# Offers the base 64 encoding and decoding algorithms
module base64
-redef class String
-
+redef class NativeString
# Alphabet used by the base64 algorithm
- private fun base64_chars : String
+ private fun base64_chars : SequenceRead[Byte]
do
- return "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
+ return "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".bytes
end
- private fun inverted_base64_chars : HashMap[Char,Int]
+
+ # Reversed alphabet for base64
+ private fun inverted_base64_chars : HashMap[Byte, Byte]
do
- var inv_base64_chars = new HashMap[Char,Int]
- for k in [0..base64_chars.length[ do
- inv_base64_chars[ base64_chars[k] ] = k
+ var inv_base64_chars = new HashMap[Byte, Byte]
+ var l = base64_chars.length
+ for k in [0 .. l[ do
+ inv_base64_chars[base64_chars[k]] = k.to_b
end
return inv_base64_chars
end
- # Encodes the receiver string to base64.
+ # Encodes `self` to base64.
+ #
# By default, uses "=" for padding.
- fun encode_base64 : String do return encode_base64_custom_padding( '=' )
- fun encode_base64_custom_padding( padding : Char ) : String
- do
- var base64_chars = once base64_chars
- var length = length
-
+ #
+ # assert "string".encode_base64 == "c3RyaW5n"
+ private fun encode_base64(length: Int, padding: nullable Byte): Bytes do
+ var base64_bytes = once base64_chars
+ if padding == null then padding = '='.ascii
var steps = length / 3
- var chars_in_last_step = length % 3
- var result_length = steps*4
- if chars_in_last_step > 0 then result_length += 4
- var result = (padding.to_s*result_length).to_cstring
-
- var mask_6bit = 63
-
- for s in [0..steps[ do
- var e = 0
- for ss in [0..3[ do
- e += self[s*3+ss].ascii.lshift((2-ss)*8)
- end
- for ss in [0..4[ do
- result[s*4+3-ss] = base64_chars[ e.rshift(ss*6).bin_and( mask_6bit ) ]
- end
+ var bytes_in_last_step = length % 3
+ var result_length = steps * 4
+ if bytes_in_last_step > 0 then result_length += 4
+ var result = new Bytes.with_capacity(result_length)
+
+ var in_off = 0
+ for s in [0 .. steps[ do
+ var ind = ((self[in_off] & 0b1111_1100u8) >> 2).to_i
+ result.add base64_bytes[ind]
+ ind = ((self[in_off] & 0b0000_0011u8) << 4).to_i | ((self[in_off + 1] & 0b1111_0000u8) >> 4).to_i
+ result.add base64_bytes[ind]
+ ind = ((self[in_off + 1] & 0b0000_1111u8) << 2).to_i | ((self[in_off + 2] & 0b1100_0000u8) >> 6).to_i
+ result.add base64_bytes[ind]
+ ind = (self[in_off + 2] & 0b0011_1111u8).to_i
+ result.add base64_bytes[ind]
+ in_off += 3
end
-
- if chars_in_last_step == 1 then
- var e = self[length-1].ascii.lshift(16)
- for ss in [0..2[ do
- result[steps*4+1-ss] = base64_chars[ e.rshift((ss+2)*6).bin_and( mask_6bit ) ]
- end
- else if chars_in_last_step == 2 then
- var e = self[length-2].ascii.lshift(16) +
- self[length-1].ascii.lshift(8)
- for ss in [0..3[ do
- result[steps*4+2-ss] = base64_chars[ e.rshift((ss+1)*6).bin_and( mask_6bit ) ]
- end
+ if bytes_in_last_step == 1 then
+ result.add base64_bytes[((self[in_off] & 0b1111_1100u8) >> 2).to_i]
+ result.add base64_bytes[((self[in_off] & 0b0000_0011u8) << 4).to_i]
+ else if bytes_in_last_step == 2 then
+ result.add base64_bytes[((self[in_off] & 0b1111_1100u8) >> 2).to_i]
+ result.add base64_bytes[(((self[in_off] & 0b0000_0011u8) << 4) | ((self[in_off + 1] & 0b1111_0000u8) >> 4)).to_i]
+ result.add base64_bytes[((self[in_off + 1] & 0b0000_1111u8) << 2).to_i]
end
+ var rempad = if bytes_in_last_step > 0 then 3 - bytes_in_last_step else 0
+ for i in [0 .. rempad[ do result.add padding
- return result.to_s
+ return result
end
- # Decodes the receiver string from base64.
- # By default, uses "=" for padding.
