1.类型说明
Byte:Represents an 8-bit unsigned integer type.
[PByte:Is a pointer to a Byte.]
Char:Represents a word-sized (16-bits) character type
AnsiChar:Represents a byte-sized (8-bits) character type
WideChar：Represents a word-sized (16-bits) character type.
[PChar：Defines a null-terminated string]
[PAnsiChar：Defines a null-terminated ANSI string.]
String：Represents an alias for the generic UnicodeString type.
AnsiString：Represents a dynamically allocated string whose maximum length is limited only by available memory.
WideString：A null-terminated string of wide characters, with no reference counting.
[PString：Is a pointer to a String.]
[PAnsiString：Is a pointer to an AnsiString.]
TBytes：declares an array of Bytes.
2.指针
1 var
2 X, Y: Integer; // X and Y are Integer variables
3 P: ^Integer; // P points to an Integer
4 begin
5 X := 17; // assign a value to X
6 P := @X; // assign the address of X to P
7 Y := P^; // dereference P; assign the result to Y
8 end;
type
PInteger = ^Integer;
var
R: Single;
I: Integer;
P: Pointer;
PI: PInteger;
begin
...
P := @R;
PI := PInteger(P);
I := PI^;
end;
3.一些点
SizeOf：Returns the number of bytes occupied by a variable or type.
Length：Returns the number of characters in a string or of elements in an array.
Move：Copies bytes from a source to a destination. e.g.: Move(PChar(@arrBuf[0])^, LPChar^, aSectorNum * 512);
ByteLength：Returns the length of a given string in bytes.
GetBytes：Encodes a set of characters into a sequence of bytes
FillChar：Fills contiguous bytes with a specified value.
4.转换
TBytes -> PChar : LPChar := PChar(LTBytes);
PChar -> TBytes：LTBytes := BytesOf(LPChar);
TBytes -> Array of AnsiChar：move(LTBytes[i],LArrayOfAnsiChar[k]);
Array of AnsiChar -> string：LString := StringOf(BytesOf(LArrayOfAnsiChar));