1// © 2016 and later: Unicode, Inc. and others.
2// License & terms of use: http://www.unicode.org/copyright.html
3/* ------------------------------------------------------------------ */
4/* Decimal Context module */
5/* ------------------------------------------------------------------ */
6/* Copyright (c) IBM Corporation, 2000-2012. All rights reserved. */
7/* */
8/* This software is made available under the terms of the */
9/* ICU License -- ICU 1.8.1 and later. */
10/* */
11/* The description and User's Guide ("The decNumber C Library") for */
12/* this software is called decNumber.pdf. This document is */
13/* available, together with arithmetic and format specifications, */
14/* testcases, and Web links, on the General Decimal Arithmetic page. */
15/* */
16/* Please send comments, suggestions, and corrections to the author: */
17/* mfc@uk.ibm.com */
18/* Mike Cowlishaw, IBM Fellow */
19/* IBM UK, PO Box 31, Birmingham Road, Warwick CV34 5JL, UK */
20/* ------------------------------------------------------------------ */
21/* This module comprises the routines for handling arithmetic */
22/* context structures. */
23/* ------------------------------------------------------------------ */
24
25#include <string.h> /* for strcmp */
26#include <stdio.h> /* for printf if DECCHECK */
27#include "decContext.h" /* context and base types */
28#include "decNumberLocal.h" /* decNumber local types, etc. */
29
30#if 0 /* ICU: No need to test endianness at runtime. */
31/* compile-time endian tester [assumes sizeof(Int)>1] */
32static const Int mfcone=1; /* constant 1 */
33static const Flag *mfctop=(Flag *)&mfcone; /* -> top byte */
34#define LITEND *mfctop /* named flag; 1=little-endian */
35#endif
36
37/* ------------------------------------------------------------------ */
38/* decContextClearStatus -- clear bits in current status */
39/* */
40/* context is the context structure to be queried */
41/* mask indicates the bits to be cleared (the status bit that */
42/* corresponds to each 1 bit in the mask is cleared) */
43/* returns context */
44/* */
45/* No error is possible. */
46/* ------------------------------------------------------------------ */
47U_CAPI decContext * U_EXPORT2 uprv_decContextClearStatus(decContext *context, uInt mask) {
48 context->status&=~mask;
49 return context;
50 } /* decContextClearStatus */
51
52/* ------------------------------------------------------------------ */
53/* decContextDefault -- initialize a context structure */
54/* */
55/* context is the structure to be initialized */
56/* kind selects the required set of default values, one of: */
57/* DEC_INIT_BASE -- select ANSI X3-274 defaults */
58/* DEC_INIT_DECIMAL32 -- select IEEE 754 defaults, 32-bit */
59/* DEC_INIT_DECIMAL64 -- select IEEE 754 defaults, 64-bit */
60/* DEC_INIT_DECIMAL128 -- select IEEE 754 defaults, 128-bit */
61/* For any other value a valid context is returned, but with */
62/* Invalid_operation set in the status field. */
63/* returns a context structure with the appropriate initial values. */
64/* ------------------------------------------------------------------ */
65U_CAPI decContext * U_EXPORT2 uprv_decContextDefault(decContext *context, Int kind) {
66 /* set defaults... */
67 context->digits=9; /* 9 digits */
68 context->emax=DEC_MAX_EMAX; /* 9-digit exponents */
69 context->emin=DEC_MIN_EMIN; /* .. balanced */
70 context->round=DEC_ROUND_HALF_UP; /* 0.5 rises */
71 context->traps=DEC_Errors; /* all but informational */
72 context->status=0; /* cleared */
73 context->clamp=0; /* no clamping */
74 #if DECSUBSET
75 context->extended=0; /* cleared */
76 #endif
77 switch (kind) {
78 case DEC_INIT_BASE:
79 /* [use defaults] */
80 break;
81 case DEC_INIT_DECIMAL32:
82 context->digits=7; /* digits */
83 context->emax=96; /* Emax */
84 context->emin=-95; /* Emin */
