2015年5月4日星期一

JNI coding

src:
http://blogforopensource.blogspot.tw/2012/08/jni-sample-java-code.html

notes:
15'5/5 :
- javah is used for JNI header
- pay attention to the c compile. It may need extra compiler like VC++

contents:

AUG

JNI sample Java Code

Blogging after a long time..

JNI - Java Native Interface.

Java interface to nonJava code.
It is Java's link to the "outside world"

• Native methods are compiled into a dynamic link
library (.dll, .so, etc.)
• OS loads and links the library into the process
that is running the Java Virtual Machine
• Part of the Java Developer Kit(JDK),
serves as a glue between Java side and
native side of an application
• Allows Java code that runs inside a Java Virtual
Machine (JVM) to inter operate with applications and
libraries written in other programming languages,
such as C, C++, and assembly

JNI w.r.t Operating System :

JNI Sequence:

If you are really interested in JNI,

You can find a Sample Code from here.

http://code.google.com/p/onlineexaminationsysteminjava/downloads/detail?name=samplejnicode.zip&can=2&q=

Reference:

http://patriot.net/~tvalesky/jninative.html

Posted 22nd August 2012 by Srikrishnan's Blog for open source

Labels: JNI sample Java Code

Add a comment

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Native Method example using JNI

Trivial JNI example

Declare your native methods in an otherwise normal Java class.

public class nativetest
{
 public native String sayHello(String s);
 public static void main(String[] argv)
 {
  String retval = null;
  nativetest nt = new nativetest();
  retval = nt.sayHello("Beavis");
  System.out.println("Invocation returned " + retval);
 }
}

javac nativetest.java
Standard Java compile

javah -jni nativetest
Generates .h files. Here is the code.

/* DO NOT EDIT THIS FILE - it is machine generated */
#include 
/* Header for class nativetest */

#ifndef _Included_nativetest
#define _Included_nativetest
#ifdef __cplusplus
extern "C" {
#endif
/*
 * Class:     nativetest
 * Method:    sayHello
 * Signature: (Ljava/lang/String;)Ljava/lang/String;
 */
JNIEXPORT jstring JNICALL Java_nativetest_sayHello
  (JNIEnv *, jobject, jstring);

#ifdef __cplusplus
}
#endif
#endif

Write your native code, using the .h file generated above Copy the function prototype from the .h file and paste it in.

#include "nativetest.h" /*double quotes tells it to search current directory*/

JNIEXPORT jstring JNICALL Java_nativetest_sayHello
  (JNIEnv *env, jobject thisobject, jstring js)

{
 return js;
}

Compile

cl -c /Ic:\jdk1.1.6\include /Ic:\jdk1.1.6\include\win32 nativetest.c 
link /libpath=c:\jdk1.1.6\lib nativetest.obj /dll

The above uses Microsoft Visual C++ command-line tools.

Modify your Java class to load the library.

public class nativetest
{
 static {
  System.loadLibrary("nativetest");
 }
 public native String sayHello(String s);
 public static void main(String[] argv)
 {
  String retval = null;
  nativetest nt = new nativetest();
  retval = nt.sayHello("Beavis");
  System.out.println("Invocation returned " + retval);
 }
}

run the example

C:\jni\hello>java nativetest
Invocation returned Beavis

notes:

2015年5月2日星期六

Mose code

src:
http://nomad1999.tripod.com/general/d015.htm

content:

通訊知識

文, 表, 程式: Blackmore

摩斯電碼進階

(這一整頁有點大, 還請大家耐心些, 訓練程式在最下面)

摩斯電碼說明

1.摩斯電碼的組成英碼每組通常為五字

例: VCDSG GTTUU POPOQ DDBNL GTRDY TTFUU DDRTY QROOP SXCGY GTTEJ

中碼(數字碼)通常每組四字

例:5548 9038 4830 8402 4850 5848 4830 47302 5849 4820

2.摩斯電碼的聲響只有長短音的分別 " . " 中文練習讀音為"滴" " - "中文練習讀音為"答"

而電碼長短之時間如下:

一個字如 Z " --.."

" . " 的時間為一個單位 " - " 的時間為三個單位

" . "和 " - "的間隔時間為三個單位

字和字如 GR 為 --. .-. 這時字和字間格的時間為三個單位

字組和字組 GTRED POQAZ 時間間格為五個時間單位

詳細摩斯電碼表

. 中文練習時念做"滴" - 中文練習時念做"答"

摩斯電碼及電話讀音法
Letter	摩斯電碼	English	American	International	NATO	American (police)
A	.-	Andrew	Abel	Amsterdam	Alfa	Adam
B	-...	Benjamin	Baker	Baltimore	Bravo	Boy
C	-.-.	Charlie	Charlie	Casablanca	Charlie	Charlie
D	-..	David	Dog	Denmark	Delta	David
E	.	Edward	Easy	Edison	Echo	Edward
F	..-.	Frederick	Fox	Florida	Foxtrot	Frank
G	--.	George	George	Gallipoli	Golf	George
H	....	Harry	How	Havana	Hotel	Henry
I	..	Isaac	Item	Italy	India	Ida
J	.---	Jack	Jig	Jerusalem	Juliet	John
K	-.-	King	King	Kilogram	Kilo	King
L	.-..	Lucy	Love	Liverpool	Lima	Lincoln
M	--	Mary	Mike	Madagascar	Mike	Mary
N	-.	Nelli	Nan	New York	November	Nora
O	---	Oliver	Oboe	Oslo	Oscar	Ocean
P	.--.	Peter	Peter	Paris	Papa	Paul
Q	--.-	Queenie	Queen	Quebec	Quebec	Queen
R	.-.	Robert	Roger	Roma	Romeo	Robert
S	...	Sugar	Sugar	Santiago	Sierra	Sam
T	-	Tommy	Tare	Tripoli	Tango	Tom
U	..-	Uncle	Uncle	Uppsala	Uniform	Union
V	...-	Victor	Victor	Valencia	Victor	Victor
W	.--	William	William	Washington	Whisky	William
X	-..-	Xmas	X (eks)	Xanthippe	X-ray	X-ray
Y	-.--	Yellow	Yoke	Yokohama	Yankee	Young
Z	--..	Zebra	Zebra	Zürich	Zulu	Zebra

數字及標點符號
數字	短碼	長碼	標點符號	Code
1	.-	.----	句點。	.-.-.-
2	..-	..---	逗點，	--..--
3	...--	...--	Colon	---...
4	....-	....-	問號 ?	..--..
5	.....	.....	撇號 ‵	.----.
6	-....	-....	連字號 -	-....-
7	--...	--...	Fraction bar	-..-.
8	-..	---..	括號( )	-.--.-
9	-.	----.	引號『　』	.-..-.
0	-	-----

訓練程式

在上面的input欄輸入英文字母或文字,選擇速度後按下play即可

英碼型式:FFKRP FKEOD SSKPQ XZLKF KOAQG KPLYO

中碼型式:1245 6543 5533 6672 0954 3367 9707 1273 0836

你也可以下載回去練習(內容包含練習表格,電報來去電紙)

完成日期99-08-26, 最後修改日期99-08-26

註: 本文是轉錄自Blackmore先生原放置於男人殺手站的文章

此文獲得Blackmore先生同意轉載於此, Nomad僅做校對與重新排版的工作

在此特別再一次的感謝Blackmore 先生能授權本站轉載這部分的內容～～

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2015年5月4日 星期一