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* bignum.c (integer_unpack_num_bdigits_small: Extracted from

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rb_integer_unpack.
  (integer_unpack_num_bdigits_generic): Ditto.
  (integer_unpack_num_bdigits_bytes): New function.
  (rb_integer_unpack): Use above functions.
  Return a Bignum for INTEGER_PACK_FORCE_BIGNUM evenwhen the result
  is zero.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41202 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
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akr 2013-06-10 03:12:44 +00:00
parent 192085bad3
commit 8c239f35de
2 changed files with 99 additions and 24 deletions
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10
ChangeLog
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@ -1,3 +1,13 @@
Mon Jun 10 12:10:06 2013 Tanaka Akira <akr@fsij.org>
* bignum.c (integer_unpack_num_bdigits_small: Extracted from
rb_integer_unpack.
(integer_unpack_num_bdigits_generic): Ditto.
(integer_unpack_num_bdigits_bytes): New function.
(rb_integer_unpack): Use above functions.
Return a Bignum for INTEGER_PACK_FORCE_BIGNUM evenwhen the result
is zero.
Mon Jun 10 05:38:23 2013 Tanaka Akira <akr@fsij.org>
* bignum.c (absint_numwords_small): New function.

113
bignum.c
View file

@ -982,6 +982,59 @@ rb_integer_pack(VALUE val, int *signp, void *words, size_t numwords, size_t word
#undef TAKE_LOWBITS
}
static size_t
integer_unpack_num_bdigits_small(size_t numwords, size_t wordsize, size_t nails)
{
size_t num_bits;
num_bits = (wordsize * CHAR_BIT - nails) * numwords;
return (num_bits + SIZEOF_BDIGITS*CHAR_BIT - 1) / (SIZEOF_BDIGITS*CHAR_BIT);
}
static size_t
integer_unpack_num_bdigits_bytes(size_t numwords, size_t wordsize)
{
/*
* num_bits = wordsize * CHAR_BIT * numwords
*
* num_bdigits = (num_bits + SIZEOF_BDIGITS*CHAR_BIT - 1) / (SIZEOF_BDIGITS*CHAR_BIT)
* = (wordsize * CHAR_BIT * numwords + SIZEOF_BDIGITS*CHAR_BIT - 1) / (SIZEOF_BDIGITS*CHAR_BIT)
* = ((wordsize * numwords + SIZEOF_BDIGITS)*CHAR_BIT - 1) / (SIZEOF_BDIGITS*CHAR_BIT)
*
* q, r = (wordsize * numwords).divmod(SIZEOF_BDIGITS)
* q * SIZEOF_BDIGITS + r = wordsize * numwords
*
* num_bdigits = ((q * SIZEOF_BDIGITS + r + SIZEOF_BDIGITS)*CHAR_BIT - 1) / (SIZEOF_BDIGITS*CHAR_BIT)
* = (q * SIZEOF_BDIGITS * CHAR_BIT + r * CHAR_BIT + SIZEOF_BDIGITS * CHAR_BIT - 1) / (SIZEOF_BDIGITS*CHAR_BIT)
* = q + (r * CHAR_BIT + SIZEOF_BDIGITS * CHAR_BIT - 1) / (SIZEOF_BDIGITS*CHAR_BIT)
*/
size_t t, q, r;
t = wordsize * numwords;
q = t / SIZEOF_BDIGITS;
r = t % SIZEOF_BDIGITS;
return q + (r * CHAR_BIT + SIZEOF_BDIGITS * CHAR_BIT - 1) / (SIZEOF_BDIGITS*CHAR_BIT);
}
static size_t
integer_unpack_num_bdigits_generic(size_t numwords, size_t wordsize, size_t nails)
{
VALUE num_bits_v, num_bdigits_v;
/* num_bits = (wordsize * CHAR_BIT - nails) * numwords */
num_bits_v = SIZET2NUM(wordsize);
num_bits_v = rb_funcall(num_bits_v, '*', 1, LONG2FIX(CHAR_BIT));