- fun decode_base64 : String do return decode_base64_custom_padding( '=' )
- fun decode_base64_custom_padding( padding : Char ) : String
- do
- var inverted_base64_chars = once inverted_base64_chars
- var length = length
+ # Decodes `self` from base64
+ #
+ # assert "c3RyaW5n".decode_base64 == "string"
+ #
+ # REQUIRE: `length % 4 == 0`
+ private fun decode_base64(length: Int, padding: nullable Byte): Bytes do
+ if padding == null then padding = '='.ascii
+ var inv = once inverted_base64_chars
+ if length == 0 then return new Bytes.empty
assert length % 4 == 0 else print "base64::decode_base64 only supports strings of length multiple of 4"
+ var bytes = self
var steps = length / 4
- var result_length = steps*3
-
- var padding_begin = padding.search_index_in( self, 0 )
- var padding_count : Int
- if padding_begin == -1 then
- padding_count = 0
- else
- padding_count = length - padding_begin
- steps -= 1
- result_length -= padding_count
- end
+ var result_length = steps * 3
- var result = ("#"*result_length).to_cstring
+ var epos = length - 1
+ var padding_len = 0
+ while epos >= 0 and bytes[epos] == padding do
+ epos -= 1
+ padding_len += 1
+ end
- var mask_8bit = 255
+ if padding_len != 0 then steps -= 1
+ if padding_len == 1 then result_length -= 1
+ if padding_len == 2 then result_length -= 2
- for s in [0..steps[ do
- var e = 0
- for ss in [0..4[ do
- e += inverted_base64_chars[self[s*4+ss]].lshift((3-ss)*6)
- end
+ var result = new Bytes.with_capacity(result_length + 1)
- for ss in [0..3[ do
- result[s*3+ss] = e.rshift((2-ss)*8).bin_and( mask_8bit ).ascii
- end
+ for s in [0 .. steps[ do
+ var c0 = inv[bytes[s * 4]]
+ var c1 = inv[bytes[s * 4 + 1]]
+ var c2 = inv[bytes[s * 4 + 2]]
+ var c3 = inv[bytes[s * 4 + 3]]
+ result.add (((c0 & 0b0011_1111u8) << 2) | ((c1 & 0b0011_0000u8) >> 4))
+ result.add (((c1 & 0b0000_1111u8) << 4) | ((c2 & 0b0011_1100u8) >> 2))
+ result.add (((c2 & 0b0000_0011u8) << 6) | (c3 & 0b0011_1111u8))
end
- var s = steps
- if padding_count == 1 then
- var e = 0
- for ss in [0..3[ do
- e += inverted_base64_chars[self[s*4+ss]].lshift((3-ss)*6)
- end
-
- for ss in [0..2[ do
- result[s*3+ss] = e.rshift((2-ss)*8).bin_and( mask_8bit ).ascii
- end
- else if padding_count == 2 then
- var e = 0
- for ss in [0..2[ do
- e += inverted_base64_chars[self[s*4+ss]].lshift((3-ss)*6)
- end
-
- result[s*3] = e.rshift(2*8).bin_and( mask_8bit ).ascii
+ var last_start = steps * 4
+ if padding_len == 1 then
+ var c0 = inv[bytes[last_start]]
+ var c1 = inv[bytes[last_start + 1]]
+ var c2 = inv[bytes[last_start + 2]]
+ result.add (((c0 & 0b0011_1111u8) << 2) | ((c1 & 0b0011_0000u8) >> 4))
+ result.add (((c1 & 0b0000_1111u8) << 4) | ((c2 & 0b0011_1100u8) >> 2))
+ else if padding_len == 2 then
+ var c0 = inv[bytes[last_start]]
+ var c1 = inv[bytes[last_start + 1]]
+ result.add (((c0 & 0b0011_1111u8) << 2) | ((c1 & 0b0011_0000u8) >> 4))
end
- return result.to_s
+ return result
+ end
+end
+
+redef class Bytes
+
+ # Encodes the receiver string to base64 using a custom padding character.
+ #
+ # If using the default padding character `=`, see `encode_base64`.
+ fun encode_base64(padding: nullable Byte): Bytes
+ do
+ return items.encode_base64(length, padding)
+ end
+
+ # Decodes the receiver string to base64 using a custom padding character.
+ #
+ # Default padding character `=`
+ fun decode_base64(padding : nullable Byte) : Bytes
+ do
+ return items.decode_base64(length, padding)
+ end
+end
+
+redef class String
+
+ # Encodes the receiver string to base64 using a custom padding character.
+ #
+ # If using the default padding character `=`, see `encode_base64`.
+ fun encode_base64(padding: nullable Byte): String
+ do
+ return to_cstring.encode_base64(bytelen, padding).to_s
+ end
+
+ # Decodes the receiver string to base64 using a custom padding character.
+ #
+ # Default padding character `=`
+ fun decode_base64(padding : nullable Byte) : String
+ do
+ return to_cstring.decode_base64(bytelen, padding).to_s
end
end
nitlanguage / nit.git / blobdiff