|
PHP对GB编码动态转UTF-8几种方法评测(4)
<?php
$arrLines = file(\"gb_unicode.txt\");
foreach ($arrLines as $strLine) {
$arrCodeTable[hexdec(substr($strLine, 0, 6))] = hexdec(substr($strLine, 7, 6));
}
ksort($arrCodeTable);
$intCount = count($arrCodeTable);
$strCount = chr($intCount % 256) . chr(floor($intCount / 256));
$fileGBU = fopen(\"gbu.dat\", \"wb\");
fwrite($fileGBU, $strCount);
foreach ($arrCodeTable as $k => $v) {
$strData = chr($k % 256) . chr(floor($k / 256)) . chr($v % 256) . chr(floor($v / 256));
fwrite($fileGBU, $strData);
}
fclose($fileGBU);
?>
执行程序后就获得了二进制的GB->Unicode对照表gbu.dat，并且数据记录按GB代码排了序，便于折半法查找。使用gbu.dat进行转码的函数如下：
function GB2UTF8_FILE1($strGB) {
if (!trim($strGB)) return $strGB;
$fileGBU = fopen(\"gbu.dat\", \"rb\");
$strBuf = fread($fileGBU, 2);
$intCount = ord($strBuf{0}) + 256 * ord($strBuf{1});
$strRet = \"\";
$intLen = strlen($strGB);
for ($i = 0; $i < $intLen; $i++) {
if (ord($strGB{$i}) > 127) {
$strCurr = substr($strGB, $i, 2);
$intGB = hexdec(bin2hex($strCurr)) - 0x8080;
$intStart = 1;
$intEnd = $intCount;
while ($intStart < $intEnd - 1) { // 折半法查找
$intMid = floor(($intStart + $intEnd) / 2);
$intOffset = 2 + 4 * ($intMid - 1);
fseek($fileGBU, $intOffset);
$strBuf = fread($fileGBU, 2);
$intCode = ord($strBuf{0}) + 256 * ord($strBuf{1});
if ($intGB == $intCode) {
$intStart = $intMid;
break;
}
|
