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A		 1/* ------------------------------------------------------------------ */
2/* Decimal Context module */
3/* ------------------------------------------------------------------ */
4/* Copyright (c) IBM Corporation, 2000-2010. All rights reserved. */
5/* */
6/* This software is made available under the terms of the */
7/* ICU License -- ICU 1.8.1 and later. */
8/* */
9/* The description and User's Guide ("The decNumber C Library") for */
10/* this software is called decNumber.pdf. This document is */
11/* available, together with arithmetic and format specifications, */
12/* testcases, and Web links, on the General Decimal Arithmetic page. */
13/* */
14/* Please send comments, suggestions, and corrections to the author: */
15/* mfc@uk.ibm.com */
16/* Mike Cowlishaw, IBM Fellow */
17/* IBM UK, PO Box 31, Birmingham Road, Warwick CV34 5JL, UK */
18/* ------------------------------------------------------------------ */
19/* This module comprises the routines for handling arithmetic */
20/* context structures. */
21/* ------------------------------------------------------------------ */
22
23#include <string.h> /* for strcmp */
24#include <stdio.h> /* for printf if DECCHECK */
25#include "decContext.h" /* context and base types */
26#include "decNumberLocal.h" /* decNumber local types, etc. */
27
28/* compile-time endian tester [assumes sizeof(Int)>1] */
29static const Int mfcone=1; /* constant 1 */
30static const Flag *mfctop=(Flag *)&mfcone; /* -> top byte */
31#define LITEND *mfctop /* named flag; 1=little-endian */
32
33/* ------------------------------------------------------------------ */
34/* round-for-reround digits */
35/* ------------------------------------------------------------------ */
36const uByte DECSTICKYTAB[10]={1,1,2,3,4,6,6,7,8,9}; /* used if sticky */
37
38/* ------------------------------------------------------------------ */
39/* Powers of ten (powers[n]==10**n, 0<=n<=9) */
40/* ------------------------------------------------------------------ */
41const uInt DECPOWERS[10]={1, 10, 100, 1000, 10000, 100000, 1000000,
42 10000000, 100000000, 1000000000};
43
44/* ------------------------------------------------------------------ */
45/* decContextClearStatus -- clear bits in current status */
46/* */
47/* context is the context structure to be queried */
48/* mask indicates the bits to be cleared (the status bit that */
49/* corresponds to each 1 bit in the mask is cleared) */
50/* returns context */
51/* */
52/* No error is possible. */
53/* ------------------------------------------------------------------ */
54U_CAPI decContext * U_EXPORT2 uprv_decContextClearStatus(decContext *context, uInt mask) {
55 context->status&=~mask;
56 return context;
57 } /* decContextClearStatus */
58
59/* ------------------------------------------------------------------ */
60/* decContextDefault -- initialize a context structure */
61/* */
62/* context is the structure to be initialized */
63/* kind selects the required set of default values, one of: */
64/* DEC_INIT_BASE -- select ANSI X3-274 defaults */
65/* DEC_INIT_DECIMAL32 -- select IEEE 754 defaults, 32-bit */
66/* DEC_INIT_DECIMAL64 -- select IEEE 754 defaults, 64-bit */
67/* DEC_INIT_DECIMAL128 -- select IEEE 754 defaults, 128-bit */
68/* For any other value a valid context is returned, but with */
69/* Invalid_operation set in the status field. */
70/* returns a context structure with the appropriate initial values. */
71/* ------------------------------------------------------------------ */
72U_CAPI decContext * U_EXPORT2 uprv_decContextDefault(decContext *context, Int kind) {
73 /* set defaults... */
74 context->digits=9; /* 9 digits */
75 context->emax=DEC_MAX_EMAX; /* 9-digit exponents */
76 context->emin=DEC_MIN_EMIN; /* .. balanced */
77 context->round=DEC_ROUND_HALF_UP; /* 0.5 rises */
78 context->traps=DEC_Errors; /* all but informational */
