sexp sexp_double_to_ratio (sexp ctx, double f) {
int sign, i;
sexp_gc_var3(res, whole, scale);
if (f == trunc(f))
return sexp_bignum_normalize(sexp_double_to_bignum(ctx, f));
sexp_gc_preserve3(ctx, res, whole, scale);
whole = sexp_double_to_bignum(ctx, trunc(f));
res = sexp_fixnum_to_bignum(ctx, SEXP_ZERO);
scale = SEXP_ONE;
sign = (f < 0 ? -1 : 1);
for (i=0, f=fabs(f-trunc(f)); f != trunc(f) && i < 15; i++) {
res = sexp_bignum_fxmul(ctx, NULL, res, 10, 0);
f = f * 10;
res = sexp_bignum_fxadd(ctx, res, double_10s_digit(f));
f = f - trunc(f);
scale = sexp_mul(ctx, scale, SEXP_TEN);
}
sexp_bignum_sign(res) = sign;
res = sexp_bignum_normalize(res);
scale = sexp_bignum_normalize(scale);
res = sexp_make_ratio(ctx, res, scale);
res = sexp_ratio_normalize(ctx, res, SEXP_FALSE);
res = sexp_add(ctx, res, whole);
sexp_gc_release3(ctx);
return res;
}
static sexp sexp_bit_and (sexp ctx, sexp self, sexp_sint_t n, sexp x, sexp y) {
sexp res;
#if SEXP_USE_BIGNUMS
sexp_sint_t len, i;
#endif
if (sexp_fixnump(x)) {
if (sexp_fixnump(y))
res = (sexp) ((sexp_uint_t)x & (sexp_uint_t)y);
#if SEXP_USE_BIGNUMS
else if (sexp_bignump(y))
res = sexp_bit_and(ctx, self, n, y, x);
#endif
else
res = sexp_type_exception(ctx, self, SEXP_FIXNUM, y);
#if SEXP_USE_BIGNUMS
} else if (sexp_bignump(x)) {
if (sexp_fixnump(y)) {
res = sexp_make_fixnum(sexp_unbox_fixnum(y) & sexp_bignum_data(x)[0]);
} else if (sexp_bignump(y)) {
if (sexp_bignum_length(x) < sexp_bignum_length(y))
res = sexp_copy_bignum(ctx, NULL, x, 0);
else
res = sexp_copy_bignum(ctx, NULL, y, 0);
for (i=0, len=sexp_bignum_length(res); i<len; i++)
sexp_bignum_data(res)[i]
= sexp_bignum_data(x)[i] & sexp_bignum_data(y)[i];
} else {
res = sexp_type_exception(ctx, self, SEXP_FIXNUM, y);
}
#endif
} else {
res = sexp_type_exception(ctx, self, SEXP_FIXNUM, x);
}
return sexp_bignum_normalize(res);
}
sexp sexp_read_bignum (sexp ctx, sexp in, sexp_uint_t init,
signed char sign, sexp_uint_t base) {
int c, digit;
sexp_gc_var1(res);
sexp_gc_preserve1(ctx, res);
res = sexp_make_bignum(ctx, SEXP_INIT_BIGNUM_SIZE);
sexp_bignum_sign(res) = sign;
sexp_bignum_data(res)[0] = init;
for (c=sexp_read_char(ctx, in); sexp_isxdigit(c); c=sexp_read_char(ctx, in)) {
digit = digit_value(c);
if ((digit < 0) || (digit >= base))
break;
res = sexp_bignum_fxmul(ctx, res, res, base, 0);
res = sexp_bignum_fxadd(ctx, res, digit);
}
if (c=='.' || c=='e' || c=='E') {
if (base != 10) {
res = sexp_read_error(ctx, "found non-base 10 float", SEXP_NULL, in);
} else {
if (c!='.') sexp_push_char(ctx, c, in); /* push the e back */
res = sexp_read_float_tail(ctx, in, sexp_bignum_to_double(res), (sign==-1));
}
#if SEXP_USE_RATIOS
} else if (c=='/') {
res = sexp_bignum_normalize(res);
res = sexp_make_ratio(ctx, res, SEXP_ONE);
sexp_ratio_denominator(res) = sexp_read_number(ctx, in, 10);
res = sexp_ratio_normalize(ctx, res, in);
#endif
#if SEXP_USE_COMPLEX
} else if (c=='i' || c=='i' || c=='+' || c=='-') {
sexp_push_char(ctx, c, in);
res = sexp_bignum_normalize(res);
res = sexp_read_complex_tail(ctx, in, res);
#endif
} else if ((c!=EOF) && ! sexp_is_separator(c)) {
res = sexp_read_error(ctx, "invalid numeric syntax",
sexp_make_character(c), in);
} else {
sexp_push_char(ctx, c, in);
}
sexp_gc_release1(ctx);
return sexp_bignum_normalize(res);
}
sexp sexp_bignum_expt (sexp ctx, sexp a, sexp b) {
sexp_sint_t e = sexp_unbox_fixnum(sexp_fx_abs(b));
sexp_gc_var2(res, acc);
sexp_gc_preserve2(ctx, res, acc);
res = sexp_fixnum_to_bignum(ctx, SEXP_ONE);
acc = sexp_copy_bignum(ctx, NULL, a, 0);
for (; e; e>>=1, acc=sexp_bignum_mul(ctx, NULL, acc, acc))
if (e & 1)
res = sexp_bignum_mul(ctx, NULL, res, acc);
sexp_gc_release2(ctx);
return sexp_bignum_normalize(res);
}
