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author | akr <akr@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2013-06-10 03:12:44 +0000 |
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committer | akr <akr@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2013-06-10 03:12:44 +0000 |
commit | 8c239f35de2a30ef3585c5a7cb9aaba7271a70cc (patch) | |
tree | e5f1ec6cb531ffcd7b9f7c90abc0b73ba675570f /bignum.c | |
parent | 192085bad3471ed7442a147f86a3c85c1958307c (diff) | |
download | ruby-8c239f35de2a30ef3585c5a7cb9aaba7271a70cc.tar.gz |
* 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.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41202 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Diffstat (limited to 'bignum.c')
-rw-r--r-- | bignum.c | 113 |
1 files changed, 89 insertions, 24 deletions
@@ -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); |