diff options
Diffstat (limited to 'array.c')
| -rw-r--r-- | array.c | 31 |
1 files changed, 18 insertions, 13 deletions
@@ -4981,7 +4981,7 @@ rb_ary_combination(VALUE ary, VALUE num) } /* - * Recursively compute repeated permutations of +r+ elements of the set + * Compute repeated permutations of +r+ elements of the set * <code>[0..n-1]</code>. * * When we have a complete repeated permutation of array indexes, copy the @@ -4990,23 +4990,28 @@ rb_ary_combination(VALUE ary, VALUE num) * n: the size of the set * r: the number of elements in each permutation * p: the array (of size r) that we're filling in - * index: what index we're filling in now * values: the Ruby array that holds the actual values to permute */ static void -rpermute0(long n, long r, long *p, long index, VALUE values) +rpermute0(const long n, const long r, long *const p, const VALUE values) { - long i; - for (i = 0; i < n; i++) { - p[index] = i; - if (index < r-1) { /* if not done yet */ - rpermute0(n, r, p, index+1, values); /* recurse */ + long i = 0, index = 0; + + p[index] = i; + for (;;) { + if (++index < r-1) { + p[index] = i = 0; + continue; } - else { + for (i = 0; i < n; ++i) { + p[index] = i; if (!yield_indexed_values(values, r, p)) { rb_raise(rb_eRuntimeError, "repeated permute reentered"); } } + do { + if (index <= 0) return; + } while ((i = ++p[--index]) >= n); } } @@ -5069,13 +5074,13 @@ rb_ary_repeated_permutation(VALUE ary, VALUE num) } } else { /* this is the general case */ - volatile VALUE t0 = tmpbuf(r, sizeof(long)); - long *p = (long*)RSTRING_PTR(t0); + volatile VALUE t0; + long *p = ALLOCV_N(long, t0, r * sizeof(long)); VALUE ary0 = ary_make_shared_copy(ary); /* private defensive copy of ary */ RBASIC_CLEAR_CLASS(ary0); - rpermute0(n, r, p, 0, ary0); /* compute and yield repeated permutations */ - tmpbuf_discard(t0); + rpermute0(n, r, p, ary0); /* compute and yield repeated permutations */ + ALLOCV_END(t0); RBASIC_SET_CLASS_RAW(ary0, rb_cArray); } return ary; |