Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
Fetching contributors…

Cannot retrieve contributors at this time

3810 lines (3359 sloc) 79.397 kb
/**********************************************************************
bignum.c -
$Author$
created at: Fri Jun 10 00:48:55 JST 1994
Copyright (C) 1993-2007 Yukihiro Matsumoto
**********************************************************************/
#include "ruby/ruby.h"
#include "ruby/util.h"
#include "internal.h"
#include <math.h>
#include <float.h>
#include <ctype.h>
#ifdef HAVE_IEEEFP_H
#include <ieeefp.h>
#endif
#include <assert.h>
VALUE rb_cBignum;
static VALUE big_three = Qnil;
#if defined __MINGW32__
#define USHORT _USHORT
#endif
#define BDIGITS(x) (RBIGNUM_DIGITS(x))
#define BITSPERDIG (SIZEOF_BDIGITS*CHAR_BIT)
#define BIGRAD ((BDIGIT_DBL)1 << BITSPERDIG)
#define BIGRAD_HALF ((BDIGIT)(BIGRAD >> 1))
#define DIGSPERLONG (SIZEOF_LONG/SIZEOF_BDIGITS)
#if HAVE_LONG_LONG
# define DIGSPERLL (SIZEOF_LONG_LONG/SIZEOF_BDIGITS)
#endif
#define BIGUP(x) ((BDIGIT_DBL)(x) << BITSPERDIG)
#define BIGDN(x) RSHIFT((x),BITSPERDIG)
#define BIGLO(x) ((BDIGIT)((x) & (BIGRAD-1)))
#define BDIGMAX ((BDIGIT)-1)
#define BIGZEROP(x) (RBIGNUM_LEN(x) == 0 || \
(BDIGITS(x)[0] == 0 && \
(RBIGNUM_LEN(x) == 1 || bigzero_p(x))))
#define BIGNUM_DEBUG 0
#if BIGNUM_DEBUG
#define ON_DEBUG(x) do { x; } while (0)
static void
dump_bignum(VALUE x)
{
long i;
printf("%c0x0", RBIGNUM_SIGN(x) ? '+' : '-');
for (i = RBIGNUM_LEN(x); i--; ) {
printf("_%08"PRIxBDIGIT, BDIGITS(x)[i]);
}
printf(", len=%lu", RBIGNUM_LEN(x));
puts("");
}
static VALUE
rb_big_dump(VALUE x)
{
dump_bignum(x);
return x;
}
#else
#define ON_DEBUG(x)
#endif
static int
bigzero_p(VALUE x)
{
long i;
BDIGIT *ds = BDIGITS(x);
for (i = RBIGNUM_LEN(x) - 1; 0 <= i; i--) {
if (ds[i]) return 0;
}
return 1;
}
int
rb_bigzero_p(VALUE x)
{
return BIGZEROP(x);
}
int
rb_cmpint(VALUE val, VALUE a, VALUE b)
{
if (NIL_P(val)) {
rb_cmperr(a, b);
}
if (FIXNUM_P(val)) {
long l = FIX2LONG(val);
if (l > 0) return 1;
if (l < 0) return -1;
return 0;
}
if (RB_TYPE_P(val, T_BIGNUM)) {
if (BIGZEROP(val)) return 0;
if (RBIGNUM_SIGN(val)) return 1;
return -1;
}
if (RTEST(rb_funcall(val, '>', 1, INT2FIX(0)))) return 1;
if (RTEST(rb_funcall(val, '<', 1, INT2FIX(0)))) return -1;
return 0;
}
#define RBIGNUM_SET_LEN(b,l) \
((RBASIC(b)->flags & RBIGNUM_EMBED_FLAG) ? \
(void)(RBASIC(b)->flags = \
(RBASIC(b)->flags & ~RBIGNUM_EMBED_LEN_MASK) | \
((l) << RBIGNUM_EMBED_LEN_SHIFT)) : \
(void)(RBIGNUM(b)->as.heap.len = (l)))
static void
rb_big_realloc(VALUE big, long len)
{
BDIGIT *ds;
if (RBASIC(big)->flags & RBIGNUM_EMBED_FLAG) {
if (RBIGNUM_EMBED_LEN_MAX < len) {
ds = ALLOC_N(BDIGIT, len);
MEMCPY(ds, RBIGNUM(big)->as.ary, BDIGIT, RBIGNUM_EMBED_LEN_MAX);
RBIGNUM(big)->as.heap.len = RBIGNUM_LEN(big);
RBIGNUM(big)->as.heap.digits = ds;
RBASIC(big)->flags &= ~RBIGNUM_EMBED_FLAG;
}
}
else {
if (len <= RBIGNUM_EMBED_LEN_MAX) {
ds = RBIGNUM(big)->as.heap.digits;
RBASIC(big)->flags |= RBIGNUM_EMBED_FLAG;
RBIGNUM_SET_LEN(big, len);
if (ds) {
MEMCPY(RBIGNUM(big)->as.ary, ds, BDIGIT, len);
xfree(ds);
}
}
else {
if (RBIGNUM_LEN(big) == 0) {
RBIGNUM(big)->as.heap.digits = ALLOC_N(BDIGIT, len);
}
else {
REALLOC_N(RBIGNUM(big)->as.heap.digits, BDIGIT, len);
}
}
}
}
void
rb_big_resize(VALUE big, long len)
{
rb_big_realloc(big, len);
RBIGNUM_SET_LEN(big, len);
}
static VALUE
bignew_1(VALUE klass, long len, int sign)
{
NEWOBJ(big, struct RBignum);
OBJSETUP(big, klass, T_BIGNUM);
RBIGNUM_SET_SIGN(big, sign?1:0);
if (len <= RBIGNUM_EMBED_LEN_MAX) {
RBASIC(big)->flags |= RBIGNUM_EMBED_FLAG;
RBIGNUM_SET_LEN(big, len);
}
else {
RBIGNUM(big)->as.heap.digits = ALLOC_N(BDIGIT, len);
RBIGNUM(big)->as.heap.len = len;
}
return (VALUE)big;
}
#define bignew(len,sign) bignew_1(rb_cBignum,(len),(sign))
VALUE
rb_big_new(long len, int sign)
{
return bignew(len, sign != 0);
}
VALUE
rb_big_clone(VALUE x)
{
long len = RBIGNUM_LEN(x);
VALUE z = bignew_1(CLASS_OF(x), len, RBIGNUM_SIGN(x));
MEMCPY(BDIGITS(z), BDIGITS(x), BDIGIT, len);
return z;
}
/* modify a bignum by 2's complement */
static void
get2comp(VALUE x)
{
long i = RBIGNUM_LEN(x);
BDIGIT *ds = BDIGITS(x);
BDIGIT_DBL num;
if (!i) return;
while (i--) ds[i] = ~ds[i];
i = 0; num = 1;
do {
num += ds[i];
ds[i++] = BIGLO(num);
num = BIGDN(num);
} while (i < RBIGNUM_LEN(x));
if (num != 0) {
rb_big_resize(x, RBIGNUM_LEN(x)+1);
ds = BDIGITS(x);
ds[RBIGNUM_LEN(x)-1] = 1;
}
}
void
rb_big_2comp(VALUE x) /* get 2's complement */
{
get2comp(x);
}
static inline VALUE
bigtrunc(VALUE x)
{
long len = RBIGNUM_LEN(x);
BDIGIT *ds = BDIGITS(x);
if (len == 0) return x;
while (--len && !ds[len]);
if (RBIGNUM_LEN(x) > len+1) {
rb_big_resize(x, len+1);
}
return x;
}
static inline VALUE
bigfixize(VALUE x)
{
long len = RBIGNUM_LEN(x);
BDIGIT *ds = BDIGITS(x);
if (len == 0) return INT2FIX(0);
if ((size_t)(len*SIZEOF_BDIGITS) <= sizeof(long)) {
long num = 0;
#if 2*SIZEOF_BDIGITS > SIZEOF_LONG
num = (long)ds[0];
#else
while (len--) {
num = (long)(BIGUP(num) + ds[len]);
}
#endif
if (num >= 0) {
if (RBIGNUM_SIGN(x)) {
if (POSFIXABLE(num)) return LONG2FIX(num);
}
else {
if (NEGFIXABLE(-num)) return LONG2FIX(-num);
}
}
}
return x;
}
static VALUE
bignorm(VALUE x)
{
if (RB_TYPE_P(x, T_BIGNUM)) {
x = bigfixize(bigtrunc(x));
}
return x;
}
VALUE
rb_big_norm(VALUE x)
{
return bignorm(x);
}
VALUE
rb_uint2big(VALUE n)
{
BDIGIT_DBL num = n;
long i = 0;
BDIGIT *digits;
VALUE big;
big = bignew(DIGSPERLONG, 1);
digits = BDIGITS(big);
while (i < DIGSPERLONG) {
digits[i++] = BIGLO(num);
num = BIGDN(num);
}
i = DIGSPERLONG;
while (--i && !digits[i]) ;
RBIGNUM_SET_LEN(big, i+1);
return big;
}
VALUE
rb_int2big(SIGNED_VALUE n)
{
long neg = 0;
VALUE big;
if (n < 0) {
n = -n;
neg = 1;
}
big = rb_uint2big(n);
if (neg) {
RBIGNUM_SET_SIGN(big, 0);
}
return big;
}
VALUE
rb_uint2inum(VALUE n)
{
if (POSFIXABLE(n)) return LONG2FIX(n);
return rb_uint2big(n);
}
VALUE
rb_int2inum(SIGNED_VALUE n)
{
if (FIXABLE(n)) return LONG2FIX(n);
return rb_int2big(n);
}
#if SIZEOF_LONG % SIZEOF_BDIGITS != 0
# error unexpected SIZEOF_LONG : SIZEOF_BDIGITS ratio
#endif
/*
* buf is an array of long integers.
* buf is ordered from least significant word to most significant word.
* buf[0] is the least significant word and
* buf[num_longs-1] is the most significant word.
* This means words in buf is little endian.
* However each word in buf is native endian.
* (buf[i]&1) is the least significant bit and
* (buf[i]&(1<<(SIZEOF_LONG*CHAR_BIT-1))) is the most significant bit
* for each 0 <= i < num_longs.
* So buf is little endian at whole on a little endian machine.
* But buf is mixed endian on a big endian machine.
*
* The buf represents negative integers as two's complement.
* So, the most significant bit of the most significant word,
* (buf[num_longs-1]>>(SIZEOF_LONG*CHAR_BIT-1)),
* is the sign bit: 1 means negative and 0 means zero or positive.
*
* If given size of buf (num_longs) is not enough to represent val,
* higier words (including a sign bit) are ignored.
