Langweiliges Zeug. Was sonst.

The T530 has two graphic chips: a low power intel and a dedicated nvidia one. Using bumblebee I was not able to get Twin View working. I just ended up with activating only the discrete nvidia chip using a BIOS setting. After that I was able activate twin view in nvidia-settings.

However, it is pretty inconvenient to navigate in that GUI every time you dock your thinkpad. That's why I created a disper cycle script in a custom gnome-keybinding-properties shortcut:

disper --cycle-stages='-d DFP-2,DFP-0 -e -t left: -d auto -e : -d auto -s : -S' -C

The use cases for these modes are:

Docked mode. Main screen on external monitor (has to be listed first), secondary screen on laptop.

Presentation mode. Main screen on laptop, secondary on beamer.

Single mode. Used before undocking

Secondary only mode.

Forget about awkward splice and indexOf loops! Use the power of closures TODAY!

File foo.dat:

# x med q25 q75 min max 1 138,5 135 146 132 228

file.plot:

You might want to encode/decode strings in java but are unable to use conventional classes. This could be for example due to a restrictive environment like google web toolkit (gwt). In this case, you can use use these two methods:

private static String byte2str(byte[] utfarray) { StringBuilder sb = new StringBuilder(); int i = 0; int c=0, c2=0, c3 = 0; while (i < utfarray.length) { c = (0xFF & utfarray[i]); if (c < 128) { sb.append((char)c); i++; } else if ((c > 191) && (c < 224)) { c2 = (0xFF & utfarray[i + 1]); sb.append((char)(((c & 31) << 6) | (c2 & 63))); i += 2; } else { c2 = (0xFF & utfarray[i + 1]); c3 = (0xFF & utfarray[i + 2]); sb.append((char)(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63))); i += 3; } } return sb.toString(); }

Using mumble and want to import your own CA certificate as trusted?

To deserialize a JSON array you can use an Overlay Type. However, those examples return objects instead of arrays. Here an example of how this is case is handled: JSON:

[{"age": 42, "name": "arthur"}, {"age": 23, "name": "adam"}]

As it turns out, associative arrays can't be used as a cheap hashSET surrogate. Consider the following source:

var hashset = {}; var obj1 = new Object(); obj1['foo'] = 42; hashset[obj] = true; for(key in hashset) alert(key.foo);

This won't work for a simple reason: Associative arrays only support simple types as key. Obj1 will be casted to string as soon as you use it as an index. Thus key.foo is inaccessible because strings don't have a property "foo". I ended up with a quick and dirty solution which should require O(1)/O(log n). Depends on the javascript implementation of associative arrays.

Download ROM, place as .zip on sd card

Unlock bootloader: www.htcdev.com/bootloader/unlock-instructions/

Get in fastboot mode, boot cwm:

./fastboot boot /tmp/recovery-clockwork-5.0.2.0-saga.img

Wipe

Install zips

Reboot

If stuck at loading screen: flash boot.img by hand

You can speed up your javascript encryption stuff by using ArrayBuffers. However, if you want to convert it back to a binary string for other API calls, it's really slow. At least if you do it by hand using something like

for(var i=0; i< view.length; ++i) str += String.fromCharCode(view[i]);

Of course you can somewhat improve it by using a stringbuilder approach, like

function convertFaster(view) { var array = new Array(view.length); for(var i=0; i< view.length; ++i) array[i] = String.fromCharCode(view[i]); return array.join(''); }

However, there is a much faster way using the FileReader API. Although its name implies only usage for files, it takes a Blob as an argument. Since every File is also a Blob, this makes it possible to read Files. But this also means, we can feed it with custom blobs. To make use of this we can convert any ArrayBuffer to a blob by using the brand new BlobBuilder

var buffer = new ArrayBuffer(3) var array = new Uint8Array(buffer); var i=0; array[i++] = 0x48; array[i++] = 0x69; array[i++] = 0x21; var blobBuilder = new BlobBuilder(); blobBuilder.append(buffer); buffer = null; var blob = blobBuilder.getBlob(); var fileReader =new FileReader(); fileReader.onload = function (e) { //conversion done }; fileReader.readAsBinaryString(blob);

To convert a binary string to a blob we can again use the BlobBuilder. Append also accept DOMStrings as argument.