79 context->status=0; /* cleared */
80 context->clamp=0; /* no clamping */
81 #if DECSUBSET
82 context->extended=0; /* cleared */
83 #endif
84 switch (kind) {
85 case DEC_INIT_BASE:
86 /* [use defaults] */
87 break;
88 case DEC_INIT_DECIMAL32:
89 context->digits=7; /* digits */
90 context->emax=96; /* Emax */
91 context->emin=-95; /* Emin */
92 context->round=DEC_ROUND_HALF_EVEN; /* 0.5 to nearest even */
93 context->traps=0; /* no traps set */
94 context->clamp=1; /* clamp exponents */
95 #if DECSUBSET
96 context->extended=1; /* set */
97 #endif
98 break;
99 case DEC_INIT_DECIMAL64:
100 context->digits=16; /* digits */
101 context->emax=384; /* Emax */
102 context->emin=-383; /* Emin */
103 context->round=DEC_ROUND_HALF_EVEN; /* 0.5 to nearest even */
104 context->traps=0; /* no traps set */
105 context->clamp=1; /* clamp exponents */
106 #if DECSUBSET
107 context->extended=1; /* set */
108 #endif
109 break;
110 case DEC_INIT_DECIMAL128:
111 context->digits=34; /* digits */
112 context->emax=6144; /* Emax */
113 context->emin=-6143; /* Emin */
114 context->round=DEC_ROUND_HALF_EVEN; /* 0.5 to nearest even */
115 context->traps=0; /* no traps set */
116 context->clamp=1; /* clamp exponents */
117 #if DECSUBSET
118 context->extended=1; /* set */
119 #endif
120 break;
121
122 default: /* invalid Kind */
123 /* use defaults, and .. */
124 uprv_decContextSetStatus(context, DEC_Invalid_operation); /* trap */
125 }
126
127 return context;} /* decContextDefault */
128
129/* ------------------------------------------------------------------ */
130/* decContextGetRounding -- return current rounding mode */
131/* */
132/* context is the context structure to be queried */
133/* returns the rounding mode */
134/* */
135/* No error is possible. */
136/* ------------------------------------------------------------------ */
137U_CAPI enum rounding U_EXPORT2 uprv_decContextGetRounding(decContext *context) {
138 return context->round;
139 } /* decContextGetRounding */
140
141/* ------------------------------------------------------------------ */
142/* decContextGetStatus -- return current status */
143/* */
144/* context is the context structure to be queried */
145/* returns status */
146/* */
147/* No error is possible. */
148/* ------------------------------------------------------------------ */
149U_CAPI uInt U_EXPORT2 uprv_decContextGetStatus(decContext *context) {
150 return context->status;
151 } /* decContextGetStatus */
152
153/* ------------------------------------------------------------------ */
154/* decContextRestoreStatus -- restore bits in current status */
155/* */
156/* context is the context structure to be updated */
157/* newstatus is the source for the bits to be restored */
158/* mask indicates the bits to be restored (the status bit that */
159/* corresponds to each 1 bit in the mask is set to the value of */
160/* the correspnding bit in newstatus) */
161/* returns context */
162/* */
163/* No error is possible. */
164/* ------------------------------------------------------------------ */
165U_CAPI decContext * U_EXPORT2 uprv_decContextRestoreStatus(decContext *context,
166 uInt newstatus, uInt mask) {
167 context->status&=~mask; /* clear the selected bits */
168 context->status|=(mask&newstatus); /* or in the new bits */
169 return context;
170 } /* decContextRestoreStatus */
171
172/* ------------------------------------------------------------------ */
173/* decContextSaveStatus -- save bits in current status */
174/* */
175/* context is the context structure to be queried */
176/* mask indicates the bits to be saved (the status bits that */
177/* correspond to each 1 bit in the mask are saved) */
178/* returns the AND of the mask and the current status */
179/* */
180/* No error is possible. */
181/* ------------------------------------------------------------------ */
182U_CAPI uInt U_EXPORT2 uprv_decContextSaveStatus(decContext *context, uInt mask) {
