static bool isleaf(scm *s, long long i)
{
if (scm_get_offset(s, i))
{
long long x = scm_get_index(s, i);
long long j;
for (int c = 0; c < 4; c++)
{
// If child c exists and has data, then x is not a leaf.
if ((j = scm_search(s, scm_page_child(x, c))) != -1)
if (scm_get_offset(s, j) > 0)
return false;
}
return true;
}
return false;
}
static void process(scm *s, scm **V, int C, int O)
{
const size_t S = (size_t) (scm_get_n(s) + 2)
* (size_t) (scm_get_n(s) + 2)
* (size_t) (scm_get_c(s));
float *p;
float *q;
// Allocate temporary and accumulator buffers.
if ((p = scm_alloc_buffer(s)) && (q = scm_alloc_buffer(s)))
{
long long b = 0;
long long m = 0;
long long i = 0;
long long o[256];
// Determine the highest page index in the input.
for (int f = 0; f < C; ++f)
{
if (m < scm_get_index(V[f], scm_get_length(V[f]) - 1))
m = scm_get_index(V[f], scm_get_length(V[f]) - 1);
o[f] = 0;
}
// Process each page of an SCM with the desired depth.
for (int x = 0; x <= m; ++x)
{
int c = scm_get_c(s);
int g = 0;
int k = 0;
// Count the SCMs contributing to page x.
for (int f = 0; f < C; ++f)
if ((i = scm_search(V[f], x)) < 0)
o[f] = 0;
else
{
o[f] = scm_get_offset(V[f], i);
g = f;
k++;
}
// If there is exactly one contributor, repeat its page.
if (k == 1)
b = scm_repeat(s, b, V[g], o[g]);
// If there is more than one, append their summed pages.
else if (k > 1)
{
memset(p, 0, S * sizeof (float));
for (int f = 0; f < C; ++f)
if (o[f] && scm_read_page(V[f], o[f], q))
switch (O)
{
case 0:
for (size_t j = 0; j < S; ++j)
p[j] = sum(p[j], q[j]);
break;
case 1:
for (size_t j = 0; j < S; ++j)
p[j] = max(p[j], q[j]);
break;
case 2:
for (size_t j = 0; j < S; ++j)
p[j] = avg(p[j], q[j]);
break;
case 3:
for (size_t j = 0; j < S; j += c)
blend(p + j, q + j, c);
break;
}
b = scm_append(s, b, x, p);
}
}
free(q);
free(p);
}
}
