Overview
| Comment: | s_expressions-encodings: new package for hexadecimal and base-64 encoding and decoding in S-expressions |
|---|---|
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
1360e35d38391823257bf2e95629a151 |
| User & Date: | nat on 2013-12-30 19:59:23 |
| Other Links: | manifest | tags |
Context
|
2013-12-31
| ||
| 14:42 | s_expressions-test_tools: new package with helper subprograms for S-expression tests check-in: b0207d9353 user: nat tags: trunk | |
|
2013-12-30
| ||
| 19:59 | s_expressions-encodings: new package for hexadecimal and base-64 encoding and decoding in S-expressions check-in: 1360e35d38 user: nat tags: trunk | |
|
2013-12-29
| ||
| 22:57 | s_expressions: new parent package for S-expression code check-in: 5a32f08c8e user: nat tags: trunk | |
Changes
Added src/natools-s_expressions-encodings.adb version [f49ff898a8].
> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 |
------------------------------------------------------------------------------
-- Copyright (c) 2013, Natacha Porté --
-- --
-- Permission to use, copy, modify, and distribute this software for any --
-- purpose with or without fee is hereby granted, provided that the above --
-- copyright notice and this permission notice appear in all copies. --
-- --
-- THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES --
-- WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF --
-- MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR --
-- ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES --
-- WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN --
-- ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF --
-- OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. --
------------------------------------------------------------------------------
package body Natools.S_Expressions.Encodings is
--------------------------
-- Hexadecimal Decoding --
--------------------------
function Is_Hex_Digit (Value : in Octet) return Boolean is
begin
case Value is
when Digit_0 .. Digit_9 => return True;
when Lower_A .. Lower_F => return True;
when Upper_A .. Upper_F => return True;
when others => return False;
end case;
end Is_Hex_Digit;
function Decode_Hex (Value : in Octet) return Octet is
begin
case Value is
when Digit_0 .. Digit_9 => return Value - Digit_0;
when Lower_A .. Lower_F => return Value - Lower_A + 10;
when Upper_A .. Upper_F => return Value - Upper_A + 10;
when others => raise Constraint_Error;
end case;
end Decode_Hex;
function Decode_Hex (High, Low : in Octet) return Octet is
begin
return Decode_Hex (High) * 16 + Decode_Hex (Low);
end Decode_Hex;
function Decode_Hex (Data : in Atom) return Atom is
Length : Count := 0;
begin
for I in Data'Range loop
if Is_Hex_Digit (Data (I)) then
Length := Length + 1;
end if;
end loop;
Length := (Length + 1) / 2;
return Result : Atom (0 .. Length - 1) do
declare
O : Offset := Result'First;
High : Octet := 0;
Has_High : Boolean := False;
begin
for I in Data'Range loop
if Is_Hex_Digit (Data (I)) then
if Has_High then
Result (O) := Decode_Hex (High, Data (I));
O := O + 1;
High := 0;
Has_High := False;
else
High := Data (I);
Has_High := True;
end if;
end if;
end loop;
if Has_High then
Result (O) := Decode_Hex (High, 0);
O := O + 1;
end if;
pragma Assert (O - 1 = Result'Last);
end;
end return;
end Decode_Hex;
--------------------------
-- Hexadecimal Encoding --
--------------------------
function Encode_Hex (Value : in Octet; Casing : in Hex_Casing)
return Octet is
begin
case Value is
when 0 .. 9 =>
return Digit_0 + Value;
when 10 .. 15 =>
case Casing is
when Upper => return Upper_A + Value - 10;
when Lower => return Lower_A + Value - 10;
end case;
when others =>
raise Constraint_Error;
end case;
end Encode_Hex;
procedure Encode_Hex
(Value : in Octet;
Casing : in Hex_Casing;
High, Low : out Octet) is
begin
High := Encode_Hex (Value / 2**4 mod 2**4, Casing);
Low := Encode_Hex (Value mod 2**4, Casing);
end Encode_Hex;
function Encode_Hex (Data : in Atom; Casing : in Hex_Casing) return Atom is
Result : Atom (0 .. Data'Length * 2 - 1);
Cursor : Offset := Result'First;
begin
for I in Data'Range loop
Encode_Hex (Data (I), Casing, Result (Cursor), Result (Cursor + 1));
Cursor := Cursor + 2;
end loop;
pragma Assert (Cursor = Result'Last + 1);
return Result;
end Encode_Hex;
----------------------
-- Base-64 Decoding --
----------------------
function Is_Base64_Digit (Value : in Octet) return Boolean is
begin
return Value in Digit_0 .. Digit_9
or Value in Lower_A .. Lower_Z