85 context->round=DEC_ROUND_HALF_EVEN; /* 0.5 to nearest even */
86 context->traps=0; /* no traps set */
87 context->clamp=1; /* clamp exponents */
88 #if DECSUBSET
89 context->extended=1; /* set */
90 #endif
91 break;
92 case DEC_INIT_DECIMAL64:
93 context->digits=16; /* digits */
94 context->emax=384; /* Emax */
95 context->emin=-383; /* Emin */
96 context->round=DEC_ROUND_HALF_EVEN; /* 0.5 to nearest even */
97 context->traps=0; /* no traps set */
98 context->clamp=1; /* clamp exponents */
99 #if DECSUBSET
100 context->extended=1; /* set */
101 #endif
102 break;
103 case DEC_INIT_DECIMAL128:
104 context->digits=34; /* digits */
105 context->emax=6144; /* Emax */
106 context->emin=-6143; /* Emin */
107 context->round=DEC_ROUND_HALF_EVEN; /* 0.5 to nearest even */
108 context->traps=0; /* no traps set */
109 context->clamp=1; /* clamp exponents */
110 #if DECSUBSET
111 context->extended=1; /* set */
112 #endif
113 break;
114
115 default: /* invalid Kind */
116 /* use defaults, and .. */
117 uprv_decContextSetStatus(context, DEC_Invalid_operation); /* trap */
118 }
119
120 return context;} /* decContextDefault */
121
122/* ------------------------------------------------------------------ */
123/* decContextGetRounding -- return current rounding mode */
124/* */
125/* context is the context structure to be queried */
126/* returns the rounding mode */
127/* */
128/* No error is possible. */
129/* ------------------------------------------------------------------ */
130U_CAPI enum rounding U_EXPORT2 uprv_decContextGetRounding(decContext *context) {
131 return context->round;
132 } /* decContextGetRounding */
133
134/* ------------------------------------------------------------------ */
135/* decContextGetStatus -- return current status */
136/* */
137/* context is the context structure to be queried */
138/* returns status */
139/* */
140/* No error is possible. */
141/* ------------------------------------------------------------------ */
142U_CAPI uInt U_EXPORT2 uprv_decContextGetStatus(decContext *context) {
143 return context->status;
144 } /* decContextGetStatus */
145
146/* ------------------------------------------------------------------ */
147/* decContextRestoreStatus -- restore bits in current status */
148/* */
149/* context is the context structure to be updated */
150/* newstatus is the source for the bits to be restored */
151/* mask indicates the bits to be restored (the status bit that */
152/* corresponds to each 1 bit in the mask is set to the value of */
153/* the correspnding bit in newstatus) */
154/* returns context */
155/* */
156/* No error is possible. */
157/* ------------------------------------------------------------------ */
158U_CAPI decContext * U_EXPORT2 uprv_decContextRestoreStatus(decContext *context,
159 uInt newstatus, uInt mask) {
160 context->status&=~mask; /* clear the selected bits */
161 context->status|=(mask&newstatus); /* or in the new bits */
162 return context;
163 } /* decContextRestoreStatus */
164
165/* ------------------------------------------------------------------ */
166/* decContextSaveStatus -- save bits in current status */
167/* */
168/* context is the context structure to be queried */
169/* mask indicates the bits to be saved (the status bits that */
170/* correspond to each 1 bit in the mask are saved) */
171/* returns the AND of the mask and the current status */
172/* */
173/* No error is possible. */
174/* ------------------------------------------------------------------ */
175U_CAPI uInt U_EXPORT2 uprv_decContextSaveStatus(decContext *context, uInt mask) {
176 return context->status&mask;
177 } /* decContextSaveStatus */
178
179/* ------------------------------------------------------------------ */
180/* decContextSetRounding -- set current rounding mode */
181/* */
182/* context is the context structure to be updated */
