out    System_Length) is
+		pragma Assert (Buffer'Length > 0);
+		Outbuf: Wide_String renames Buffer;
+
+		Rbuf: File_Buffer renames File.Rbuf;
+		Inbuf: Slim_String (Rbuf.Data'Range);
+		for Inbuf'Address use Rbuf.Data'Address;
+		
+		L1, L2, L3, I, J, K: System_Length;
+
+	begin
+		if Rbuf.Length <= 0 and then File.EOF then
+			-- raise EOF EXCEPTION. ???
+			Length := 0;
+			return;
+		end if;
+
+		K := Outbuf'First - 1;
+
+		outer: loop
+			if Rbuf.Length < Rbuf.Data'Length then
+				-- Attempt to fill the internal buffer. It may not get full with a single read.
+				OS_Read_File (File, Rbuf.Data(Rbuf.Data'First + Rbuf.Length .. Rbuf.Data'Last), L1);
+				File.EOF := (L1 <= 0);
+				Rbuf.Length := Rbuf.Length + L1;
+			end if;
+
+			if Rbuf.Length <= 0 then
+				exit outer;
+			end if;
+
+			L2 := Rbuf.Data'First + Rbuf.Length - 1; -- Last index of the internal buffer
+			I := Rbuf.Data'First;
+			loop
+				L3 := Sequence_Length (Inbuf(I));
+				if L2 - I + 1 < L3 then
+					exit;
+				end if;
+
+				K := K + 1;
+				J := I + L3;
+				Outbuf(K..K) := Slim_To_Wide(Inbuf(I .. J - 1));
+				I := J;
+				
+				--if K >= Outbuf'Last or else Outbuf(K) = Ascii.Pos.LF then -- TODO: different line terminator
+				--	L1 := I - Rbuf.Data'First + 1; -- Length of data copied to the output buffer.
+				--	Rbuf.Length := Rbuf.Length - L1; -- Residue length
+				--	Rbuf.Data(Rbuf.Data'First .. RBuf.Data'First + Rbuf.Length - 1) := Rbuf.Data(I + 1 .. L2); -- Copy residue
+				--	exit outer; -- Done
+				--end if;
+			end loop;
+
+			-- Empty the internal buffer;
+			Rbuf.Length := 0;
+		end loop outer;
+
+		Length := K + 1 - Outbuf'First;
+	end Read;
+
+	procedure Read_Line (File:   in out File_Record;
+	                     Buffer: in out Slim_String;
+	                     Length: out   System_Length) is
+
+		pragma Assert (Buffer'Length > 0);
+
+		Outbuf: System_Byte_Array (Buffer'Range);
+		for Outbuf'Address use Buffer'Address;
+
+		Rbuf: File_Buffer renames File.Rbuf;
+		L1, L2, K: System_Length;
+
+		package Ascii is new H2.Ascii (Slim_Character);
+	begin
+		-- Unlike Read, this procedure should use the internal buffer
+		-- regardless of the output buffer size as the position of
+		-- the line terminator is unknown. 
+		--
+		-- If the buffer is not large enough to hold a line, the output
+		-- is just truncated truncated to the buffer size.
+
+		if Rbuf.Length <= 0 and then File.EOF then
+			-- raise EOF EXCEPTION. ???
+			Length := 0;
+			return;
+		end if;
+
+		K := Outbuf'First - 1;
+
+		outer: loop
+			if Rbuf.Length < Rbuf.Data'Length then
+				-- Attempt to fill the internal buffer. It may not get full with a single read.
+				OS_Read_File (File, Rbuf.Data(Rbuf.Data'First + Rbuf.Length .. Rbuf.Data'Last), L1);
+				File.EOF := (L1 <= 0);
+				Rbuf.Length := Rbuf.Length + L1;
+			end if;
+
+			if Rbuf.Length <= 0 then
+				exit outer;
+			end if;
+
+			L2 := Rbuf.Data'First + Rbuf.Length - 1; -- Last index of the internal buffer
+			for I in Rbuf.Data'First .. L2 loop
+				K := K + 1;
+				Outbuf(K) := Rbuf.Data(I);
+				if K >= Outbuf'Last or else Outbuf(K) = Ascii.Pos.LF then -- TODO: different line terminator
+					L1 := I - Rbuf.Data'First + 1; -- Length of data copied to the output buffer.
+					Rbuf.Length := Rbuf.Length - L1; -- Residue length
+					Rbuf.Data(Rbuf.Data'First .. RBuf.Data'First + Rbuf.Length - 1) := Rbuf.Data(I + 1 .. L2); -- Copy residue
+					exit outer; -- Done
+				end if;
+			end loop;
+
+			-- Empty the internal buffer;
+			Rbuf.Length := 0;
+		end loop outer;
+
+		Length := K + 1 - Outbuf'First;
+	end Read_Line;
+
+	procedure Read_Line (File:   in out File_Record;
+	                     Buffer: in out Wide_String;
+	                     Length: out   System_Length) is
 	begin
 		null;
-	end Read;
+	end Read_Line;
 