*/
void
rb_big_pack(VALUE val, unsigned long *buf, long num_longs)
{
val = rb_to_int(val);
if (num_longs == 0)
return;
if (FIXNUM_P(val)) {
long i;
long tmp = FIX2LONG(val);
buf[0] = (unsigned long)tmp;
tmp = tmp < 0 ? ~0L : 0;
for (i = 1; i < num_longs; i++)
buf[i] = (unsigned long)tmp;
return;
}
else {
long len = RBIGNUM_LEN(val);
BDIGIT *ds = BDIGITS(val), *dend = ds + len;
long i, j;
for (i = 0; i < num_longs && ds < dend; i++) {
unsigned long l = 0;
for (j = 0; j < DIGSPERLONG && ds < dend; j++, ds++) {
l |= ((unsigned long)*ds << (j * BITSPERDIG));
}
buf[i] = l;
}
for (; i < num_longs; i++)
buf[i] = 0;
if (RBIGNUM_NEGATIVE_P(val)) {
for (i = 0; i < num_longs; i++) {
buf[i] = ~buf[i];
}
for (i = 0; i < num_longs; i++) {
buf[i]++;
if (buf[i] != 0)
return;
}
}
}
}
/* See rb_big_pack comment for endianness and sign of buf. */
VALUE
rb_big_unpack(unsigned long *buf, long num_longs)
{
while (2 <= num_longs) {
if (buf[num_longs-1] == 0 && (long)buf[num_longs-2] >= 0)
num_longs--;
else if (buf[num_longs-1] == ~0UL && (long)buf[num_longs-2] < 0)
num_longs--;
else
break;
}
if (num_longs == 0)
return INT2FIX(0);
else if (num_longs == 1)
return LONG2NUM((long)buf[0]);
else {
VALUE big;
BDIGIT *ds;
long len = num_longs * DIGSPERLONG;
long i;
big = bignew(len, 1);
ds = BDIGITS(big);
for (i = 0; i < num_longs; i++) {
unsigned long d = buf[i];
#if SIZEOF_LONG == SIZEOF_BDIGITS
*ds++ = d;
#else
int j;
for (j = 0; j < DIGSPERLONG; j++) {
*ds++ = BIGLO(d);
d = BIGDN(d);
}
#endif
}
if ((long)buf[num_longs-1] < 0) {
get2comp(big);
RBIGNUM_SET_SIGN(big, 0);
}
return bignorm(big);
}
}
#define QUAD_SIZE 8
#if SIZEOF_LONG_LONG == QUAD_SIZE && SIZEOF_BDIGITS*2 == SIZEOF_LONG_LONG
void
rb_quad_pack(char *buf, VALUE val)
{
LONG_LONG q;
val = rb_to_int(val);
if (FIXNUM_P(val)) {
q = FIX2LONG(val);
}
else {
long len = RBIGNUM_LEN(val);
BDIGIT *ds;
if (len > SIZEOF_LONG_LONG/SIZEOF_BDIGITS) {
len = SIZEOF_LONG_LONG/SIZEOF_BDIGITS;
}
ds = BDIGITS(val);
q = 0;
while (len--) {
q = BIGUP(q);
q += ds[len];
}
if (!RBIGNUM_SIGN(val)) q = -q;
}
memcpy(buf, (char*)&q, SIZEOF_LONG_LONG);
}
VALUE
rb_quad_unpack(const char *buf, int sign)
{
unsigned LONG_LONG q;
long neg = 0;
long i;
BDIGIT *digits;
VALUE big;
memcpy(&q, buf, SIZEOF_LONG_LONG);
if (sign) {
if (FIXABLE((LONG_LONG)q)) return LONG2FIX((LONG_LONG)q);
if ((LONG_LONG)q < 0) {
q = -(LONG_LONG)q;
neg = 1;
}
}
else {
if (POSFIXABLE(q)) return LONG2FIX(q);
}
i = 0;
big = bignew(DIGSPERLL, 1);
digits = BDIGITS(big);
while (i < DIGSPERLL) {
digits[i++] = BIGLO(q);
q = BIGDN(q);
}
i = DIGSPERLL;
while (i-- && !digits[i]) ;
RBIGNUM_SET_LEN(big, i+1);
if (neg) {
RBIGNUM_SET_SIGN(big, 0);
}
return bignorm(big);
}
#else
static int
quad_buf_complement(char *buf, size_t len)
{
size_t i;
for (i = 0; i < len; i++)
buf[i] = ~buf[i];
for (i = 0; i < len; i++) {
buf[i]++;
if (buf[i] != 0)
return 0;
}
return 1;
}
void
rb_quad_pack(char *buf, VALUE val)
{
long len;
memset(buf, 0, QUAD_SIZE);
val = rb_to_int(val);
if (FIXNUM_P(val)) {
val = rb_int2big(FIX2LONG(val));
}
len = RBIGNUM_LEN(val) * SIZEOF_BDIGITS;
if (len > QUAD_SIZE) {
len = QUAD_SIZE;
}
memcpy(buf, (char*)BDIGITS(val), len);
if (RBIGNUM_NEGATIVE_P(val)) {
quad_buf_complement(buf, QUAD_SIZE);
}
}
#define BNEG(b) (RSHIFT(((BDIGIT*)(b))[QUAD_SIZE/SIZEOF_BDIGITS-1],BITSPERDIG-1) != 0)
VALUE
rb_quad_unpack(const char *buf, int sign)
{
VALUE big = bignew(QUAD_SIZE/SIZEOF_BDIGITS, 1);
memcpy((char*)BDIGITS(big), buf, QUAD_SIZE);
if (sign && BNEG(buf)) {
char *tmp = (char*)BDIGITS(big);
RBIGNUM_SET_SIGN(big, 0);
quad_buf_complement(tmp, QUAD_SIZE);
}
return bignorm(big);
}
#endif
VALUE
rb_cstr_to_inum(const char *str, int base, int badcheck)
{
const char *s = str;
char *end;
char sign = 1, nondigit = 0;
int c;
BDIGIT_DBL num;
long len, blen = 1;
long i;
VALUE z;
BDIGIT *zds;
#undef ISDIGIT
#define ISDIGIT(c) ('0' <= (c) && (c) <= '9')
#define conv_digit(c) \
(!ISASCII(c) ? -1 : \
ISDIGIT(c) ? ((c) - '0') : \
ISLOWER(c) ? ((c) - 'a' + 10) : \
ISUPPER(c) ? ((c) - 'A' + 10) : \
-1)
if (!str) {
if (badcheck) goto bad;
return INT2FIX(0);
}
while (ISSPACE(*str)) str++;
if (str[0] == '+') {
str++;
}
else if (str[0] == '-') {
str++;
sign = 0;
}
if (str[0] == '+' || str[0] == '-') {
if (badcheck) goto bad;
return INT2FIX(0);
}
if (base <= 0) {
if (str[0] == '0') {
switch (str[1]) {
case 'x': case 'X':
base = 16;
break;
case 'b': case 'B':
base = 2;
break;
case 'o': case 'O':
base = 8;
break;
case 'd': case 'D':
base = 10;
break;
default:
base = 8;
}
}
else if (base < -1) {
base = -base;
}
else {
base = 10;
}
}
switch (base) {
case 2:
len = 1;
if (str[0] == '0' && (str[1] == 'b'||str[1] == 'B')) {
str += 2;
}
break;
case 3:
len = 2;
break;
case 8:
if (str[0] == '0' && (str[1] == 'o'||str[1] == 'O')) {
str += 2;
}
case 4: case 5: case 6: case 7:
len = 3;
break;
case 10:
if (str[0] == '0' && (str[1] == 'd'||str[1] == 'D')) {
str += 2;
}
case 9: case 11: case 12: case 13: case 14: case 15:
len = 4;
break;
case 16:
len = 4;
if (str[0] == '0' && (str[1] == 'x'||str[1] == 'X')) {
str += 2;
}
break;
default:
if (base < 2 || 36 < base) {
rb_raise(rb_eArgError, "invalid radix %d", base);
}
if (base <= 32) {
len = 5;
}
else {
len = 6;
}
break;
}
if (*str == '0') { /* squeeze preceding 0s */
int us = 0;
while ((c = *++str) == '0' || c == '_') {
if (c == '_') {
if (++us >= 2)
break;
} else
us = 0;
}
if (!(c = *str) || ISSPACE(c)) --str;
}
c = *str;
c = conv_digit(c);
if (c < 0 || c >= base) {
if (badcheck) goto bad;
return INT2FIX(0);
}
len *= strlen(str)*sizeof(char);
if ((size_t)len <= (sizeof(long)*CHAR_BIT)) {
unsigned long val = STRTOUL(str, &end, base);
if (str < end && *end == '_') goto bigparse;
if (badcheck) {
if (end == str) goto bad; /* no number */
while (*end && ISSPACE(*end)) end++;
if (*end) goto bad; /* trailing garbage */
}
if (POSFIXABLE(val)) {
if (sign) return LONG2FIX(val);
else {
long result = -(long)val;
return LONG2FIX(result);
}
}
else {
VALUE big = rb_uint2big(val);
RBIGNUM_SET_SIGN(big, sign);
return bignorm(big);
}
}
bigparse:
len = (len/BITSPERDIG)+1;
if (badcheck && *str == '_') goto bad;
z = bignew(len, sign);
zds = BDIGITS(z);
for (i=len;i--;) zds[i]=0;
while ((c = *str++) != 0) {
if (c == '_') {
if (nondigit) {
if (badcheck) goto bad;
break;
}
nondigit = c;
continue;
}
else if ((c = conv_digit(c)) < 0) {
break;
}
if (c >= base) break;
nondigit = 0;
i = 0;
num = c;
for (;;) {
while (i<blen) {
num += (BDIGIT_DBL)zds[i]*base;
zds[i++] = BIGLO(num);
num = BIGDN(num);
}
if (num) {
blen++;
continue;
}
break;
}
}
if (badcheck) {
str--;
if (s+1 < str && str[-1] == '_') goto bad;
while (*str && ISSPACE(*str)) str++;
if (*str) {
bad:
rb_invalid_str(s, "Integer()");
}
}
return bignorm(z);
}
VALUE
rb_str_to_inum(VALUE str, int base, int badcheck)
{
char *s;
long len;
VALUE v = 0;
VALUE ret;
StringValue(str);
rb_must_asciicompat(str);
if (badcheck) {
s = StringValueCStr(str);
}
else {
s = RSTRING_PTR(str);
}
if (s) {
len = RSTRING_LEN(str);
if (s[len]) { /* no sentinel somehow */
char *p = ALLOCV(v, len+1);
MEMCPY(p, s, char, len);
p[len] = '\0';
s = p;
}
}
ret = rb_cstr_to_inum(s, base, badcheck);
if (v)
ALLOCV_END(v);
return ret;
}
#if HAVE_LONG_LONG
static VALUE
rb_ull2big(unsigned LONG_LONG n)
{
BDIGIT_DBL num = n;
long i = 0;
BDIGIT *digits;
VALUE big;
big = bignew(DIGSPERLL, 1);
digits = BDIGITS(big);
while (i < DIGSPERLL) {
digits[i++] = BIGLO(num);
num = BIGDN(num);
}
i = DIGSPERLL;
while (i-- && !digits[i]) ;
RBIGNUM_SET_LEN(big, i+1);
return big;
}
static VALUE
rb_ll2big(LONG_LONG n)
{
long neg = 0;
VALUE big;
if (n < 0) {
n = -n;
neg = 1;
}
big = rb_ull2big(n);
if (neg) {
RBIGNUM_SET_SIGN(big, 0);
}
return big;
}
VALUE
rb_ull2inum(unsigned LONG_LONG n)
{
if (POSFIXABLE(n)) return LONG2FIX(n);
return rb_ull2big(n);
}
VALUE
rb_ll2inum(LONG_LONG n)
{
if (FIXABLE(n)) return LONG2FIX(n);
return rb_ll2big(n);
}
#endif /* HAVE_LONG_LONG */
VALUE
rb_cstr2inum(const char *str, int base)
{
return rb_cstr_to_inum(str, base, base==0);
}
VALUE
rb_str2inum(VALUE str, int base)
{
return rb_str_to_inum(str, base, base==0);
}
const char ruby_digitmap[] = "0123456789abcdefghijklmnopqrstuvwxyz";
static VALUE bigsqr(VALUE x);
static void bigdivmod(VALUE x, VALUE y, volatile VALUE *divp, volatile VALUE *modp);
#define POW2_P(x) (((x)&((x)-1))==0)
static inline int
ones(register unsigned long x)
{
#if SIZEOF_LONG == 8
# define MASK_55 0x5555555555555555UL
# define MASK_33 0x3333333333333333UL
# define MASK_0f 0x0f0f0f0f0f0f0f0fUL
#else
# define MASK_55 0x55555555UL
# define MASK_33 0x33333333UL
# define MASK_0f 0x0f0f0f0fUL
#endif
x -= (x >> 1) & MASK_55;
x = ((x >> 2) & MASK_33) + (x & MASK_33);
x = ((x >> 4) + x) & MASK_0f;
x += (x >> 8);
x += (x >> 16);
#if SIZEOF_LONG == 8
x += (x >> 32);
#endif
return (int)(x & 0x7f);
#undef MASK_0f
#undef MASK_33
#undef MASK_55
}
static inline unsigned long
next_pow2(register unsigned long x)
{
x |= x >> 1;
x |= x >> 2;
x |= x >> 4;
x |= x >> 8;
x |= x >> 16;
#if SIZEOF_LONG == 8
x |= x >> 32;
#endif
return x + 1;
}
static inline int
floor_log2(register unsigned long x)
{
x |= x >> 1;
x |= x >> 2;
x |= x >> 4;
x |= x >> 8;
x |= x >> 16;
#if SIZEOF_LONG == 8
x |= x >> 32;
#endif
return (int)ones(x) - 1;
}
static inline int
ceil_log2(register unsigned long x)
{
return floor_log2(x) + !POW2_P(x);
}
#define LOG2_KARATSUBA_DIGITS 7
#define KARATSUBA_DIGITS (1L<<LOG2_KARATSUBA_DIGITS)
#define MAX_BIG2STR_TABLE_ENTRIES 64
static VALUE big2str_power_cache[35][MAX_BIG2STR_TABLE_ENTRIES];
static void
power_cache_init(void)
{
int i, j;
for (i = 0; i < 35; ++i) {
for (j = 0; j < MAX_BIG2STR_TABLE_ENTRIES; ++j) {
big2str_power_cache[i][j] = Qnil;
}
}
}
static inline VALUE
power_cache_get_power0(int base, int i)
{
if (NIL_P(big2str_power_cache[base - 2][i])) {
big2str_power_cache[base - 2][i] =
i == 0 ? rb_big_pow(rb_int2big(base), INT2FIX(KARATSUBA_DIGITS))
: bigsqr(power_cache_get_power0(base, i - 1));
rb_gc_register_mark_object(big2str_power_cache[base - 2][i]);
}
return big2str_power_cache[base - 2][i];
}
static VALUE
power_cache_get_power(int base, long n1, long* m1)
{
int i, m;
long j;
VALUE t;
if (n1 <= KARATSUBA_DIGITS)
rb_bug("n1 > KARATSUBA_DIGITS");
m = ceil_log2(n1);
if (m1) *m1 = 1 << m;
i = m - LOG2_KARATSUBA_DIGITS;
if (i >= MAX_BIG2STR_TABLE_ENTRIES)
i = MAX_BIG2STR_TABLE_ENTRIES - 1;
t = power_cache_get_power0(base, i);
j = KARATSUBA_DIGITS*(1 << i);
while (n1 > j) {
t = bigsqr(t);
j *= 2;
}
return t;
}
/* big2str_muraken_find_n1
*
* Let a natural number x is given by:
* x = 2^0 * x_0 + 2^1 * x_1 + ... + 2^(B*n_0 - 1) * x_{B*n_0 - 1},
* where B is BITSPERDIG (i.e. BDIGITS*CHAR_BIT) and n_0 is
* RBIGNUM_LEN(x).
*
* Now, we assume n_1 = min_n \{ n | 2^(B*n_0/2) <= b_1^(n_1) \}, so
* it is realized that 2^(B*n_0) <= {b_1}^{2*n_1}, where b_1 is a
* given radix number. And then, we have n_1 <= (B*n_0) /
* (2*log_2(b_1)), therefore n_1 is given by ceil((B*n_0) /
* (2*log_2(b_1))).
