xref: /haiku/src/system/libroot/posix/glibc/stdio-common/_itoa.c (revision 52c4471a3024d2eb81fe88e2c3982b9f8daa5e56)
1 /* Internal function for converting integers to ASCII.
2    Copyright (C) 1994, 1995, 1996, 1999, 2000, 2002, 2003, 2007
3    Free Software Foundation, Inc.
4    This file is part of the GNU C Library.
5    Contributed by Torbjorn Granlund <tege@matematik.su.se>
6    and Ulrich Drepper <drepper@gnu.org>.
7 
8    The GNU C Library is free software; you can redistribute it and/or
9    modify it under the terms of the GNU Lesser General Public
10    License as published by the Free Software Foundation; either
11    version 2.1 of the License, or (at your option) any later version.
12 
13    The GNU C Library is distributed in the hope that it will be useful,
14    but WITHOUT ANY WARRANTY; without even the implied warranty of
15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16    Lesser General Public License for more details.
17 
18    You should have received a copy of the GNU Lesser General Public
19    License along with the GNU C Library; if not, write to the Free
20    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
21    02111-1307 USA.  */
22 
23 #include <gmp-mparam.h>
24 #include <gmp.h>
25 #include <stdlib/gmp-impl.h>
26 #include <stdlib/longlong.h>
27 
28 #include "_itoa.h"
29 
30 
31 /* Canonize environment.  For some architectures not all values might
32    be defined in the GMP header files.  */
33 #ifndef UMUL_TIME
34 # define UMUL_TIME 1
35 #endif
36 #ifndef UDIV_TIME
37 # define UDIV_TIME 3
38 #endif
39 
40 /* Control memory layout.  */
41 #ifdef PACK
42 # undef PACK
43 # define PACK __attribute__ ((packed))
44 #else
45 # define PACK
46 #endif
47 
48 
49 /* Declare local types.  */
50 struct base_table_t
51 {
52 #if (UDIV_TIME > 2 * UMUL_TIME)
53   mp_limb_t base_multiplier;
54 #endif
55   char flag;
56   char post_shift;
57 #if BITS_PER_MP_LIMB == 32
58   struct
59     {
60       char normalization_steps;
61       char ndigits;
62       mp_limb_t base PACK;
63 #if UDIV_TIME > 2 * UMUL_TIME
64       mp_limb_t base_ninv PACK;
65 #endif
66     } big;
67 #endif
68 };
69 
70 /* To reduce the memory needed we include some fields of the tables
71    only conditionally.  */
72 #if UDIV_TIME > 2 * UMUL_TIME
73 # define SEL1(X) X,
74 # define SEL2(X) ,X
75 #else
76 # define SEL1(X)
77 # define SEL2(X)
78 #endif
79 
80 
81 /* Local variables.  */
82 const struct base_table_t _itoa_base_table[] attribute_hidden =
83 {
84 #if BITS_PER_MP_LIMB == 64
85   /*  2 */ {SEL1(0ull) 1, 1},
86   /*  3 */ {SEL1(0xaaaaaaaaaaaaaaabull) 0, 1},
87   /*  4 */ {SEL1(0ull) 1, 2},
88   /*  5 */ {SEL1(0xcccccccccccccccdull) 0, 2},
89   /*  6 */ {SEL1(0xaaaaaaaaaaaaaaabull) 0, 2},
90   /*  7 */ {SEL1(0x2492492492492493ull) 1, 3},
91   /*  8 */ {SEL1(0ull) 1, 3},
92   /*  9 */ {SEL1(0xe38e38e38e38e38full) 0, 3},
93   /* 10 */ {SEL1(0xcccccccccccccccdull) 0, 3},
94   /* 11 */ {SEL1(0x2e8ba2e8ba2e8ba3ull) 0, 1},
95   /* 12 */ {SEL1(0xaaaaaaaaaaaaaaabull) 0, 3},
96   /* 13 */ {SEL1(0x4ec4ec4ec4ec4ec5ull) 0, 2},