183 return context->status&mask;
184 } /* decContextSaveStatus */
185
186/* ------------------------------------------------------------------ */
187/* decContextSetRounding -- set current rounding mode */
188/* */
189/* context is the context structure to be updated */
190/* newround is the value which will replace the current mode */
191/* returns context */
192/* */
193/* No error is possible. */
194/* ------------------------------------------------------------------ */
195U_CAPI decContext * U_EXPORT2 uprv_decContextSetRounding(decContext *context,
196 enum rounding newround) {
197 context->round=newround;
198 return context;
199 } /* decContextSetRounding */
200
201/* ------------------------------------------------------------------ */
202/* decContextSetStatus -- set status and raise trap if appropriate */
203/* */
204/* context is the context structure to be updated */
205/* status is the DEC_ exception code */
206/* returns the context structure */
207/* */
208/* Control may never return from this routine, if there is a signal */
209/* handler and it takes a long jump. */
210/* ------------------------------------------------------------------ */
211U_CAPI decContext * U_EXPORT2 uprv_decContextSetStatus(decContext *context, uInt status) {
212 context->status|=status;
213 if (status & context->traps) raise(SIGFPE);
214 return context;} /* decContextSetStatus */
215
216/* ------------------------------------------------------------------ */
217/* decContextSetStatusFromString -- set status from a string + trap */
218/* */
219/* context is the context structure to be updated */
220/* string is a string exactly equal to one that might be returned */
221/* by decContextStatusToString */
222/* */
223/* The status bit corresponding to the string is set, and a trap */
224/* is raised if appropriate. */
225/* */
226/* returns the context structure, unless the string is equal to */
227/* DEC_Condition_MU or is not recognized. In these cases NULL is */
228/* returned. */
229/* ------------------------------------------------------------------ */
230U_CAPI decContext * U_EXPORT2 uprv_decContextSetStatusFromString(decContext *context,
231 const char *string) {
232 if (strcmp(string, DEC_Condition_CS)==0)
233 return uprv_decContextSetStatus(context, DEC_Conversion_syntax);
234 if (strcmp(string, DEC_Condition_DZ)==0)
235 return uprv_decContextSetStatus(context, DEC_Division_by_zero);
236 if (strcmp(string, DEC_Condition_DI)==0)
237 return uprv_decContextSetStatus(context, DEC_Division_impossible);
238 if (strcmp(string, DEC_Condition_DU)==0)
239 return uprv_decContextSetStatus(context, DEC_Division_undefined);
240 if (strcmp(string, DEC_Condition_IE)==0)
241 return uprv_decContextSetStatus(context, DEC_Inexact);
242 if (strcmp(string, DEC_Condition_IS)==0)
243 return uprv_decContextSetStatus(context, DEC_Insufficient_storage);
244 if (strcmp(string, DEC_Condition_IC)==0)
245 return uprv_decContextSetStatus(context, DEC_Invalid_context);
246 if (strcmp(string, DEC_Condition_IO)==0)
247 return uprv_decContextSetStatus(context, DEC_Invalid_operation);
248 #if DECSUBSET
249 if (strcmp(string, DEC_Condition_LD)==0)
250 return uprv_decContextSetStatus(context, DEC_Lost_digits);
251 #endif
252 if (strcmp(string, DEC_Condition_OV)==0)
253 return uprv_decContextSetStatus(context, DEC_Overflow);
254 if (strcmp(string, DEC_Condition_PA)==0)
255 return uprv_decContextSetStatus(context, DEC_Clamped);
256 if (strcmp(string, DEC_Condition_RO)==0)
257 return uprv_decContextSetStatus(context, DEC_Rounded);
258 if (strcmp(string, DEC_Condition_SU)==0)
259 return uprv_decContextSetStatus(context, DEC_Subnormal);
260 if (strcmp(string, DEC_Condition_UN)==0)
261 return uprv_decContextSetStatus(context, DEC_Underflow);
262 if (strcmp(string, DEC_Condition_ZE)==0)
263 return context;
264 return NULL; /* Multiple status, or unknown */