*/
static long
big2str_find_n1(VALUE x, int base)
{
static const double log_2[] = {
1.0, 1.58496250072116, 2.0,
2.32192809488736, 2.58496250072116, 2.8073549220576,
3.0, 3.16992500144231, 3.32192809488736,
3.4594316186373, 3.58496250072116, 3.70043971814109,
3.8073549220576, 3.90689059560852, 4.0,
4.08746284125034, 4.16992500144231, 4.24792751344359,
4.32192809488736, 4.39231742277876, 4.4594316186373,
4.52356195605701, 4.58496250072116, 4.64385618977472,
4.70043971814109, 4.75488750216347, 4.8073549220576,
4.85798099512757, 4.90689059560852, 4.95419631038688,
5.0, 5.04439411935845, 5.08746284125034,
5.12928301694497, 5.16992500144231
};
long bits;
if (base < 2 || 36 < base)
rb_bug("invalid radix %d", base);
if (FIXNUM_P(x)) {
bits = (SIZEOF_LONG*CHAR_BIT - 1)/2 + 1;
}
else if (BIGZEROP(x)) {
return 0;
}
else if (RBIGNUM_LEN(x) >= LONG_MAX/BITSPERDIG) {
rb_raise(rb_eRangeError, "bignum too big to convert into `string'");
}
else {
bits = BITSPERDIG*RBIGNUM_LEN(x);
}
return (long)ceil(bits/log_2[base - 2]);
}
static long
big2str_orig(VALUE x, int base, char* ptr, long len, long hbase, int trim)
{
long i = RBIGNUM_LEN(x), j = len;
BDIGIT* ds = BDIGITS(x);
while (i && j > 0) {
long k = i;
BDIGIT_DBL num = 0;
while (k--) { /* x / hbase */
num = BIGUP(num) + ds[k];
ds[k] = (BDIGIT)(num / hbase);
num %= hbase;
}
if (trim && ds[i-1] == 0) i--;
k = SIZEOF_BDIGITS;
while (k--) {
ptr[--j] = ruby_digitmap[num % base];
num /= base;
if (j <= 0) break;
if (trim && i == 0 && num == 0) break;
}
}
if (trim) {
while (j < len && ptr[j] == '0') j++;
MEMMOVE(ptr, ptr + j, char, len - j);
len -= j;
}
return len;
}
static long
big2str_karatsuba(VALUE x, int base, char* ptr,
long n1, long len, long hbase, int trim)
{
long lh, ll, m1;
VALUE b, q, r;
if (BIGZEROP(x)) {
if (trim) return 0;
else {
memset(ptr, '0', len);
return len;
}
}
if (n1 <= KARATSUBA_DIGITS) {
return big2str_orig(x, base, ptr, len, hbase, trim);
}
b = power_cache_get_power(base, n1, &m1);
bigdivmod(x, b, &q, &r);
lh = big2str_karatsuba(q, base, ptr, (len - m1)/2,
len - m1, hbase, trim);
rb_big_resize(q, 0);
ll = big2str_karatsuba(r, base, ptr + lh, m1/2,
m1, hbase, !lh && trim);
rb_big_resize(r, 0);
return lh + ll;
}
VALUE
rb_big2str0(VALUE x, int base, int trim)
{
int off;
VALUE ss, xx;
long n1, n2, len, hbase;
char* ptr;
if (FIXNUM_P(x)) {
return rb_fix2str(x, base);
}
if (BIGZEROP(x)) {
return rb_usascii_str_new2("0");
}
if (base < 2 || 36 < base)
rb_raise(rb_eArgError, "invalid radix %d", base);
n2 = big2str_find_n1(x, base);
n1 = (n2 + 1) / 2;
ss = rb_usascii_str_new(0, n2 + 1); /* plus one for sign */
ptr = RSTRING_PTR(ss);
ptr[0] = RBIGNUM_SIGN(x) ? '+' : '-';
hbase = base*base;
#if SIZEOF_BDIGITS > 2
hbase *= hbase;
#endif
off = !(trim && RBIGNUM_SIGN(x)); /* erase plus sign if trim */
xx = rb_big_clone(x);
RBIGNUM_SET_SIGN(xx, 1);
if (n1 <= KARATSUBA_DIGITS) {
len = off + big2str_orig(xx, base, ptr + off, n2, hbase, trim);
}
else {
len = off + big2str_karatsuba(xx, base, ptr + off, n1,
n2, hbase, trim);
}
rb_big_resize(xx, 0);
ptr[len] = '\0';
rb_str_resize(ss, len);
return ss;
}
VALUE
rb_big2str(VALUE x, int base)
{
return rb_big2str0(x, base, 1);
}
/*
* call-seq:
* big.to_s(base=10) -> string
*
* Returns a string containing the representation of <i>big</i> radix
* <i>base</i> (2 through 36).
*
* 12345654321.to_s #=> "12345654321"
* 12345654321.to_s(2) #=> "1011011111110110111011110000110001"
* 12345654321.to_s(8) #=> "133766736061"
* 12345654321.to_s(16) #=> "2dfdbbc31"
* 78546939656932.to_s(36) #=> "rubyrules"
*/
static VALUE
rb_big_to_s(int argc, VALUE *argv, VALUE x)
{
int base;
if (argc == 0) base = 10;
else {
VALUE b;
rb_scan_args(argc, argv, "01", &b);
base = NUM2INT(b);
}
return rb_big2str(x, base);
}
static VALUE
big2ulong(VALUE x, const char *type, int check)
{
long len = RBIGNUM_LEN(x);
BDIGIT_DBL num;
BDIGIT *ds;
if (len > DIGSPERLONG) {
if (check)
rb_raise(rb_eRangeError, "bignum too big to convert into `%s'", type);
len = DIGSPERLONG;
}
ds = BDIGITS(x);
num = 0;
while (len--) {
num = BIGUP(num);
num += ds[len];
}
return (VALUE)num;
}
VALUE
rb_big2ulong_pack(VALUE x)
{
VALUE num = big2ulong(x, "unsigned long", FALSE);
if (!RBIGNUM_SIGN(x)) {
return (VALUE)(-(SIGNED_VALUE)num);
}
return num;
}
VALUE
rb_big2ulong(VALUE x)
{
VALUE num = big2ulong(x, "unsigned long", TRUE);
if (!RBIGNUM_SIGN(x)) {
unsigned long v = (unsigned long)(-(long)num);
if (v <= LONG_MAX)
rb_raise(rb_eRangeError, "bignum out of range of unsigned long");
return (VALUE)v;
}
return num;
}
SIGNED_VALUE
rb_big2long(VALUE x)
{
VALUE num = big2ulong(x, "long", TRUE);
if ((long)num < 0 &&
(RBIGNUM_SIGN(x) || (long)num != LONG_MIN)) {
rb_raise(rb_eRangeError, "bignum too big to convert into `long'");
}
if (!RBIGNUM_SIGN(x)) return -(SIGNED_VALUE)num;
return num;
}
#if HAVE_LONG_LONG
static unsigned LONG_LONG
big2ull(VALUE x, const char *type)
{
long len = RBIGNUM_LEN(x);
BDIGIT_DBL num;
BDIGIT *ds;
if (len > SIZEOF_LONG_LONG/SIZEOF_BDIGITS)
rb_raise(rb_eRangeError, "bignum too big to convert into `%s'", type);
ds = BDIGITS(x);
num = 0;
while (len--) {
num = BIGUP(num);
num += ds[len];
}
return num;
}
unsigned LONG_LONG
rb_big2ull(VALUE x)
{
unsigned LONG_LONG num = big2ull(x, "unsigned long long");
if (!RBIGNUM_SIGN(x)) {
LONG_LONG v = -(LONG_LONG)num;
/* FIXNUM_MIN-1 .. LLONG_MIN mapped into 0xbfffffffffffffff .. LONG_MAX+1 */
if ((unsigned LONG_LONG)v <= LLONG_MAX)
rb_raise(rb_eRangeError, "bignum out of range of unsigned long long");
return v;
}
return num;
}
LONG_LONG
rb_big2ll(VALUE x)
{
unsigned LONG_LONG num = big2ull(x, "long long");
if ((LONG_LONG)num < 0 && (RBIGNUM_SIGN(x)
|| (LONG_LONG)num != LLONG_MIN)) {
rb_raise(rb_eRangeError, "bignum too big to convert into `long long'");
}
if (!RBIGNUM_SIGN(x)) return -(LONG_LONG)num;
return num;
}
#endif /* HAVE_LONG_LONG */
static VALUE
dbl2big(double d)
{
long i = 0;
BDIGIT c;
BDIGIT *digits;
VALUE z;
double u = (d < 0)?-d:d;
if (isinf(d)) {
rb_raise(rb_eFloatDomainError, d < 0 ? "-Infinity" : "Infinity");
}
if (isnan(d)) {
rb_raise(rb_eFloatDomainError, "NaN");
}
while (!POSFIXABLE(u) || 0 != (long)u) {
u /= (double)(BIGRAD);
i++;
}
z = bignew(i, d>=0);
digits = BDIGITS(z);
while (i--) {
u *= BIGRAD;
c = (BDIGIT)u;
u -= c;
digits[i] = c;
}
return z;
}
VALUE
rb_dbl2big(double d)
{
return bignorm(dbl2big(d));
}
static int
nlz(BDIGIT x)
{
BDIGIT y;
int n = BITSPERDIG;
#if BITSPERDIG > 64
y = x >> 64; if (y) {n -= 64; x = y;}
#endif
#if BITSPERDIG > 32
y = x >> 32; if (y) {n -= 32; x = y;}
#endif
#if BITSPERDIG > 16
y = x >> 16; if (y) {n -= 16; x = y;}
#endif
y = x >> 8; if (y) {n -= 8; x = y;}
y = x >> 4; if (y) {n -= 4; x = y;}
y = x >> 2; if (y) {n -= 2; x = y;}
y = x >> 1; if (y) {return n - 2;}
return n - x;
}
static double
big2dbl(VALUE x)
{
double d = 0.0;
long i = (bigtrunc(x), RBIGNUM_LEN(x)), lo = 0, bits;
BDIGIT *ds = BDIGITS(x), dl;
if (i) {
bits = i * BITSPERDIG - nlz(ds[i-1]);
if (bits > DBL_MANT_DIG+DBL_MAX_EXP) {
d = HUGE_VAL;
}
else {
if (bits > DBL_MANT_DIG+1)
lo = (bits -= DBL_MANT_DIG+1) / BITSPERDIG;
else
bits = 0;
while (--i > lo) {
d = ds[i] + BIGRAD*d;
}
dl = ds[i];
if (bits && (dl & (1UL << (bits %= BITSPERDIG)))) {
int carry = dl & ~(~(BDIGIT)0 << bits);
if (!carry) {
while (i-- > 0) {
if ((carry = ds[i]) != 0) break;
}
}
if (carry) {
dl &= (BDIGIT)~0 << bits;
dl += (BDIGIT)1 << bits;
if (!dl) d += 1;
}
}
d = dl + BIGRAD*d;
if (lo) {
if (lo > INT_MAX / BITSPERDIG)
d = HUGE_VAL;
else if (lo < INT_MIN / BITSPERDIG)
d = 0.0;
else
d = ldexp(d, (int)(lo * BITSPERDIG));
}
}
}
if (!RBIGNUM_SIGN(x)) d = -d;
return d;
}
double
rb_big2dbl(VALUE x)
{
double d = big2dbl(x);
if (isinf(d)) {
rb_warning("Bignum out of Float range");
if (d < 0.0)
d = -HUGE_VAL;
else
d = HUGE_VAL;
}
return d;
}
/*
* call-seq:
* big.to_f -> float
*
* Converts <i>big</i> to a <code>Float</code>. If <i>big</i> doesn't
* fit in a <code>Float</code>, the result is infinity.
*
*/
static VALUE
rb_big_to_f(VALUE x)
{
return DBL2NUM(rb_big2dbl(x));
}
/*
* call-seq:
* big <=> numeric -> -1, 0, +1 or nil
*
* Comparison---Returns -1, 0, or +1 depending on whether <i>big</i> is
* less than, equal to, or greater than <i>numeric</i>. This is the
* basis for the tests in <code>Comparable</code>.
*
*/
VALUE
rb_big_cmp(VALUE x, VALUE y)
{
long xlen = RBIGNUM_LEN(x);
BDIGIT *xds, *yds;
switch (TYPE(y)) {
case T_FIXNUM:
y = rb_int2big(FIX2LONG(y));
break;
case T_BIGNUM:
break;
case T_FLOAT:
{
double a = RFLOAT_VALUE(y);
if (isinf(a)) {
if (a > 0.0) return INT2FIX(-1);
else return INT2FIX(1);
}
return rb_dbl_cmp(rb_big2dbl(x), a);
}
default:
return rb_num_coerce_cmp(x, y, rb_intern("<=>"));
}
if (RBIGNUM_SIGN(x) > RBIGNUM_SIGN(y)) return INT2FIX(1);
if (RBIGNUM_SIGN(x) < RBIGNUM_SIGN(y)) return INT2FIX(-1);
if (xlen < RBIGNUM_LEN(y))
return (RBIGNUM_SIGN(x)) ? INT2FIX(-1) : INT2FIX(1);
if (xlen > RBIGNUM_LEN(y))
return (RBIGNUM_SIGN(x)) ? INT2FIX(1) : INT2FIX(-1);
xds = BDIGITS(x);
yds = BDIGITS(y);
while(xlen-- && (xds[xlen]==yds[xlen]));
if (-1 == xlen) return INT2FIX(0);
return (xds[xlen] > yds[xlen]) ?
