diff options
Diffstat (limited to 'bignum.c')
| -rw-r--r-- | bignum.c | 113 |
1 files changed, 66 insertions, 47 deletions
@@ -4213,15 +4213,29 @@ big2str_find_n1(VALUE x, int base) } struct big2str_struct { + int negative; int base; BDIGIT hbase; int hbase_numdigits; BDIGIT_DBL hbase2; int hbase2_numdigits; + VALUE result; + char *ptr; }; -static size_t -big2str_orig(struct big2str_struct *b2s, VALUE x, char* ptr, size_t len, int trim) +static void +big2str_alloc(struct big2str_struct *b2s, size_t len) +{ + if (LONG_MAX-1 < len) + rb_raise(rb_eArgError, "too big number"); + b2s->result = rb_usascii_str_new(0, (long)(len + 1)); /* plus one for sign */ + b2s->ptr = RSTRING_PTR(b2s->result); + if (b2s->negative) + *b2s->ptr++ = '-'; +} + +static void +big2str_orig(struct big2str_struct *b2s, VALUE x, size_t len, size_t taillen) { long i = RBIGNUM_LEN(x); size_t j; @@ -4229,24 +4243,28 @@ big2str_orig(struct big2str_struct *b2s, VALUE x, char* ptr, size_t len, int tri BDIGIT* ds = BDIGITS(x); BDIGIT_DBL num; char buf[SIZEOF_BDIGIT_DBL*CHAR_BIT], *p; + int trim = !b2s->ptr; assert(i <= 2); + num = 0; + if (0 < i) + num = ds[0]; + if (1 < i) + num |= BIGUP(ds[1]); + + if (num == 0) + return; + if (trim) { p = buf; j = sizeof(buf); } else { - p = ptr; + p = b2s->ptr; j = len; } - num = 0; - if (0 < i) - num = ds[0]; - if (1 < i) - num |= BIGUP(ds[1]); - k = b2s->hbase2_numdigits; while (k--) { p[--j] = ruby_digitmap[num % b2s->base]; @@ -4255,45 +4273,43 @@ big2str_orig(struct big2str_struct *b2s, VALUE x, char* ptr, size_t len, int tri if (trim && num == 0) break; } if (trim) { - while (j < sizeof(buf) && p[j] == '0') j++; - assert(sizeof(buf)-j <= len); - MEMCPY(ptr, p + j, char, sizeof(buf) - j); + while (j < sizeof(buf) && buf[j] == '0') + j++; len = sizeof(buf) - j; + big2str_alloc(b2s, len + taillen); + MEMCPY(b2s->ptr, buf + j, char, len); } - return len; + b2s->ptr += len; } -static size_t -big2str_karatsuba(struct big2str_struct *b2s, VALUE x, char* ptr, - int power_level, size_t len, int trim) +static void +big2str_karatsuba(struct big2str_struct *b2s, VALUE x, + int power_level, size_t len, size_t taillen) { - size_t lh, ll, m1; + size_t m1; VALUE b, q, r; if (BIGZEROP(x)) { - if (trim) return 0; - else { - memset(ptr, '0', len); - return len; + if (b2s->ptr) { + memset(b2s->ptr, '0', len); + b2s->ptr += len; } + return; } if (power_level < 0) { - return big2str_orig(b2s, x, ptr, len, trim); + big2str_orig(b2s, x, len, taillen); + return; } b = power_cache_get_power(b2s->base, power_level, &m1); bigdivmod(x, b, &q, &r); rb_obj_hide(q); rb_obj_hide(r); - lh = big2str_karatsuba(b2s, q, ptr, power_level-1, - len - m1, trim); + big2str_karatsuba(b2s, q, power_level-1, len ? len-m1 : 0, m1+taillen); rb_big_resize(q, 0); - ll = big2str_karatsuba(b2s, r, ptr + lh, power_level-1, - m1, !lh && trim); + big2str_karatsuba(b2s, r, power_level-1, m1, taillen); rb_big_resize(r, 0); - - return lh + ll; } static VALUE @@ -4330,10 +4346,8 @@ big2str_base_powerof2(VALUE x, size_t len, int base, int trim) static VALUE rb_big2str1(VALUE x, int base, int trim) { - int off; - VALUE ss, xx; + VALUE xx; size_t n2, len; - char* ptr; struct big2str_struct b2s_data; int power_level; VALUE power; @@ -4355,13 +4369,6 @@ rb_big2str1(VALUE x, int base, int trim) return big2str_base_powerof2(x, n2, base, trim); } - if (LONG_MAX-1 < n2) - rb_raise(rb_eArgError, "too big number"); - - ss = rb_usascii_str_new(0, (long)(n2 + 1)); /* plus one for sign */ - ptr = RSTRING_PTR(ss); - ptr[0] = RBIGNUM_SIGN(x) ? '+' : '-'; - power_level = 0; power = power_cache_get_power(base, power_level, NULL); while (power_level < MAX_BIG2STR_TABLE_ENTRIES && @@ -4380,27 +4387,39 @@ rb_big2str1(VALUE x, int base, int trim) #endif } + b2s_data.negative = RBIGNUM_NEGATIVE_P(x); b2s_data.base = base; b2s_data.hbase = maxpow_in_bdigit(base, &b2s_data.hbase_numdigits); b2s_data.hbase2 = maxpow_in_bdigit_dbl(base, &b2s_data.hbase2_numdigits); - off = !(trim && RBIGNUM_SIGN(x)); /* erase plus sign if trim */ + + if (trim) { + b2s_data.result = Qnil; + b2s_data.ptr = NULL; + len = 0; + } + else { + len = n2; + if (LONG_MAX-1 < n2) + rb_raise(rb_eArgError, "too big number"); + b2s_data.result = rb_usascii_str_new(0, (long)(n2 + 1)); /* plus one for sign */ + b2s_data.ptr = RSTRING_PTR(b2s_data.result); + *b2s_data.ptr++ = b2s_data.negative ? '-' : '+'; + } + xx = rb_big_clone(x); RBIGNUM_SET_SIGN(xx, 1); if (power_level < 0) { - len = off + big2str_orig(&b2s_data, xx, ptr + off, n2, trim); + big2str_orig(&b2s_data, xx, len, 0); } else { - len = off + big2str_karatsuba(&b2s_data, xx, ptr + off, power_level, - n2, trim); + big2str_karatsuba(&b2s_data, xx, power_level, len, 0); } rb_big_resize(xx, 0); - assert(len <= LONG_MAX); - - ptr[len] = '\0'; - rb_str_resize(ss, (long)len); + *b2s_data.ptr = '\0'; + rb_str_resize(b2s_data.result, (long)(b2s_data.ptr - RSTRING_PTR(b2s_data.result))); - return ss; + return b2s_data.result; } /* deprecated */ |