183/* newround is the value which will replace the current mode */
184/* returns context */
185/* */
186/* No error is possible. */
187/* ------------------------------------------------------------------ */
188U_CAPI decContext * U_EXPORT2 uprv_decContextSetRounding(decContext *context,
189 enum rounding newround) {
190 context->round=newround;
191 return context;
192 } /* decContextSetRounding */
193
194/* ------------------------------------------------------------------ */
195/* decContextSetStatus -- set status and raise trap if appropriate */
196/* */
197/* context is the context structure to be updated */
198/* status is the DEC_ exception code */
199/* returns the context structure */
200/* */
201/* Control may never return from this routine, if there is a signal */
202/* handler and it takes a long jump. */
203/* ------------------------------------------------------------------ */
204U_CAPI decContext * U_EXPORT2 uprv_decContextSetStatus(decContext *context, uInt status) {
205 context->status|=status;
206#if 0 /* ICU: Do not raise signals. */
207 if (status & context->traps) raise(SIGFPE);
208#endif
209 return context;} /* decContextSetStatus */
210
211/* ------------------------------------------------------------------ */
212/* decContextSetStatusFromString -- set status from a string + trap */
213/* */
214/* context is the context structure to be updated */
215/* string is a string exactly equal to one that might be returned */
216/* by decContextStatusToString */
217/* */
218/* The status bit corresponding to the string is set, and a trap */
219/* is raised if appropriate. */
220/* */
221/* returns the context structure, unless the string is equal to */
222/* DEC_Condition_MU or is not recognized. In these cases NULL is */
223/* returned. */
224/* ------------------------------------------------------------------ */
225U_CAPI decContext * U_EXPORT2 uprv_decContextSetStatusFromString(decContext *context,
226 const char *string) {
227 if (strcmp(string, DEC_Condition_CS)==0)
228 return uprv_decContextSetStatus(context, DEC_Conversion_syntax);
229 if (strcmp(string, DEC_Condition_DZ)==0)
230 return uprv_decContextSetStatus(context, DEC_Division_by_zero);
231 if (strcmp(string, DEC_Condition_DI)==0)
232 return uprv_decContextSetStatus(context, DEC_Division_impossible);
233 if (strcmp(string, DEC_Condition_DU)==0)
234 return uprv_decContextSetStatus(context, DEC_Division_undefined);
235 if (strcmp(string, DEC_Condition_IE)==0)
236 return uprv_decContextSetStatus(context, DEC_Inexact);
237 if (strcmp(string, DEC_Condition_IS)==0)
238 return uprv_decContextSetStatus(context, DEC_Insufficient_storage);
239 if (strcmp(string, DEC_Condition_IC)==0)
240 return uprv_decContextSetStatus(context, DEC_Invalid_context);
241 if (strcmp(string, DEC_Condition_IO)==0)
242 return uprv_decContextSetStatus(context, DEC_Invalid_operation);
243 #if DECSUBSET
244 if (strcmp(string, DEC_Condition_LD)==0)
245 return uprv_decContextSetStatus(context, DEC_Lost_digits);
246 #endif
247 if (strcmp(string, DEC_Condition_OV)==0)
248 return uprv_decContextSetStatus(context, DEC_Overflow);
249 if (strcmp(string, DEC_Condition_PA)==0)
250 return uprv_decContextSetStatus(context, DEC_Clamped);
251 if (strcmp(string, DEC_Condition_RO)==0)
252 return uprv_decContextSetStatus(context, DEC_Rounded);
253 if (strcmp(string, DEC_Condition_SU)==0)
254 return uprv_decContextSetStatus(context, DEC_Subnormal);
255 if (strcmp(string, DEC_Condition_UN)==0)
256 return uprv_decContextSetStatus(context, DEC_Underflow);
257 if (strcmp(string, DEC_Condition_ZE)==0)
258 return context;
259 return NULL; /* Multiple status, or unknown */
260 } /* decContextSetStatusFromString */
261
262/* ------------------------------------------------------------------ */
263/* decContextSetStatusFromStringQuiet -- set status from a string */