(RBIGNUM_SIGN(x) ? INT2FIX(1) : INT2FIX(-1)) :
(RBIGNUM_SIGN(x) ? INT2FIX(-1) : INT2FIX(1));
}
static VALUE
big_op(VALUE x, VALUE y, int op)
{
VALUE rel;
int n;
switch (TYPE(y)) {
case T_FIXNUM:
case T_BIGNUM:
rel = rb_big_cmp(x, y);
break;
case T_FLOAT:
{
double a = RFLOAT_VALUE(y);
if (isinf(a)) {
if (a > 0.0) rel = INT2FIX(-1);
else rel = INT2FIX(1);
break;
}
rel = rb_dbl_cmp(rb_big2dbl(x), a);
break;
}
default:
{
ID id = 0;
switch (op) {
case 0: id = '>'; break;
case 1: id = rb_intern(">="); break;
case 2: id = '<'; break;
case 3: id = rb_intern("<="); break;
}
return rb_num_coerce_relop(x, y, id);
}
}
if (NIL_P(rel)) return Qfalse;
n = FIX2INT(rel);
switch (op) {
case 0: return n > 0 ? Qtrue : Qfalse;
case 1: return n >= 0 ? Qtrue : Qfalse;
case 2: return n < 0 ? Qtrue : Qfalse;
case 3: return n <= 0 ? Qtrue : Qfalse;
}
return Qundef;
}
/*
* call-seq:
* big > real -> true or false
*
* Returns <code>true</code> if the value of <code>big</code> is
* greater than that of <code>real</code>.
*/
static VALUE
big_gt(VALUE x, VALUE y)
{
return big_op(x, y, 0);
}
/*
* call-seq:
* big >= real -> true or false
*
* Returns <code>true</code> if the value of <code>big</code> is
* greater than or equal to that of <code>real</code>.
*/
static VALUE
big_ge(VALUE x, VALUE y)
{
return big_op(x, y, 1);
}
/*
* call-seq:
* big < real -> true or false
*
* Returns <code>true</code> if the value of <code>big</code> is
* less than that of <code>real</code>.
*/
static VALUE
big_lt(VALUE x, VALUE y)
{
return big_op(x, y, 2);
}
/*
* call-seq:
* big <= real -> true or false
*
* Returns <code>true</code> if the value of <code>big</code> is
* less than or equal to that of <code>real</code>.
*/
static VALUE
big_le(VALUE x, VALUE y)
{
return big_op(x, y, 3);
}
/*
* call-seq:
* big == obj -> true or false
*
* Returns <code>true</code> only if <i>obj</i> has the same value
* as <i>big</i>. Contrast this with <code>Bignum#eql?</code>, which
* requires <i>obj</i> to be a <code>Bignum</code>.
*
* 68719476736 == 68719476736.0 #=> true
*/
VALUE
rb_big_eq(VALUE x, VALUE y)
{
switch (TYPE(y)) {
case T_FIXNUM:
y = rb_int2big(FIX2LONG(y));
break;
case T_BIGNUM:
break;
case T_FLOAT:
{
volatile double a, b;
a = RFLOAT_VALUE(y);
if (isnan(a) || isinf(a)) return Qfalse;
b = rb_big2dbl(x);
return (a == b)?Qtrue:Qfalse;
}
default:
return rb_equal(y, x);
}
if (RBIGNUM_SIGN(x) != RBIGNUM_SIGN(y)) return Qfalse;
if (RBIGNUM_LEN(x) != RBIGNUM_LEN(y)) return Qfalse;
if (MEMCMP(BDIGITS(x),BDIGITS(y),BDIGIT,RBIGNUM_LEN(y)) != 0) return Qfalse;
return Qtrue;
}
/*
* call-seq:
* big.eql?(obj) -> true or false
*
* Returns <code>true</code> only if <i>obj</i> is a
* <code>Bignum</code> with the same value as <i>big</i>. Contrast this
* with <code>Bignum#==</code>, which performs type conversions.
*
* 68719476736.eql?(68719476736.0) #=> false
*/
static VALUE
rb_big_eql(VALUE x, VALUE y)
{
if (!RB_TYPE_P(y, T_BIGNUM)) return Qfalse;
if (RBIGNUM_SIGN(x) != RBIGNUM_SIGN(y)) return Qfalse;
if (RBIGNUM_LEN(x) != RBIGNUM_LEN(y)) return Qfalse;
if (MEMCMP(BDIGITS(x),BDIGITS(y),BDIGIT,RBIGNUM_LEN(y)) != 0) return Qfalse;
return Qtrue;
}
/*
* call-seq:
* -big -> integer
*
* Unary minus (returns an integer whose value is 0-big)
*/
VALUE
rb_big_uminus(VALUE x)
{
VALUE z = rb_big_clone(x);
RBIGNUM_SET_SIGN(z, !RBIGNUM_SIGN(x));
return bignorm(z);
}
/*
* call-seq:
* ~big -> integer
*
* Inverts the bits in big. As Bignums are conceptually infinite
* length, the result acts as if it had an infinite number of one
* bits to the left. In hex representations, this is displayed
* as two periods to the left of the digits.
*
* sprintf("%X", ~0x1122334455) #=> "..FEEDDCCBBAA"
*/
static VALUE
rb_big_neg(VALUE x)
{
VALUE z = rb_big_clone(x);
BDIGIT *ds;
long i;
if (!RBIGNUM_SIGN(x)) get2comp(z);
ds = BDIGITS(z);
i = RBIGNUM_LEN(x);
if (!i) return INT2FIX(~(SIGNED_VALUE)0);
while (i--) {
ds[i] = ~ds[i];
}
RBIGNUM_SET_SIGN(z, !RBIGNUM_SIGN(z));
if (RBIGNUM_SIGN(x)) get2comp(z);
return bignorm(z);
}
static void
bigsub_core(BDIGIT *xds, long xn, BDIGIT *yds, long yn, BDIGIT *zds, long zn)
{
BDIGIT_DBL_SIGNED num;
long i;
for (i = 0, num = 0; i < yn; i++) {
num += (BDIGIT_DBL_SIGNED)xds[i] - yds[i];
zds[i] = BIGLO(num);
num = BIGDN(num);
}
while (num && i < xn) {
num += xds[i];
zds[i++] = BIGLO(num);
num = BIGDN(num);
}
while (i < xn) {
zds[i] = xds[i];
i++;
}
assert(i <= zn);
while (i < zn) {
zds[i++] = 0;
}
}
static VALUE
bigsub(VALUE x, VALUE y)
{
VALUE z = 0;
long i = RBIGNUM_LEN(x);
BDIGIT *xds, *yds;
/* if x is smaller than y, swap */
if (RBIGNUM_LEN(x) < RBIGNUM_LEN(y)) {
z = x; x = y; y = z; /* swap x y */
}
else if (RBIGNUM_LEN(x) == RBIGNUM_LEN(y)) {
xds = BDIGITS(x);
yds = BDIGITS(y);
while (i > 0) {
i--;
if (xds[i] > yds[i]) {
break;
}
if (xds[i] < yds[i]) {
z = x; x = y; y = z; /* swap x y */
break;
}
}
}
z = bignew(RBIGNUM_LEN(x), z==0);
bigsub_core(BDIGITS(x), RBIGNUM_LEN(x),
BDIGITS(y), RBIGNUM_LEN(y),
BDIGITS(z), RBIGNUM_LEN(z));
return z;
}
static VALUE bigadd_int(VALUE x, long y);
static VALUE
bigsub_int(VALUE x, long y0)
{
VALUE z;
BDIGIT *xds, *zds;
long xn;
BDIGIT_DBL_SIGNED num;
long i, y;
y = y0;
xds = BDIGITS(x);
xn = RBIGNUM_LEN(x);
z = bignew(xn, RBIGNUM_SIGN(x));
zds = BDIGITS(z);
#if SIZEOF_BDIGITS == SIZEOF_LONG
num = (BDIGIT_DBL_SIGNED)xds[0] - y;
if (xn == 1 && num < 0) {
RBIGNUM_SET_SIGN(z, !RBIGNUM_SIGN(x));
zds[0] = (BDIGIT)-num;
RB_GC_GUARD(x);
return bignorm(z);
}
zds[0] = BIGLO(num);
num = BIGDN(num);
i = 1;
#else
num = 0;
for (i=0; i<(int)(sizeof(y)/sizeof(BDIGIT)); i++) {
num += (BDIGIT_DBL_SIGNED)xds[i] - BIGLO(y);
zds[i] = BIGLO(num);
num = BIGDN(num);
y = BIGDN(y);
}
#endif
while (num && i < xn) {
num += xds[i];
zds[i++] = BIGLO(num);
num = BIGDN(num);
}
while (i < xn) {
zds[i] = xds[i];
i++;
}
if (num < 0) {
z = bigsub(x, rb_int2big(y0));
}
RB_GC_GUARD(x);
return bignorm(z);
}
static VALUE
bigadd_int(VALUE x, long y)
{
VALUE z;
BDIGIT *xds, *zds;
long xn, zn;
BDIGIT_DBL num;
long i;
xds = BDIGITS(x);
xn = RBIGNUM_LEN(x);
if (xn < 2) {
zn = 3;
}
else {
zn = xn + 1;
}
z = bignew(zn, RBIGNUM_SIGN(x));
zds = BDIGITS(z);
#if SIZEOF_BDIGITS == SIZEOF_LONG
num = (BDIGIT_DBL)xds[0] + y;
zds[0] = BIGLO(num);
num = BIGDN(num);
i = 1;
#else
num = 0;
for (i=0; i<(int)(sizeof(y)/sizeof(BDIGIT)); i++) {
num += (BDIGIT_DBL)xds[i] + BIGLO(y);
zds[i] = BIGLO(num);
num = BIGDN(num);
y = BIGDN(y);
}
#endif
while (num && i < xn) {
num += xds[i];
zds[i++] = BIGLO(num);
num = BIGDN(num);
}
if (num) zds[i++] = (BDIGIT)num;
else while (i < xn) {
zds[i] = xds[i];
i++;
}
assert(i <= zn);
while (i < zn) {
zds[i++] = 0;
}
RB_GC_GUARD(x);
return bignorm(z);
}
static void
bigadd_core(BDIGIT *xds, long xn, BDIGIT *yds, long yn, BDIGIT *zds, long zn)
{
BDIGIT_DBL num = 0;
long i;
if (xn > yn) {
BDIGIT *tds;
tds = xds; xds = yds; yds = tds;
i = xn; xn = yn; yn = i;
}
i = 0;
while (i < xn) {
num += (BDIGIT_DBL)xds[i] + yds[i];
zds[i++] = BIGLO(num);
num = BIGDN(num);
}
while (num && i < yn) {
num += yds[i];
zds[i++] = BIGLO(num);
num = BIGDN(num);
}
while (i < yn) {
zds[i] = yds[i];
i++;
}
if (num) zds[i++] = (BDIGIT)num;
assert(i <= zn);
while (i < zn) {
zds[i++] = 0;
}
}
static VALUE
bigadd(VALUE x, VALUE y, int sign)
{
VALUE z;
long len;
sign = (sign == RBIGNUM_SIGN(y));
if (RBIGNUM_SIGN(x) != sign) {
if (sign) return bigsub(y, x);
return bigsub(x, y);
}
if (RBIGNUM_LEN(x) > RBIGNUM_LEN(y)) {
len = RBIGNUM_LEN(x) + 1;
}
else {
len = RBIGNUM_LEN(y) + 1;
}
z = bignew(len, sign);
bigadd_core(BDIGITS(x), RBIGNUM_LEN(x),
BDIGITS(y), RBIGNUM_LEN(y),
BDIGITS(z), RBIGNUM_LEN(z));
return z;
}
/*
* call-seq:
* big + other -> Numeric
*
* Adds big and other, returning the result.
*/
VALUE
rb_big_plus(VALUE x, VALUE y)
{
long n;
switch (TYPE(y)) {
case T_FIXNUM:
n = FIX2LONG(y);
if ((n > 0) != RBIGNUM_SIGN(x)) {
if (n < 0) {
n = -n;
}
return bigsub_int(x, n);
}
if (n < 0) {
n = -n;
}
return bigadd_int(x, n);
case T_BIGNUM:
return bignorm(bigadd(x, y, 1));
case T_FLOAT:
return DBL2NUM(rb_big2dbl(x) + RFLOAT_VALUE(y));
default:
return rb_num_coerce_bin(x, y, '+');
}
}
/*
* call-seq:
* big - other -> Numeric
*
* Subtracts other from big, returning the result.
