File : i-pacdec.adb
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- I N T E R F A C E S . P A C K E D _ D E C I M A L --
6 -- --
7 -- B o d y --
8 -- (Version for IBM Mainframe Packed Decimal Format) --
9 -- --
10 -- Copyright (C) 1992-2009, Free Software Foundation, Inc. --
11 -- --
12 -- GNAT is free software; you can redistribute it and/or modify it under --
13 -- terms of the GNU General Public License as published by the Free Soft- --
14 -- ware Foundation; either version 3, or (at your option) any later ver- --
15 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
16 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
17 -- or FITNESS FOR A PARTICULAR PURPOSE. --
18 -- --
19 -- --
20 -- --
21 -- --
22 -- --
23 -- You should have received a copy of the GNU General Public License and --
24 -- a copy of the GCC Runtime Library Exception along with this program; --
25 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
26 -- <http://www.gnu.org/licenses/>. --
27 -- --
28 -- GNAT was originally developed by the GNAT team at New York University. --
29 -- Extensive contributions were provided by Ada Core Technologies Inc. --
30 -- --
31 ------------------------------------------------------------------------------
32
33 with System; use System;
34
35 with Ada.Unchecked_Conversion;
36
37 package body Interfaces.Packed_Decimal is
38
39 type Packed is array (Byte_Length) of Unsigned_8;
40 -- The type used internally to represent packed decimal
41
42 type Packed_Ptr is access Packed;
43 function To_Packed_Ptr is
44 new Ada.Unchecked_Conversion (Address, Packed_Ptr);
45
46 -- The following array is used to convert a value in the range 0-99 to
47 -- a packed decimal format with two hexadecimal nibbles. It is worth
48 -- using table look up in this direction because divides are expensive.
49
50 Packed_Byte : constant array (00 .. 99) of Unsigned_8 :=
51 (16#00#, 16#01#, 16#02#, 16#03#, 16#04#,
52 16#05#, 16#06#, 16#07#, 16#08#, 16#09#,
53 16#10#, 16#11#, 16#12#, 16#13#, 16#14#,
54 16#15#, 16#16#, 16#17#, 16#18#, 16#19#,
55 16#20#, 16#21#, 16#22#, 16#23#, 16#24#,
56 16#25#, 16#26#, 16#27#, 16#28#, 16#29#,
57 16#30#, 16#31#, 16#32#, 16#33#, 16#34#,
58 16#35#, 16#36#, 16#37#, 16#38#, 16#39#,
59 16#40#, 16#41#, 16#42#, 16#43#, 16#44#,
60 16#45#, 16#46#, 16#47#, 16#48#, 16#49#,
61 16#50#, 16#51#, 16#52#, 16#53#, 16#54#,
62 16#55#, 16#56#, 16#57#, 16#58#, 16#59#,
63 16#60#, 16#61#, 16#62#, 16#63#, 16#64#,
64 16#65#, 16#66#, 16#67#, 16#68#, 16#69#,
65 16#70#, 16#71#, 16#72#, 16#73#, 16#74#,
66 16#75#, 16#76#, 16#77#, 16#78#, 16#79#,
67 16#80#, 16#81#, 16#82#, 16#83#, 16#84#,
68 16#85#, 16#86#, 16#87#, 16#88#, 16#89#,
69 16#90#, 16#91#, 16#92#, 16#93#, 16#94#,
70 16#95#, 16#96#, 16#97#, 16#98#, 16#99#);
71
72 ---------------------
73 -- Int32_To_Packed --
74 ---------------------
75
76 procedure Int32_To_Packed (V : Integer_32; P : System.Address; D : D32) is
77 PP : constant Packed_Ptr := To_Packed_Ptr (P);
78 Empty_Nibble : constant Boolean := ((D rem 2) = 0);
79 B : constant Byte_Length := (D / 2) + 1;
80 VV : Integer_32 := V;
81
82 begin
83 -- Deal with sign byte first
84
85 if VV >= 0 then
86 PP (B) := Unsigned_8 (VV rem 10) * 16 + 16#C#;
87 VV := VV / 10;
88
89 else
90 VV := -VV;
91 PP (B) := Unsigned_8 (VV rem 10) * 16 + 16#D#;
92 end if;
93
94 for J in reverse B - 1 .. 2 loop
95 if VV = 0 then
96 for K in 1 .. J loop
97 PP (K) := 16#00#;
98 end loop;
99
100 return;
101
102 else
103 PP (J) := Packed_Byte (Integer (VV rem 100));
104 VV := VV / 100;
105 end if;
106 end loop;
107
108 -- Deal with leading byte
109
110 if Empty_Nibble then
111 if VV > 9 then
112 raise Constraint_Error;
113 else
114 PP (1) := Unsigned_8 (VV);
115 end if;
116
117 else
118 if VV > 99 then
119 raise Constraint_Error;
120 else
121 PP (1) := Packed_Byte (Integer (VV));
122 end if;
123 end if;
124
125 end Int32_To_Packed;
126
127 ---------------------
128 -- Int64_To_Packed --
129 ---------------------
130
131 procedure Int64_To_Packed (V : Integer_64; P : System.Address; D : D64) is
132 PP : constant Packed_Ptr := To_Packed_Ptr (P);
133 Empty_Nibble : constant Boolean := ((D rem 2) = 0);
134 B : constant Byte_Length := (D / 2) + 1;
135 VV : Integer_64 := V;
136
137 begin
138 -- Deal with sign byte first
139
140 if VV >= 0 then
141 PP (B) := Unsigned_8 (VV rem 10) * 16 + 16#C#;
142 VV := VV / 10;
143
144 else
145 VV := -VV;
146 PP (B) := Unsigned_8 (VV rem 10) * 16 + 16#D#;
147 end if;
148
149 for J in reverse B - 1 .. 2 loop
150 if VV = 0 then
151 for K in 1 .. J loop
152 PP (K) := 16#00#;
153 end loop;
154
155 return;
156
157 else
158 PP (J) := Packed_Byte (Integer (VV rem 100));
159 VV := VV / 100;
160 end if;
161 end loop;
162
163 -- Deal with leading byte
164
165 if Empty_Nibble then
166 if VV > 9 then
167 raise Constraint_Error;
168 else
169 PP (1) := Unsigned_8 (VV);
170 end if;
171
172 else
173 if VV > 99 then
174 raise Constraint_Error;
175 else
176 PP (1) := Packed_Byte (Integer (VV));
177 end if;
178 end if;
179
180 end Int64_To_Packed;
181
182 ---------------------
183 -- Packed_To_Int32 --
184 ---------------------
185
186 function Packed_To_Int32 (P : System.Address; D : D32) return Integer_32 is
187 PP : constant Packed_Ptr := To_Packed_Ptr (P);
188 Empty_Nibble : constant Boolean := ((D mod 2) = 0);
189 B : constant Byte_Length := (D / 2) + 1;
190 V : Integer_32;
191 Dig : Unsigned_8;
192 Sign : Unsigned_8;
193 J : Positive;
194
195 begin
196 -- Cases where there is an unused (zero) nibble in the first byte.
