085b520879
- decode_string_to_buffer (v: STRING; a_buffer: STRING) - decode_string_to_output_medium (v: STRING; a_output: IO_MEDIUM)
306 lines
7.1 KiB
Plaintext
306 lines
7.1 KiB
Plaintext
note
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description: "Summary description for {BASE64}."
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legal: "See notice at end of class."
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status: "See notice at end of class."
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date: "$Date$"
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revision: "$Revision$"
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class
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BASE64
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inherit
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ENCODER [STRING_8, STRING_8]
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redefine
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valid_encoded_string
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end
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feature -- Access
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name: READABLE_STRING_8
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do
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create {IMMUTABLE_STRING_8} Result.make_from_string ("base64")
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end
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feature -- Status report
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has_error: BOOLEAN
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valid_encoded_string (v: STRING): BOOLEAN
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do
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Result := Precursor (v) and then
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(v.is_empty or v.count >= 4)
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end
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feature -- base64 encoder
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encoded_string (s: STRING): STRING_8
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-- base64 encoded value of `s'.
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local
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i,n: INTEGER
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c: INTEGER
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f: SPECIAL [BOOLEAN]
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base64chars: STRING_8
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do
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has_error := False
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base64chars := character_map
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from
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n := s.count
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i := (8 * n) \\ 6
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if i > 0 then
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create f.make_filled (False, 8 * n + (6 - i))
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else
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create f.make_filled (False, 8 * n)
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end
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i := 0
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until
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i > n - 1
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loop
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c := s.item (i + 1).code
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f[8 * i + 0] := c.bit_test(7)
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f[8 * i + 1] := c.bit_test(6)
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f[8 * i + 2] := c.bit_test(5)
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f[8 * i + 3] := c.bit_test(4)
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f[8 * i + 4] := c.bit_test(3)
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f[8 * i + 5] := c.bit_test(2)
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f[8 * i + 6] := c.bit_test(1)
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f[8 * i + 7] := c.bit_test(0)
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i := i + 1
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end
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from
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i := 0
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n := f.count
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create Result.make (n // 6)
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until
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i > n - 1
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loop
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c := 0
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if f[i + 0] then c := c + 0x20 end
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if f[i + 1] then c := c + 0x10 end
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if f[i + 2] then c := c + 0x8 end
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if f[i + 3] then c := c + 0x4 end
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if f[i + 4] then c := c + 0x2 end
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if f[i + 5] then c := c + 0x1 end
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Result.extend (base64chars.item (c + 1))
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i := i + 6
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end
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i := s.count \\ 3
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if i > 0 then
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from until i > 2 loop
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Result.extend ('=')
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i := i + 1
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end
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end
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end
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feature -- Decoder
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decoded_string (v: STRING): STRING
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-- base64 decoded value of `s'.
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do
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create Result.make (v.count)
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decode_string_to_buffer (v, Result)
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end
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decode_string_to_buffer (v: STRING; a_buffer: STRING)
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-- Write base64 decoded value of `s' into `a_buffer'
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local
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byte_count: INTEGER
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pos, n: INTEGER
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byte1, byte2, byte3, byte4, tmp1, tmp2: INTEGER
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done: BOOLEAN
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base64chars: STRING_8
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c: CHARACTER
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do
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has_error := False
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base64chars := character_map
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n := v.count
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from
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pos := 0
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invariant
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n = v.count
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until
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(pos >= n) or done
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loop
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byte_count := 0
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pos := next_encoded_character_position (v, pos)
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if pos <= n then
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byte1 := base64chars.index_of (v[pos], 1) - 1
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byte_count := byte_count + 1
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pos := next_encoded_character_position (v, pos)
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if pos <= n then
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byte2 := base64chars.index_of (v[pos], 1) - 1
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byte_count := byte_count + 1
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pos := next_encoded_character_position (v, pos)
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if pos <= n then
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c := v[pos]
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if c /= '=' then
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byte3 := base64chars.index_of (c, 1) - 1
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byte_count := byte_count + 1
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end
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pos := next_encoded_character_position (v, pos)
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if pos <= n then
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c := v[pos]
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if c /= '=' then
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byte4 := base64chars.index_of (c, 1) - 1
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byte_count := byte_count + 1
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end
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end
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end
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end
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end
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-- pos := pos + byte_count
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done := byte_count < 4
