updated base64.nim
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1 changed files with 127 additions and 127 deletions
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#
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#
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#
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#
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# Nim's Runtime Library
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# Nim's Runtime Library
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# (c) Copyright 2010 Andreas Rumpf
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# (c) Copyright 2010 Andreas Rumpf
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#
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#
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# See the file "copying.txt", included in this
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# See the file "copying.txt", included in this
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# distribution, for details about the copyright.
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# distribution, for details about the copyright.
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#
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#
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## This module implements a base64 encoder and decoder.
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## This module implements a base64 encoder and decoder.
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const
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const
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cb64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
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cb64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
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template encodeInternal(s: expr, lineLen: int, newLine: string): stmt {.immediate.} =
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template encodeInternal(s: expr, lineLen: int, newLine: string): stmt {.immediate.} =
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## encodes `s` into base64 representation. After `lineLen` characters, a
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## encodes `s` into base64 representation. After `lineLen` characters, a
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## `newline` is added.
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## `newline` is added.
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var total = ((len(s) + 2) div 3) * 4
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var total = ((len(s) + 2) div 3) * 4
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var numLines = (total + lineLen - 1) div lineLen
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var numLines = (total + lineLen - 1) div lineLen
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if numLines > 0: inc(total, (numLines-1) * newLine.len)
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if numLines > 0: inc(total, (numLines-1) * newLine.len)
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result = newString(total)
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result = newString(total)
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var i = 0
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var i = 0
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var r = 0
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var r = 0
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var currLine = 0
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var currLine = 0
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while i < s.len - 2:
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while i < s.len - 2:
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var a = ord(s[i])
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var a = ord(s[i])
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var b = ord(s[i+1])
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var b = ord(s[i+1])
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var c = ord(s[i+2])
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var c = ord(s[i+2])
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result[r] = cb64[a shr 2]
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result[r] = cb64[a shr 2]
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result[r+1] = cb64[((a and 3) shl 4) or ((b and 0xF0) shr 4)]
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result[r+1] = cb64[((a and 3) shl 4) or ((b and 0xF0) shr 4)]
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result[r+2] = cb64[((b and 0x0F) shl 2) or ((c and 0xC0) shr 6)]
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result[r+2] = cb64[((b and 0x0F) shl 2) or ((c and 0xC0) shr 6)]
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result[r+3] = cb64[c and 0x3F]
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result[r+3] = cb64[c and 0x3F]
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inc(r, 4)
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inc(r, 4)
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inc(i, 3)
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inc(i, 3)
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inc(currLine, 4)
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inc(currLine, 4)
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if currLine >= lineLen and i != s.len-2:
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if currLine >= lineLen and i != s.len-2:
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for x in items(newLine):
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for x in items(newLine):
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result[r] = x
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result[r] = x
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inc(r)
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inc(r)
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currLine = 0
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currLine = 0
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if i < s.len-1:
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if i < s.len-1:
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var a = ord(s[i])
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var a = ord(s[i])
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var b = ord(s[i+1])
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var b = ord(s[i+1])
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result[r] = cb64[a shr 2]
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result[r] = cb64[a shr 2]
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result[r+1] = cb64[((a and 3) shl 4) or ((b and 0xF0) shr 4)]
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result[r+1] = cb64[((a and 3) shl 4) or ((b and 0xF0) shr 4)]
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result[r+2] = cb64[((b and 0x0F) shl 2)]
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result[r+2] = cb64[((b and 0x0F) shl 2)]
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result[r+3] = '='
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result[r+3] = '='
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if r+4 != result.len:
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if r+4 != result.len:
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setLen(result, r+4)
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setLen(result, r+4)
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elif i < s.len:
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elif i < s.len:
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var a = ord(s[i])
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var a = ord(s[i])
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result[r] = cb64[a shr 2]
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result[r] = cb64[a shr 2]
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result[r+1] = cb64[(a and 3) shl 4]
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result[r+1] = cb64[(a and 3) shl 4]
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result[r+2] = '='
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result[r+2] = '='
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result[r+3] = '='
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result[r+3] = '='
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if r+4 != result.len:
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if r+4 != result.len:
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setLen(result, r+4)
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setLen(result, r+4)
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else:
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else:
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#assert(r == result.len)
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#assert(r == result.len)
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proc encode*[T:TInteger|char](s: openarray[T], lineLen = 75, newLine="\13\10"): string =
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proc encode*[T:SomeInteger|char](s: openarray[T], lineLen = 75, newLine="\13\10"): string =
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## encodes `s` into base64 representation. After `lineLen` characters, a
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## encodes `s` into base64 representation. After `lineLen` characters, a
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## `newline` is added.
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## `newline` is added.
