зеркало из https://github.com/github/ruby.git
* bignum.c (rb_big2str0): faster Bugnum#to_s using Karatsuba
algorithm. a patch from Yusuke ENDOH <mame AT tsg.ne.jp> in [ruby-dev:31312], slightly modified by Kenta Murata <muraken AT gmail.com> in [ruby-dev:31339]. git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@12864 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
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@ -13,6 +13,13 @@ Thu Aug 2 23:42:57 2007 Nobuyoshi Nakada <nobu@ruby-lang.org>
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* re.c (rb_reg_compile): append regexp options to error message.
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[ruby-dev:31334]
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Thu Aug 2 22:05:32 2007 Yukihiro Matsumoto <matz@ruby-lang.org>
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* bignum.c (rb_big2str0): faster Bugnum#to_s using Karatsuba
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algorithm. a patch from Yusuke ENDOH <mame AT tsg.ne.jp>
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in [ruby-dev:31312], slightly modified by Kenta Murata
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<muraken AT gmail.com> in [ruby-dev:31339].
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Thu Aug 2 13:46:39 2007 Nobuyoshi Nakada <nobu@ruby-lang.org>
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* sprintf.c (rb_f_sprintf): should not check positional number as
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130
bignum.c
130
bignum.c
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@ -595,11 +595,98 @@ rb_str2inum(VALUE str, int base)
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}
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const char ruby_digitmap[] = "0123456789abcdefghijklmnopqrstuvwxyz";
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static inline int
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big2str_normal(VALUE x, long j, int base, int hbase, char *s, int trim)
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{
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long i = RBIGNUM(x)->len;
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BDIGIT *ds = BDIGITS(x);
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while (i && j > 1) {
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long k = i;
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BDIGIT_DBL num = 0;
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while (k--) {
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num = BIGUP(num) + ds[k];
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ds[k] = (BDIGIT)(num / hbase);
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num %= hbase;
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}
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if (trim && ds[i-1] == 0) i--;
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k = SIZEOF_BDIGITS;
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while (k--) {
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s[--j] = ruby_digitmap[num % base];
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num /= base;
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if (!trim && j < 1) break;
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if (trim && i == 0 && num == 0) break;
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}
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}
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return j;
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}
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#define KARATSUBA_DIGITS 128
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#define MAX_BIG2STR_TABLE_ENTRIES 64
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static VALUE big2str_table[37][MAX_BIG2STR_TABLE_ENTRIES];
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static VALUE bigsqr(VALUE x);
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static void bigdivmod(VALUE x, VALUE y, VALUE *divp, VALUE *modp);
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static inline int
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big2str_karatsuba(VALUE x, int n, int base, int hbase, char *s, int trim)
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{
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long i, j, k, bs_len, sign = RBIGNUM(x)->sign;
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volatile VALUE t = big2str_table[base][0], t2;
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VALUE *as, *bs, q, r;
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j = RBIGNUM(t)->len;
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for (i=0; j <= RBIGNUM(x)->len; i++) j *= 2;
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as = ALLOCA_N(VALUE, i);
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for (i=0,j=1; ; i++,j*=2) {
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as[i] = t;
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if(big2str_table[base][i + 1]) {
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t2 = big2str_table[base][i + 1];
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}
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else {
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t2 = bigsqr(t);
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if(i + 1 < MAX_BIG2STR_TABLE_ENTRIES) {
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big2str_table[base][i + 1] = t2;
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rb_global_variable(&big2str_table[base][i + 1]);
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}
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}
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if(RBIGNUM(x)->len < RBIGNUM(t2)->len) break;
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t = t2;
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}
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bs_len = j * 2;
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bs = ALLOCA_N(VALUE, bs_len);
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bs[0] = x;
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RBIGNUM(x)->sign = 1;
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for (; j>0; i--, j/=2) {
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for (k=0; k<bs_len; k+=j*2) {
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bigdivmod(bs[k], as[i], &q, &r);
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bs[k] = q;
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bs[k + j] = r;
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}
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}
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RBIGNUM(x)->sign = sign;
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j = 0;
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while(RBIGNUM(bs[j])->len == 1 && BDIGITS(bs[j])[0] == 0) j++;
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for (i=bs_len-1; i>j; i--) {
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k = big2str_normal(
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bs[i], KARATSUBA_DIGITS, base, hbase,
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s + n - KARATSUBA_DIGITS, Qfalse);
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n -= KARATSUBA_DIGITS - k;
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}
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n = big2str_normal(bs[j], n, base, hbase, s, trim);
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return n;
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}
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VALUE
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rb_big2str0(VALUE x, int base, int trim)
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{
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volatile VALUE t;
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BDIGIT *ds;
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long i, j, hbase;
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VALUE ss;
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char *s;
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@ -646,28 +733,15 @@ rb_big2str0(VALUE x, int base, int trim)
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#endif
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t = rb_big_clone(x);
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ds = BDIGITS(t);
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ss = rb_str_new(0, j+1);
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s = RSTRING_PTR(ss);
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s[0] = RBIGNUM(x)->sign ? '+' : '-';
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while (i && j > 1) {
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long k = i;
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BDIGIT_DBL num = 0;
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while (k--) {
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num = BIGUP(num) + ds[k];
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ds[k] = (BDIGIT)(num / hbase);
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num %= hbase;
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}
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if (trim && ds[i-1] == 0) i--;
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k = SIZEOF_BDIGITS;
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while (k--) {
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s[--j] = ruby_digitmap[num % base];
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num /= base;
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if (!trim && j < 1) break;
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if (trim && i == 0 && num == 0) break;
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}
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if (RBIGNUM(x)->len > RBIGNUM(big2str_table[base][0])->len * 4) {
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j = big2str_karatsuba(t, j, base, hbase, s, trim);
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}
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else {
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j = big2str_normal(t, j, base, hbase, s, trim);
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}
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if (trim) {while (s[j] == '0') j++;}
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i = RSTRING_LEN(ss) - j;
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@ -683,6 +757,22 @@ rb_big2str0(VALUE x, int base, int trim)
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return ss;
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}
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static void
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init_big2str_table(void)
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{
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int i, j;
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VALUE v;
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for (i=0; i<37; i++) {
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v = rb_big_pow(rb_int2big(i), INT2FIX(KARATSUBA_DIGITS));
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big2str_table[i][0] = v;
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rb_global_variable(&big2str_table[i][0]);
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for (j=1; j < MAX_BIG2STR_TABLE_ENTRIES; j++) {
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big2str_table[i][j] = Qfalse;
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}
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}
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}
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VALUE
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rb_big2str(VALUE x, int base)
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{
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@ -2225,4 +2315,6 @@ Init_Bignum(void)
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rb_define_method(rb_cBignum, "to_f", rb_big_to_f, 0);
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rb_define_method(rb_cBignum, "abs", rb_big_abs, 0);
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rb_define_method(rb_cBignum, "size", rb_big_size, 0);
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init_big2str_table();
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}
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