197 -- Deal with the single digit nibble at the right of this byte
198
199 if Empty_Nibble then
200 V := Integer_32 (PP (1));
201 J := 2;
202
203 if V > 9 then
204 raise Constraint_Error;
205 end if;
206
207 -- Cases where all nibbles are used
208
209 else
210 V := 0;
211 J := 1;
212 end if;
213
214 -- Loop to process bytes containing two digit nibbles
215
216 while J < B loop
217 Dig := Shift_Right (PP (J), 4);
218
219 if Dig > 9 then
220 raise Constraint_Error;
221 else
222 V := V * 10 + Integer_32 (Dig);
223 end if;
224
225 Dig := PP (J) and 16#0F#;
226
227 if Dig > 9 then
228 raise Constraint_Error;
229 else
230 V := V * 10 + Integer_32 (Dig);
231 end if;
232
233 J := J + 1;
234 end loop;
235
236 -- Deal with digit nibble in sign byte
237
238 Dig := Shift_Right (PP (J), 4);
239
240 if Dig > 9 then
241 raise Constraint_Error;
242 else
243 V := V * 10 + Integer_32 (Dig);
244 end if;
245
246 Sign := PP (J) and 16#0F#;
247
248 -- Process sign nibble (deal with most common cases first)
249
250 if Sign = 16#C# then
251 return V;
252
253 elsif Sign = 16#D# then
254 return -V;
255
256 elsif Sign = 16#B# then
257 return -V;
258
259 elsif Sign >= 16#A# then
260 return V;
261
262 else
263 raise Constraint_Error;
264 end if;
265 end Packed_To_Int32;
266
267 ---------------------
268 -- Packed_To_Int64 --
269 ---------------------
270
271 function Packed_To_Int64 (P : System.Address; D : D64) return Integer_64 is
272 PP : constant Packed_Ptr := To_Packed_Ptr (P);
273 Empty_Nibble : constant Boolean := ((D mod 2) = 0);
274 B : constant Byte_Length := (D / 2) + 1;
275 V : Integer_64;
276 Dig : Unsigned_8;
277 Sign : Unsigned_8;
278 J : Positive;
279
280 begin
281 -- Cases where there is an unused (zero) nibble in the first byte.
282 -- Deal with the single digit nibble at the right of this byte
283
284 if Empty_Nibble then
285 V := Integer_64 (PP (1));
286 J := 2;
287
288 if V > 9 then
289 raise Constraint_Error;
290 end if;
291
292 -- Cases where all nibbles are used
293
294 else
295 J := 1;
296 V := 0;
297 end if;
298
299 -- Loop to process bytes containing two digit nibbles
300
301 while J < B loop
302 Dig := Shift_Right (PP (J), 4);
303
304 if Dig > 9 then
305 raise Constraint_Error;
306 else
307 V := V * 10 + Integer_64 (Dig);
308 end if;
309
310 Dig := PP (J) and 16#0F#;
311
312 if Dig > 9 then
313 raise Constraint_Error;
314 else
315 V := V * 10 + Integer_64 (Dig);
316 end if;
317
318 J := J + 1;
319 end loop;
320
321 -- Deal with digit nibble in sign byte
322
323 Dig := Shift_Right (PP (J), 4);
324
325 if Dig > 9 then
326 raise Constraint_Error;
327 else
328 V := V * 10 + Integer_64 (Dig);
329 end if;
330
331 Sign := PP (J) and 16#0F#;
332
333 -- Process sign nibble (deal with most common cases first)
334
335 if Sign = 16#C# then
336 return V;
337
338 elsif Sign = 16#D# then
339 return -V;
340
341 elsif Sign = 16#B# then
342 return -V;
343
344 elsif Sign >= 16#A# then
345 return V;
346
347 else
348 raise Constraint_Error;
349 end if;
350 end Packed_To_Int64;
351
352 end Interfaces.Packed_Decimal;