or Value in Upper_A .. Upper_Z
or Value = Plus
or Value = Slash;
end Is_Base64_Digit;
function Decode_Base64 (Value : in Octet) return Octet is
begin
case Value is
when Upper_A .. Upper_Z => return Value - Upper_A + 0;
when Lower_A .. Lower_Z => return Value - Lower_A + 26;
when Digit_0 .. Digit_9 => return Value - Digit_0 + 52;
when Plus => return 62;
when Slash => return 63;
when others => raise Constraint_Error;
end case;
end Decode_Base64;
function Decode_Base64 (A, B : in Octet) return Atom is
VA : constant Octet := Decode_Base64 (A);
VB : constant Octet := Decode_Base64 (B);
begin
return (0 => VA * 2**2 + VB / 2**4);
end Decode_Base64;
function Decode_Base64 (A, B, C : in Octet) return Atom is
VA : constant Octet := Decode_Base64 (A);
VB : constant Octet := Decode_Base64 (B);
VC : constant Octet := Decode_Base64 (C);
begin
return (0 => VA * 2**2 + VB / 2**4,
1 => VB * 2**4 + VC / 2**2);
end Decode_Base64;
function Decode_Base64 (A, B, C, D : in Octet) return Atom is
VA : constant Octet := Decode_Base64 (A);
VB : constant Octet := Decode_Base64 (B);
VC : constant Octet := Decode_Base64 (C);
VD : constant Octet := Decode_Base64 (D);
begin
return (0 => VA * 2**2 + VB / 2**4,
1 => VB * 2**4 + VC / 2**2,
2 => VC * 2**6 + VD);
end Decode_Base64;
function Decode_Base64 (Data : in Atom) return Atom is
Length : Count := 0;
begin
for I in Data'Range loop
if Is_Base64_Digit (Data (I)) then
Length := Length + 1;
end if;
end loop;
declare
Chunks : constant Count := Length / 4;
Remains : constant Count := Length mod 4;
begin
if Remains >= 2 then
Length := Chunks * 3 + Remains - 1;
else
Length := Chunks * 3;
end if;
end;
return Result : Atom (0 .. Length - 1) do
declare
O : Count := Result'First;
Buffer : Atom (0 .. 3);
Accumulated : Count := 0;
begin
for I in Data'Range loop
if Is_Base64_Digit (Data (I)) then
Buffer (Accumulated) := Data (I);
Accumulated := Accumulated + 1;
if Accumulated = 4 then
Result (O .. O + 2) := Decode_Base64 (Buffer (0),
Buffer (1),
Buffer (2),
Buffer (3));
O := O + 3;
Accumulated := 0;
end if;
end if;
end loop;
if Accumulated = 2 then
Result (O .. O) := Decode_Base64 (Buffer (0), Buffer (1));
O := O + 1;
elsif Accumulated = 3 then
Result (O .. O + 1) := Decode_Base64 (Buffer (0),
Buffer (1),
Buffer (2));
O := O + 2;
end if;
pragma Assert (O = Length);
end;
end return;
end Decode_Base64;
----------------------
-- Base-64 Encoding --
----------------------
function Encode_Base64 (Value : in Octet) return Octet is
begin
case Value is
when 0 .. 25 =>
return Upper_A + Value;
when 26 .. 51 =>
return Lower_A + Value - 26;
when 52 .. 61 =>
return Digit_0 + Value - 52;
when 62 =>
return Plus;
when 63 =>
return Slash;
when others =>
raise Constraint_Error;
end case;
end Encode_Base64;
procedure Encode_Base64 (Output : out Atom; A : in Octet) is
begin
Output (Output'First + 0) := Encode_Base64 (A / 2**2 mod 2**6);
Output (Output'First + 1) := Encode_Base64 (A * 2**4 mod 2**6);
Output (Output'First + 2) := Base64_Filler;
Output (Output'First + 3) := Base64_Filler;
end Encode_Base64;
procedure Encode_Base64 (Output : out Atom; A, B : in Octet) is
begin
Output (Output'First + 0) := Encode_Base64 (A / 2**2 mod 2**6);
Output (Output'First + 1) := Encode_Base64 ((A * 2**4 + B / 2**4)
mod 2**6);
Output (Output'First + 2) := Encode_Base64 (B * 2**2 mod 2**6);
Output (Output'First + 3) := Base64_Filler;
end Encode_Base64;
procedure Encode_Base64 (Output : out Atom; A, B, C : in Octet) is
begin
Output (Output'First + 0) := Encode_Base64 (A / 2**2 mod 2**6);
Output (Output'First + 1) := Encode_Base64 ((A * 2**4 + B / 2**4)
mod 2**6);
Output (Output'First + 2) := Encode_Base64 ((B * 2**2 + C / 2**6)
mod 2**6);
Output (Output'First + 3) := Encode_Base64 (C mod 2**6);
end Encode_Base64;
function Encode_Base64 (Data : in Atom) return Atom is
Chunks : constant Count := (Data'Length + 2) / 3;
Result : Atom (0 .. Chunks * 4 - 1);
Cursor : Offset := Result'First;
I : Offset := Data'First;
begin
while I in Data'Range loop
if I + 2 in Data'Range then
Encode_Base64
(Result (Cursor .. Cursor + 3),
Data (I),
Data (I + 1),
Data (I + 2));
I := I + 3;
elsif I + 1 in Data'Range then
Encode_Base64
(Result (Cursor .. Cursor + 3),
Data (I),
Data (I + 1));
I := I + 2;
else
Encode_Base64
(Result (Cursor .. Cursor + 3),
Data (I));
I := I + 1;
end if;
Cursor := Cursor + 4;
end loop;
return Result;
end Encode_Base64;
end Natools.S_Expressions.Encodings;
|
Added src/natools-s_expressions-encodings.ads version [37bb5afca8].
> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 |
------------------------------------------------------------------------------
-- Copyright (c) 2013, Natacha Porté --
-- --
-- Permission to use, copy, modify, and distribute this software for any --
-- purpose with or without fee is hereby granted, provided that the above --
-- copyright notice and this permission notice appear in all copies. --
-- --
-- THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES --
-- WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF --
-- MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR --
-- ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES --
-- WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN --
-- ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF --
-- OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. --
------------------------------------------------------------------------------
package Natools.S_Expressions.Encodings is
pragma Pure (Natools.S_Expressions.Encodings);
-----------------------------
-- Meaningful Octet Values --
-----------------------------
-- S-expression Active Characters --
Base64_Atom_Begin : constant Octet := Character'Pos ('|');
Base64_Atom_End : constant Octet := Character'Pos ('|');
Base64_Expr_Begin : constant Octet := Character'Pos ('{');
Base64_Expr_End : constant Octet := Character'Pos ('}');
Base64_Filler : constant Octet := Character'Pos ('=');
Escape : constant Octet := Character'Pos ('\');
Hex_Atom_Begin : constant Octet := Character'Pos ('#');
Hex_Atom_End : constant Octet := Character'Pos ('#');
List_Begin : constant Octet := Character'Pos ('(');
List_End : constant Octet := Character'Pos (')');
Quoted_Atom_Begin : constant Octet := Character'Pos ('"');
Quoted_Atom_End : constant Octet := Character'Pos ('"');
Verbatim_Begin : constant Octet := Character'Pos (':');
-- Blanks --
HT : constant Octet := 9;
LF : constant Octet := 10;
VT : constant Octet := 11;
FF : constant Octet := 12;
CR : constant Octet := 13;
Space : constant Octet := 32;
-- Encoding-related Values --
Digit_0 : constant Octet := Character'Pos ('0');
Digit_9 : constant Octet := Character'Pos ('9');
Lower_A : constant Octet := Character'Pos ('a');
Lower_F : constant Octet := Character'Pos ('f');
Lower_Z : constant Octet := Character'Pos ('z');
Upper_A : constant Octet := Character'Pos ('A');
Upper_F : constant Octet := Character'Pos ('F');
Upper_Z : constant Octet := Character'Pos ('Z');
Plus : constant Octet := Character'Pos ('+');
Slash : constant Octet := Character'Pos ('/');
---------------------------------------
-- Hexadecimal Encoding and Decoding --
---------------------------------------
type Hex_Casing is (Upper, Lower);
function Is_Hex_Digit (Value : in Octet) return Boolean;
function Decode_Hex (Value : in Octet) return Octet;
function Decode_Hex (High, Low : in Octet) return Octet;
function Decode_Hex (Data : in Atom) return Atom;
function Encode_Hex (Value : in Octet; Casing : in Hex_Casing) return Octet;
procedure Encode_Hex
(Value : in Octet;
Casing : in Hex_Casing;
High, Low : out Octet);
function Encode_Hex (Data : in Atom; Casing : in Hex_Casing) return Atom;
-----------------------------------
-- Base-64 Encoding and Decoding --
-----------------------------------
function Is_Base64_Digit (Value : in Octet) return Boolean;
function Decode_Base64 (Value : in Octet) return Octet;
function Decode_Base64 (A, B : in Octet) return Atom;
function Decode_Base64 (A, B, C : in Octet) return Atom;
function Decode_Base64 (A, B, C, D : in Octet) return Atom;
function Decode_Base64 (Data : in Atom) return Atom;
function Encode_Base64 (Value : in Octet) return Octet;
procedure Encode_Base64 (Output : out Atom; A : in Octet);
procedure Encode_Base64 (Output : out Atom; A, B : in Octet);
procedure Encode_Base64 (Output : out Atom; A, B, C : in Octet);
function Encode_Base64 (Data : in Atom) return Atom;
end Natools.S_Expressions.Encodings;
|