num_bits_v = rb_funcall(num_bits_v, '-', 1, SIZET2NUM(nails));
num_bits_v = rb_funcall(num_bits_v, '*', 1, SIZET2NUM(numwords));
if (num_bits_v == LONG2FIX(0))
return 0;
/* num_bdigits = (num_bits + SIZEOF_BDIGITS*CHAR_BIT - 1) / (SIZEOF_BDIGITS*CHAR_BIT) */
num_bdigits_v = rb_funcall(num_bits_v, '+', 1, LONG2FIX(SIZEOF_BDIGITS*CHAR_BIT-1));
num_bdigits_v = rb_funcall(num_bdigits_v, '/', 1, LONG2FIX(SIZEOF_BDIGITS*CHAR_BIT));
return NUM2SIZET(num_bdigits_v);
}
static inline void
integer_unpack_push_bits(int data, int numbits, BDIGIT_DBL *ddp, int *numbits_in_dd_p, BDIGIT **dpp)
{
@ -1012,6 +1065,7 @@ rb_integer_unpack(int sign, const void *words, size_t numwords, size_t wordsize,
{
VALUE result;
const unsigned char *buf = words;
size_t num_bdigits;
BDIGIT *dp;
BDIGIT *de;
@ -1035,33 +1089,44 @@ rb_integer_unpack(int sign, const void *words, size_t numwords, size_t wordsize,
rb_raise(rb_eArgError, "unexpected sign: %d", sign);
if (numwords <= (SIZE_MAX - (SIZEOF_BDIGITS*CHAR_BIT-1)) / CHAR_BIT / wordsize) {
size_t num_bits, num_bdigits;
num_bits = (wordsize * CHAR_BIT - nails) * numwords;
if (num_bits == 0)
return LONG2FIX(0);
num_bdigits = (num_bits + SIZEOF_BDIGITS*CHAR_BIT - 1) / (SIZEOF_BDIGITS*CHAR_BIT);
if (LONG_MAX < num_bdigits)
rb_raise(rb_eArgError, "too big to unpack as an integer");
result = bignew((long)num_bdigits, 0 <= sign);
num_bdigits = integer_unpack_num_bdigits_small(numwords, wordsize, nails);
#if 0
{
static int first = 1;
if (first)
first = 0;
else {
size_t num_bdigits1 = integer_unpack_num_bdigits_generic(numwords, wordsize, nails);
assert(num_bdigits == num_bdigits1);
}
}
#endif
}
else if (nails == 0) {
num_bdigits = integer_unpack_num_bdigits_bytes(numwords, wordsize);
#if 0
{
static int first = 1;
if (first)
first = 0;
else {
size_t num_bdigits1 = integer_unpack_num_bdigits_generic(numwords, wordsize, nails);
assert(num_bdigits == num_bdigits1);
}
}
#endif
}
else {
VALUE num_bits, num_bdigits;
/* num_bits = (wordsize * CHAR_BIT - nails) * numwords */
num_bits = SIZET2NUM(wordsize);
num_bits = rb_funcall(num_bits, '*', 1, LONG2FIX(CHAR_BIT));
num_bits = rb_funcall(num_bits, '-', 1, SIZET2NUM(nails));
num_bits = rb_funcall(num_bits, '*', 1, SIZET2NUM(numwords));
if (num_bits == LONG2FIX(0))
return LONG2FIX(0);
/* num_bdigits = (num_bits + SIZEOF_BDIGITS*CHAR_BIT - 1) / (SIZEOF_BDIGITS*CHAR_BIT) */
num_bdigits = rb_funcall(num_bits, '+', 1, LONG2FIX(SIZEOF_BDIGITS*CHAR_BIT-1));
num_bdigits = rb_funcall(num_bdigits, '/', 1, LONG2FIX(SIZEOF_BDIGITS*CHAR_BIT));
result = bignew(NUM2LONG(num_bdigits), 0 <= sign);
num_bdigits = integer_unpack_num_bdigits_generic(numwords, wordsize, nails);
}
if (num_bdigits == 0) {
if (flags & INTEGER_PACK_FORCE_BIGNUM)
return rb_int2big(0);
return LONG2FIX(0);
}
if (LONG_MAX < num_bdigits)
rb_raise(rb_eArgError, "too big to unpack as an integer");
result = bignew((long)num_bdigits, 0 <= sign);
dp = BDIGITS(result);
de = dp + RBIGNUM_LEN(result);