lix/src/libexpr/attr-set.cc
Eelco Dolstra c8bb2371eb Optimize empty sets
This reduces the number of Bindings allocations by about 10%.
2015-07-23 23:11:08 +02:00

64 lines
1.2 KiB
C++

#include "attr-set.hh"
#include "eval.hh"
#include <algorithm>
namespace nix {
static void * allocBytes(size_t n)
{
void * p;
#if HAVE_BOEHMGC
p = GC_malloc(n);
#else
p = malloc(n);
#endif
if (!p) throw std::bad_alloc();
return p;
}
/* Allocate a new array of attributes for an attribute set with a specific
capacity. The space is implicitly reserved after the Bindings
structure. */
Bindings * EvalState::allocBindings(Bindings::size_t capacity)
{
return new (allocBytes(sizeof(Bindings) + sizeof(Attr) * capacity)) Bindings(capacity);
}
void EvalState::mkAttrs(Value & v, unsigned int capacity)
{
if (capacity == 0) {
v = vEmptySet;
return;
}
clearValue(v);
v.type = tAttrs;
v.attrs = allocBindings(capacity);
nrAttrsets++;
nrAttrsInAttrsets += capacity;
}
/* Create a new attribute named 'name' on an existing attribute set stored
in 'vAttrs' and return the newly allocated Value which is associated with
this attribute. */
Value * EvalState::allocAttr(Value & vAttrs, const Symbol & name)
{
Value * v = allocValue();
vAttrs.attrs->push_back(Attr(name, v));
return v;
}
void Bindings::sort()
{
std::sort(begin(), end());
}
}