264/* */
265/* context is the context structure to be updated */
266/* string is a string exactly equal to one that might be returned */
267/* by decContextStatusToString */
268/* */
269/* The status bit corresponding to the string is set; no trap is */
270/* raised. */
271/* */
272/* returns the context structure, unless the string is equal to */
273/* DEC_Condition_MU or is not recognized. In these cases NULL is */
274/* returned. */
275/* ------------------------------------------------------------------ */
276U_CAPI decContext * U_EXPORT2 uprv_decContextSetStatusFromStringQuiet(decContext *context,
277 const char *string) {
278 if (strcmp(string, DEC_Condition_CS)==0)
279 return uprv_decContextSetStatusQuiet(context, DEC_Conversion_syntax);
280 if (strcmp(string, DEC_Condition_DZ)==0)
281 return uprv_decContextSetStatusQuiet(context, DEC_Division_by_zero);
282 if (strcmp(string, DEC_Condition_DI)==0)
283 return uprv_decContextSetStatusQuiet(context, DEC_Division_impossible);
284 if (strcmp(string, DEC_Condition_DU)==0)
285 return uprv_decContextSetStatusQuiet(context, DEC_Division_undefined);
286 if (strcmp(string, DEC_Condition_IE)==0)
287 return uprv_decContextSetStatusQuiet(context, DEC_Inexact);
288 if (strcmp(string, DEC_Condition_IS)==0)
289 return uprv_decContextSetStatusQuiet(context, DEC_Insufficient_storage);
290 if (strcmp(string, DEC_Condition_IC)==0)
291 return uprv_decContextSetStatusQuiet(context, DEC_Invalid_context);
292 if (strcmp(string, DEC_Condition_IO)==0)
293 return uprv_decContextSetStatusQuiet(context, DEC_Invalid_operation);
294 #if DECSUBSET
295 if (strcmp(string, DEC_Condition_LD)==0)
296 return uprv_decContextSetStatusQuiet(context, DEC_Lost_digits);
297 #endif
298 if (strcmp(string, DEC_Condition_OV)==0)
299 return uprv_decContextSetStatusQuiet(context, DEC_Overflow);
300 if (strcmp(string, DEC_Condition_PA)==0)
301 return uprv_decContextSetStatusQuiet(context, DEC_Clamped);
302 if (strcmp(string, DEC_Condition_RO)==0)
303 return uprv_decContextSetStatusQuiet(context, DEC_Rounded);
304 if (strcmp(string, DEC_Condition_SU)==0)
305 return uprv_decContextSetStatusQuiet(context, DEC_Subnormal);
306 if (strcmp(string, DEC_Condition_UN)==0)
307 return uprv_decContextSetStatusQuiet(context, DEC_Underflow);
308 if (strcmp(string, DEC_Condition_ZE)==0)
309 return context;
310 return NULL; /* Multiple status, or unknown */
311 } /* decContextSetStatusFromStringQuiet */
312
313/* ------------------------------------------------------------------ */
314/* decContextSetStatusQuiet -- set status without trap */
315/* */
316/* context is the context structure to be updated */
317/* status is the DEC_ exception code */
318/* returns the context structure */
319/* */
320/* No error is possible. */
321/* ------------------------------------------------------------------ */
322U_CAPI decContext * U_EXPORT2 uprv_decContextSetStatusQuiet(decContext *context, uInt status) {
323 context->status|=status;
324 return context;} /* decContextSetStatusQuiet */
325
326/* ------------------------------------------------------------------ */
327/* decContextStatusToString -- convert status flags to a string */
328/* */
329/* context is a context with valid status field */
330/* */
331/* returns a constant string describing the condition. If multiple */
332/* (or no) flags are set, a generic constant message is returned. */
333/* ------------------------------------------------------------------ */
334U_CAPI const char * U_EXPORT2 uprv_decContextStatusToString(const decContext *context) {
335 Int status=context->status;
336
337 /* test the five IEEE first, as some of the others are ambiguous when */
338 /* DECEXTFLAG=0 */
339 if (status==DEC_Invalid_operation ) return DEC_Condition_IO;
340 if (status==DEC_Division_by_zero ) return DEC_Condition_DZ;