 	procedure Write (File:   in out File_Record; 
 	                 Buffer: in     Slim_String;
-	                 Last:   out    System_Length) is
+	                 Length: out    System_Length) is
 	begin
 		null;
 	end Write;
 
 	procedure Write (File:   in out File_Record; 
 	                 Buffer: in     Wide_String;
-	                 Last:   out    System_Length) is
+	                 Length: out    System_Length) is
 	begin
 		null;
 	end Write;

lib/h2-io.ads

@@ -1,4 +1,4 @@
-with H2.Sysapi;
+with H2.OS;
 
 generic
 	type Slim_Character is (<>);
@@ -7,31 +7,36 @@ generic
 	type Wide_String is array(System_Index range<>) of Wide_Character;
 	with function Slim_To_Wide (Slim: in Slim_String) return Wide_String;
 	with function Wide_To_Slim (Wide: in Wide_String) return Slim_String;
-
+	with function Sequence_Length (Slim: in Slim_Character) return System_Length;
 
 package H2.IO is
 
-	package Sysapi is new H2.Sysapi (Slim_Character, Wide_Character, Slim_String, Wide_String, Slim_To_Wide, Wide_To_Slim);
+	package OS is new H2.OS (Slim_Character, Wide_Character, Slim_String, Wide_String, Slim_To_Wide, Wide_To_Slim);
 
 	package File is
 
-		subtype Flag_Record is Sysapi.File.Flag_Record;
+		subtype Flag_Record is OS.File.Flag_Record;
+		subtype Flag_Bits is OS.File.Flag_Bits;
 
-		FLAG_READ:       constant := Sysapi.File.FLAG_READ;
+		FLAG_READ:       constant Flag_Bits := OS.File.FLAG_READ;
-		FLAG_WRITE:      constant := Sysapi.File.FLAG_WRITE;
+		FLAG_WRITE:      constant Flag_Bits := OS.File.FLAG_WRITE;
-		FLAG_CREATE:     constant := Sysapi.File.FLAG_CREATE;
+		FLAG_CREATE:     constant Flag_Bits := OS.File.FLAG_CREATE;
-		FLAG_EXCLUSIVE:  constant := Sysapi.File.FLAG_EXCLUSIVE;
+		FLAG_EXCLUSIVE:  constant Flag_Bits := OS.File.FLAG_EXCLUSIVE;
-		FLAG_TRUNCATE:   constant := Sysapi.File.FLAG_TRUNCATE;
+		FLAG_TRUNCATE:   constant Flag_Bits := OS.File.FLAG_TRUNCATE;
-		FLAG_APPEND:     constant := Sysapi.File.FLAG_APPEND;
+		FLAG_APPEND:     constant Flag_Bits := OS.File.FLAG_APPEND;
-		FLAG_NONBLOCK:   constant := Sysapi.File.FLAG_NONBLOCK;
+		FLAG_NONBLOCK:   constant Flag_Bits := OS.File.FLAG_NONBLOCK;
-		FLAG_SYNC:       constant := Sysapi.File.FLAG_SYNC;
+		FLAG_SYNC:       constant Flag_Bits := OS.File.FLAG_SYNC;
-		FLAG_NOFOLLOW:   constant := Sysapi.File.FLAG_NOFOLLOW;
+		FLAG_NOFOLLOW:   constant Flag_Bits := OS.File.FLAG_NOFOLLOW;
 
