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* numbers.c (scm_i_fraction_reduce): move logic into

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scm_i_make_ratio(), so fractions are only read.
scm_i_fraction_reduce() modifies a fraction when reading it.  A
race condition might lead to fractions being corrupted by reading
them concurrently.

* numbers.h: remove SCM_FRACTION_SET_NUMERATOR,
SCM_FRACTION_SET_DENOMINATOR, SCM_FRACTION_REDUCED_BIT,
SCM_FRACTION_REDUCED_SET, SCM_FRACTION_REDUCED_CLEAR,
SCM_FRACTION_REDUCED.
This commit is contained in:
Han-Wen Nienhuys 2006-12-23 20:55:47 +00:00
parent 33bb60df9f
commit f82ca609d3
3 changed files with 30 additions and 39 deletions
Download patch file Download diff file Expand all files Collapse all files

45
libguile/numbers.c
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@ -452,28 +452,21 @@ scm_i_make_ratio (SCM numerator, SCM denominator)
/* No, it's a proper fraction.
*/
return scm_double_cell (scm_tc16_fraction,
SCM_UNPACK (numerator),
SCM_UNPACK (denominator), 0);
{
SCM divisor = scm_gcd (numerator, denominator);
if (!(scm_is_eq (divisor, SCM_I_MAKINUM(1))))
{
numerator = scm_divide (numerator, divisor);
denominator = scm_divide (denominator, divisor);
}
return scm_double_cell (scm_tc16_fraction,
SCM_UNPACK (numerator),
SCM_UNPACK (denominator), 0);
}
}
#undef FUNC_NAME
static void scm_i_fraction_reduce (SCM z)
{
if (!(SCM_FRACTION_REDUCED (z)))
{
SCM divisor;
divisor = scm_gcd (SCM_FRACTION_NUMERATOR (z), SCM_FRACTION_DENOMINATOR (z));
if (!(scm_is_eq (divisor, SCM_I_MAKINUM(1))))
{
/* is this safe? */
SCM_FRACTION_SET_NUMERATOR (z, scm_divide (SCM_FRACTION_NUMERATOR (z), divisor));
SCM_FRACTION_SET_DENOMINATOR (z, scm_divide (SCM_FRACTION_DENOMINATOR (z), divisor));
}
SCM_FRACTION_REDUCED_SET (z);
}
}
double
scm_i_fraction2double (SCM z)
{
@ -2387,7 +2380,6 @@ SCM_DEFINE (scm_number_to_string, "number->string", 1, 1, 0,
}
else if (SCM_FRACTIONP (n))
{
scm_i_fraction_reduce (n);
return scm_string_append (scm_list_3 (scm_number_to_string (SCM_FRACTION_NUMERATOR (n), radix),
scm_from_locale_string ("/"),
scm_number_to_string (SCM_FRACTION_DENOMINATOR (n), radix)));
@ -2441,7 +2433,6 @@ int
scm_i_print_fraction (SCM sexp, SCM port, scm_print_state *pstate SCM_UNUSED)
{
SCM str;
scm_i_fraction_reduce (sexp);
str = scm_number_to_string (sexp, SCM_UNDEFINED);
scm_lfwrite (scm_i_string_chars (str), scm_i_string_length (str), port);
scm_remember_upto_here_1 (str);
@ -3109,8 +3100,6 @@ scm_complex_equalp (SCM x, SCM y)
SCM
scm_i_fraction_equalp (SCM x, SCM y)
{
scm_i_fraction_reduce (x);
scm_i_fraction_reduce (y);
if (scm_is_false (scm_equal_p (SCM_FRACTION_NUMERATOR (x),
SCM_FRACTION_NUMERATOR (y)))
|| scm_is_false (scm_equal_p (SCM_FRACTION_DENOMINATOR (x),
@ -5434,10 +5423,7 @@ scm_numerator (SCM z)
else if (SCM_BIGP (z))
return z;
else if (SCM_FRACTIONP (z))
{
scm_i_fraction_reduce (z);
return SCM_FRACTION_NUMERATOR (z);
}
return SCM_FRACTION_NUMERATOR (z);
else if (SCM_REALP (z))
return scm_exact_to_inexact (scm_numerator (scm_inexact_to_exact (z)));
else
@ -5456,10 +5442,7 @@ scm_denominator (SCM z)
else if (SCM_BIGP (z))
return SCM_I_MAKINUM (1);
else if (SCM_FRACTIONP (z))
{
scm_i_fraction_reduce (z);
return SCM_FRACTION_DENOMINATOR (z);
}
return SCM_FRACTION_DENOMINATOR (z);
else if (SCM_REALP (z))
return scm_exact_to_inexact (scm_denominator (scm_inexact_to_exact (z)));
else