*/
VALUE
rb_big_minus(VALUE x, VALUE y)
{
long n;
switch (TYPE(y)) {
case T_FIXNUM:
n = FIX2LONG(y);
if ((n > 0) != RBIGNUM_SIGN(x)) {
if (n < 0) {
n = -n;
}
return bigadd_int(x, n);
}
if (n < 0) {
n = -n;
}
return bigsub_int(x, n);
case T_BIGNUM:
return bignorm(bigadd(x, y, 0));
case T_FLOAT:
return DBL2NUM(rb_big2dbl(x) - RFLOAT_VALUE(y));
default:
return rb_num_coerce_bin(x, y, '-');
}
}
static long
big_real_len(VALUE x)
{
long i = RBIGNUM_LEN(x);
BDIGIT *xds = BDIGITS(x);
while (--i && !xds[i]);
return i + 1;
}
static VALUE
bigmul1_single(VALUE x, VALUE y)
{
BDIGIT_DBL n;
VALUE z = bignew(2, RBIGNUM_SIGN(x)==RBIGNUM_SIGN(y));
BDIGIT *xds, *yds, *zds;
xds = BDIGITS(x);
yds = BDIGITS(y);
zds = BDIGITS(z);
n = (BDIGIT_DBL)xds[0] * yds[0];
zds[0] = BIGLO(n);
zds[1] = (BDIGIT)BIGDN(n);
return z;
}
static VALUE
bigmul1_normal(VALUE x, VALUE y)
{
long xl = RBIGNUM_LEN(x), yl = RBIGNUM_LEN(y), i, j = xl + yl + 1;
BDIGIT_DBL n = 0;
VALUE z = bignew(j, RBIGNUM_SIGN(x)==RBIGNUM_SIGN(y));
BDIGIT *xds, *yds, *zds;
xds = BDIGITS(x);
yds = BDIGITS(y);
zds = BDIGITS(z);
while (j--) zds[j] = 0;
for (i = 0; i < xl; i++) {
BDIGIT_DBL dd;
dd = xds[i];
if (dd == 0) continue;
n = 0;
for (j = 0; j < yl; j++) {
BDIGIT_DBL ee = n + (BDIGIT_DBL)dd * yds[j];
n = zds[i + j] + ee;
if (ee) zds[i + j] = BIGLO(n);
n = BIGDN(n);
}
if (n) {
zds[i + j] = (BDIGIT)n;
}
}
rb_thread_check_ints();
return z;
}
static VALUE bigmul0(VALUE x, VALUE y);
/* balancing multiplication by slicing larger argument */
static VALUE
bigmul1_balance(VALUE x, VALUE y)
{
VALUE z, t1, t2;
long i, xn, yn, r, n;
BDIGIT *yds, *zds, *t1ds;
xn = RBIGNUM_LEN(x);
yn = RBIGNUM_LEN(y);
assert(2 * xn <= yn || 3 * xn <= 2*(yn+2));
z = bignew(xn + yn, RBIGNUM_SIGN(x)==RBIGNUM_SIGN(y));
t1 = bignew(xn, 1);
yds = BDIGITS(y);
zds = BDIGITS(z);
t1ds = BDIGITS(t1);
for (i = 0; i < xn + yn; i++) zds[i] = 0;
n = 0;
while (yn > 0) {
r = xn > yn ? yn : xn;
MEMCPY(t1ds, yds + n, BDIGIT, r);
RBIGNUM_SET_LEN(t1, r);
t2 = bigmul0(x, t1);
bigadd_core(zds + n, RBIGNUM_LEN(z) - n,
BDIGITS(t2), big_real_len(t2),
zds + n, RBIGNUM_LEN(z) - n);
yn -= r;
n += r;
}
return z;
}
/* split a bignum into high and low bignums */
static void
big_split(VALUE v, long n, volatile VALUE *ph, volatile VALUE *pl)
{
long hn = 0, ln = RBIGNUM_LEN(v);
VALUE h, l;
BDIGIT *vds = BDIGITS(v);
if (ln > n) {
hn = ln - n;
ln = n;
}
if (!hn) {
h = rb_uint2big(0);
}
else {
while (--hn && !vds[hn + ln]);
h = bignew(hn += 2, 1);
MEMCPY(BDIGITS(h), vds + ln, BDIGIT, hn - 1);
BDIGITS(h)[hn - 1] = 0; /* margin for carry */
}
while (--ln && !vds[ln]);
l = bignew(ln += 2, 1);
MEMCPY(BDIGITS(l), vds, BDIGIT, ln - 1);
BDIGITS(l)[ln - 1] = 0; /* margin for carry */
*pl = l;
*ph = h;
}
/* multiplication by karatsuba method */
static VALUE
bigmul1_karatsuba(VALUE x, VALUE y)
{
long i, n, xn, yn, t1n, t2n;
VALUE xh, xl, yh, yl, z, t1, t2, t3;
BDIGIT *zds;
xn = RBIGNUM_LEN(x);
yn = RBIGNUM_LEN(y);
n = yn / 2;
big_split(x, n, &xh, &xl);
if (x == y) {
yh = xh; yl = xl;
}
else big_split(y, n, &yh, &yl);
/* x = xh * b + xl
* y = yh * b + yl
*
* Karatsuba method:
* x * y = z2 * b^2 + z1 * b + z0
* where
* z2 = xh * yh
* z0 = xl * yl
* z1 = (xh + xl) * (yh + yl) - z2 - z0
*
* ref: http://en.wikipedia.org/wiki/Karatsuba_algorithm
*/
/* allocate a result bignum */
z = bignew(xn + yn, RBIGNUM_SIGN(x)==RBIGNUM_SIGN(y));
zds = BDIGITS(z);
/* t1 <- xh * yh */
t1 = bigmul0(xh, yh);
t1n = big_real_len(t1);
/* copy t1 into high bytes of the result (z2) */
MEMCPY(zds + 2 * n, BDIGITS(t1), BDIGIT, t1n);
for (i = 2 * n + t1n; i < xn + yn; i++) zds[i] = 0;
if (!BIGZEROP(xl) && !BIGZEROP(yl)) {
/* t2 <- xl * yl */
t2 = bigmul0(xl, yl);
t2n = big_real_len(t2);
/* copy t2 into low bytes of the result (z0) */
MEMCPY(zds, BDIGITS(t2), BDIGIT, t2n);
for (i = t2n; i < 2 * n; i++) zds[i] = 0;
}
else {
t2 = Qundef;
t2n = 0;
/* copy 0 into low bytes of the result (z0) */
for (i = 0; i < 2 * n; i++) zds[i] = 0;
}
/* xh <- xh + xl */
if (RBIGNUM_LEN(xl) > RBIGNUM_LEN(xh)) {
t3 = xl; xl = xh; xh = t3;
}
/* xh has a margin for carry */
bigadd_core(BDIGITS(xh), RBIGNUM_LEN(xh),
BDIGITS(xl), RBIGNUM_LEN(xl),
BDIGITS(xh), RBIGNUM_LEN(xh));
/* yh <- yh + yl */
if (x != y) {
if (RBIGNUM_LEN(yl) > RBIGNUM_LEN(yh)) {
t3 = yl; yl = yh; yh = t3;
}
/* yh has a margin for carry */
bigadd_core(BDIGITS(yh), RBIGNUM_LEN(yh),
BDIGITS(yl), RBIGNUM_LEN(yl),
BDIGITS(yh), RBIGNUM_LEN(yh));
}
else yh = xh;
/* t3 <- xh * yh */
t3 = bigmul0(xh, yh);
i = xn + yn - n;
/* subtract t1 from t3 */
bigsub_core(BDIGITS(t3), big_real_len(t3), BDIGITS(t1), t1n, BDIGITS(t3), big_real_len(t3));
/* subtract t2 from t3; t3 is now the middle term of the product */
if (t2 != Qundef) bigsub_core(BDIGITS(t3), big_real_len(t3), BDIGITS(t2), t2n, BDIGITS(t3), big_real_len(t3));
/* add t3 to middle bytes of the result (z1) */
bigadd_core(zds + n, i, BDIGITS(t3), big_real_len(t3), zds + n, i);
return z;
}
static void
biglsh_bang(BDIGIT *xds, long xn, unsigned long shift)
{
long const s1 = shift/BITSPERDIG;
int const s2 = (int)(shift%BITSPERDIG);
int const s3 = BITSPERDIG-s2;
BDIGIT* zds;
BDIGIT num;
long i;
if (s1 >= xn) {
MEMZERO(xds, BDIGIT, xn);
return;
}
zds = xds + xn - 1;
xn -= s1 + 1;
num = xds[xn]<<s2;
do {
*zds-- = num | xds[--xn]>>s3;
num = xds[xn]<<s2;
}
while (xn > 0);
*zds = num;
for (i = s1; i > 0; --i)
*zds-- = 0;
}
static void
bigrsh_bang(BDIGIT* xds, long xn, unsigned long shift)
{
long s1 = shift/BITSPERDIG;
int s2 = (int)(shift%BITSPERDIG);
int s3 = BITSPERDIG - s2;
int i;
BDIGIT num;
BDIGIT* zds;
if (s1 >= xn) {
MEMZERO(xds, BDIGIT, xn);
return;
}
i = 0;
zds = xds + s1;
num = *zds++>>s2;
do {
xds[i++] = (BDIGIT)(*zds<<s3) | num;
num = *zds++>>s2;
}
while (i < xn - s1 - 1);
xds[i] = num;
MEMZERO(xds + xn - s1, BDIGIT, s1);
}
static void
big_split3(VALUE v, long n, volatile VALUE* p0, volatile VALUE* p1, volatile VALUE* p2)
{
VALUE v0, v12, v1, v2;
big_split(v, n, &v12, &v0);
big_split(v12, n, &v2, &v1);
*p0 = bigtrunc(v0);
*p1 = bigtrunc(v1);
*p2 = bigtrunc(v2);
}
static VALUE big_lshift(VALUE, unsigned long);
static VALUE big_rshift(VALUE, unsigned long);
static VALUE bigdivrem(VALUE, VALUE, volatile VALUE*, volatile VALUE*);
static VALUE
bigmul1_toom3(VALUE x, VALUE y)
{
long n, xn, yn, zn;
VALUE x0, x1, x2, y0, y1, y2;
VALUE u0, u1, u2, u3, u4, v1, v2, v3;
VALUE z0, z1, z2, z3, z4, z, t;
BDIGIT* zds;
xn = RBIGNUM_LEN(x);
yn = RBIGNUM_LEN(y);
assert(xn <= yn); /* assume y >= x */
n = (yn + 2) / 3;
big_split3(x, n, &x0, &x1, &x2);
if (x == y) {
y0 = x0; y1 = x1; y2 = x2;
}
else big_split3(y, n, &y0, &y1, &y2);
/*
* ref. http://en.wikipedia.org/wiki/Toom%E2%80%93Cook_multiplication
*
* x(b) = x0 * b^0 + x1 * b^1 + x2 * b^2
* y(b) = y0 * b^0 + y1 * b^1 + y2 * b^2
*
* z(b) = x(b) * y(b)
* z(b) = z0 * b^0 + z1 * b^1 + z2 * b^2 + z3 * b^3 + z4 * b^4
* where:
* z0 = x0 * y0
* z1 = x0 * y1 + x1 * y0
* z2 = x0 * y2 + x1 * y1 + x2 * y0
* z3 = x1 * y2 + x2 * y1
* z4 = x2 * y2
*
* Toom3 method (a.k.a. Toom-Cook method):
* (Step1) calculating 5 points z(b0), z(b1), z(b2), z(b3), z(b4),
* where:
* b0 = 0, b1 = 1, b2 = -1, b3 = -2, b4 = inf,
* z(0) = x(0) * y(0) = x0 * y0
* z(1) = x(1) * y(1) = (x0 + x1 + x2) * (y0 + y1 + y2)
* z(-1) = x(-1) * y(-1) = (x0 - x1 + x2) * (y0 - y1 + y2)
* z(-2) = x(-2) * y(-2) = (x0 - 2 * (x1 - 2 * x2)) * (y0 - 2 * (y1 - 2 * y2))
* z(inf) = x(inf) * y(inf) = x2 * y2
*
* (Step2) interpolating z0, z1, z2, z3, z4, and z5.
*
* (Step3) Substituting base value into b of the polynomial z(b),
*/
/*
* [Step1] calculating 5 points z(b0), z(b1), z(b2), z(b3), z(b4)
*/
/* u1 <- x0 + x2 */
u1 = bigtrunc(bigadd(x0, x2, 1));
/* x(-1) : u2 <- u1 - x1 = x0 - x1 + x2 */
u2 = bigtrunc(bigsub(u1, x1));
/* x(1) : u1 <- u1 + x1 = x0 + x1 + x2 */
u1 = bigtrunc(bigadd(u1, x1, 1));
/* x(-2) : u3 <- 2 * (u2 + x2) - x0 = x0 - 2 * (x1 - 2 * x2) */
u3 = bigadd(u2, x2, 1);
if (BDIGITS(u3)[RBIGNUM_LEN(u3)-1] & BIGRAD_HALF) {
rb_big_resize(u3, RBIGNUM_LEN(u3) + 1);
BDIGITS(u3)[RBIGNUM_LEN(u3)-1] = 0;
}
biglsh_bang(BDIGITS(u3), RBIGNUM_LEN(u3), 1);
u3 = bigtrunc(bigadd(bigtrunc(u3), x0, 0));
if (x == y) {
v1 = u1; v2 = u2; v3 = u3;
}
else {
/* v1 <- y0 + y2 */
v1 = bigtrunc(bigadd(y0, y2, 1));
/* y(-1) : v2 <- v1 - y1 = y0 - y1 + y2 */
v2 = bigtrunc(bigsub(v1, y1));
/* y(1) : v1 <- v1 + y1 = y0 + y1 + y2 */
v1 = bigtrunc(bigadd(v1, y1, 1));
/* y(-2) : v3 <- 2 * (v2 + y2) - y0 = y0 - 2 * (y1 - 2 * y2) */
v3 = bigadd(v2, y2, 1);
if (BDIGITS(v3)[RBIGNUM_LEN(v3)-1] & BIGRAD_HALF) {
rb_big_resize(v3, RBIGNUM_LEN(v3) + 1);
BDIGITS(v3)[RBIGNUM_LEN(v3)-1] = 0;
}
biglsh_bang(BDIGITS(v3), RBIGNUM_LEN(v3), 1);
v3 = bigtrunc(bigadd(bigtrunc(v3), y0, 0));
}
/* z(0) : u0 <- x0 * y0 */
u0 = bigtrunc(bigmul0(x0, y0));
/* z(1) : u1 <- u1 * v1 */
u1 = bigtrunc(bigmul0(u1, v1));
/* z(-1) : u2 <- u2 * v2 */
u2 = bigtrunc(bigmul0(u2, v2));
/* z(-2) : u3 <- u3 * v3 */
u3 = bigtrunc(bigmul0(u3, v3));
/* z(inf) : u4 <- x2 * y2 */
u4 = bigtrunc(bigmul0(x2, y2));
/* for GC */
v1 = v2 = v3 = Qnil;
/*
* [Step2] interpolating z0, z1, z2, z3, z4, and z5.
