simple parallel processing in windows

玩data mining有個好處就是在處理大量資料的時候可以盡情的加速...do as whatever you can do :)

所以現在在coding的時候發現可以加速的地方都會加速..

so 底下提供一些sample, 把你要parallel的指令放入一個list, 然後call c_parallen()就可以達到parallel.

如果用MinGW 記得加上 -mwindows
windows.h記得include

1. #define UNICODE
2. 
   
3. #include <windows.h>
4. #include <iostream>
5. #include <vector>
6. 
   
7. using namespace std;
8. 
   
9. PROCESS_INFORMATION* c_fork(const char * cmd){
10. 
    
11. STARTUPINFO si;
12. PROCESS_INFORMATION *pi = (PROCESS_INFORMATION*)malloc(sizeof(PROCESS_INFORMATION) );
13. 
    
14. ZeroMemory( &si, sizeof(si) );
15. si.cb = sizeof(si);
16. ZeroMemory( pi, sizeof(PROCESS_INFORMATION) );
17. 
    
18. TCHAR Tcmd [4096];
19. mbstowcs(Tcmd, cmd, (sizeof(TCHAR) * strlen(cmd) ));
20. 
    
21. 
    
22. 
    
23. // Start the child process.
24. if( !CreateProcess( NULL, // No module name (use command line)
25. Tcmd, // Command line
26. NULL, // Process handle not inheritable
27. NULL, // Thread handle not inheritable
28. FALSE, // Set handle inheritance to FALSE
29. 0, // No creation flags
30. NULL, // Use parent's environment block
31. NULL, // Use parent's starting directory
32. &si, // Pointer to STARTUPINFO structure
33. pi ) // Pointer to PROCESS_INFORMATION structure
34. )
35. {
36. printf( "CreateProcess failed (%d)\n", GetLastError() );
37. return NULL;
38. }
39. 
    
40. return pi;
41. }
42. 
    
43. void c_parallel(const char* cmdlist){
44. 
    
45. ifstream in(cmdlist, ios::binary);
46. string line;
47. vector<PROCESS_INFORMATION*> process;
48. while( ! in.eof()){
49. 
    
50. getline(in, line);
51. 
    
52. if( !line.empty() ){
53. 
    
54. cout << "do:" << line << endl;
55. process.push_back( c_fork( line.c_str() )) ;
56. 
    
57. 
    
58. }
59. 
    
60. }
61. //joint
62. for(int i=0; i < process.size(); i++){
63. WaitForSingleObject( process[i]->hProcess, INFINITE );
64. }
65. //close
66. for(int i=0; i < process.size(); i++){
67. CloseHandle( process[i]->hProcess );
68. CloseHandle( process[i]->hThread );
69. free(process[i]);
70. }
71. }

simple byte-oriented file copy

1. /**
2. * simple copy image,
3. * @param src
4. * @param dest
5. */
6. public void copyImage(File src, File dest){
8. byte[] buffer = new byte[1024];
9. FileInputStream r = null;
10. FileOutputStream w = null;
11. int r_num=0;
12. try{
14. r = new FileInputStream( src);
15. w = new FileOutputStream( dest);
16. r_num = r.read(buffer, 0, 1024);
17. while(r_num != -1){
19. w.write(buffer, 0, r_num);
20. r_num = r.read(buffer, 0, 1024);
21. }
22. }
23. catch(IOException e){
24. e.printStackTrace();
25. }
26. finally{
27. try{
28. if(r != null)
29. r.close();
30. if(w != null)
31. w.close();
32. }
33. catch(IOException ex){
34. ex.printStackTrace();
35. }
36. }
37. }

可用於任何byte-oriented file, ex: image

簡易的java compression and decompression

目前在做之前學長的Video Annotation tool多個model的整合...常常training出來的model感覺檔案都很大...(因為我只有把它tar起來XD)...有鑑於此,,所以寫了一個簡易的compression/decompression的程式..主要改自Simple String Compression Functions 不過為了符合我的需要,input/output都是一個file,,不過這個blog好像沒辦法上傳檔案..XD所以底下大概看一下吧XD

compression 的infile就是原先的tar起來的file, outfile就是compression放置的地方
decompression的動作就是相反.