97   /* 14 */ {SEL1(0x2492492492492493ull) 1, 4},
98   /* 15 */ {SEL1(0x8888888888888889ull) 0, 3},
99   /* 16 */ {SEL1(0ull) 1, 4},
100   /* 17 */ {SEL1(0xf0f0f0f0f0f0f0f1ull) 0, 4},
101   /* 18 */ {SEL1(0xe38e38e38e38e38full) 0, 4},
102   /* 19 */ {SEL1(0xd79435e50d79435full) 0, 4},
103   /* 20 */ {SEL1(0xcccccccccccccccdull) 0, 4},
104   /* 21 */ {SEL1(0x8618618618618619ull) 1, 5},
105   /* 22 */ {SEL1(0x2e8ba2e8ba2e8ba3ull) 0, 2},
106   /* 23 */ {SEL1(0x642c8590b21642c9ull) 1, 5},
107   /* 24 */ {SEL1(0xaaaaaaaaaaaaaaabull) 0, 4},
108   /* 25 */ {SEL1(0x47ae147ae147ae15ull) 1, 5},
109   /* 26 */ {SEL1(0x4ec4ec4ec4ec4ec5ull) 0, 3},
110   /* 27 */ {SEL1(0x97b425ed097b425full) 0, 4},
111   /* 28 */ {SEL1(0x2492492492492493ull) 1, 5},
112   /* 29 */ {SEL1(0x1a7b9611a7b9611bull) 1, 5},
113   /* 30 */ {SEL1(0x8888888888888889ull) 0, 4},
114   /* 31 */ {SEL1(0x0842108421084211ull) 1, 5},
115   /* 32 */ {SEL1(0ull) 1, 5},
116   /* 33 */ {SEL1(0x0f83e0f83e0f83e1ull) 0, 1},
117   /* 34 */ {SEL1(0xf0f0f0f0f0f0f0f1ull) 0, 5},
118   /* 35 */ {SEL1(0xea0ea0ea0ea0ea0full) 0, 5},
119   /* 36 */ {SEL1(0xe38e38e38e38e38full) 0, 5}
120 #endif
121 #if BITS_PER_MP_LIMB == 32
122   /*  2 */ {SEL1(0ul) 1, 1, {0, 31, 0x80000000ul SEL2(0xfffffffful)}},
123   /*  3 */ {SEL1(0xaaaaaaabul) 0, 1, {0, 20, 0xcfd41b91ul SEL2(0x3b563c24ul)}},
124   /*  4 */ {SEL1(0ul) 1, 2, {1, 15, 0x40000000ul SEL2(0xfffffffful)}},
125   /*  5 */ {SEL1(0xcccccccdul) 0, 2, {1, 13, 0x48c27395ul SEL2(0xc25c2684ul)}},
126   /*  6 */ {SEL1(0xaaaaaaabul) 0, 2, {0, 12, 0x81bf1000ul SEL2(0xf91bd1b6ul)}},
127   /*  7 */ {SEL1(0x24924925ul) 1, 3, {1, 11, 0x75db9c97ul SEL2(0x1607a2cbul)}},
128   /*  8 */ {SEL1(0ul) 1, 3, {1, 10, 0x40000000ul SEL2(0xfffffffful)}},
129   /*  9 */ {SEL1(0x38e38e39ul) 0, 1, {0, 10, 0xcfd41b91ul SEL2(0x3b563c24ul)}},
130   /* 10 */ {SEL1(0xcccccccdul) 0, 3, {2, 9, 0x3b9aca00ul SEL2(0x12e0be82ul)}},
131   /* 11 */ {SEL1(0xba2e8ba3ul) 0, 3, {0, 9, 0x8c8b6d2bul SEL2(0xd24cde04ul)}},
132   /* 12 */ {SEL1(0xaaaaaaabul) 0, 3, {3, 8, 0x19a10000ul SEL2(0x3fa39ab5ul)}},
133   /* 13 */ {SEL1(0x4ec4ec4ful) 0, 2, {2, 8, 0x309f1021ul SEL2(0x50f8ac5ful)}},
134   /* 14 */ {SEL1(0x24924925ul) 1, 4, {1, 8, 0x57f6c100ul SEL2(0x74843b1eul)}},
135   /* 15 */ {SEL1(0x88888889ul) 0, 3, {0, 8, 0x98c29b81ul SEL2(0xad0326c2ul)}},
136   /* 16 */ {SEL1(0ul) 1, 4, {3, 7, 0x10000000ul SEL2(0xfffffffful)}},
137   /* 17 */ {SEL1(0xf0f0f0f1ul) 0, 4, {3, 7, 0x18754571ul SEL2(0x4ef0b6bdul)}},
138   /* 18 */ {SEL1(0x38e38e39ul) 0, 2, {2, 7, 0x247dbc80ul SEL2(0xc0fc48a1ul)}},
139   /* 19 */ {SEL1(0xaf286bcbul) 1, 5, {2, 7, 0x3547667bul SEL2(0x33838942ul)}},
140   /* 20 */ {SEL1(0xcccccccdul) 0, 4, {1, 7, 0x4c4b4000ul SEL2(0xad7f29abul)}},
141   /* 21 */ {SEL1(0x86186187ul) 1, 5, {1, 7, 0x6b5a6e1dul SEL2(0x313c3d15ul)}},
142   /* 22 */ {SEL1(0xba2e8ba3ul) 0, 4, {0, 7, 0x94ace180ul SEL2(0xb8cca9e0ul)}},
143   /* 23 */ {SEL1(0xb21642c9ul) 0, 4, {0, 7, 0xcaf18367ul SEL2(0x42ed6de9ul)}},
144   /* 24 */ {SEL1(0xaaaaaaabul) 0, 4, {4, 6, 0x0b640000ul SEL2(0x67980e0bul)}},
145   /* 25 */ {SEL1(0x51eb851ful) 0, 3, {4, 6, 0x0e8d4a51ul SEL2(0x19799812ul)}},
