97 lines
4.0 KiB
Tcl
97 lines
4.0 KiB
Tcl
# Base 64 encoding and decoding
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_enc := "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/":utf8_bytes()
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_EQUAL_BYTE := 0x3D[B]
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_dec := [
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255[B], 255[B], 255[B], 255[B], 255[B], 255[B], 255[B], 255[B],
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255[B], 255[B], 255[B], 255[B], 255[B], 255[B], 255[B], 255[B],
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255[B], 255[B], 255[B], 255[B], 255[B], 255[B], 255[B], 255[B],
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255[B], 255[B], 255[B], 255[B], 255[B], 255[B], 255[B], 255[B],
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255[B], 255[B], 255[B], 255[B], 255[B], 255[B], 255[B], 255[B],
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255[B], 255[B], 255[B], 62[B], 255[B], 255[B], 255[B], 63[B],
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52[B], 53[B], 54[B], 55[B], 56[B], 57[B], 58[B], 59[B],
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60[B], 61[B], 255[B], 255[B], 255[B], 255[B], 255[B], 255[B],
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255[B], 0[B], 1[B], 2[B], 3[B], 4[B], 5[B], 6[B],
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7[B], 8[B], 9[B], 10[B], 11[B], 12[B], 13[B], 14[B],
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15[B], 16[B], 17[B], 18[B], 19[B], 20[B], 21[B], 22[B],
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23[B], 24[B], 25[B], 255[B], 255[B], 255[B], 255[B], 255[B],
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255[B], 26[B], 27[B], 28[B], 29[B], 30[B], 31[B], 32[B],
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33[B], 34[B], 35[B], 36[B], 37[B], 38[B], 39[B], 40[B],
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41[B], 42[B], 43[B], 44[B], 45[B], 46[B], 47[B], 48[B],
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49[B], 50[B], 51[B], 255[B], 255[B], 255[B], 255[B], 255[B],
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]
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lang Base64:
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func from_text(text:Text -> Base64?):
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return Base64.from_bytes(text:utf8_bytes())
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func from_bytes(bytes:[Byte] -> Base64?):
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output := [0[B] for _ in bytes.length * 4 / 3 + 4]
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src := 1[64]
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dest := 1[64]
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while src + 2[64] <= bytes.length:
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chunk24 := (
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(Int32(bytes[src]) <<< 16) or (Int32(bytes[src+1[64]]) <<< 8) or Int32(bytes[src+2[64]])
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)
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src += 3
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output[dest] = _enc[1[32] + ((chunk24 >>> 18) and 0b111111[32])]
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output[dest+1[64]] = _enc[1[32] + ((chunk24 >>> 12) and 0b111111[32])]
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output[dest+2[64]] = _enc[1[32] + ((chunk24 >>> 6) and 0b111111[32])]
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output[dest+3[64]] = _enc[1[32] + (chunk24 and 0b111111[32])]
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dest += 4
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if src + 1[64] == bytes.length:
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chunk16 := (
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(Int32(bytes[src]) <<< 8) or Int32(bytes[src+1[64]])
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)
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output[dest] = _enc[1[32] + ((chunk16 >>> 10) and 0b111111[32])]
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output[dest+1[64]] = _enc[1[32] + ((chunk16 >>> 4) and 0b111111[32])]
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output[dest+2[64]] = _enc[1[32] + ((chunk16 <<< 2)and 0b111111[32])]
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output[dest+3[64]] = _EQUAL_BYTE
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else if src == bytes.length:
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chunk8 := Int32(bytes[src])
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output[dest] = _enc[1[32] + ((chunk8 >>> 2) and 0b111111[32])]
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output[dest+1[64]] = _enc[1[32] + ((chunk8 <<< 4) and 0b111111[32])]
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output[dest+2[64]] = _EQUAL_BYTE
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output[dest+3[64]] = _EQUAL_BYTE
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return Base64.without_escaping(Text.from_bytes(output) or return !Base64)
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func decode_text(b64:Base64 -> Text?):
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return Text.from_bytes(b64:decode_bytes() or return !Text)
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func decode_bytes(b64:Base64 -> [Byte]?):
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bytes := b64.text_content:utf8_bytes()
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output := [0[B] for _ in bytes.length/4 * 3]
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src := 1[64]
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dest := 1[64]
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while src + 3[64] <= bytes.length:
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chunk24 := (
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(Int32(_dec[1[B]+bytes[src]]) <<< 18) or
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(Int32(_dec[1[B]+bytes[src+1[64]]]) <<< 12) or
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(Int32(_dec[1[B]+bytes[src+2[64]]]) <<< 6) or
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Int32(_dec[1[B]+bytes[src+3[64]]])
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)
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src += 4
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output[dest] = Byte((chunk24 >>> 16) and 0xFF[32])
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output[dest+1[64]] = Byte((chunk24 >>> 8) and 0xFF[32])
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output[dest+2[64]] = Byte(chunk24 and 0xFF[32])
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dest += 3
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while output[-1] == 0xFF[B]:
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output = output:to(-2)
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return output
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func main(input=(/dev/stdin), decode=no):
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if decode:
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b := Base64.without_escaping(input:read()!)
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say(b:decode_text()!)
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else:
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text := input:read()!
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say(Base64.from_text(text)!.text_content)
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