1. /**
2. * the input is the file that we want to compression
3. * the output is the compressed file
4. * @param infile
5. * @param outfile
6. * @return
7. * @throws IOException
8. */
9. static public void compression(String infile, String outfile)throws IOException{
11. BufferedInputStream fin = null;
12. BufferedOutputStream fout = null;
14. try{
15. byte[] buffer = new byte[1024];
16. int offset = -1;
17. fin = new BufferedInputStream( new FileInputStream(infile));
18. fout = new BufferedOutputStream ( new FileOutputStream(outfile));
20. ByteArrayOutputStream out = new ByteArrayOutputStream();
21. ZipOutputStream zout = new ZipOutputStream(out);
22. zout.putNextEntry(new ZipEntry("0"));
23. while( (offset = fin.read(buffer)) != -1){
25. zout.write(buffer, 0, offset);
27. }
28. zout.closeEntry();
29. byte[] compressed = out.toByteArray();
30. zout.close();
31. fout.write(compressed);
33. fout.close();
36. }
37. catch(IOException e){
38. new IOException("simpleCompression.compression exception");
39. }
40. finally{
41. if(fin != null){
42. fin.close();
43. }
44. if(fout != null){
45. fout.flush();
46. fout.close();
47. }
49. }
50. }
51. /**
52. * the input is the compressed file
53. * the output is the original file
54. * @param compressed
55. * @return
56. * @throws IOException
57. */
58. static public void decompression(String infile, String outfile)throws IOException{
60. int read=0;
61. byte[] buffer = new byte[1024];
62. BufferedInputStream fin = null;
63. BufferedWriter fout = null;
64. ZipInputStream zin = null;
65. ByteArrayOutputStream out = null;
66. try{
67. fin = new BufferedInputStream( new FileInputStream(infile));
68. zin = new ZipInputStream(fin);
69. ZipEntry entry = zin.getNextEntry();
70. out = new ByteArrayOutputStream();
71. int offset = -1;
72. while((offset = zin.read(buffer)) != -1) {
73. out.write(buffer, 0, offset);
74. }
75. fout = new BufferedWriter(new FileWriter(outfile));
76. fout.write(out.toString());
78. }
79. catch(IOException e){
80. new IOException("simpleCompression.decompression exception");
81. }
82. finally{
83. if(fin != null)
84. fin.close();
85. if(fout != null){
86. fout.flush();
87. fout.close();
88. }
89. if(out != null)
90. out.close();
91. if(zin != null)
92. zin.close();
94. }
96. }

split edit panel in eclipse

以前用慣了vim的一個功能: split filename

就會把目前editing panel split into two parts..

這個功能蠻適合在編寫code或是找bug的時候用...

然而,這個功能要怎樣在eclipse上實現呢?

其實很簡單...從 window->new Editor ,

之後會產生一個tab,,,把該tab用拖曳的方式拉到上下左右隨便一個就會產生split的效果了

build jbuilder project using eclipse

最近要修改一些學長的code,
就發現了jbuilder一些很不合理的地方...
在jbuilder裡面可以利用一些內建拖曳的功能去實做GUI...
但是jbuilder也會自動幫你import一些屬於他自己內建的library..
ex: import com.borland.jbcl.xxxx.xxx;
也就是說這個project就算給你source code,
除非你用jbuilder這套軟體去修改...否則你也沒辦法rebuild..
(這跟偉大的邪惡帝國有什麼區別....)
不過...還好可以從jbuilder裡面安裝的lib找到想要的.jar
再把想要的.jar加入到classpath底下即可.
以上面的例子來說,可以從安裝jbuilder目錄底下lib/jbcl.jar
然後把該 jar file 的path加入classpath底下,,rebuild,,then 收工!

這是第一篇

這是第一篇文章,,不知道自己會持續寫多久

anyway,就當一個記錄自己在求學過程的一些經驗以及一些人生觀 :)