-		type File_Record is limited record
+		type File_Buffer is private;
-			File: Sysapi.File.File_Pointer := null;
+		type File_Record is limited private;
-			Buffer: System_Byte_Array (1 .. 2048);
+			
-			Last: System_Length := System_Length'First;
+
-		end record;
+		procedure Set_Flag_Bits (Flag: in out Flag_Record; 
+		                         Bits: in     Flag_Bits) renames OS.File.Set_Flag_Bits;
+
+		procedure Clear_Flag_Bits (Flag: in out Flag_Record;
+		                           Bits: in     Flag_Bits) renames OS.File.Clear_Flag_Bits;
 
 		procedure Open (File: in out File_Record; 
 					 Name: in     Slim_String;
@@ -47,21 +52,43 @@ package H2.IO is
 
 		procedure Read (File:   in out File_Record; 
 					 Buffer: in out Slim_String;
-					 Last:   out    System_Length);
+					 Length: out    System_Length);
 
 		procedure Read (File:   in out File_Record;
 					 Buffer: in out Wide_String;
-					 Last:   out    System_Length);
+					 Length: out    System_Length);
+
+		procedure Read_Line (File:   in out File_Record; 
+					      Buffer: in out Slim_String;
+					      Length: out    System_Length);
+
+		procedure Read_Line (File:   in out File_Record;
+					      Buffer: in out Wide_String;
+					      Length: out    System_Length);
 
 		procedure Write (File:   in out File_Record; 
 					  Buffer: in     Slim_String;
-					  Last:   out    System_Length);
+					  Length: out    System_Length);
 
 		procedure Write (File:   in out File_Record;
 					  Buffer: in     Wide_String;
-					  Last:   out    System_Length);
+					  Length: out    System_Length);
 
 		procedure Flush (File: in out File_Record);
+
+	private
+		type File_Buffer is record
+			Data: System_Byte_Array (1 .. 2048); -- TODO: determine the best size
+			Length: System_Length := 0;
+		end record;
+
+		type File_Record is limited record
+			File: OS.File.File_Pointer := null;
+			Rbuf: File_Buffer;
+			Wbuf: File_Buffer;
+			EOF: Standard.Boolean := false;
+		end record;
+
 	end File;
 
 end H2.IO;

lib/h2-os.adb

@@ -1,4 +1,4 @@
-package body H2.Sysapi is
+package body H2.OS is
 
 	package body File is separate;
 
@@ -12,4 +12,4 @@ package body H2.Sysapi is
 		Flag.Bits := Flag.Bits and not Bits;
 	end Clear_File_Flag_Bits;
 
-end H2.Sysapi;
+end H2.OS;

lib/h2-os.ads

@@ -7,7 +7,7 @@ generic
 	with function Slim_To_Wide (Slim: in Slim_String) return Wide_String;
 	with function Wide_To_Slim (Wide: in Wide_String) return Slim_String;
 
-package H2.Sysapi is
+package H2.OS is
 
 
 
@@ -21,17 +21,20 @@ package H2.Sysapi is
 		Bits: File_Mode_Bits := 0;
 	end record;
 