146   /* 26 */ {SEL1(0x4ec4ec4ful) 0, 3, {3, 6, 0x1269ae40ul SEL2(0xbce85396ul)}},
147   /* 27 */ {SEL1(0x2f684bdbul) 1, 5, {3, 6, 0x17179149ul SEL2(0x62c103a9ul)}},
148   /* 28 */ {SEL1(0x24924925ul) 1, 5, {3, 6, 0x1cb91000ul SEL2(0x1d353d43ul)}},
149   /* 29 */ {SEL1(0x8d3dcb09ul) 0, 4, {2, 6, 0x23744899ul SEL2(0xce1deceaul)}},
150   /* 30 */ {SEL1(0x88888889ul) 0, 4, {2, 6, 0x2b73a840ul SEL2(0x790fc511ul)}},
151   /* 31 */ {SEL1(0x08421085ul) 1, 5, {2, 6, 0x34e63b41ul SEL2(0x35b865a0ul)}},
152   /* 32 */ {SEL1(0ul) 1, 5, {1, 6, 0x40000000ul SEL2(0xfffffffful)}},
153   /* 33 */ {SEL1(0x3e0f83e1ul) 0, 3, {1, 6, 0x4cfa3cc1ul SEL2(0xa9aed1b3ul)}},
154   /* 34 */ {SEL1(0xf0f0f0f1ul) 0, 5, {1, 6, 0x5c13d840ul SEL2(0x63dfc229ul)}},
155   /* 35 */ {SEL1(0xd41d41d5ul) 1, 6, {1, 6, 0x6d91b519ul SEL2(0x2b0fee30ul)}},
156   /* 36 */ {SEL1(0x38e38e39ul) 0, 3, {0, 6, 0x81bf1000ul SEL2(0xf91bd1b6ul)}}
157 #endif
158 };
159 
160 /* Lower-case digits.  */
161 extern const char _itoa_lower_digits[];
162 extern const char _itoa_lower_digits_internal[] attribute_hidden;
163 /* Upper-case digits.  */
164 extern const char _itoa_upper_digits[];
165 extern const char _itoa_upper_digits_internal[] attribute_hidden;
166 
167 
168 char *
169 _itoa (value, buflim, base, upper_case)
170      unsigned long long int value;
171      char *buflim;
172      unsigned int base;
173      int upper_case;
174 {
175   const char *digits = (upper_case
176 			? INTUSE(_itoa_upper_digits)
177 			: INTUSE(_itoa_lower_digits));
178   const struct base_table_t *brec = &_itoa_base_table[base - 2];
179 
180   switch (base)
181     {
182 #define RUN_2N(BITS) \
183       do								      \
184         {								      \
185 	  /* `unsigned long long int' always has 64 bits.  */		      \
186 	  mp_limb_t work_hi = value >> (64 - BITS_PER_MP_LIMB);		      \
187 									      \
188 	  if (BITS_PER_MP_LIMB == 32)					      \
189 	    {								      \
190 	      if (work_hi != 0)						      \
191 		{							      \
192 		  mp_limb_t work_lo;					      \
193 		  int cnt;						      \
194 									      \
195 		  work_lo = value & 0xfffffffful;			      \
196 		  for (cnt = BITS_PER_MP_LIMB / BITS; cnt > 0; --cnt)	      \
197 		    {							      \
198 		      *--buflim = digits[work_lo & ((1ul << BITS) - 1)];      \
199 		      work_lo >>= BITS;					      \
200 		    }							      \
201 		  if (BITS_PER_MP_LIMB % BITS != 0)			      \
202 		    {							      \
203 		      work_lo						      \
204 			|= ((work_hi					      \
205 			     & ((1 << (BITS - BITS_PER_MP_LIMB%BITS))	      \
206 				- 1))					      \
207 			    << BITS_PER_MP_LIMB % BITS);		      \
208 		      work_hi >>= BITS - BITS_PER_MP_LIMB % BITS;	      \
209 		      if (work_hi == 0)					      \
210 			work_hi = work_lo;				      \
211 		      else						      \
212 			*--buflim = digits[work_lo];			      \
213 		    }							      \
214 		}							      \
215 	      else							      \
216 		work_hi = value & 0xfffffffful;				      \
217 	    }								      \
218 	  do								      \