341 if (status==DEC_Overflow ) return DEC_Condition_OV;
342 if (status==DEC_Underflow ) return DEC_Condition_UN;
343 if (status==DEC_Inexact ) return DEC_Condition_IE;
344
345 if (status==DEC_Division_impossible ) return DEC_Condition_DI;
346 if (status==DEC_Division_undefined ) return DEC_Condition_DU;
347 if (status==DEC_Rounded ) return DEC_Condition_RO;
348 if (status==DEC_Clamped ) return DEC_Condition_PA;
349 if (status==DEC_Subnormal ) return DEC_Condition_SU;
350 if (status==DEC_Conversion_syntax ) return DEC_Condition_CS;
351 if (status==DEC_Insufficient_storage ) return DEC_Condition_IS;
352 if (status==DEC_Invalid_context ) return DEC_Condition_IC;
353 #if DECSUBSET
354 if (status==DEC_Lost_digits ) return DEC_Condition_LD;
355 #endif
356 if (status==0 ) return DEC_Condition_ZE;
357 return DEC_Condition_MU; /* Multiple errors */
358 } /* decContextStatusToString */
359
360/* ------------------------------------------------------------------ */
361/* decContextTestEndian -- test whether DECLITEND is set correctly */
362/* */
363/* quiet is 1 to suppress message; 0 otherwise */
364/* returns 0 if DECLITEND is correct */
365/* 1 if DECLITEND is incorrect and should be 1 */
366/* -1 if DECLITEND is incorrect and should be 0 */
367/* */
368/* A message is displayed if the return value is not 0 and quiet==0. */
369/* */
370/* No error is possible. */
371/* ------------------------------------------------------------------ */
372#if 0 /* ICU: Unused function. Anyway, do not call printf(). */
373U_CAPI Int U_EXPORT2 uprv_decContextTestEndian(Flag quiet) {
374 Int res=0; /* optimist */
375 uInt dle=(uInt)DECLITEND; /* unsign */
376 if (dle>1) dle=1; /* ensure 0 or 1 */
377
378 if (LITEND!=DECLITEND) {
379 const char *adj;
380 if (!quiet) {
381 if (LITEND) adj="little";
382 else adj="big";
383 printf("Warning: DECLITEND is set to %d, but this computer appears to be %s-endian\n",
384 DECLITEND, adj);
385 }
386 res=(Int)LITEND-dle;
387 }
388 return res;
389 } /* decContextTestEndian */
390#endif
391
392/* ------------------------------------------------------------------ */
393/* decContextTestSavedStatus -- test bits in saved status */
394/* */
395/* oldstatus is the status word to be tested */
396/* mask indicates the bits to be tested (the oldstatus bits that */
397/* correspond to each 1 bit in the mask are tested) */
398/* returns 1 if any of the tested bits are 1, or 0 otherwise */
399/* */
400/* No error is possible. */
401/* ------------------------------------------------------------------ */
402U_CAPI uInt U_EXPORT2 uprv_decContextTestSavedStatus(uInt oldstatus, uInt mask) {
403 return (oldstatus&mask)!=0;
404 } /* decContextTestSavedStatus */
405
406/* ------------------------------------------------------------------ */
407/* decContextTestStatus -- test bits in current status */
408/* */
409/* context is the context structure to be updated */
410/* mask indicates the bits to be tested (the status bits that */
411/* correspond to each 1 bit in the mask are tested) */
412/* returns 1 if any of the tested bits are 1, or 0 otherwise */
413/* */
414/* No error is possible. */
415/* ------------------------------------------------------------------ */
416U_CAPI uInt U_EXPORT2 uprv_decContextTestStatus(decContext *context, uInt mask) {
417 return (context->status&mask)!=0;
418 } /* decContextTestStatus */
419
420/* ------------------------------------------------------------------ */
421/* decContextZeroStatus -- clear all status bits */
422/* */
423/* context is the context structure to be updated */
424/* returns context */
425/* */
426/* No error is possible. */
427/* ------------------------------------------------------------------ */
428U_CAPI decContext * U_EXPORT2 uprv_decContextZeroStatus(decContext *context) {
429 context->status=0;
430 return context;
431 } /* decContextZeroStatus */
432
433