-	procedure Set_File_Flag_Bits (Flag: in out File_Flag_Record; Bits: in File_Flag_Bits);
+	procedure Set_File_Flag_Bits (Flag: in out File_Flag_Record; 
-	procedure Clear_File_Flag_Bits (Flag: in out File_Flag_Record; Bits: in File_Flag_Bits);
+	                              Bits: in     File_Flag_Bits);
+
+	procedure Clear_File_Flag_Bits (Flag: in out File_Flag_Record;
+	                                Bits: in     File_Flag_Bits);
 
 	package File is
 		type File_Record is tagged null record;
 		type File_Pointer is access all File_Record'Class;
 
-		subtype Flag_Bits is Sysapi.File_Flag_Bits;
+		subtype Flag_Bits is OS.File_Flag_Bits;
-		subtype Mode_Bits is Sysapi.File_Mode_Bits;
+		subtype Mode_Bits is OS.File_Mode_Bits;
-		subtype Flag_Record is Sysapi.File_Flag_Record;
+		subtype Flag_Record is OS.File_Flag_Record;
-		subtype Mode_Record is Sysapi.File_Mode_Record;
+		subtype Mode_Record is OS.File_Mode_Record;
 
 		FLAG_READ:       constant Flag_Bits := 2#0000_0000_0000_0001#;
 		FLAG_WRITE:      constant Flag_Bits := 2#0000_0000_0000_0010#;
@@ -59,10 +62,10 @@ package H2.Sysapi is
 		DEFAULT_MODE: constant Mode_Record := ( Bits => 2#110_100_100# );
 
 		procedure Set_Flag_Bits (Flag: in out Flag_Record;
-		                         Bits: in     Flag_Bits) renames Sysapi.Set_File_Flag_Bits;
+		                         Bits: in     Flag_Bits) renames OS.Set_File_Flag_Bits;
 
 		procedure Clear_Flag_Bits (Flag: in out Flag_Record;
-		                           Bits: in     Flag_Bits) renames Sysapi.Clear_File_Flag_Bits;
+		                           Bits: in     Flag_Bits) renames OS.Clear_File_Flag_Bits;
 
 		function Get_Stdin return File_Pointer;
 		function Get_Stdout return File_Pointer;
@@ -84,11 +87,11 @@ package H2.Sysapi is
 
 		procedure Read (File:   in     File_Pointer; 
 		                Buffer: in out System_Byte_Array; 
-		                Last:   out    System_Length);
+		                Length: out    System_Length);
 
 		procedure Write (File:   in  File_Pointer; 
 		                 Buffer: in  System_Byte_Array; 
-		                 Last:   out System_Length);
+		                 Length: out System_Length);
 
 		pragma Inline (Get_Stdin);
 		pragma Inline (Get_Stdout);
@@ -100,4 +103,4 @@ package H2.Sysapi is
 	--                Mode: in  Mode_Record) renames File.Open;
 	--procedure Close_File (File: in out File_Pointer) renames File.Close;
 
-end H2.Sysapi;
+end H2.OS;

lib/h2-utf8.ads

@@ -6,6 +6,9 @@ generic
 package H2.Utf8 is
 	pragma Preelaborate (Utf8);
 
+	--Invalid_Unicode_Character: exception renames Invalid_Wide_Character;
+	--Invalid_Utf8_Sequence: exception renames Invalid_Slim_Sequence;
+	--Insufficient_Utf8_Sequence: exception renames Insifficient_Slim_Sequence;
 	Invalid_Unicode_Character: exception;
 	Invalid_Utf8_Sequence: exception;
 	Insufficient_Utf8_Sequence: exception;

lib/lib.gpr.in

@@ -1,10 +1,14 @@
 project Lib is
 
+	type Platform_Type is ("posix", "win32");
+	Platform: Platform_Type := external ("platform", "posix");
+
 	for Source_Dirs use (
 		"@abs_srcdir@",
-		"@abs_srcdir@/posix",
+		"@abs_srcdir@/" & Platform,
-		"@abs_builddir@/posix"
+		"@abs_builddir@/" & Platform
 	);
+
 	for Library_Name use "h2";
 	for Library_Kind use "dynamic";
 	for Library_Dir use ".";
@@ -13,10 +17,13 @@ project Lib is
 