219 	    {								      \
220 	      *--buflim = digits[work_hi & ((1 << BITS) - 1)];		      \
221 	      work_hi >>= BITS;						      \
222 	    }								      \
223 	  while (work_hi != 0);						      \
224 	}								      \
225       while (0)
226     case 8:
227       RUN_2N (3);
228       break;
229 
230     case 16:
231       RUN_2N (4);
232       break;
233 
234     default:
235       {
236 	char *bufend = buflim;
237 #if BITS_PER_MP_LIMB == 64
238 	mp_limb_t base_multiplier = brec->base_multiplier;
239 	if (brec->flag)
240 	  while (value != 0)
241 	    {
242 	      mp_limb_t quo, rem, x, dummy;
243 
244 	      umul_ppmm (x, dummy, value, base_multiplier);
245 	      quo = (x + ((value - x) >> 1)) >> (brec->post_shift - 1);
246 	      rem = value - quo * base;
247 	      *--buflim = digits[rem];
248 	      value = quo;
249 	    }
250 	else
251 	  while (value != 0)
252 	    {
253 	      mp_limb_t quo, rem, x, dummy;
254 
255 	      umul_ppmm (x, dummy, value, base_multiplier);
256 	      quo = x >> brec->post_shift;
257 	      rem = value - quo * base;
258 	      *--buflim = digits[rem];
259 	      value = quo;
260 	    }
261 #endif
262 #if BITS_PER_MP_LIMB == 32
263 	mp_limb_t t[3];
264 	int n;
265 
266 	/* First convert x0 to 1-3 words in base s->big.base.
267 	   Optimize for frequent cases of 32 bit numbers.  */
268 	if ((mp_limb_t) (value >> 32) >= 1)
269 	  {
270 #if UDIV_TIME > 2 * UMUL_TIME || UDIV_NEEDS_NORMALIZATION
271 	    int big_normalization_steps = brec->big.normalization_steps;
272 	    mp_limb_t big_base_norm
273 	      = brec->big.base << big_normalization_steps;
274 #endif
275 	    if ((mp_limb_t) (value >> 32) >= brec->big.base)
276 	      {
277 		mp_limb_t x1hi, x1lo, r;
278 		/* If you want to optimize this, take advantage of
279 		   that the quotient in the first udiv_qrnnd will
280 		   always be very small.  It might be faster just to
281 		   subtract in a tight loop.  */
282 
283 #if UDIV_TIME > 2 * UMUL_TIME
284 		mp_limb_t x, xh, xl;
285 
286 		if (big_normalization_steps == 0)
287 		  xh = 0;
288 		else
289 		  xh = (mp_limb_t) (value >> (64 - big_normalization_steps));
290 		xl = (mp_limb_t) (value >> (32 - big_normalization_steps));
291 		udiv_qrnnd_preinv (x1hi, r, xh, xl, big_base_norm,
292 				   brec->big.base_ninv);
293 
294 		xl = ((mp_limb_t) value) << big_normalization_steps;
295 		udiv_qrnnd_preinv (x1lo, x, r, xl, big_base_norm,
296 				   brec->big.base_ninv);
297 		t[2] = x >> big_normalization_steps;
298 
299 		if (big_normalization_steps == 0)
300 		  xh = x1hi;
301 		else
302 		  xh = ((x1hi << big_normalization_steps)
303 			| (x1lo >> (32 - big_normalization_steps)));
304 		xl = x1lo << big_normalization_steps;
305 		udiv_qrnnd_preinv (t[0], x, xh, xl, big_base_norm,
306 				   brec->big.base_ninv);
307 		t[1] = x >> big_normalization_steps;
308 #elif UDIV_NEEDS_NORMALIZATION
309 		mp_limb_t x, xh, xl;
310 
311 		if (big_normalization_steps == 0)
312 		  xh = 0;
313 		else
314 		  xh = (mp_limb_t) (value >> 64 - big_normalization_steps);
315 		xl = (mp_limb_t) (value >> 32 - big_normalization_steps);
