Changeset 291 for CoolStreaming/UBitStream.pas

Timestamp:

Nov 4, 2011, 11:46:15 AM (13 years ago)

Author:

george

Message:

• Modified: Method of StreamHelper for reading string data with defined length.
• Modified: BitStream now use class TPositionMemory from package Common instead of TMemoryStream for storing data. TMemoryStream allocate too huge data (4 kB) even if only few bytes are used.

File:

• CoolStreaming/UBitStream.pas (modified) (10 diffs)

CoolStreaming/UBitStream.pas

@@ -8 +8 @@
 
 uses
-  Classes, SysUtils, RtlConsts, Math;
+  Classes, SysUtils, RtlConsts, Math, UMemory;
 
 type
@@ -47 +47 @@
   TMemoryBitStream = class(TBitStream)
   private
-    FStream: TMemoryStream;
+    FMemory: TPositionMemory;
     FPosition: LongInt;
     FSize: LongInt;
@@ -61 +61 @@
     constructor Create;
     destructor Destroy; override;
-    property Stream: TMemoryStream read FStream;
+    property Memory: TPositionMemory read FMemory;
   end;
 
@@ -175 +175 @@
 function TBitStream.ReadNumber(Count: Byte): QWord;
 begin
+  Result := 0;
   Read(Result, Count);
   Result := Result and ((QWord(1) shl Count) - 1);
@@ -224 +225 @@
 begin
   FSize := AValue;
-  Stream.Size := Ceil(AValue / 8);
+  FMemory.Size := Ceil(AValue / 8);
   if FPosition > FSize then FPosition := FSize;
 end;
@@ -251 +252 @@
     ByteCount := Ceil(Count / 8);
     PosInByte := FPosition mod 8;
-    Stream.Position := Trunc(FPosition / 8);
-    Data := Stream.ReadByte; // Read first byte
+    FMemory.Position := Trunc(FPosition / 8);
+    Data := FMemory.ReadByte; // Read first byte
     for I := 0 to ByteCount - 1 do begin
       TBytes(Buffer)[I] := (Data shr PosInByte) and ((1 shl (8 - PosInByte)) - 1);
-      if (I < ByteCount) and (Stream.Position < Stream.Size) then
-        Data := Stream.ReadByte else Data := 0;
+      if (I < ByteCount) and (FMemory.Position < FMemory.Size) then begin
+        Data := FMemory.ReadByte;
+      end else Data := 0;
       if PosInByte > 0 then
         TBytes(Buffer)[I] := TBytes(Buffer)[I] or
@@ -293 +295 @@
   BitCount := Count;
   ByteCount := Ceil(Count / 8);
-  Stream.Position := Trunc(FPosition / 8);
+  FMemory.Position := Trunc(FPosition / 8);
   BytePos := FPosition mod 8;
   I := 0;
   while (I < ByteCount) or (RestBitCount > 0) do begin
     WriteBitCount := Min(8 - BytePos, BitCount);
-    if (Stream.Position < Stream.Size) and (WriteBitCount < 8) then begin
-      Data := Stream.ReadByte;
-      Stream.Position := Stream.Position - 1;
+    if (FMemory.Position < FMemory.Size) and (WriteBitCount < 8) then begin
+      Data := FMemory.ReadByte;
+      FMemory.Position := FMemory.Position - 1;
     end else Data := 0;
 
@@ -311 +313 @@
     // Write part up to one byte from source to target
     Dec(BitCount, WriteToByte(Data, TBytes(Buffer)[I], BytePos, WriteBitCount));
-    Stream.WriteByte(Data);
+    FMemory.WriteByte(Data);
 
     RestBitCount := Min(8 - WriteBitCount, BitCount);
@@ -334 +336 @@
 constructor TMemoryBitStream.Create;
 begin
-  FStream := TMemoryStream.Create;
+  FMemory := TPositionMemory.Create;
   FPosition := 0;
   FSize := 0;
@@ -341 +343 @@
 destructor TMemoryBitStream.Destroy;
 begin
-  FStream.Free;
+  FMemory.Free;
   inherited Destroy;
 end;