實(shí)現(xiàn)最優(yōu)二叉樹的構(gòu)造;在此基礎(chǔ)上完成哈夫曼編碼器與譯碼器。 假設(shè)報(bào)文中只會出現(xiàn)如下表所示的字符:
字符 A B C D E F G H I J K L M N
頻度 186 64 13 22 32 103 21 15 47 57 1 5 32 20 57
字符 O P Q R S T U V W X Y Z , .
頻度 63 15 1 48 51 80 23 8 18 1 16 1 6 2
要求完成的系統(tǒng)應(yīng)具備如下的功能:
1.初始化。從終端(文件)讀入字符集的數(shù)據(jù)信息,。建立哈夫曼樹。
2.編碼:利用已建好的哈夫曼樹對明文文件進(jìn)行編碼,并存入目標(biāo)文件(哈夫曼碼文件)。
3.譯碼:利用已建好的哈夫曼樹對目標(biāo)文件(哈夫曼碼文件)進(jìn)行編碼,并存入指定的明文文件。
4.輸出哈夫曼編碼文件:輸出每一個(gè)字符的哈夫曼編碼。
Abstract:This article elaborats the RFID system,multianalysised the concrete function of RFID middleware,and proposed a kind of
RFID data transmission design model with news transmission mechanism,for realizing data transmission more effectively,
RFID data transmission design model with news transmission mechanism,for realizing data transmission more effectively,
I made a lot of changed on this object,such as *
// 1.Encapsulates all code in one userobjet,since PB does not *
// support "Address of Function" , so we can not set new *
// WndProc, just makes the object more easy to use. *
// 2.Uses structure array instead of Datastore *
// 3.Calc width of menuitem at runtime(MEASUREITEM) *
// 4.Draw disabled status
This standard describes a keyed-hash message authentication code (HMAC), a
mechanism for message authentication using cryptographic hash functions. HMAC can
be used with any iterative Approved cryptographic hash function, in combination with a
shared secret key. The cryptographic strength of HMAC depends on the properties of the
underlying hash function. The HMAC specification in this standard is a generalization of
Internet RFC 2104, HMAC, Keyed-Hashing for Message Authentication, and ANSI
X9.71, Keyed Hash Message Authentication Code.
This file contains a C++Builder 4 project called SimplyChaos-X ver 3.1 (SCX31).
SCX31 is an encryption tool. I designed it as my graduation paper work. SCX31 is a symmetric stream cipher built on chaos function, one time pad cipher and inspiration from Ground Effect (aviation). The key length can be up to 40 characters (320 bits).