diff options
Diffstat (limited to 'bignum.c')
| -rw-r--r-- | bignum.c | 40 |
1 files changed, 27 insertions, 13 deletions
@@ -267,13 +267,17 @@ bytes_2comp(unsigned char *buf, size_t len) return 1; } +static void +bary_neg(BDIGIT *ds, size_t n) +{ + while (n--) + ds[n] = BIGLO(~ds[n]); +} + static int -bary_2comp(BDIGIT *ds, size_t n) +bary_plus_one(BDIGIT *ds, size_t n) { - size_t i = n; - if (!n) return 1; - while (i--) ds[i] = BIGLO(~ds[i]); - i = 0; + size_t i; for (i = 0; i < n; i++) { ds[i] = BIGLO(ds[i]+1); if (ds[i] != 0) @@ -282,6 +286,21 @@ bary_2comp(BDIGIT *ds, size_t n) return 1; } +static int +bary_2comp(BDIGIT *ds, size_t n) +{ + if (!n) return 1; + bary_neg(ds, n); + return bary_plus_one(ds, n); +} + +static void +big_extend_carry(VALUE x) +{ + rb_big_resize(x, RBIGNUM_LEN(x)+1); + BDIGITS(x)[RBIGNUM_LEN(x)-1] = 1; +} + /* modify a bignum by 2's complement */ static void get2comp(VALUE x) @@ -290,9 +309,7 @@ get2comp(VALUE x) BDIGIT *ds = BDIGITS(x); if (bary_2comp(ds, i)) { - rb_big_resize(x, RBIGNUM_LEN(x)+1); - ds = BDIGITS(x); - ds[RBIGNUM_LEN(x)-1] = 1; + big_extend_carry(x); } } @@ -1696,8 +1713,7 @@ rb_integer_unpack(const void *words, size_t numwords, size_t wordsize, size_t na if (sign == -2) { if (val) { - rb_big_resize(val, (long)num_bdigits+1); - BDIGITS(val)[num_bdigits] = 1; + big_extend_carry(val); } else if (num_bdigits == numberof(fixbuf)) { val = bignew((long)num_bdigits+1, 0); @@ -3026,9 +3042,7 @@ rb_big_neg(VALUE x) ds = BDIGITS(z); i = RBIGNUM_LEN(x); if (!i) return INT2FIX(~(SIGNED_VALUE)0); - while (i--) { - ds[i] = BIGLO(~ds[i]); - } + bary_neg(ds, i); RBIGNUM_SET_SIGN(z, !RBIGNUM_SIGN(z)); if (RBIGNUM_SIGN(x)) get2comp(z); |