if (window.MozBlobBuilder) window.BlobBuilder = MozBlobBuilder; if (window.WebKitBlobBuilder) window.BlobBuilder = WebKitBlobBuilder; function arrayBufferPerformance() { var count=prompt("Size of array in bytes?","5000000"); if(count == null) return; count = parseInt(count); var buffer = new ArrayBuffer(count) var array = new Uint8Array(buffer); var start = (new Date).getTime(); var join = new Array(count); for(var i=0; i<array.length; ++i) join[i] = String.fromCharCode(array[i]); join.join(''); var diff = (new Date).getTime() - start; alert("classical approach: "+diff+"ms"); window.start = (new Date).getTime(); var blobBuilder = new BlobBuilder(); blobBuilder.append(buffer); buffer = null; var blob = blobBuilder.getBlob(); var fileReader =new FileReader(); fileReader.onload = function (e) { var diff = (new Date).getTime() - window.start; alert("arraybuffer approach: "+diff+"ms"); }; fileReader.readAsBinaryString(blob); }

Last but not least a nice performance comparison (ArrayBuffer to BinaryString): click me.

Some results with 5000000 bytes on a Core2Duo 6300:

Firefox 9.0.1: 884ms vs 89ms

Chromium 14.0.835.202: 1886ms vs 101ms

I tried to benchmark an encryption function by passing an empty array to it:

var data = new Array(10* 1024* 1024); var start = (new Date).getTime(); rc4.secureEncrypt([1, 2, 3, 4, 5, 6,7,8,9,0], data); var diff = (new Date).getTime() - start; alert("spent "+diff+" ms on encryption");

It was slow, but I didn't know why. I gradually debugged the code and discovered, that 90% of the time was spent in that line:

plantext[i] = encrypted;

Why should accessing a simple array take that long? It's an O(1) operation! Well, it turns out that the array is a sparse array. Since most of it will never be accessed, it's simply empty (empty != 0) and is created on first access. Just filling the array caused the function to be executed 3 to 4 times faster. The encryption itself turned out to be pretty fast, it was just a bad benchmark testing input.

!(wlan.fc.type_subtype == 0x1d) && !(wlan.sa == $MY_ADDRESS) && !(wlan.fc.type_subtype == 0x08) 0x1d = beacon 0x08 = ack

Searching for a simple function to convert javascript strings to byte arrays, I stumbled over this stackoverflow answer.

While it's implementation is correct, it has a significant performance problem. For large strings, the internal byte array is recreated too often. It's somewhat similar to using the += operator on strings in java instead of using a StringBuilder. A faster function is below.

function stringToBytesFaster ( str ) { var ch, st, re = [], j=0; for (var i = 0; i < str.length; i++ ) { ch = str.charCodeAt(i); if(ch < 127) { re[j++] = ch & 0xFF; } else { st = []; // clear stack do { st.push( ch & 0xFF ); // push byte to stack ch = ch >> 8; // shift value down by 1 byte } while ( ch ); // add stack contents to result // done because chars have "wrong" endianness st = st.reverse(); for(var k=0;k<st.length; ++k) re[j++] = st[k]; } } // return an array of bytes return re; }

function stringToBytesFaster ( str ) { var ch, st, re = [], j=0; for (var i = 0; i < str.length; i++ ) { ch = str.charCodeAt(i); if(ch < 127) { re[j++] = ch & 0xFF; } else { st = []; // clear stack do { st.push( ch & 0xFF ); // push byte to stack ch = ch >> 8; // shift value down by 1 byte } while ( ch ); // add stack contents to result // done because chars have "wrong" endianness st = st.reverse(); for(var k=0;k<st.length; ++k) re[j++] = st[k]; } } // return an array of bytes return re; } function stringToBytes ( str ) { var ch, st, re = []; for (var i = 0; i < str.length; i++ ) { ch = str.charCodeAt(i); // get char st = []; // set up "stack" do { st.push( ch & 0xFF ); // push byte to stack ch = ch >> 8; // shift value down by 1 byte } while ( ch ); // add stack contents to result // done because chars have "wrong" endianness re = re.concat( st.reverse() ); } // return an array of bytes return re; } function performanceTest() { var count=prompt("Size of the teststring?","1000"); if(count == null) return; count = parseInt(count); var testStr = ''; for(var i=0; i< count; ++i) testStr += String.fromCharCode(i); var start = new Date().getTime(); var v1 = stringToBytes(testStr); var timeOld = new Date().getTime()-start; var start = new Date().getTime(); var v2 = stringToBytesFaster(testStr); var timeNew = new Date().getTime()-start; for(var i=0; i< v1.length; ++i) { if(v1[i] != v2[i]) alert('difference at index '+i+': expected '+v1[i]+' but got' + v2[i]); } alert('Old: ' + timeOld+'ms\nNew: '+timeNew+'ms\n\nSpeedup factor:' + (timeOld/timeNew)); } To round up things, you can start a performance test here: clickme