PB实现URL模式及MIME模式的BASE64加解密

BASE64编码

标准编码

将任意字节流编码为字符串，每3字节转换为4个字符，用于编码的字符集合为如下64个字符：
ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/

URL编码

标准编码的字符集合中，把+换成-，把/换成_，即编码的字符集合为：
ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_

MIME编码

标准编码每76个字符换行一次

编码与解码测试

测试文本

Base64编码可用于在HTTP环境下传递较长的标识信息。例如，在Java Persistence系统Hibernate中，就采用了Base64来将一个较长的一个标识符（一般为128-bit的UUID）编码为一个字符串，用作HTTP表单和HTTP GET URL中的参数。在其他应用程序中，也常常需要把二进制数据编码为适合放在URL（包括隐藏表单域）中的形式。此时，采用Base64编码不仅比较简短，同时也具有不可读性，即所编码的数据不会被人用肉眼所直接看到。

URL模式

编码

n_base64 ln_base64
blob lblb_plain

lblb_plain = blob(mle_1.text,encodingUTF8!)
mle_2.text = ln_base64.urlencode(lblb_plain)

return 0

解码

n_base64 ln_base64
blob lblb_plain

lblb_plain = ln_base64.urldecode(mle_1.text)
mle_2.text = string(lblb_plain,encodingUTF8!)

return 0

MIME模式

编码

n_base64 ln_base64
blob lblb_plain

lblb_plain = blob(mle_1.text,encodingUTF8!)
mle_2.text = ln_base64.mimeencode(lblb_plain)

return 0

解码

n_base64 ln_base64
blob lblb_plain

lblb_plain = ln_base64.mimedecode(mle_1.text)
mle_2.text = string(lblb_plain,encodingUTF8!)

return 0

标准模式

编码

n_base64 ln_base64
blob lblb_plain

lblb_plain = blob(mle_1.text,encodingUTF8!)
mle_2.text = ln_base64.encode(lblb_plain)

return 0

解码

n_base64 ln_base64
blob lblb_plain

lblb_plain = ln_base64.decode(mle_1.text)
mle_2.text = string(lblb_plain,encodingUTF8!)

return 0

源代码

发现BUG请留言或私信，以便修正（QQ：768310524 TEL：18649713925）
代码拷贝到文本编辑器，另存为 n_base64.sru

$PBExportHeader$n_base64.sru
forward
global type n_base64 from nonvisualobject
end type
end forward

global type n_base64 from nonvisualobject autoinstantiate
end type

type variables
private:
	char code[]
	
	char standardCode[] =  'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
	char urlCode[] = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_'
end variables

forward prototypes
public function string encode (blob plain)
public function blob decode (string cypher)
public function string urlencode (blob plain)
public function blob urldecode (string cypher)
public function string mimeencode (blob plain)
public function blob mimedecode (string cypher)
public function string _enc (blob plain)
public function blob _dec (string cypher)
end prototypes

public function string encode (blob plain);
code = standardCode

return _enc(plain)
end function

public function blob decode (string cypher);
code = standardCode

return _dec(cypher)
end function

public function string urlencode (blob plain);
code = urlCode

return _enc(plain)
end function

public function blob urldecode (string cypher);
code = urlCode

return _dec(cypher)
end function

public function string mimeencode (blob plain);long i,ll_loop
string ls_cypher

code = standardCode

ll_loop = ceiling(len(plain) / 57)
for i = 1 to ll_loop
	ls_cypher += _enc(blobmid(plain,57 * i - 56,57)) + '~r~n'
next

return left(ls_cypher,len(ls_cypher) - 2)
end function

public function blob mimedecode (string cypher);char lch_cypher[],lch[]
long i,j,ll_len

code = standardCode

lch = cypher
ll_len = len(cypher)
for i = 1 to ll_len
	if lch[i] <> '~r' and lch[i] <> '~n' then
		j++
		lch_cypher[j] = lch[i]
	end if
next

return _dec(lch_cypher)
end function

public function string _enc (blob plain);byte lbyte[]
char lc_cypher[]
long i,j,ll_loop
ulong lul_len,lul_tmp
int li_mod

lbyte = getByteArray(plain)
lul_len = upperbound(lbyte)
li_mod = mod(lul_len,3)
choose case li_mod
	case 1
		lbyte[lul_len + 1] = 0
		lbyte[lul_len + 2] = 0
	case 2
		lbyte[lul_len + 1] = 0
end choose

ll_loop =upperbound(lbyte) / 3

for i = 1 to ll_loop
	lul_tmp = lbyte[3 * i - 2] * 65536 + lbyte[3 * i - 1] * 256 + lbyte[3 * i]
	j += 1
	lc_cypher[j] = code[lul_tmp / 262144 + 1]
	lul_tmp = mod(lul_tmp,262144)
	j += 1
	lc_cypher[j] = code[lul_tmp / 4096 + 1]
	lul_tmp = mod(lul_tmp,4096)
	j += 1
	lc_cypher[j] = code[lul_tmp / 64 + 1]
	lul_tmp = mod(lul_tmp,64)
	j += 1
	lc_cypher[j] = code[lul_tmp + 1]
next

choose case li_mod
	case 1
		lc_cypher[j] = '='
		lc_cypher[j - 1] = '='
	case 2
		lc_cypher[j] = '='
end choose

return lc_cypher

end function

public function blob _dec (string cypher);blob lblb_plain
long i,j,ll_loop
char lc_cypher[]
ulong lul_tmp,lul_len
byte lbyte[]
int li_mod
string ls_codes

lc_cypher = cypher
lul_len = upperbound(lc_cypher)
if lc_cypher[lul_len] = '=' then
	li_mod = 2
	lc_cypher[lul_len] = 'A'
end if
if lc_cypher[lul_len - 1] = '=' then
	li_mod = 1
	lc_cypher[lul_len - 1] = 'A'
end if

ls_codes = code
ll_loop = upperbound(lc_cypher) / 4
for i = 1 to ll_loop
	lul_tmp = (pos(ls_codes,lc_cypher[4 * i - 3]) - 1) * 262144 +&
				 (pos(ls_codes,lc_cypher[4 * i - 2]) - 1) * 4096 +&
				 (pos(ls_codes,lc_cypher[4 * i - 1]) - 1) * 64 +&
				 (pos(ls_codes,lc_cypher[4 * i]) - 1)
	
	j += 1
	lbyte[j] = lul_tmp / 65536
	lul_tmp = mod(lul_tmp,65536)
	j += 1
	lbyte[j] = lul_tmp / 256
	lul_tmp = mod(lul_tmp,256)
	j += 1
	lbyte[j] = lul_tmp
next

lblb_plain = blob(lbyte)
choose case li_mod
	case 1
		lblb_plain = blobmid(lblb_plain,1,len(lblb_plain) - 2)
	case 2
		lblb_plain = blobmid(lblb_plain,1,len(lblb_plain) - 1)
end choose

return lblb_plain
end function

on n_base64.create
call super::create
TriggerEvent( this, "constructor" )
end on

on n_base64.destroy
TriggerEvent( this, "destructor" )
call super::destroy
end on