/** * utf8转gbk * * @param *        	$utfstr */function utf8_to_gbk($utfstr) {	global $UC2GBTABLE;	$okstr = '';	if (empty ( $UC2GBTABLE )) {		$filename = CODETABLEDIR . 'gb-unicode.table';		$fp = fopen ( $filename, 'rb' );		while ( $l = fgets ( $fp, 15 ) ) {			$UC2GBTABLE [hexdec ( substr ( $l, 7, 6 ) )] = hexdec ( substr ( $l, 0, 6 ) );		}		fclose ( $fp );	}	$okstr = '';	$ulen = strlen ( $utfstr );	for($i = 0; $i < $ulen; $i ++) {		$c = $utfstr [$i];		$cb = decbin ( ord ( $utfstr [$i] ) );		if (strlen ( $cb ) == 8) {			$csize = strpos ( decbin ( ord ( $cb ) ), '0' );			for($j = 0; $j < $csize; $j ++) {				$i ++;				$c .= $utfstr [$i];			}			$c = utf8_to_unicode ( $c );			if (isset ( $UC2GBTABLE [$c] )) {				$c = dechex ( $UC2GBTABLE [$c] + 0x8080 );				$okstr .= chr ( hexdec ( $c [0] . $c [1] ) ) . chr ( hexdec ( $c [2] . $c [3] ) );			} else {				$okstr .= '&#' . $c . ';';			}		} else {			$okstr .= $c;		}	}	$okstr = trim ( $okstr );	return $okstr;}/** * gbk转utf8 * * @param *        	$gbstr */function gbk_to_utf8($gbstr) {	global $CODETABLE;	if (empty ( $CODETABLE )) {		$filename = CODETABLEDIR . 'gb-unicode.table';		$fp = fopen ( $filename, 'rb' );		while ( $l = fgets ( $fp, 15 ) ) {			$CODETABLE [hexdec ( substr ( $l, 0, 6 ) )] = substr ( $l, 7, 6 );		}		fclose ( $fp );	}	$ret = '';	$utf8 = '';	while ( $gbstr ) {		if (ord ( substr ( $gbstr, 0, 1 ) ) > 0x80) {			$thisW = substr ( $gbstr, 0, 2 );			$gbstr = substr ( $gbstr, 2, strlen ( $gbstr ) );			$utf8 = '';			@$utf8 = unicode_to_utf8 ( hexdec ( $CODETABLE [hexdec ( bin2hex ( $thisW ) ) - 0x8080] ) );			if ($utf8 != '') {				for($i = 0; $i < strlen ( $utf8 ); $i += 3)					$ret .= chr ( substr ( $utf8, $i, 3 ) );			}		} else {			$ret .= substr ( $gbstr, 0, 1 );			$gbstr = substr ( $gbstr, 1, strlen ( $gbstr ) );		}	}	return $ret;}/** * unicode转utf8 * * @param *        	$c */function unicode_to_utf8($c) {	$str = '';	if ($c < 0x80) {		$str .= $c;	} elseif ($c < 0x800) {		$str .= (0xC0 | $c >> 6);		$str .= (0x80 | $c & 0x3F);	} elseif ($c < 0x10000) {		$str .= (0xE0 | $c >> 12);		$str .= (0x80 | $c >> 6 & 0x3F);		$str .= (0x80 | $c & 0x3F);	} elseif ($c < 0x200000) {		$str .= (0xF0 | $c >> 18);		$str .= (0x80 | $c >> 12 & 0x3F);		$str .= (0x80 | $c >> 6 & 0x3F);		$str .= (0x80 | $c & 0x3F);	}	return $str;}/** * utf8转unicode * * @param *        	$c */function utf8_to_unicode($c) {	switch (strlen ( $c )) {		case 1 :			return ord ( $c );		case 2 :			$n = (ord ( $c [0] ) & 0x3f) << 6;			$n += ord ( $c [1] ) & 0x3f;			return $n;		case 3 :			$n = (ord ( $c [0] ) & 0x1f) << 12;			$n += (ord ( $c [1] ) & 0x3f) << 6;			$n += ord ( $c [2] ) & 0x3f;			return $n;		case 4 :			$n = (ord ( $c [0] ) & 0x0f) << 18;			$n += (ord ( $c [1] ) & 0x3f) << 12;			$n += (ord ( $c [2] ) & 0x3f) << 6;			$n += ord ( $c [3] ) & 0x3f;			return $n;	}}