*/
/* z0 <- z(0) == u0 */
z0 = u0;
/* z4 <- z(inf) == u4 */
z4 = u4;
/* z3 <- (z(-2) - z(1)) / 3 == (u3 - u1) / 3 */
z3 = bigadd(u3, u1, 0);
bigdivrem(z3, big_three, &z3, NULL); /* TODO: optimize */
bigtrunc(z3);
/* z1 <- (z(1) - z(-1)) / 2 == (u1 - u2) / 2 */
z1 = bigtrunc(bigadd(u1, u2, 0));
bigrsh_bang(BDIGITS(z1), RBIGNUM_LEN(z1), 1);
/* z2 <- z(-1) - z(0) == u2 - u0 */
z2 = bigtrunc(bigadd(u2, u0, 0));
/* z3 <- (z2 - z3) / 2 + 2 * z(inf) == (z2 - z3) / 2 + 2 * u4 */
z3 = bigadd(z2, z3, 0);
bigrsh_bang(BDIGITS(z3), RBIGNUM_LEN(z3), 1);
t = big_lshift(u4, 1); /* TODO: combining with next addition */
z3 = bigtrunc(bigadd(z3, t, 1));
/* z2 <- z2 + z1 - z(inf) == z2 + z1 - u4 */
z2 = bigtrunc(bigadd(z2, z1, 1));
z2 = bigtrunc(bigadd(z2, u4, 0));
/* z1 <- z1 - z3 */
z1 = bigtrunc(bigadd(z1, z3, 0));
/*
* [Step3] Substituting base value into b of the polynomial z(b),
*/
zn = 6*n + 1;
z = bignew(zn, RBIGNUM_SIGN(x)==RBIGNUM_SIGN(y));
zds = BDIGITS(z);
MEMCPY(zds, BDIGITS(z0), BDIGIT, RBIGNUM_LEN(z0));
MEMZERO(zds + RBIGNUM_LEN(z0), BDIGIT, zn - RBIGNUM_LEN(z0));
bigadd_core(zds + n, zn - n, BDIGITS(z1), big_real_len(z1), zds + n, zn - n);
bigadd_core(zds + 2*n, zn - 2*n, BDIGITS(z2), big_real_len(z2), zds + 2*n, zn - 2*n);
bigadd_core(zds + 3*n, zn - 3*n, BDIGITS(z3), big_real_len(z3), zds + 3*n, zn - 3*n);
bigadd_core(zds + 4*n, zn - 4*n, BDIGITS(z4), big_real_len(z4), zds + 4*n, zn - 4*n);
z = bignorm(z);
return bignorm(z);
}
/* efficient squaring (2 times faster than normal multiplication)
* ref: Handbook of Applied Cryptography, Algorithm 14.16
* http://www.cacr.math.uwaterloo.ca/hac/about/chap14.pdf
*/
static VALUE
bigsqr_fast(VALUE x)
{
long len = RBIGNUM_LEN(x), i, j;
VALUE z = bignew(2 * len + 1, 1);
BDIGIT *xds = BDIGITS(x), *zds = BDIGITS(z);
BDIGIT_DBL c, v, w;
for (i = 2 * len + 1; i--; ) zds[i] = 0;
for (i = 0; i < len; i++) {
v = (BDIGIT_DBL)xds[i];
if (!v) continue;
c = (BDIGIT_DBL)zds[i + i] + v * v;
zds[i + i] = BIGLO(c);
c = BIGDN(c);
v *= 2;
for (j = i + 1; j < len; j++) {
w = (BDIGIT_DBL)xds[j];
c += (BDIGIT_DBL)zds[i + j] + BIGLO(v) * w;
zds[i + j] = BIGLO(c);
c = BIGDN(c);
if (BIGDN(v)) c += w;
}
if (c) {
c += (BDIGIT_DBL)zds[i + len];
zds[i + len] = BIGLO(c);
c = BIGDN(c);
}
if (c) zds[i + len + 1] += (BDIGIT)c;
}
return z;
}
#define KARATSUBA_MUL_DIGITS 70
#define TOOM3_MUL_DIGITS 150
/* determine whether a bignum is sparse or not by random sampling */
static inline VALUE
big_sparse_p(VALUE x)
{
long c = 0, n = RBIGNUM_LEN(x);
if ( BDIGITS(x)[rb_genrand_ulong_limited(n / 2) + n / 4]) c++;
if (c <= 1 && BDIGITS(x)[rb_genrand_ulong_limited(n / 2) + n / 4]) c++;
if (c <= 1 && BDIGITS(x)[rb_genrand_ulong_limited(n / 2) + n / 4]) c++;
return (c <= 1) ? Qtrue : Qfalse;
}
static VALUE
bigmul0(VALUE x, VALUE y)
{
long xn, yn;
xn = RBIGNUM_LEN(x);
yn = RBIGNUM_LEN(y);
/* make sure that y is longer than x */
if (xn > yn) {
VALUE t;
long tn;
t = x; x = y; y = t;
tn = xn; xn = yn; yn = tn;
}
assert(xn <= yn);
/* normal multiplication when x is small */
if (xn < KARATSUBA_MUL_DIGITS) {
normal:
if (x == y) return bigsqr_fast(x);
if (xn == 1 && yn == 1) return bigmul1_single(x, y);
return bigmul1_normal(x, y);
}
/* normal multiplication when x or y is a sparse bignum */
if (big_sparse_p(x)) goto normal;
if (big_sparse_p(y)) return bigmul1_normal(y, x);
/* balance multiplication by slicing y when x is much smaller than y */
if (2 * xn <= yn) return bigmul1_balance(x, y);
if (xn < TOOM3_MUL_DIGITS) {
/* multiplication by karatsuba method */
return bigmul1_karatsuba(x, y);
}
else if (3*xn <= 2*(yn + 2))
return bigmul1_balance(x, y);
return bigmul1_toom3(x, y);
}
/*
* call-seq:
* big * other -> Numeric
*
* Multiplies big and other, returning the result.
*/
VALUE
rb_big_mul(VALUE x, VALUE y)
{
switch (TYPE(y)) {
case T_FIXNUM:
y = rb_int2big(FIX2LONG(y));
break;
case T_BIGNUM:
break;
case T_FLOAT:
return DBL2NUM(rb_big2dbl(x) * RFLOAT_VALUE(y));
default:
return rb_num_coerce_bin(x, y, '*');
}
return bignorm(bigmul0(x, y));
}
struct big_div_struct {
long nx, ny;
BDIGIT *yds, *zds;
VALUE stop;
};
static VALUE
bigdivrem1(void *ptr)
{
struct big_div_struct *bds = (struct big_div_struct*)ptr;
long nx = bds->nx, ny = bds->ny;
long i, j, nyzero;
BDIGIT *yds = bds->yds, *zds = bds->zds;
BDIGIT_DBL t2;
BDIGIT_DBL_SIGNED num;
BDIGIT q;
j = nx==ny?nx+1:nx;
for (nyzero = 0; !yds[nyzero]; nyzero++);
do {
if (bds->stop) return Qnil;
if (zds[j] == yds[ny-1]) q = (BDIGIT)BIGRAD-1;
else q = (BDIGIT)((BIGUP(zds[j]) + zds[j-1])/yds[ny-1]);
if (q) {
i = nyzero; num = 0; t2 = 0;
do { /* multiply and subtract */
BDIGIT_DBL ee;
t2 += (BDIGIT_DBL)yds[i] * q;
ee = num - BIGLO(t2);
num = (BDIGIT_DBL)zds[j - ny + i] + ee;
if (ee) zds[j - ny + i] = BIGLO(num);
num = BIGDN(num);
t2 = BIGDN(t2);
} while (++i < ny);
num += zds[j - ny + i] - t2;/* borrow from high digit; don't update */
while (num) { /* "add back" required */
i = 0; num = 0; q--;
do {
BDIGIT_DBL ee = num + yds[i];
num = (BDIGIT_DBL)zds[j - ny + i] + ee;
if (ee) zds[j - ny + i] = BIGLO(num);
num = BIGDN(num);
} while (++i < ny);
num--;
}
}
zds[j] = q;
} while (--j >= ny);
return Qnil;
}
static void
rb_big_stop(void *ptr)
{
VALUE *stop = (VALUE*)ptr;
*stop = Qtrue;
}
static VALUE
bigdivrem(VALUE x, VALUE y, volatile VALUE *divp, volatile VALUE *modp)
{
struct big_div_struct bds;
long nx = RBIGNUM_LEN(x), ny = RBIGNUM_LEN(y);
long i, j;
VALUE z, yy, zz;
BDIGIT *xds, *yds, *zds, *tds;
BDIGIT_DBL t2;
BDIGIT dd, q;
if (BIGZEROP(y)) rb_num_zerodiv();
xds = BDIGITS(x);
yds = BDIGITS(y);
if (nx < ny || (nx == ny && xds[nx - 1] < yds[ny - 1])) {
if (divp) *divp = rb_int2big(0);
if (modp) *modp = x;
return Qnil;
}
if (ny == 1) {
dd = yds[0];
z = rb_big_clone(x);
zds = BDIGITS(z);
t2 = 0; i = nx;
while (i--) {
t2 = BIGUP(t2) + zds[i];
zds[i] = (BDIGIT)(t2 / dd);
t2 %= dd;
}
RBIGNUM_SET_SIGN(z, RBIGNUM_SIGN(x)==RBIGNUM_SIGN(y));
if (modp) {
*modp = rb_uint2big((VALUE)t2);
RBIGNUM_SET_SIGN(*modp, RBIGNUM_SIGN(x));
}
if (divp) *divp = z;
return Qnil;
}
z = bignew(nx==ny?nx+2:nx+1, RBIGNUM_SIGN(x)==RBIGNUM_SIGN(y));
zds = BDIGITS(z);
if (nx==ny) zds[nx+1] = 0;
while (!yds[ny-1]) ny--;
dd = 0;
q = yds[ny-1];
while ((q & (BDIGIT)(1UL<<(BITSPERDIG-1))) == 0) {
q <<= 1UL;
dd++;
}
if (dd) {
yy = rb_big_clone(y);
tds = BDIGITS(yy);
j = 0;
t2 = 0;
while (j<ny) {
t2 += (BDIGIT_DBL)yds[j]<<dd;
tds[j++] = BIGLO(t2);
t2 = BIGDN(t2);
}
yds = tds;
RB_GC_GUARD(y) = yy;
j = 0;
t2 = 0;
while (j<nx) {
t2 += (BDIGIT_DBL)xds[j]<<dd;
zds[j++] = BIGLO(t2);
t2 = BIGDN(t2);
}
zds[j] = (BDIGIT)t2;
}
else {
zds[nx] = 0;
j = nx;
while (j--) zds[j] = xds[j];
}
bds.nx = nx;
bds.ny = ny;
bds.zds = zds;
bds.yds = yds;
bds.stop = Qfalse;
if (nx > 10000 || ny > 10000) {
rb_thread_blocking_region(bigdivrem1, &bds, rb_big_stop, &bds.stop);
}
else {
bigdivrem1(&bds);
}
if (divp) { /* move quotient down in z */
*divp = zz = rb_big_clone(z);
zds = BDIGITS(zz);
j = (nx==ny ? nx+2 : nx+1) - ny;
for (i = 0;i < j;i++) zds[i] = zds[i+ny];
if (!zds[i-1]) i--;
RBIGNUM_SET_LEN(zz, i);
}
if (modp) { /* normalize remainder */
*modp = zz = rb_big_clone(z);
zds = BDIGITS(zz);
while (--ny && !zds[ny]); ++ny;
if (dd) {
t2 = 0; i = ny;
while(i--) {
t2 = (t2 | zds[i]) >> dd;
q = zds[i];
zds[i] = BIGLO(t2);
t2 = BIGUP(q);
}
}
if (!zds[ny-1]) ny--;
RBIGNUM_SET_LEN(zz, ny);
RBIGNUM_SET_SIGN(zz, RBIGNUM_SIGN(x));
}
return z;
}
static void
bigdivmod(VALUE x, VALUE y, volatile VALUE *divp, volatile VALUE *modp)
{
VALUE mod;
bigdivrem(x, y, divp, &mod);
if (RBIGNUM_SIGN(x) != RBIGNUM_SIGN(y) && !BIGZEROP(mod)) {
if (divp) *divp = bigadd(*divp, rb_int2big(1), 0);
if (modp) *modp = bigadd(mod, y, 1);
}
else if (modp) {
*modp = mod;
}
}
static VALUE
rb_big_divide(VALUE x, VALUE y, ID op)
{
VALUE z;
switch (TYPE(y)) {
case T_FIXNUM:
y = rb_int2big(FIX2LONG(y));
break;
case T_BIGNUM:
break;
case T_FLOAT:
{
if (op == '/') {
return DBL2NUM(rb_big2dbl(x) / RFLOAT_VALUE(y));
}
else {
double dy = RFLOAT_VALUE(y);
if (dy == 0.0) rb_num_zerodiv();
return rb_dbl2big(rb_big2dbl(x) / dy);
}
}
default:
return rb_num_coerce_bin(x, y, op);
}
bigdivmod(x, y, &z, 0);
return bignorm(z);
}
/*
* call-seq:
* big / other -> Numeric
*
* Performs division: the class of the resulting object depends on
* the class of <code>numeric</code> and on the magnitude of the
* result.
*/
VALUE
rb_big_div(VALUE x, VALUE y)
{
return rb_big_divide(x, y, '/');
}
/*
* call-seq:
* big.div(other) -> integer
*
* Performs integer division: returns integer value.
