<html>
<head>
<title>JavaScript字符串之壓縮與還原</title>
<meta?http-equiv="Content-Type"?content="text/html;?charset=utf-8"?/>
<script?type="text/javascript">
<!--
/**
?*?壓縮
?*/
function?Compress(strNormalString)?{
????alert("壓縮前長度："?+?strNormalString.length);
????var?strCompressedString?=?"";
????var?ht?=?new?Array();
????for(i?=?0;?i?<?128;?i++)?{
????????ht[i]?=?i;
????}
????var?used?=?128;
????var?intLeftOver?=?0;
????var?intOutputCode?=?0;
????var?pcode?=?0;
????var?ccode?=?0;
????var?k?=?0;
????for(var?i=0;?i<strNormalString.length;?i++)?{
????????ccode?=?strNormalString.charCodeAt(i);
????????k?=?(pcode?<<?8)?|?ccode;
????????if(ht[k]?!=?null)?{
????????????pcode?=?ht[k];
????????}?else?{
????????????intLeftOver?+=?12;
????????????intOutputCode?<<=?12;
????????????intOutputCode?|=?pcode;
????????????pcode?=?ccode;
????????????if(intLeftOver?>=?16)?{
????????????????strCompressedString?+=?String.fromCharCode(?intOutputCode?>>?(?intLeftOver?-?16?)?);
????????????????intOutputCode?&=?(Math.pow(2,?(intLeftOver?-?16))?-?1);
????????????????intLeftOver?-=?16;
????????????}
????????????if(used?<?4096)?{
????????????????used?++;
????????????????ht[k]?=?used?-?1;
????????????}
????????}
????}
????if(pcode?!=?0)?{
????????intLeftOver?+=?12;
????????intOutputCode?<<=?12;
????????intOutputCode?|=?pcode;
????}
????if(intLeftOver?>=?16)?{
????????strCompressedString?+=?String.fromCharCode(?intOutputCode?>>?(?intLeftOver?-?16?)?);
????????intOutputCode?&=?(Math.pow(2,(intLeftOver?-?16))?-?1);
????????intLeftOver?-=?16;
????}
????if(?intLeftOver?>?0)?{
????????intOutputCode?<<=?(16?-?intLeftOver);
????????strCompressedString?+=?String.fromCharCode(?intOutputCode?);
????}
????alert("壓縮后長度："?+?strCompressedString.length);
????return?strCompressedString;
}
/**
?*?解壓縮
?*/
function?Decompress(strCompressedString)?{
????var?strNormalString?=?"";
????var?ht?=?new?Array();
????for(i?=?0;?i?<?128;?i++)?{
????????ht[i]?=?String.fromCharCode(i);
????}
????var?used?=?128;
????var?intLeftOver?=?0;
????var?intOutputCode?=?0;
????var?ccode?=?0;
????var?pcode?=?0;
????var?key?=?0;
????for(var?i=0;?i<strCompressedString.length;?i++)?{
????????intLeftOver?+=?16;
????????intOutputCode?<<=?16;
????????intOutputCode?|=?strCompressedString.charCodeAt(i);
????????while(1)?{
????????????if(intLeftOver?>=?12)?{
????????????????ccode?=?intOutputCode?>>?(intLeftOver?-?12);
????????????????if(?typeof(?key?=?ht[ccode]?)?!=?"undefined"?)?{
?????????????????????strNormalString?+=?key;
????????????????????if(used?>?128)?{
????????????????????????ht[ht.length]?=?ht[pcode]?+?key.substr(0,?1);
????????????????????}
?????????????????????pcode?=?ccode;
????????????????}?else?{
????????????????????key?=?ht[pcode]?+?ht[pcode].substr(0,?1);
????????????????????strNormalString?+=?key;
????????????????????ht[ht.length]?=?ht[pcode]?+?key.substr(0,?1);
????????????????????pcode?=?ht.length?-?1;
????????????????}
????????????????used?++;
????????????????intLeftOver?-=?12;
????????????????intOutputCode?&=?(Math.pow(2,intLeftOver)?-?1);
????????????}?else?{
????????????????break;
????????????}
????????}
????}
????return?strNormalString;
}
//-->
</script>
</head>
<body>
壓縮前：
<input?type="text"?id="txtNormal"?value=""?/>
<input?type="button"?value="↓壓縮"?onclick="document.getElementById('txtCompressed').value=Compress(document.getElementById('txtNormal').value);"?/>
<input?type="button"?value="清除"?onclick="document.getElementById('txtNormal').value='';"?/>
壓縮后：<br>
<input?type="text"?id="txtCompressed"?value=""?/>
<input?type="button"?value="↑解壓"?onclick="document.getElementById('txtNormal').value=Decompress(document.getElementById('txtCompressed').value);"?/>
<input?type="button"?value="清除"?onclick="document.getElementById('txtCompressed').value='';"?/>
</body>
</html>