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if byte_count > 1 then
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tmp1 := byte1.bit_shift_left (2) & 0xff
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tmp2 := byte2.bit_shift_right (4) & 0x03
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a_buffer.extend ((tmp1 | tmp2).to_character_8)
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if byte_count > 2 then
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tmp1 := byte2.bit_shift_left (4) & 0xff
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tmp2 := byte3.bit_shift_right (2) & 0x0f
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a_buffer.extend ((tmp1 | tmp2).to_character_8)
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if byte_count > 3 then
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a_buffer.extend(
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((byte4 | byte3.bit_shift_left(6))& 0xff).to_character_8)
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end
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end
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end
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end
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end
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decode_string_to_output_medium (v: STRING; a_output: IO_MEDIUM)
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-- Write base64 decoded value of `s' into `a_output' medium
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require
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a_output_writable: a_output.is_open_write
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local
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byte_count: INTEGER
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pos, n: INTEGER
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byte1, byte2, byte3, byte4, tmp1, tmp2: INTEGER
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done: BOOLEAN
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base64chars: STRING_8
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c: CHARACTER
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buf: STRING
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do
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has_error := False
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base64chars := character_map
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n := v.count
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create buf.make (10)
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from
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pos := 0
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invariant
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n = v.count
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until
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(pos >= n) or done
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loop
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byte_count := 0
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pos := next_encoded_character_position (v, pos)
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if pos <= n then
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byte1 := base64chars.index_of (v[pos], 1) - 1
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byte_count := byte_count + 1
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pos := next_encoded_character_position (v, pos)
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if pos <= n then
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byte2 := base64chars.index_of (v[pos], 1) - 1
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byte_count := byte_count + 1
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pos := next_encoded_character_position (v, pos)
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if pos <= n then
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c := v[pos]
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if c /= '=' then
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byte3 := base64chars.index_of (c, 1) - 1
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byte_count := byte_count + 1
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end
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pos := next_encoded_character_position (v, pos)
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if pos <= n then
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c := v[pos]
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if c /= '=' then
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byte4 := base64chars.index_of (c, 1) - 1
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byte_count := byte_count + 1
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end
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end
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end
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end
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end
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-- pos := pos + byte_count
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done := byte_count < 4
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if byte_count > 1 then
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tmp1 := byte1.bit_shift_left (2) & 0xff
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tmp2 := byte2.bit_shift_right (4) & 0x03
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buf.extend ((tmp1 | tmp2).to_character_8)
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if byte_count > 2 then
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tmp1 := byte2.bit_shift_left (4) & 0xff
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tmp2 := byte3.bit_shift_right (2) & 0x0f
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buf.extend ((tmp1 | tmp2).to_character_8)
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if byte_count > 3 then
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buf.extend(
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((byte4 | byte3.bit_shift_left(6))& 0xff).to_character_8)
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end
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end
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a_output.put_string (buf)
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buf.wipe_out
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end
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end
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end
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next_encoded_character_position (v: STRING; from_pos: INTEGER): INTEGER
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-- Next encoded character position from `v' starting after `from_pos' index.
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-- Result over `v.count' denodes no remaining decodable position
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--| Mainly to handle base64 encoded text on multiple line
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--| thus we just skip %N, %R and eventually all blanks
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require
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v_attached: v /= Void
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valid_from_pos: v.valid_index (from_pos + 1)
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local
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n: INTEGER
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l_map: like character_map
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do
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l_map := character_map
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from
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Result := from_pos + 1
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n := v.count
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until
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in_character_map (v[Result]) or Result > n
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loop
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Result := Result + 1
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end
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ensure
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result_after_from_pos: Result > from_pos
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end
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in_character_map (c: CHARACTER): BOOLEAN
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-- Is a character map element?
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do
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inspect c
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when 'A' .. 'Z', 'a' .. 'z', '0'..'9', '+', '/', '=' then
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Result := True
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else
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end
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end
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feature {NONE} -- Constants
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character_map: STRING = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/="
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note
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copyright: "Copyright (c) 1984-2011, Eiffel Software and others"
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license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)"
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source: "[
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Eiffel Software
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5949 Hollister Ave., Goleta, CA 93117 USA
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Telephone 805-685-1006, Fax 805-685-6869
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Website http://www.eiffel.com
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Customer support http://support.eiffel.com
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]"
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end
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