php實作的一個UTF8編碼轉Unicode的函數

function Utf8ToUnicode(strUtf8)
{
var bstr = “”;
var nTotalChars = strUtf8.length; // total chars to be processed.
var nOffset = 0; // processing point on strUtf8
var nRemainingBytes = nTotalChars; // how many bytes left to be converted
var nOutputPosition = 0;
var iCode, iCode1, iCode2; // the value of the unicode.
while (nOffset < nTotalChars)
{
iCode = strUtf8.charCodeAt(nOffset);
if ((iCode & 0×80) == 0) // 1 byte.
{
if ( nRemainingBytes < 1 ) // not enough data
break;
bstr += String.fromCharCode(iCode & 0×7F);
nOffset ++;
nRemainingBytes -= 1;
}
else if ((iCode & 0xE0) == 0xC0) // 2 bytes
{
iCode1 = strUtf8.charCodeAt(nOffset + 1);
if ( nRemainingBytes < 2 || // not enough data
(iCode1 & 0xC0) != 0×80 ) // invalid pattern
{
break;
}
bstr += String.fromCharCode(((iCode & 0×3F) << 6) | ( iCode1 & 0×3F));
nOffset += 2;
nRemainingBytes -= 2;
}
else if ((iCode & 0xF0) == 0xE0) // 3 bytes
{
iCode1 = strUtf8.charCodeAt(nOffset + 1);
iCode2 = strUtf8.charCodeAt(nOffset + 2);
if ( nRemainingBytes < 3 || // not enough data
(iCode1 & 0xC0) != 0×80 || // invalid pattern
(iCode2 & 0xC0) != 0×80 )
{
break;
}
bstr += String.fromCharCode(((iCode & 0×0F) << 12) |
((iCode1 & 0×3F) << 6) |
(iCode2 & 0×3F));
nOffset += 3;
nRemainingBytes -= 3;
}
else // 4 or more bytes — unsupported
break;
}
if (nRemainingBytes != 0)
{
// bad UTF8 string.
return “”;
}
return bstr;
}
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