:: Base64.cmd Beta -- Base64 编码解码 01/28/2007 By 0401

@echo off
setlocal enabledelayedexpansion
set op=
set Key=ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=
set hexstr=0 1 2 3 4 5 6 7 8 9 A B C D E F
set d=0
for %%i in (%hexstr%) do set d!d!=%%i&set/a d+=1

if "%~1"=="" goto :help
if "%~1"=="/?" goto :help
for %%i in (d D e E h H) do (
	if "%~1"=="/%%i" call :arg%%i %*
	if exist "%~1" (
		if exist "%~1\" set error=Sorry，不支持对一个目录进行 Base64 编码。& goto :error
		set op=encode
		set infile=%~sf1
	)
)
if defined error goto :error
if defined op goto :%op%
set error=无效的参数或文件名：%1。& goto :error


:arge
set op=encode
:argd
if not defined op set op=decode
set infile=%~sf2
if not defined infile set error=没有指定输入文件。& exit/b
if not exist "%infile%" set error=找不到指定文件：%infile%。& exit/b
set outfile=%~f3
goto :eof
:argh
set op=help
goto :eof
:error
echo %error%
exit/b


goto :encode

s 文件大小
l 文件加上100H f子命令填充内存的长度。
c 只用来计算第一次编码的时间
k 判断 c1 c2 c3
w 每行生成几组4个字节的编码字符，默认18
q 判断等于w时输出一行编码字符串
n 用来过滤掉重复的字节

:encode
>nul (chcp 437&graftabl 936)
cls

for %%i in (%infile%) do set s=%%~zi
if %s% equ 0 exit/b
if %s% gtr 65535 set error=编码失败，文件大小上限为 64KB。& goto :error

set/p=编码初始化中，请稍等。<nul
set of=B64ENC
set/p=<nul>"%~dp0%of%"
set/a l=s+255
call :d2h %l%
set l=%hex%
call :d2h %s%
echo exit|%comspec%/kprompt f cs:100 l %l% 0A$_r cx$_%hex%$_n a.t1$_w$_f cs:100 l %l% 0D$_n b.t1$_w$_q$_|debug>nul

fc/b %infile% a.t1|find ": ">.t1
fc/b %infile% b.t1|find ": ">>.t1
sort .t1>.t2

call :time t1

set n=
set c=0
set k=0
set q=0
set w=18
for /f "tokens=1,2" %%i in (.t2) do (
	if not "!n!"=="%%i" (
		set/a d=0x%%j
		set/a k+=1
		if !k! equ 1 set c1=!d!
		if !k! equ 2 set c2=!d!
		if !k! equ 3 set c3=!d!
		if !k! equ 3 (
			set/a e1="c1>>2!
			set/a e2="((c1&3)<<4)|(c2>>4)"
			set/a e3="((c2&15)<<2)|(c3>>6)"
			set/a e4="c3&63"
			call set b64=!b64!%%Key:~!e1!,1%%%%Key:~!e2!,1%%%%Key:~!e3!,1%%%%Key:~!e4!,1%%
			set/a q+=1
			if !q! equ !w! (
				echo !b64!>>"%~dp0%of%"
				set b64=
				set q=0
				if !c! equ 0 (
					set/a c+=1
					call :time t2
					set/a t="s/(w*3)*(t2-t1)/100"
					echo 估计剩余时间 !t! 秒。
				)
				set/p=#<nul
			)
			set k=0
		)
	)
	set n=%%i
)

if !k! equ 1 (
	set/a e1="c1>>2"
	set/a e2="(c1&3)<<4"
	call set b64=!b64!%%Key:~!e1!,1%%%%Key:~!e2!,1%%==
)

if !k! equ 2 (
	set/a e1="c1>>2"
	set/a e2="((c1&3)<<4)|(c2>>4)"
	set/a e3="((c2&15)<<2)"
	call set b64=!b64!%%Key:~!e1!,1%%%%Key:~!e2!,1%%%%Key:~!e3!,1%%=
)

echo.
if defined b64 echo %b64%>>"%~dp0%of%"
if defined outfile move/y "%~dp0%of%" "%outfile%"
echo 编码完成。
del a.t1 b.t1 .t1 .t2
::chcp 936>nul
exit/b



goto :decode

k 用来判断 e1 e2 e3 e4
e e子命令每行写入的字节数，默认是24个字节生成一个debug的e子命令。可自行修改（3<=e<=24）
s1 转换后的HEX串
m 判断s1是否包含指定的字节数
q 每行有（几个字节*3）被编码
cx 表示文件大小（字节），每运算一次加3，因为每4个字节解码为3个字节
cs e子命令在cs段地址内的多少偏移处写入
v1 每行字节数加2（2个字节既回车与换行）
v2 行数
v3 q的3倍 用来判断处理第1行所用时间

