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[PATCH 006/188] update leb encoding utils

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From d55f93d5b74595e35ed82bb3fe5048c39259db52 Mon Sep 17 00:00:00 2001
From: Dmitry Boyarintsev <skalogryz.lists@gmail.com>
Date: Wed, 25 Sep 2019 16:35:43 -0400

git-svn-id: branches/wasm@46002 -
This commit is contained in:
nickysn 2020-08-03 12:58:48 +00:00
parent 8f456bbeb5
commit a9755e1c28
1 changed files with 51 additions and 35 deletions
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86
utils/wasmbin/lebutils.pas
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@ -8,14 +8,8 @@ uses
function ReadU(src: TStream): UInt64;
function ReadS(src: TStream; bits: Integer): Int64;
procedure WriteU8 (src: TStream; vl: UInt8);
procedure WriteU16(src: TStream; vl: UInt16);
procedure WriteU32(src: TStream; vl: UInt32);
procedure WriteU64(src: TStream; vl: UInt64);
procedure WriteS8 (src: TStream; vl: Int8);
procedure WriteS16(src: TStream; vl: Int16);
procedure WriteS32(src: TStream; vl: Int32);
procedure WriteS64(src: TStream; vl: Int64);
procedure WriteU(src: TStream; vl: UInt64; bits: integer; fixedSize: Boolean = false);
procedure WriteS(src: TStream; vl: Int64; bits: integer);
implementation
@ -30,7 +24,9 @@ begin
b := src.ReadByte;
Result := Result or ((b and $7f) shl sh);
if (b and $80)>0 then inc(sh, 7)
else break;
else begin
break;
end;
end;
end;
@ -39,53 +35,73 @@ var
b : byte;
sh : Integer;
begin
result := 0;
Result := 0;
sh := 0;
repeat
b := src.ReadByte;
result := Result or ((b and $77) shl sh);
Result := Result or ((b and $7F) shl sh);
inc(sh, 7);
until ((b and $80) = 0);
// sign bit of byte is second high order bit (0x40)
if (sh < bits) and ((b and $40) > 0) then
// sign extend
result := result or ( (not 0) shl sh);
result := result or ( (not 0) shl sh);
end;
procedure WriteU8(src: TStream; vl: UInt8);
procedure WriteU(src: TStream; vl: UInt64; bits: integer; fixedSize: Boolean = false);
var
b: byte;
begin
if (bits < 0) then bits := sizeof(vl)*8;
repeat
b := (vl and $7f);
vl := vl shr 7;
if bits >0 then begin
dec(bits,7);
if bits<0 then bits := 0;
end;
if (vl <> 0) or (fixedSize and (bits > 0)) then
b := b or $80;
src.WriteByte(b);
until ((vl=0) and not fixedSize) or (bits = 0)
end;
procedure WriteU16(src: TStream; vl: UInt16);
procedure WriteS(src: TStream; vl: Int64; bits: integer);
var
more : Boolean;
negative : Boolean;
b : byte;
begin
negative := vl < 0;
end;
more := true;
negative := (vl < 0);
procedure WriteU32(src: TStream; vl: UInt32);
begin
if (bits < 0) then bits := sizeof(vl);
end;
while more do begin
b := (vl and $7f);
vl := vl shr 7;
procedure WriteU64(src: TStream; vl: UInt64);
begin
end;
{ the following is only necessary if the implementation of >>= uses a
logical shift rather than an arithmetic shift for a signed left operand }
if (negative) then
vl := vl or ((not 0) shl (bits - 7)); // sign extend
procedure WriteS8 (src: TStream; vl: Int8);
begin
end;
procedure WriteS16(src: TStream; vl: Int16);
begin
end;
procedure WriteS32(src: TStream; vl: Int32);
begin
end;
procedure WriteS64(src: TStream; vl: Int64);
begin
{ sign bit of byte is second high order bit (0x40) }
if ((vl = 0) and (b and $40 = 0))
or ((vl = -1) and (b and $40 <> 0))
then
more := false
else
b := b or $80;
src.WriteByte(b);
end;
end;
end.