*/
VALUE
rb_big_idiv(VALUE x, VALUE y)
{
return rb_big_divide(x, y, rb_intern("div"));
}
/*
* call-seq:
* big % other -> Numeric
* big.modulo(other) -> Numeric
*
* Returns big modulo other. See Numeric.divmod for more
* information.
*/
VALUE
rb_big_modulo(VALUE x, VALUE y)
{
VALUE z;
switch (TYPE(y)) {
case T_FIXNUM:
y = rb_int2big(FIX2LONG(y));
break;
case T_BIGNUM:
break;
default:
return rb_num_coerce_bin(x, y, '%');
}
bigdivmod(x, y, 0, &z);
return bignorm(z);
}
/*
* call-seq:
* big.remainder(numeric) -> number
*
* Returns the remainder after dividing <i>big</i> by <i>numeric</i>.
*
* -1234567890987654321.remainder(13731) #=> -6966
* -1234567890987654321.remainder(13731.24) #=> -9906.22531493148
*/
static VALUE
rb_big_remainder(VALUE x, VALUE y)
{
VALUE z;
switch (TYPE(y)) {
case T_FIXNUM:
y = rb_int2big(FIX2LONG(y));
break;
case T_BIGNUM:
break;
default:
return rb_num_coerce_bin(x, y, rb_intern("remainder"));
}
bigdivrem(x, y, 0, &z);
return bignorm(z);
}
/*
* call-seq:
* big.divmod(numeric) -> array
*
* See <code>Numeric#divmod</code>.
*
*/
VALUE
rb_big_divmod(VALUE x, VALUE y)
{
VALUE div, mod;
switch (TYPE(y)) {
case T_FIXNUM:
y = rb_int2big(FIX2LONG(y));
break;
case T_BIGNUM:
break;
default:
return rb_num_coerce_bin(x, y, rb_intern("divmod"));
}
bigdivmod(x, y, &div, &mod);
return rb_assoc_new(bignorm(div), bignorm(mod));
}
static int
bdigbitsize(BDIGIT x)
{
int size = 1;
int nb = BITSPERDIG / 2;
BDIGIT bits = (~0 << nb);
if (!x) return 0;
while (x > 1) {
if (x & bits) {
size += nb;
x >>= nb;
}
x &= ~bits;
nb /= 2;
bits >>= nb;
}
return size;
}
static VALUE big_lshift(VALUE, unsigned long);
static VALUE big_rshift(VALUE, unsigned long);
static VALUE
big_shift(VALUE x, long n)
{
if (n < 0)
return big_lshift(x, (unsigned long)-n);
else if (n > 0)
return big_rshift(x, (unsigned long)n);
return x;
}
static VALUE
big_fdiv(VALUE x, VALUE y)
{
#define DBL_BIGDIG ((DBL_MANT_DIG + BITSPERDIG) / BITSPERDIG)
VALUE z;
long l, ex, ey;
int i;
bigtrunc(x);
l = RBIGNUM_LEN(x) - 1;
ex = l * BITSPERDIG;
ex += bdigbitsize(BDIGITS(x)[l]);
ex -= 2 * DBL_BIGDIG * BITSPERDIG;
if (ex) x = big_shift(x, ex);
switch (TYPE(y)) {
case T_FIXNUM:
y = rb_int2big(FIX2LONG(y));
case T_BIGNUM:
bigtrunc(y);
l = RBIGNUM_LEN(y) - 1;
ey = l * BITSPERDIG;
ey += bdigbitsize(BDIGITS(y)[l]);
ey -= DBL_BIGDIG * BITSPERDIG;
if (ey) y = big_shift(y, ey);
break;
case T_FLOAT:
y = dbl2big(ldexp(frexp(RFLOAT_VALUE(y), &i), DBL_MANT_DIG));
ey = i - DBL_MANT_DIG;
break;
default:
rb_bug("big_fdiv");
}
bigdivrem(x, y, &z, 0);
l = ex - ey;
#if SIZEOF_LONG > SIZEOF_INT
{
/* Visual C++ can't be here */
if (l > INT_MAX) return DBL2NUM(INFINITY);
if (l < INT_MIN) return DBL2NUM(0.0);
}
#endif
return DBL2NUM(ldexp(big2dbl(z), (int)l));
}
/*
* call-seq:
* big.fdiv(numeric) -> float
*
* Returns the floating point result of dividing <i>big</i> by
* <i>numeric</i>.
*
* -1234567890987654321.fdiv(13731) #=> -89910996357705.5
* -1234567890987654321.fdiv(13731.24) #=> -89909424858035.7
*
*/
VALUE
rb_big_fdiv(VALUE x, VALUE y)
{
double dx, dy;
dx = big2dbl(x);
switch (TYPE(y)) {
case T_FIXNUM:
dy = (double)FIX2LONG(y);
if (isinf(dx))
return big_fdiv(x, y);
break;
case T_BIGNUM:
dy = rb_big2dbl(y);
if (isinf(dx) || isinf(dy))
return big_fdiv(x, y);
break;
case T_FLOAT:
dy = RFLOAT_VALUE(y);
if (isnan(dy))
return y;
if (isinf(dx))
return big_fdiv(x, y);
break;
default:
return rb_num_coerce_bin(x, y, rb_intern("fdiv"));
}
return DBL2NUM(dx / dy);
}
static VALUE
bigsqr(VALUE x)
{
return bigtrunc(bigmul0(x, x));
}
/*
* call-seq:
* big ** exponent -> numeric
*
* Raises _big_ to the _exponent_ power (which may be an integer, float,
* or anything that will coerce to a number). The result may be
* a Fixnum, Bignum, or Float
*
* 123456789 ** 2 #=> 15241578750190521
* 123456789 ** 1.2 #=> 5126464716.09932
* 123456789 ** -2 #=> 6.5610001194102e-17
*/
VALUE
rb_big_pow(VALUE x, VALUE y)
{
double d;
SIGNED_VALUE yy;
if (y == INT2FIX(0)) return INT2FIX(1);
switch (TYPE(y)) {
case T_FLOAT:
d = RFLOAT_VALUE(y);
if ((!RBIGNUM_SIGN(x) && !BIGZEROP(x)) && d != round(d))
return rb_funcall(rb_complex_raw1(x), rb_intern("**"), 1, y);
break;
case T_BIGNUM:
rb_warn("in a**b, b may be too big");
d = rb_big2dbl(y);
break;
case T_FIXNUM:
yy = FIX2LONG(y);
if (yy < 0)
return rb_funcall(rb_rational_raw1(x), rb_intern("**"), 1, y);
else {
VALUE z = 0;
SIGNED_VALUE mask;
const long xlen = RBIGNUM_LEN(x) - 1;
const long xbits = ffs(RBIGNUM_DIGITS(x)[xlen]) + SIZEOF_BDIGITS*BITSPERDIG*xlen;
const long BIGLEN_LIMIT = BITSPERDIG*1024*1024;
if ((xbits > BIGLEN_LIMIT) || (xbits * yy > BIGLEN_LIMIT)) {
rb_warn("in a**b, b may be too big");
d = (double)yy;
break;
}
for (mask = FIXNUM_MAX + 1; mask; mask >>= 1) {
if (z) z = bigsqr(z);
if (yy & mask) {
z = z ? bigtrunc(bigmul0(z, x)) : x;
}
}
return bignorm(z);
}
/* NOTREACHED */
break;
default:
return rb_num_coerce_bin(x, y, rb_intern("**"));
}
return DBL2NUM(pow(rb_big2dbl(x), d));
}
static inline VALUE
bit_coerce(VALUE x)
{
while (!FIXNUM_P(x) && !RB_TYPE_P(x, T_BIGNUM)) {
rb_raise(rb_eTypeError,
"can't convert %s into Integer for bitwise arithmetic",
rb_obj_classname(x));
x = rb_to_int(x);
}
return x;
}
static VALUE
bigand_int(VALUE x, long y)
{
VALUE z;
BDIGIT *xds, *zds;
long xn, zn;
long i;
char sign;
if (y == 0) return INT2FIX(0);
sign = (y > 0);
xds = BDIGITS(x);
zn = xn = RBIGNUM_LEN(x);
#if SIZEOF_BDIGITS == SIZEOF_LONG
if (sign) {
y &= xds[0];
return LONG2NUM(y);
}
#endif
z = bignew(zn, RBIGNUM_SIGN(x) || sign);
zds = BDIGITS(z);
#if SIZEOF_BDIGITS == SIZEOF_LONG
i = 1;
zds[0] = xds[0] & y;
#else
{
BDIGIT_DBL num = y;
for (i=0; i<(int)(sizeof(y)/sizeof(BDIGIT)); i++) {
zds[i] = xds[i] & BIGLO(num);
num = BIGDN(num);
}
}
#endif
while (i < xn) {
zds[i] = sign?0:xds[i];
i++;
}
if (!RBIGNUM_SIGN(z)) get2comp(z);
return bignorm(z);
}
/*
* call-seq:
* big & numeric -> integer
*
* Performs bitwise +and+ between _big_ and _numeric_.
*/
VALUE
rb_big_and(VALUE xx, VALUE yy)
{
volatile VALUE x, y, z;
BDIGIT *ds1, *ds2, *zds;
long i, l1, l2;
char sign;
x = xx;
y = bit_coerce(yy);
if (!RBIGNUM_SIGN(x)) {
x = rb_big_clone(x);
get2comp(x);
}
if (FIXNUM_P(y)) {
return bigand_int(x, FIX2LONG(y));
}
if (!RBIGNUM_SIGN(y)) {
y = rb_big_clone(y);
get2comp(y);
}
if (RBIGNUM_LEN(x) > RBIGNUM_LEN(y)) {
l1 = RBIGNUM_LEN(y);
l2 = RBIGNUM_LEN(x);
ds1 = BDIGITS(y);
ds2 = BDIGITS(x);
sign = RBIGNUM_SIGN(y);
}
else {
l1 = RBIGNUM_LEN(x);
l2 = RBIGNUM_LEN(y);
ds1 = BDIGITS(x);
ds2 = BDIGITS(y);
sign = RBIGNUM_SIGN(x);
}
z = bignew(l2, RBIGNUM_SIGN(x) || RBIGNUM_SIGN(y));
zds = BDIGITS(z);
for (i=0; i<l1; i++) {
zds[i] = ds1[i] & ds2[i];
}
for (; i<l2; i++) {
zds[i] = sign?0:ds2[i];
}
if (!RBIGNUM_SIGN(z)) get2comp(z);
return bignorm(z);
}
static VALUE
bigor_int(VALUE x, long y)
{
VALUE z;
BDIGIT *xds, *zds;
long xn, zn;
long i;
char sign;
sign = (y >= 0);
xds = BDIGITS(x);
zn = xn = RBIGNUM_LEN(x);
z = bignew(zn, RBIGNUM_SIGN(x) && sign);
zds = BDIGITS(z);
#if SIZEOF_BDIGITS == SIZEOF_LONG
i = 1;
zds[0] = xds[0] | y;
#else
{
BDIGIT_DBL num = y;
for (i=0; i<(int)(sizeof(y)/sizeof(BDIGIT)); i++) {
zds[i] = xds[i] | BIGLO(num);
num = BIGDN(num);
}
}
#endif
while (i < xn) {
zds[i] = sign?xds[i]:(BDIGIT)(BIGRAD-1);
i++;
}
if (!RBIGNUM_SIGN(z)) get2comp(z);
return bignorm(z);
}
/*
* call-seq:
* big | numeric -> integer
*
* Performs bitwise +or+ between _big_ and _numeric_.
*/
VALUE
rb_big_or(VALUE xx, VALUE yy)
{
volatile VALUE x, y, z;
BDIGIT *ds1, *ds2, *zds;
long i, l1, l2;
char sign;
x = xx;
y = bit_coerce(yy);
if (!RBIGNUM_SIGN(x)) {
x = rb_big_clone(x);
get2comp(x);
}
if (FIXNUM_P(y)) {
return bigor_int(x, FIX2LONG(y));
}
if (!RBIGNUM_SIGN(y)) {
y = rb_big_clone(y);
get2comp(y);
}
if (RBIGNUM_LEN(x) > RBIGNUM_LEN(y)) {
l1 = RBIGNUM_LEN(y);
l2 = RBIGNUM_LEN(x);
ds1 = BDIGITS(y);
ds2 = BDIGITS(x);
sign = RBIGNUM_SIGN(y);
}
else {
l1 = RBIGNUM_LEN(x);
l2 = RBIGNUM_LEN(y);
ds1 = BDIGITS(x);
ds2 = BDIGITS(y);
sign = RBIGNUM_SIGN(x);
}
z = bignew(l2, RBIGNUM_SIGN(x) && RBIGNUM_SIGN(y));
zds = BDIGITS(z);
for (i=0; i<l1; i++) {
zds[i] = ds1[i] | ds2[i];
}
for (; i<l2; i++) {
zds[i] = sign?ds2[i]:(BDIGIT)(BIGRAD-1);
}
if (!RBIGNUM_SIGN(z)) get2comp(z);
return bignorm(z);
}
static VALUE
bigxor_int(VALUE x, long y)
{
VALUE z;
BDIGIT *xds, *zds;
long xn, zn;
long i;
char sign;
sign = (y >= 0) ? 1 : 0;
xds = BDIGITS(x);
zn = xn = RBIGNUM_LEN(x);
z = bignew(zn, !(RBIGNUM_SIGN(x) ^ sign));
zds = BDIGITS(z);
#if SIZEOF_BDIGITS == SIZEOF_LONG
i = 1;
zds[0] = xds[0] ^ y;
#else
{
BDIGIT_DBL num = y;
for (i=0; i<(int)(sizeof(y)/sizeof(BDIGIT)); i++) {
zds[i] = xds[i] ^ BIGLO(num);
num = BIGDN(num);
}
}
#endif
while (i < xn) {
zds[i] = sign?xds[i]:~xds[i];
i++;
}
if (!RBIGNUM_SIGN(z)) get2comp(z);
return bignorm(z);
}
/*
* call-seq:
* big ^ numeric -> integer
*
* Performs bitwise +exclusive or+ between _big_ and _numeric_.
