在做跟手机短信相关的东东时候常遇到各种编码格式数据的转换，特写了几个函数，供参考。

function EncodeEnglish(var s:string):string;
var
i,j,len:Integer;
cur:Integer;
t:String;
begin
Result:='';
len:=Length(s);
//j 用于移位计数
i:=1;j:=0;
while i<=len do
begin
if i<len then
//数据变换
cur:=(ord(s[i]) shr j) or ((ord(s[i+1]) shl (7-j)) and $ff)
else
cur:=(ord(s[i]) shr j) and $7f;
FmtStr(t,'％2.2X',[cur]);

Result:=Result+t;
inc(i);
//移位计数达到7位的特别处理
j:=(j+1) mod 7;
if j=0 then inc(i);
end;
end;
//end;　　
function BinaryUniCode2Gb2312(ABinaryString:PChar;APosStart,APosEnd:integer):string;
var
 i,iLen:integer;
 AscHexText,TmpHexStr:string;
 AsciiInt:integer ;
 AscLen,AscUniLen:integer;
 UniHexstr,GB2312:string;
begin
 iLen:=Length(ABinaryString);
  for i:= APosStart-1 to APosEnd-1 do
   begin
    AsciiInt:=ord(ABinaryString[i]);
    TmpHexStr:=Format('%x',[AsciiInt]);
    if length(TmpHexStr)=1 then
     TmpHexStr:='0'+TmpHexStr;
    AscHexText:=AscHexText+TmpHexStr;
  end; //for
  AscLen:=Length(AscHexText);
  AscUniLen:=AscLen div 4;
   for i:=0 to AscUniLen-1 do
     begin
      UniHexstr:=Copy(AscHexText,i*4+1,4);
    //  Gb2312 := Gb2312 + UnicodeToGb2312(HexAscii2DecimalInt(uniHexstr));
   end;    // for
   result := Gb2312 ;
end;

function WideStringToUnicode_Ex(s:WideString;ADestStr:PChar;Limit:integer):integer;
var sLen:integer;
 buffer:array[1..1024] of char;
 tmpchar:char;
 i:integer;
begin
  sLen:=Length(s);
  if sLen>0 then
    begin
     CopyMemory(@buffer,Pointer(s),2*SLen);
     for i:=0 to SLen-1 do
      begin
       tmpchar:=buffer[2*i+1];
       buffer[2*i+1]:=buffer[2*i+2];
       buffer[2*i+2]:=tmpchar;
     end;
     if SLen>Limit then
      SLen:=Limit;
      CopyMemory(ADestStr,@buffer,2*SLen);
      result:=SLen*2;
      result:=2*SLen;
     end
     else
      begin
       result:=0;
      end;
end;