316 		udiv_qrnnd (x1hi, r, xh, xl, big_base_norm);
317 
318 		xl = ((mp_limb_t) value) << big_normalization_steps;
319 		udiv_qrnnd (x1lo, x, r, xl, big_base_norm);
320 		t[2] = x >> big_normalization_steps;
321 
322 		if (big_normalization_steps == 0)
323 		  xh = x1hi;
324 		else
325 		  xh = ((x1hi << big_normalization_steps)
326 			| (x1lo >> 32 - big_normalization_steps));
327 		xl = x1lo << big_normalization_steps;
328 		udiv_qrnnd (t[0], x, xh, xl, big_base_norm);
329 		t[1] = x >> big_normalization_steps;
330 #else
331 		udiv_qrnnd (x1hi, r, 0, (mp_limb_t) (value >> 32),
332 			    brec->big.base);
333 		udiv_qrnnd (x1lo, t[2], r, (mp_limb_t) value, brec->big.base);
334 		udiv_qrnnd (t[0], t[1], x1hi, x1lo, brec->big.base);
335 #endif
336 		n = 3;
337 	      }
338 	    else
339 	      {
340 #if (UDIV_TIME > 2 * UMUL_TIME)
341 		mp_limb_t x;
342 
343 		value <<= brec->big.normalization_steps;
344 		udiv_qrnnd_preinv (t[0], x, (mp_limb_t) (value >> 32),
345 				   (mp_limb_t) value, big_base_norm,
346 				   brec->big.base_ninv);
347 		t[1] = x >> brec->big.normalization_steps;
348 #elif UDIV_NEEDS_NORMALIZATION
349 		mp_limb_t x;
350 
351 		value <<= big_normalization_steps;
352 		udiv_qrnnd (t[0], x, (mp_limb_t) (value >> 32),
353 			    (mp_limb_t) value, big_base_norm);
354 		t[1] = x >> big_normalization_steps;
355 #else
356 		udiv_qrnnd (t[0], t[1], (mp_limb_t) (value >> 32),
357 			    (mp_limb_t) value, brec->big.base);
358 #endif
359 		n = 2;
360 	      }
361 	  }
362 	else
363 	  {
364 	    t[0] = value;
365 	    n = 1;
366 	  }
367 
368 	/* Convert the 1-3 words in t[], word by word, to ASCII.  */
369 	do
370 	  {
371 	    mp_limb_t ti = t[--n];
372 	    int ndig_for_this_limb = 0;
373 
374 #if UDIV_TIME > 2 * UMUL_TIME
375 	    mp_limb_t base_multiplier = brec->base_multiplier;
376 	    if (brec->flag)
377 	      while (ti != 0)
378 		{
379 		  mp_limb_t quo, rem, x, dummy;
380 
381 		  umul_ppmm (x, dummy, ti, base_multiplier);
382 		  quo = (x + ((ti - x) >> 1)) >> (brec->post_shift - 1);
383 		  rem = ti - quo * base;
384 		  *--buflim = digits[rem];
385 		  ti = quo;
386 		  ++ndig_for_this_limb;
387 		}
388 	    else
389 	      while (ti != 0)
390 		{
391 		  mp_limb_t quo, rem, x, dummy;
392 
393 		  umul_ppmm (x, dummy, ti, base_multiplier);
394 		  quo = x >> brec->post_shift;
395 		  rem = ti - quo * base;
396 		  *--buflim = digits[rem];
397 		  ti = quo;
398 		  ++ndig_for_this_limb;
399 		}
400 #else
401 	    while (ti != 0)
402 	      {
403 		mp_limb_t quo, rem;
404 
405 		quo = ti / base;
406 		rem = ti % base;
407 		*--buflim = digits[rem];
408 		ti = quo;
409 		++ndig_for_this_limb;
410 	      }
411 #endif
412 	    /* If this wasn't the most significant word, pad with zeros.  */
413 	    if (n != 0)
414 	      while (ndig_for_this_limb < brec->big.ndigits)
415 		{
416 		  *--buflim = '0';
417 		  ++ndig_for_this_limb;
418 		}
419 	  }
420 	while (n != 0);
421 #endif
422 	if (buflim == bufend)
423 	  *--buflim = '0';
424       }
425       break;
426     }
427 
428   return buflim;
429 }
430