*/
VALUE
rb_big_xor(VALUE xx, VALUE yy)
{
volatile VALUE x, y;
VALUE z;
BDIGIT *ds1, *ds2, *zds;
long i, l1, l2;
char sign;
x = xx;
y = bit_coerce(yy);
if (!RBIGNUM_SIGN(x)) {
x = rb_big_clone(x);
get2comp(x);
}
if (FIXNUM_P(y)) {
return bigxor_int(x, FIX2LONG(y));
}
if (!RBIGNUM_SIGN(y)) {
y = rb_big_clone(y);
get2comp(y);
}
if (RBIGNUM_LEN(x) > RBIGNUM_LEN(y)) {
l1 = RBIGNUM_LEN(y);
l2 = RBIGNUM_LEN(x);
ds1 = BDIGITS(y);
ds2 = BDIGITS(x);
sign = RBIGNUM_SIGN(y);
}
else {
l1 = RBIGNUM_LEN(x);
l2 = RBIGNUM_LEN(y);
ds1 = BDIGITS(x);
ds2 = BDIGITS(y);
sign = RBIGNUM_SIGN(x);
}
RBIGNUM_SET_SIGN(x, RBIGNUM_SIGN(x)?1:0);
RBIGNUM_SET_SIGN(y, RBIGNUM_SIGN(y)?1:0);
z = bignew(l2, !(RBIGNUM_SIGN(x) ^ RBIGNUM_SIGN(y)));
zds = BDIGITS(z);
for (i=0; i<l1; i++) {
zds[i] = ds1[i] ^ ds2[i];
}
for (; i<l2; i++) {
zds[i] = sign?ds2[i]:~ds2[i];
}
if (!RBIGNUM_SIGN(z)) get2comp(z);
return bignorm(z);
}
static VALUE
check_shiftdown(VALUE y, VALUE x)
{
if (!RBIGNUM_LEN(x)) return INT2FIX(0);
if (RBIGNUM_LEN(y) > SIZEOF_LONG / SIZEOF_BDIGITS) {
return RBIGNUM_SIGN(x) ? INT2FIX(0) : INT2FIX(-1);
}
return Qnil;
}
/*
* call-seq:
* big << numeric -> integer
*
* Shifts big left _numeric_ positions (right if _numeric_ is negative).
*/
VALUE
rb_big_lshift(VALUE x, VALUE y)
{
long shift;
int neg = 0;
for (;;) {
if (FIXNUM_P(y)) {
shift = FIX2LONG(y);
if (shift < 0) {
neg = 1;
shift = -shift;
}
break;
}
else if (RB_TYPE_P(y, T_BIGNUM)) {
if (!RBIGNUM_SIGN(y)) {
VALUE t = check_shiftdown(y, x);
if (!NIL_P(t)) return t;
neg = 1;
}
shift = big2ulong(y, "long", TRUE);
break;
}
y = rb_to_int(y);
}
x = neg ? big_rshift(x, shift) : big_lshift(x, shift);
return bignorm(x);
}
static VALUE
big_lshift(VALUE x, unsigned long shift)
{
BDIGIT *xds, *zds;
long s1 = shift/BITSPERDIG;
int s2 = (int)(shift%BITSPERDIG);
VALUE z;
BDIGIT_DBL num = 0;
long len, i;
len = RBIGNUM_LEN(x);
z = bignew(len+s1+1, RBIGNUM_SIGN(x));
zds = BDIGITS(z);
for (i=0; i<s1; i++) {
*zds++ = 0;
}
xds = BDIGITS(x);
for (i=0; i<len; i++) {
num = num | (BDIGIT_DBL)*xds++<<s2;
*zds++ = BIGLO(num);
num = BIGDN(num);
}
*zds = BIGLO(num);
return z;
}
/*
* call-seq:
* big >> numeric -> integer
*
* Shifts big right _numeric_ positions (left if _numeric_ is negative).
*/
VALUE
rb_big_rshift(VALUE x, VALUE y)
{
long shift;
int neg = 0;
for (;;) {
if (FIXNUM_P(y)) {
shift = FIX2LONG(y);
if (shift < 0) {
neg = 1;
shift = -shift;
}
break;
}
else if (RB_TYPE_P(y, T_BIGNUM)) {
if (RBIGNUM_SIGN(y)) {
VALUE t = check_shiftdown(y, x);
if (!NIL_P(t)) return t;
}
else {
neg = 1;
}
shift = big2ulong(y, "long", TRUE);
break;
}
y = rb_to_int(y);
}
x = neg ? big_lshift(x, shift) : big_rshift(x, shift);
return bignorm(x);
}
static VALUE
big_rshift(VALUE x, unsigned long shift)
{
BDIGIT *xds, *zds;
long s1 = shift/BITSPERDIG;
int s2 = (int)(shift%BITSPERDIG);
VALUE z;
BDIGIT_DBL num = 0;
long i, j;
volatile VALUE save_x;
if (s1 > RBIGNUM_LEN(x)) {
if (RBIGNUM_SIGN(x))
return INT2FIX(0);
else
return INT2FIX(-1);
}
if (!RBIGNUM_SIGN(x)) {
x = rb_big_clone(x);
get2comp(x);
}
save_x = x;
xds = BDIGITS(x);
i = RBIGNUM_LEN(x); j = i - s1;
if (j == 0) {
if (RBIGNUM_SIGN(x)) return INT2FIX(0);
else return INT2FIX(-1);
}
z = bignew(j, RBIGNUM_SIGN(x));
if (!RBIGNUM_SIGN(x)) {
num = ((BDIGIT_DBL)~0) << BITSPERDIG;
}
zds = BDIGITS(z);
while (i--, j--) {
num = (num | xds[i]) >> s2;
zds[j] = BIGLO(num);
num = BIGUP(xds[i]);
}
if (!RBIGNUM_SIGN(x)) {
get2comp(z);
}
RB_GC_GUARD(save_x);
return z;
}
/*
* call-seq:
* big[n] -> 0, 1
*
* Bit Reference---Returns the <em>n</em>th bit in the (assumed) binary
* representation of <i>big</i>, where <i>big</i>[0] is the least
* significant bit.
*
* a = 9**15
* 50.downto(0) do |n|
* print a[n]
* end
*
* <em>produces:</em>
*
* 000101110110100000111000011110010100111100010111001
*
*/
static VALUE
rb_big_aref(VALUE x, VALUE y)
{
BDIGIT *xds;
BDIGIT_DBL num;
VALUE shift;
long i, s1, s2;
if (RB_TYPE_P(y, T_BIGNUM)) {
if (!RBIGNUM_SIGN(y))
return INT2FIX(0);
bigtrunc(y);
if (RBIGNUM_LEN(y) > DIGSPERLONG) {
out_of_range:
return RBIGNUM_SIGN(x) ? INT2FIX(0) : INT2FIX(1);
}
shift = big2ulong(y, "long", FALSE);
}
else {
i = NUM2LONG(y);
if (i < 0) return INT2FIX(0);
shift = (VALUE)i;
}
s1 = shift/BITSPERDIG;
s2 = shift%BITSPERDIG;
if (s1 >= RBIGNUM_LEN(x)) goto out_of_range;
if (!RBIGNUM_SIGN(x)) {
xds = BDIGITS(x);
i = 0; num = 1;
while (num += ~xds[i], ++i <= s1) {
num = BIGDN(num);
}
}
else {
num = BDIGITS(x)[s1];
}
if (num & ((BDIGIT_DBL)1<<s2))
return INT2FIX(1);
return INT2FIX(0);
}
/*
* call-seq:
* big.hash -> fixnum
*
* Compute a hash based on the value of _big_.
*/
static VALUE
rb_big_hash(VALUE x)
{
st_index_t hash;
hash = rb_memhash(BDIGITS(x), sizeof(BDIGIT)*RBIGNUM_LEN(x)) ^ RBIGNUM_SIGN(x);
return INT2FIX(hash);
}
/*
* MISSING: documentation
*/
static VALUE
rb_big_coerce(VALUE x, VALUE y)
{
if (FIXNUM_P(y)) {
y = rb_int2big(FIX2LONG(y));
}
else if (!RB_TYPE_P(y, T_BIGNUM)) {
rb_raise(rb_eTypeError, "can't coerce %s to Bignum",
rb_obj_classname(y));
}
return rb_assoc_new(y, x);
}
/*
* call-seq:
* big.abs -> aBignum
*
* Returns the absolute value of <i>big</i>.
*
* -1234567890987654321.abs #=> 1234567890987654321
*/
static VALUE
rb_big_abs(VALUE x)
{
if (!RBIGNUM_SIGN(x)) {
x = rb_big_clone(x);
RBIGNUM_SET_SIGN(x, 1);
}
return x;
}
/*
* call-seq:
* big.size -> integer
*
* Returns the number of bytes in the machine representation of
* <i>big</i>.
*
* (256**10 - 1).size #=> 12
* (256**20 - 1).size #=> 20
* (256**40 - 1).size #=> 40
*/
static VALUE
rb_big_size(VALUE big)
{
return LONG2FIX(RBIGNUM_LEN(big)*SIZEOF_BDIGITS);
}
/*
* call-seq:
* big.odd? -> true or false
*
* Returns <code>true</code> if <i>big</i> is an odd number.
*/
static VALUE
rb_big_odd_p(VALUE num)
{
if (BDIGITS(num)[0] & 1) {
return Qtrue;
}
return Qfalse;
}
/*
* call-seq:
* big.even? -> true or false
*
* Returns <code>true</code> if <i>big</i> is an even number.
*/
static VALUE
rb_big_even_p(VALUE num)
{
if (BDIGITS(num)[0] & 1) {
return Qfalse;
}
return Qtrue;
}
/*
* Bignum objects hold integers outside the range of
* Fixnum. Bignum objects are created
* automatically when integer calculations would otherwise overflow a
* Fixnum. When a calculation involving
* Bignum objects returns a result that will fit in a
* Fixnum, the result is automatically converted.
*
* For the purposes of the bitwise operations and <code>[]</code>, a
* Bignum is treated as if it were an infinite-length
* bitstring with 2's complement representation.
*
* While Fixnum values are immediate, Bignum
* objects are not---assignment and parameter passing work with
* references to objects, not the objects themselves.
*
*/
void
Init_Bignum(void)
{
rb_cBignum = rb_define_class("Bignum", rb_cInteger);
rb_define_method(rb_cBignum, "to_s", rb_big_to_s, -1);
rb_define_method(rb_cBignum, "coerce", rb_big_coerce, 1);
rb_define_method(rb_cBignum, "-@", rb_big_uminus, 0);
rb_define_method(rb_cBignum, "+", rb_big_plus, 1);
rb_define_method(rb_cBignum, "-", rb_big_minus, 1);
rb_define_method(rb_cBignum, "*", rb_big_mul, 1);
rb_define_method(rb_cBignum, "/", rb_big_div, 1);
rb_define_method(rb_cBignum, "%", rb_big_modulo, 1);
rb_define_method(rb_cBignum, "div", rb_big_idiv, 1);
rb_define_method(rb_cBignum, "divmod", rb_big_divmod, 1);
rb_define_method(rb_cBignum, "modulo", rb_big_modulo, 1);
rb_define_method(rb_cBignum, "remainder", rb_big_remainder, 1);
rb_define_method(rb_cBignum, "fdiv", rb_big_fdiv, 1);
rb_define_method(rb_cBignum, "**", rb_big_pow, 1);
rb_define_method(rb_cBignum, "&", rb_big_and, 1);
rb_define_method(rb_cBignum, "|", rb_big_or, 1);
rb_define_method(rb_cBignum, "^", rb_big_xor, 1);
rb_define_method(rb_cBignum, "~", rb_big_neg, 0);
rb_define_method(rb_cBignum, "<<", rb_big_lshift, 1);
rb_define_method(rb_cBignum, ">>", rb_big_rshift, 1);
rb_define_method(rb_cBignum, "[]", rb_big_aref, 1);
rb_define_method(rb_cBignum, "<=>", rb_big_cmp, 1);
rb_define_method(rb_cBignum, "==", rb_big_eq, 1);
rb_define_method(rb_cBignum, ">", big_gt, 1);
rb_define_method(rb_cBignum, ">=", big_ge, 1);
rb_define_method(rb_cBignum, "<", big_lt, 1);
rb_define_method(rb_cBignum, "<=", big_le, 1);
rb_define_method(rb_cBignum, "===", rb_big_eq, 1);
rb_define_method(rb_cBignum, "eql?", rb_big_eql, 1);
rb_define_method(rb_cBignum, "hash", rb_big_hash, 0);
rb_define_method(rb_cBignum, "to_f", rb_big_to_f, 0);
rb_define_method(rb_cBignum, "abs", rb_big_abs, 0);
rb_define_method(rb_cBignum, "magnitude", rb_big_abs, 0);
rb_define_method(rb_cBignum, "size", rb_big_size, 0);
rb_define_method(rb_cBignum, "odd?", rb_big_odd_p, 0);
rb_define_method(rb_cBignum, "even?", rb_big_even_p, 0);
power_cache_init();
big_three = rb_uint2big(3);
rb_gc_register_mark_object(big_three);
}
Jump to Line
Something went wrong with that request. Please try again.