265 } /* decContextSetStatusFromString */
266
267/* ------------------------------------------------------------------ */
268/* decContextSetStatusFromStringQuiet -- set status from a string */
269/* */
270/* context is the context structure to be updated */
271/* string is a string exactly equal to one that might be returned */
272/* by decContextStatusToString */
273/* */
274/* The status bit corresponding to the string is set; no trap is */
275/* raised. */
276/* */
277/* returns the context structure, unless the string is equal to */
278/* DEC_Condition_MU or is not recognized. In these cases NULL is */
279/* returned. */
280/* ------------------------------------------------------------------ */
281U_CAPI decContext * U_EXPORT2 uprv_decContextSetStatusFromStringQuiet(decContext *context,
282 const char *string) {
283 if (strcmp(string, DEC_Condition_CS)==0)
284 return uprv_decContextSetStatusQuiet(context, DEC_Conversion_syntax);
285 if (strcmp(string, DEC_Condition_DZ)==0)
286 return uprv_decContextSetStatusQuiet(context, DEC_Division_by_zero);
287 if (strcmp(string, DEC_Condition_DI)==0)
288 return uprv_decContextSetStatusQuiet(context, DEC_Division_impossible);
289 if (strcmp(string, DEC_Condition_DU)==0)
290 return uprv_decContextSetStatusQuiet(context, DEC_Division_undefined);
291 if (strcmp(string, DEC_Condition_IE)==0)
292 return uprv_decContextSetStatusQuiet(context, DEC_Inexact);
293 if (strcmp(string, DEC_Condition_IS)==0)
294 return uprv_decContextSetStatusQuiet(context, DEC_Insufficient_storage);
295 if (strcmp(string, DEC_Condition_IC)==0)
296 return uprv_decContextSetStatusQuiet(context, DEC_Invalid_context);
297 if (strcmp(string, DEC_Condition_IO)==0)
298 return uprv_decContextSetStatusQuiet(context, DEC_Invalid_operation);
299 #if DECSUBSET
300 if (strcmp(string, DEC_Condition_LD)==0)
301 return uprv_decContextSetStatusQuiet(context, DEC_Lost_digits);
302 #endif
303 if (strcmp(string, DEC_Condition_OV)==0)
304 return uprv_decContextSetStatusQuiet(context, DEC_Overflow);
305 if (strcmp(string, DEC_Condition_PA)==0)
306 return uprv_decContextSetStatusQuiet(context, DEC_Clamped);
307 if (strcmp(string, DEC_Condition_RO)==0)
308 return uprv_decContextSetStatusQuiet(context, DEC_Rounded);
309 if (strcmp(string, DEC_Condition_SU)==0)
310 return uprv_decContextSetStatusQuiet(context, DEC_Subnormal);
311 if (strcmp(string, DEC_Condition_UN)==0)
312 return uprv_decContextSetStatusQuiet(context, DEC_Underflow);
313 if (strcmp(string, DEC_Condition_ZE)==0)
314 return context;
315 return NULL; /* Multiple status, or unknown */
316 } /* decContextSetStatusFromStringQuiet */
317
318/* ------------------------------------------------------------------ */
319/* decContextSetStatusQuiet -- set status without trap */
320/* */
321/* context is the context structure to be updated */
322/* status is the DEC_ exception code */
323/* returns the context structure */
324/* */
325/* No error is possible. */
326/* ------------------------------------------------------------------ */
327U_CAPI decContext * U_EXPORT2 uprv_decContextSetStatusQuiet(decContext *context, uInt status) {
328 context->status|=status;
329 return context;} /* decContextSetStatusQuiet */
330
331/* ------------------------------------------------------------------ */
332/* decContextStatusToString -- convert status flags to a string */
333/* */
334/* context is a context with valid status field */
335/* */
336/* returns a constant string describing the condition. If multiple */
337/* (or no) flags are set, a generic constant message is returned. */
338/* ------------------------------------------------------------------ */
339U_CAPI const char * U_EXPORT2 uprv_decContextStatusToString(const decContext *context) {
340 Int status=context->status;
341
342 /* test the five IEEE first, as some of the others are ambiguous when */
343 /* DECEXTFLAG=0 */
344 if (status==DEC_Invalid_operation ) return DEC_Condition_IO;