:decode
>nul (chcp 437&graftabl 936)
cls
set/p=解码中<nul

set/p=<nul>dbg.src
set/p v1=<%infile%
set/p=%v1%<nul>.t1
for %%i in (.t1) do set/a q=%%~zi/4&set v1=%%~zi+2&del .t1
for %%i in (%infile%) do set/a v2=%%~zi/v1+1
set/a v3="q*3"

call :time t1
set e=24
set k=1
set m=1
set cx=0
set cs=256
for /f %%i in (%infile%) do (
	set str=%%i
	for /l %%j in (1,1,%q%) do (
		if not defined str if %%j lss %q% goto :decend
		for /l %%k in (0,1,3) do (
			for /l %%l in (0,1,64) do (
				if "!str:~%%k,1!"=="!Key:~%%l,1!" (
					if !k! equ 1 set e1=%%l
					if !k! equ 2 set e2=%%l
					if !k! equ 3 set e3=%%l
					if !k! equ 4 set e4=%%l
					set/a k+=1
				)
			)
		)
		set/a c1="(e1<<2)|(e2>>4)"
		call :d2h !c1!
		set s1=!s1! !hex!
		set/a c2="((e2&15)<<4)|(e3>>2)"
		call :d2h !c2!
		set s1=!s1! !hex!
		set/a c3="((e3&3)<<6)|e4"
		call :d2h !c3!
		set s1=!s1! !hex!
		
		set k=1
		set/a cx+=3
		set/a m=cx"%%"e
		if !m! equ 0 (
			if !e4! equ 64 (
				set/a cx-=1
				set s1=!s1:~0,-3!
				if !e3! equ 64 (
					set/a cx-=1
					set s1=!s1:~0,-3!
				)
			)
			call :d2h !cs!
			echo e !hex! !s1! >>dbg.src
			set/a cs+=e
			set s1=
		)
		set str=!str:~4!
	)
	if !cx! equ %v3% (
		call :time t2
		set/a ts=t2-t1
		set/a t="ts*v2/100"
		echo ，文件共 !v2! 行，每行用时约 !ts! 毫秒，估计剩余时间 !t! 秒。
	)
	set/p=#<nul
)
:decend
if defined s1 (
	if %e4% equ 64 (
		set/a cx-=1
		set s1=!s1:~0,-3!
		if %e3% equ 64 (
			set/a cx-=1
			set s1=!s1:~0,-3!
		)
	)
	call :d2h %cs%
	echo e !hex! !s1! >>dbg.src
)

call :d2h %cx%
(echo r cx
 echo %hex%
 echo n b64dec
 echo w
 echo q) >>dbg.src

echo.
debug<dbg.src>nul
if defined outfile move/y b64dec "%outfile%"
echo 解码完成。
del dbg.src
::chcp 936>nul
exit/b


:time
for /f "tokens=1-4 delims=:." %%i in ("%time%") do (
	set/a time1="%%i*360000"
	set/a time2="(1%%j-100)*6000"
	set/a time3="(1%%k-100)*100"
	set/a time4="1%%l-100"
)
set/a %~1=time1+time2+time3+time4
exit/b

:d2h
set/a d=%1
set hex=
if %d% equ 0 set hex=00&exit/b
if %d% gtr 255 (set c=4) else (set c=2)
for /l %%i in (1,1,%c%) do (
	set/a td=d"&"15
	set/a d">>="4
	call set hex=%%d!td!%%!hex!
)
exit/b


:help
for /f "tokens=1 delims=:" %%i in ('findstr/n /c:"=help=" "%~f0"') do more +%%i "%~f0">con & goto :eof

Base64 Encode n Decode Beta By 0401

Usage:
Base64 [/e] filename1 [filename2]
       [/d filename1] [filename2]
       [/h]
    /e        Base64 编码操作，处理文件大小上限 64KB
    /d        Base64 解码操作
    filename1 输入文件名
    filename2 输出文件名
              /e 缺省输出文件名为 B64ENC
	      /d 缺省输出文件名为 B64DEC
    /h        帮助

:help
for /f "delims=:" %%i in ('findstr /n /x :helpdoc "%~f0"') do (
    more +%%i "%~f0">con
    if "%~0"=="%~f0" pause
)
goto :eof

:helpdoc
Base64 Encode n Decode Beta By 0401

Usage:
Base64 [/e] filename1 [filename2]
       [/d filename1] [filename2]
       [/h]
    /e    Base64 编码操作，处理文件大小上限 64KB
    /d    Base64 解码操作
    filename1 输入文件名
    filename2 输出文件名
        /e 缺省输出文件名为 B64ENC
        /d 缺省输出文件名为 B64DEC
    直接将输入文件拖动到批处理中执行时，缺省进行编码，得到B64ENC    
    /h    显示本文档

set/p=编码初始化中，请稍等。<nul
set of=B64ENC
set/p=<nul>%of%

set/p=<nul>"%~dp0%of%"