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* random.c (scm_c_random_bignum): use SCM_CHAR_BIT.

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This commit is contained in:
Rob Browning 2003-04-16 19:44:55 +00:00
commit 0d79003d44
1 changed files with 4 additions and 3 deletions
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7
libguile/random.c
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@ -251,9 +251,10 @@ scm_c_random_bignum (scm_t_rstate *state, SCM m)
SCM result = scm_i_mkbig ();
const size_t m_bits = mpz_sizeinbase (SCM_I_BIG_MPZ (m), 2);
/* how many bits would only partially fill the last unsigned long? */
const size_t end_bits = m_bits % (sizeof (unsigned long) * 8);
const size_t end_bits = m_bits % (sizeof (unsigned long) * SCM_CHAR_BIT);
unsigned long *random_chunks = NULL;
const unsigned long num_full_chunks = m_bits / (sizeof (unsigned long) * 8);
const unsigned long num_full_chunks =
m_bits / (sizeof (unsigned long) * SCM_CHAR_BIT);
const unsigned long num_chunks = num_full_chunks + ((end_bits) ? 1 : 0);
/* we know the result will be this big */
@ -275,7 +276,7 @@ scm_c_random_bignum (scm_t_rstate *state, SCM m)
/* generate a mask with ones in the end_bits position, i.e. if
end_bits is 3, then we'd have a mask of ...0000000111 */
const unsigned long rndbits = scm_the_rng.random_bits (state);
int rshift = (sizeof (unsigned long) * 8) - end_bits;
int rshift = (sizeof (unsigned long) * SCM_CHAR_BIT) - end_bits;
unsigned long mask = ((unsigned long) ULONG_MAX) >> rshift;
unsigned long highest_bits = rndbits & mask;
*current_chunk-- = highest_bits;