<head>
<title>JavaScript字符串之壓縮與還原</title>
<meta?http-equiv="Content-Type"?content="text/html;?charset=utf-8"?/>
<script?type="text/javascript">
<!--
/**
?*?壓縮
?*/
function?Compress(strNormalString)?{
????alert("壓縮前長度："?+?strNormalString.length);
????var?strCompressedString?=?"";
????var?ht?=?new?Array();
????for(i?=?0;?i?<?128;?i++)?{
????????ht[i]?=?i;
????}
????var?used?=?128;
????var?intLeftOver?=?0;
????var?intOutputCode?=?0;
????var?pcode?=?0;
????var?ccode?=?0;
????var?k?=?0;
????for(var?i=0;?i<strNormalString.length;?i++)?{
????????ccode?=?strNormalString.charCodeAt(i);
????????k?=?(pcode?<<?8)?|?ccode;
????????if(ht[k]?!=?null)?{
????????????pcode?=?ht[k];
????????}?else?{
????????????intLeftOver?+=?12;
????????????intOutputCode?<<=?12;
????????????intOutputCode?|=?pcode;
????????????pcode?=?ccode;
????????????if(intLeftOver?>=?16)?{
????????????????strCompressedString?+=?String.fromCharCode(?intOutputCode?>>?(?intLeftOver?-?16?)?);
????????????????intOutputCode?&=?(Math.pow(2,?(intLeftOver?-?16))?-?1);
????????????????intLeftOver?-=?16;
????????????}
????????????if(used?<?4096)?{
????????????????used?++;
????????????????ht[k]?=?used?-?1;
????????????}
????????}
????}
????if(pcode?!=?0)?{
????????intLeftOver?+=?12;
????????intOutputCode?<<=?12;
????????intOutputCode?|=?pcode;
????}
????if(intLeftOver?>=?16)?{
????????strCompressedString?+=?String.fromCharCode(?intOutputCode?>>?(?intLeftOver?-?16?)?);
????????intOutputCode?&=?(Math.pow(2,(intLeftOver?-?16))?-?1);
????????intLeftOver?-=?16;
????}
????if(?intLeftOver?>?0)?{
????????intOutputCode?<<=?(16?-?intLeftOver);
????????strCompressedString?+=?String.fromCharCode(?intOutputCode?);
????}
????alert("壓縮后長度："?+?strCompressedString.length);
????return?strCompressedString;
}
/**
?*?解壓縮
?*/
function?Decompress(strCompressedString)?{
????var?strNormalString?=?"";
????var?ht?=?new?Array();
????for(i?=?0;?i?<?128;?i++)?{
????????ht[i]?=?String.fromCharCode(i);
????}
????var?used?=?128;
????var?intLeftOver?=?0;
????var?intOutputCode?=?0;
????var?ccode?=?0;
????var?pcode?=?0;
????var?key?=?0;
????for(var?i=0;?i<strCompressedString.length;?i++)?{
????????intLeftOver?+=?16;
????????intOutputCode?<<=?16;
????????intOutputCode?|=?strCompressedString.charCodeAt(i);
????????while(1)?{
????????????if(intLeftOver?>=?12)?{
????????????????ccode?=?intOutputCode?>>?(intLeftOver?-?12);
????????????????if(?typeof(?key?=?ht[ccode]?)?!=?"undefined"?)?{
?????????????????????strNormalString?+=?key;
????????????????????if(used?>?128)?{
????????????????????????ht[ht.length]?=?ht[pcode]?+?key.substr(0,?1);
????????????????????}
?????????????????????pcode?=?ccode;
????????????????}?else?{
????????????????????key?=?ht[pcode]?+?ht[pcode].substr(0,?1);
????????????????????strNormalString?+=?key;
????????????????????ht[ht.length]?=?ht[pcode]?+?key.substr(0,?1);
????????????????????pcode?=?ht.length?-?1;
????????????????}
????????????????used?++;
????????????????intLeftOver?-=?12;
????????????????intOutputCode?&=?(Math.pow(2,intLeftOver)?-?1);
????????????}?else?{
????????????????break;
????????????}
????????}
????}
????return?strNormalString;
}
//-->
</script>
</head>
<body>
壓縮前：
<input?type="text"?id="txtNormal"?value=""?/>
<input?type="button"?value="↓壓縮"?onclick="document.getElementById('txtCompressed').value=Compress(document.getElementById('txtNormal').value);"?/>
<input?type="button"?value="清除"?onclick="document.getElementById('txtNormal').value='';"?/>
壓縮后：<br>
<input?type="text"?id="txtCompressed"?value=""?/>
<input?type="button"?value="↑解壓"?onclick="document.getElementById('txtNormal').value=Decompress(document.getElementById('txtCompressed').value);"?/>
<input?type="button"?value="清除"?onclick="document.getElementById('txtCompressed').value='';"?/>
</body>
</html>
及Viterbi算法)