345 if (status==DEC_Division_by_zero ) return DEC_Condition_DZ;
346 if (status==DEC_Overflow ) return DEC_Condition_OV;
347 if (status==DEC_Underflow ) return DEC_Condition_UN;
348 if (status==DEC_Inexact ) return DEC_Condition_IE;
349
350 if (status==DEC_Division_impossible ) return DEC_Condition_DI;
351 if (status==DEC_Division_undefined ) return DEC_Condition_DU;
352 if (status==DEC_Rounded ) return DEC_Condition_RO;
353 if (status==DEC_Clamped ) return DEC_Condition_PA;
354 if (status==DEC_Subnormal ) return DEC_Condition_SU;
355 if (status==DEC_Conversion_syntax ) return DEC_Condition_CS;
356 if (status==DEC_Insufficient_storage ) return DEC_Condition_IS;
357 if (status==DEC_Invalid_context ) return DEC_Condition_IC;
358 #if DECSUBSET
359 if (status==DEC_Lost_digits ) return DEC_Condition_LD;
360 #endif
361 if (status==0 ) return DEC_Condition_ZE;
362 return DEC_Condition_MU; /* Multiple errors */
363 } /* decContextStatusToString */
364
365/* ------------------------------------------------------------------ */
366/* decContextTestEndian -- test whether DECLITEND is set correctly */
367/* */
368/* quiet is 1 to suppress message; 0 otherwise */
369/* returns 0 if DECLITEND is correct */
370/* 1 if DECLITEND is incorrect and should be 1 */
371/* -1 if DECLITEND is incorrect and should be 0 */
372/* */
373/* A message is displayed if the return value is not 0 and quiet==0. */
374/* */
375/* No error is possible. */
376/* ------------------------------------------------------------------ */
377U_CAPI Int U_EXPORT2 uprv_decContextTestEndian(Flag quiet) {
378 Int res=0; /* optimist */
379 uInt dle=(uInt)DECLITEND; /* unsign */
380 if (dle>1) dle=1; /* ensure 0 or 1 */
381
382 if (LITEND!=DECLITEND) {
383 const char *adj;
384 if (!quiet) {
385 if (LITEND) adj="little";
386 else adj="big";
387 printf("Warning: DECLITEND is set to %d, but this computer appears to be %s-endian\n",
388 DECLITEND, adj);
389 }
390 res=(Int)LITEND-dle;
391 }
392 return res;
393 } /* decContextTestEndian */
394
395/* ------------------------------------------------------------------ */
396/* decContextTestSavedStatus -- test bits in saved status */
397/* */
398/* oldstatus is the status word to be tested */
399/* mask indicates the bits to be tested (the oldstatus bits that */
400/* correspond to each 1 bit in the mask are tested) */
401/* returns 1 if any of the tested bits are 1, or 0 otherwise */
402/* */
403/* No error is possible. */
404/* ------------------------------------------------------------------ */
405U_CAPI uInt U_EXPORT2 uprv_decContextTestSavedStatus(uInt oldstatus, uInt mask) {
406 return (oldstatus&mask)!=0;
407 } /* decContextTestSavedStatus */
408
409/* ------------------------------------------------------------------ */
410/* decContextTestStatus -- test bits in current status */
411/* */
412/* context is the context structure to be updated */
413/* mask indicates the bits to be tested (the status bits that */
414/* correspond to each 1 bit in the mask are tested) */
415/* returns 1 if any of the tested bits are 1, or 0 otherwise */
416/* */
417/* No error is possible. */
418/* ------------------------------------------------------------------ */
419U_CAPI uInt U_EXPORT2 uprv_decContextTestStatus(decContext *context, uInt mask) {
420 return (context->status&mask)!=0;
421 } /* decContextTestStatus */
422
423/* ------------------------------------------------------------------ */
424/* decContextZeroStatus -- clear all status bits */
425/* */
426/* context is the context structure to be updated */
427/* returns context */
428/* */
429/* No error is possible. */
430/* ------------------------------------------------------------------ */
431U_CAPI decContext * U_EXPORT2 uprv_decContextZeroStatus(decContext *context) {
432 context->status=0;
433 return context;
434 } /* decContextZeroStatus */
435
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