 	for Source_Files use (
 		"h2.ads",
-		"h2-sysdef.ads",
 		"h2-ascii.ads",
 		"h2-pool.adb",
 		"h2-pool.ads",
+		"h2-os.adb",
+		"h2-os.ads",
+		"h2-os-file.adb",
+		"h2-sysdef.ads",
 		"h2-io.ads",
 		"h2-io.adb",
 		"h2-io-file.adb",
@@ -28,9 +35,6 @@ project Lib is
 		"h2-scheme-execute-evaluate.adb",
 		"h2-scheme-token.adb",
 		"h2-slim.ads",
-		"h2-sysapi.adb",
-		"h2-sysapi.ads",
-		"h2-sysapi-file.adb",
 		"h2-utf8.adb",
 		"h2-utf8.ads",
 		"h2-wide.ads",
@@ -43,8 +47,8 @@ project Lib is
 		"h2.pool",
 		"h2.scheme",
 		"h2.slim",
-		"h2.sysapi",
 		"h2.sysdef",
+		"h2.os",
 		"h2.utf8",
 		"h2.wide",
 		"h2.wide_wide"
@@ -56,6 +60,15 @@ project Lib is
 		);
 	end Compiler;
 
+	--package Naming is
+	--	case Platform is
+	--		when "posix" =>
+	--			for Body ("H2.OS.File") use "h2-os-file-posix.adb";
+	--		when "win32" =>
+	--			for Body ("H2.OS.File") use "h2-os-file-win32.adb";
+	--	end case;
+	--end Naming;
+
 	--package Install is
 	--	for Prefix use "@prefix@";
 	--end Install;

lib/posix/h2-os-file.adb

@@ -2,7 +2,7 @@
 with H2.Pool;
 with H2.Sysdef;
 
-separate (H2.Sysapi)
+separate (H2.OS)
 
 package body File is
 
@@ -131,32 +131,35 @@ package body File is
 		end if;
 	end Close;
 
-	procedure Read (File: in File_Pointer; Buffer: in out System_Byte_Array; Last: out System_Length) is
+	procedure Read (File:   in     File_Pointer; 
+	                Buffer: in out System_Byte_Array;
+	                Length: out    System_Length) is
+		pragma Assert (Buffer'Length > 0);
 		F: Posix_File_Pointer := Posix_File_Pointer(File);
 		N: Sysdef.ssize_t;
 	begin
 		N := Sys_Read (F.Handle, Buffer'Address, Buffer'Length);
 		if Sysdef."<=" (N, ERROR_RETURN) then
 			raise Constraint_Error; -- TODO rename exception
-		elsif Sysdef."=" (N, 0) then
-			Last := Buffer'First - 1;
 		else
-			Last := Buffer'First + System_Length(N) - 1;
+			Length := System_Length(N);
 		end if;
 	end Read;
 
-	procedure Write (File: in File_Pointer; Buffer: in System_Byte_Array; Last: out System_Length) is
+	procedure Write (File:   in  File_Pointer; 
+	                 Buffer: in  System_Byte_Array;
+	                 Length: out System_Length) is
+		pragma Assert (Buffer'Length > 0);
 		F: Posix_File_Pointer := Posix_File_Pointer(File);
 		N: Sysdef.ssize_t;
 	begin
 		N := Sys_Write (F.Handle, Buffer'Address, Buffer'Length);
 		if Sysdef."<=" (N, ERROR_RETURN) then
 			raise Constraint_Error; -- TODO rename exception
-		elsif Sysdef."=" (N, 0) then
-			Last := Buffer'First - 1;
 		else
-			Last := Buffer'First + System_Length(N) - 1;
+			Length := System_Length(N);
 		end if;
+
 	end Write;
 
 end File;