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encodeInternal(s, lineLen, newLine)
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encodeInternal(s, lineLen, newLine)
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proc encode*(s: string, lineLen = 75, newLine="\13\10"): string =
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proc encode*(s: string, lineLen = 75, newLine="\13\10"): string =
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## encodes `s` into base64 representation. After `lineLen` characters, a
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## encodes `s` into base64 representation. After `lineLen` characters, a
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## `newline` is added.
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## `newline` is added.
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encodeInternal(s, lineLen, newLine)
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encodeInternal(s, lineLen, newLine)
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proc decodeByte(b: char): int {.inline.} =
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proc decodeByte(b: char): int {.inline.} =
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case b
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case b
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of '+': result = ord('>')
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of '+': result = ord('>')
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of '0'..'9': result = ord(b) + 4
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of '0'..'9': result = ord(b) + 4
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of 'A'..'Z': result = ord(b) - ord('A')
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of 'A'..'Z': result = ord(b) - ord('A')
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of 'a'..'z': result = ord(b) - 71
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of 'a'..'z': result = ord(b) - 71
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else: result = 63
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else: result = 63
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proc decode*(s: string): string =
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proc decode*(s: string): string =
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## decodes a string in base64 representation back into its original form.
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## decodes a string in base64 representation back into its original form.
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## Whitespace is skipped.
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## Whitespace is skipped.
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const Whitespace = {' ', '\t', '\v', '\r', '\l', '\f'}
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const Whitespace = {' ', '\t', '\v', '\r', '\l', '\f'}
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var total = ((len(s) + 3) div 4) * 3
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var total = ((len(s) + 3) div 4) * 3
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# total is an upper bound, as we will skip arbitrary whitespace:
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# total is an upper bound, as we will skip arbitrary whitespace:
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result = newString(total)
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result = newString(total)
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var i = 0
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var i = 0
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var r = 0
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var r = 0
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while true:
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while true:
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while s[i] in Whitespace: inc(i)
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while s[i] in Whitespace: inc(i)
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if i < s.len-3:
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if i < s.len-3:
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var a = s[i].decodeByte
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var a = s[i].decodeByte
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var b = s[i+1].decodeByte
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var b = s[i+1].decodeByte
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var c = s[i+2].decodeByte
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var c = s[i+2].decodeByte
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var d = s[i+3].decodeByte
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var d = s[i+3].decodeByte
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result[r] = chr((a shl 2) and 0xff or ((b shr 4) and 0x03))
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result[r] = chr((a shl 2) and 0xff or ((b shr 4) and 0x03))
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result[r+1] = chr((b shl 4) and 0xff or ((c shr 2) and 0x0F))
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result[r+1] = chr((b shl 4) and 0xff or ((c shr 2) and 0x0F))
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result[r+2] = chr((c shl 6) and 0xff or (d and 0x3F))
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result[r+2] = chr((c shl 6) and 0xff or (d and 0x3F))
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inc(r, 3)
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inc(r, 3)
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inc(i, 4)
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inc(i, 4)
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else: break
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else: break
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assert i == s.len
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assert i == s.len
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# adjust the length:
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# adjust the length:
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if i > 0 and s[i-1] == '=':
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if i > 0 and s[i-1] == '=':
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dec(r)
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dec(r)
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if i > 1 and s[i-2] == '=': dec(r)
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if i > 1 and s[i-2] == '=': dec(r)
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setLen(result, r)
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setLen(result, r)
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when isMainModule:
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when isMainModule:
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assert encode("leasure.") == "bGVhc3VyZS4="
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assert encode("leasure.") == "bGVhc3VyZS4="
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assert encode("easure.") == "ZWFzdXJlLg=="
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assert encode("easure.") == "ZWFzdXJlLg=="
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assert encode("asure.") == "YXN1cmUu"
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assert encode("asure.") == "YXN1cmUu"
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assert encode("sure.") == "c3VyZS4="
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assert encode("sure.") == "c3VyZS4="
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const longText = """Man is distinguished, not only by his reason, but by this
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const longText = """Man is distinguished, not only by his reason, but by this
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singular passion from other animals, which is a lust of the mind,
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singular passion from other animals, which is a lust of the mind,
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that by a perseverance of delight in the continued and indefatigable
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that by a perseverance of delight in the continued and indefatigable
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generation of knowledge, exceeds the short vehemence of any carnal
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generation of knowledge, exceeds the short vehemence of any carnal
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pleasure."""
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pleasure."""
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const tests = ["", "abc", "xyz", "man", "leasure.", "sure.", "easure.",
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const tests = ["", "abc", "xyz", "man", "leasure.", "sure.", "easure.",
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"asure.", longText]
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"asure.", longText]
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for t in items(tests):
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for t in items(tests):
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assert decode(encode(t)) == t
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assert decode(encode(t)) == t
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