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Added convenient features to BASE64

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- decode_string_to_buffer (v: STRING; a_buffer: STRING)
   - decode_string_to_output_medium (v: STRING; a_output: IO_MEDIUM)
This commit is contained in:
Jocelyn Fiat
2011-10-31 08:45:50 +01:00
parent c115a40922
commit 085b520879
1 changed files with 88 additions and 4 deletions
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92
library/text/encoder/src/base64.e
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@@ -97,6 +97,13 @@ feature -- Decoder
decoded_string (v: STRING): STRING
-- base64 decoded value of `s'.
do
create Result.make (v.count)
decode_string_to_buffer (v, Result)
end
decode_string_to_buffer (v: STRING; a_buffer: STRING)
-- Write base64 decoded value of `s' into `a_buffer'
local
byte_count: INTEGER
pos, n: INTEGER
@@ -108,7 +115,82 @@ feature -- Decoder
has_error := False
base64chars := character_map
n := v.count
create Result.make (n)
from
pos := 0
invariant
n = v.count
until
(pos >= n) or done
loop
byte_count := 0
pos := next_encoded_character_position (v, pos)
if pos <= n then
byte1 := base64chars.index_of (v[pos], 1) - 1
byte_count := byte_count + 1
pos := next_encoded_character_position (v, pos)
if pos <= n then
byte2 := base64chars.index_of (v[pos], 1) - 1
byte_count := byte_count + 1
pos := next_encoded_character_position (v, pos)
if pos <= n then
c := v[pos]
if c /= '=' then
byte3 := base64chars.index_of (c, 1) - 1
byte_count := byte_count + 1
end
pos := next_encoded_character_position (v, pos)
if pos <= n then
c := v[pos]
if c /= '=' then
byte4 := base64chars.index_of (c, 1) - 1
byte_count := byte_count + 1
end
end
end
end
end
-- pos := pos + byte_count
done := byte_count < 4
if byte_count > 1 then
tmp1 := byte1.bit_shift_left (2) & 0xff
tmp2 := byte2.bit_shift_right (4) & 0x03
a_buffer.extend ((tmp1 | tmp2).to_character_8)
if byte_count > 2 then
tmp1 := byte2.bit_shift_left (4) & 0xff
tmp2 := byte3.bit_shift_right (2) & 0x0f
a_buffer.extend ((tmp1 | tmp2).to_character_8)
if byte_count > 3 then
a_buffer.extend(
((byte4 | byte3.bit_shift_left(6))& 0xff).to_character_8)
end
end
end
end
end
decode_string_to_output_medium (v: STRING; a_output: IO_MEDIUM)
-- Write base64 decoded value of `s' into `a_output' medium
require
a_output_writable: a_output.is_open_write
local
byte_count: INTEGER
pos, n: INTEGER
byte1, byte2, byte3, byte4, tmp1, tmp2: INTEGER
done: BOOLEAN
base64chars: STRING_8
c: CHARACTER
buf: STRING
do
has_error := False
base64chars := character_map
n := v.count
create buf.make (10)
from
pos := 0
@@ -155,16 +237,18 @@ feature -- Decoder
if byte_count > 1 then
tmp1 := byte1.bit_shift_left (2) & 0xff
tmp2 := byte2.bit_shift_right (4) & 0x03
Result.extend ((tmp1 | tmp2).to_character_8)
buf.extend ((tmp1 | tmp2).to_character_8)
if byte_count > 2 then
tmp1 := byte2.bit_shift_left (4) & 0xff
tmp2 := byte3.bit_shift_right (2) & 0x0f
Result.extend ((tmp1 | tmp2).to_character_8)
buf.extend ((tmp1 | tmp2).to_character_8)
if byte_count > 3 then
Result.extend(
buf.extend(
((byte4 | byte3.bit_shift_left(6))& 0xff).to_character_8)
end
end
a_output.put_string (buf)
buf.wipe_out
end
end
end