Files
linguist/samples/D/aa.d
Martin Nowak fa6ae1116f better heuristic distinction of .d files (#3145)
* fix benchmark

- require json for Hash.to_json

* better heuristic distinction of .d files

- properly recongnize dtrace probes
- recongnize \ in Makefile paths
- recongnize single line `file.ext : dep.ext` make targets
- recognize D module, import, function, and unittest declarations
- add more representative D samples

D changed from 31.2% to 28.1%
DTrace changed from 33.5% to 32.5%
Makefile changed from 35.3% to 39.4%

See
https://gist.github.com/MartinNowak/fda24fdef64f2dbb05c5a5ceabf22bd3
for the scraper used to get a test corpus.
2017-03-30 18:25:53 +01:00

441 lines
11 KiB
D

/**
* Implementation of associative arrays.
*
* Copyright: Martin Nowak 2015 -.
* License: $(LINK2 http://www.boost.org/LICENSE_1_0.txt, Boost License 1.0)
* Authors: Martin Nowak
*/
module core.aa;
import core.memory : GC;
private
{
// grow threshold
enum GROW_NUM = 4;
enum GROW_DEN = 5;
// shrink threshold
enum SHRINK_NUM = 1;
enum SHRINK_DEN = 8;
// grow factor
enum GROW_FAC = 4;
// growing the AA doubles it's size, so the shrink threshold must be
// smaller than half the grow threshold to have a hysteresis
static assert(GROW_FAC * SHRINK_NUM * GROW_DEN < GROW_NUM * SHRINK_DEN);
// initial load factor (for literals), mean of both thresholds
enum INIT_NUM = (GROW_DEN * SHRINK_NUM + GROW_NUM * SHRINK_DEN) / 2;
enum INIT_DEN = SHRINK_DEN * GROW_DEN;
// magic hash constants to distinguish empty, deleted, and filled buckets
enum HASH_EMPTY = 0;
enum HASH_DELETED = 0x1;
enum HASH_FILLED_MARK = size_t(1) << 8 * size_t.sizeof - 1;
}
enum INIT_NUM_BUCKETS = 8;
struct AA(Key, Val)
{
this(size_t sz)
{
impl = new Impl(nextpow2(sz));
}
@property bool empty() const pure nothrow @safe @nogc
{
return !length;
}
@property size_t length() const pure nothrow @safe @nogc
{
return impl is null ? 0 : impl.length;
}
void opIndexAssign(Val val, in Key key)
{
// lazily alloc implementation
if (impl is null)
impl = new Impl(INIT_NUM_BUCKETS);
// get hash and bucket for key
immutable hash = calcHash(key);
// found a value => assignment
if (auto p = impl.findSlotLookup(hash, key))
{
p.entry.val = val;
return;
}
auto p = findSlotInsert(hash);
if (p.deleted)
--deleted;
// check load factor and possibly grow
else if (++used * GROW_DEN > dim * GROW_NUM)
{
grow();
p = findSlotInsert(hash);
assert(p.empty);
}
// update search cache and allocate entry
firstUsed = min(firstUsed, cast(uint)(p - buckets.ptr));
p.hash = hash;
p.entry = new Impl.Entry(key, val); // TODO: move
return;
}
ref inout(Val) opIndex(in Key key) inout @trusted
{
auto p = opIn_r(key);
assert(p !is null);
return *p;
}
inout(Val)* opIn_r(in Key key) inout @trusted
{
if (empty)
return null;
immutable hash = calcHash(key);
if (auto p = findSlotLookup(hash, key))
return &p.entry.val;
return null;
}
bool remove(in Key key)
{
if (empty)
return false;
immutable hash = calcHash(key);
if (auto p = findSlotLookup(hash, key))
{
// clear entry
p.hash = HASH_DELETED;
p.entry = null;
++deleted;
if (length * SHRINK_DEN < dim * SHRINK_NUM)
shrink();
return true;
}
return false;
}
Val get(in Key key, lazy Val val)
{
auto p = opIn_r(key);
return p is null ? val : *p;
}
ref Val getOrSet(in Key key, lazy Val val)
{
// lazily alloc implementation
if (impl is null)
impl = new Impl(INIT_NUM_BUCKETS);
// get hash and bucket for key
immutable hash = calcHash(key);
// found a value => assignment
if (auto p = impl.findSlotLookup(hash, key))
return p.entry.val;
auto p = findSlotInsert(hash);
if (p.deleted)
--deleted;
// check load factor and possibly grow
else if (++used * GROW_DEN > dim * GROW_NUM)
{
grow();
p = findSlotInsert(hash);
assert(p.empty);
}
// update search cache and allocate entry
firstUsed = min(firstUsed, cast(uint)(p - buckets.ptr));
p.hash = hash;
p.entry = new Impl.Entry(key, val);
return p.entry.val;
}
/**
Convert the AA to the type of the builtin language AA.
*/
Val[Key] toBuiltinAA() pure nothrow
{
return cast(Val[Key]) _aaFromCoreAA(impl, rtInterface);
}
private:
private this(inout(Impl)* impl) inout
{
this.impl = impl;
}
ref Val getLValue(in Key key)
{
// lazily alloc implementation
if (impl is null)
impl = new Impl(INIT_NUM_BUCKETS);
// get hash and bucket for key
immutable hash = calcHash(key);
// found a value => assignment
if (auto p = impl.findSlotLookup(hash, key))
return p.entry.val;
auto p = findSlotInsert(hash);
if (p.deleted)
--deleted;
// check load factor and possibly grow
else if (++used * GROW_DEN > dim * GROW_NUM)
{
grow();
p = findSlotInsert(hash);
assert(p.empty);
}
// update search cache and allocate entry
firstUsed = min(firstUsed, cast(uint)(p - buckets.ptr));
p.hash = hash;
p.entry = new Impl.Entry(key); // TODO: move
return p.entry.val;
}
static struct Impl
{
this(size_t sz)
{
buckets = allocBuckets(sz);
}
@property size_t length() const pure nothrow @nogc
{
assert(used >= deleted);
return used - deleted;
}
@property size_t dim() const pure nothrow @nogc
{
return buckets.length;
}
@property size_t mask() const pure nothrow @nogc
{
return dim - 1;
}
// find the first slot to insert a value with hash
inout(Bucket)* findSlotInsert(size_t hash) inout pure nothrow @nogc
{
for (size_t i = hash & mask, j = 1;; ++j)
{
if (!buckets[i].filled)
return &buckets[i];
i = (i + j) & mask;
}
}
// lookup a key
inout(Bucket)* findSlotLookup(size_t hash, in Key key) inout
{
for (size_t i = hash & mask, j = 1;; ++j)
{
if (buckets[i].hash == hash && key == buckets[i].entry.key)
return &buckets[i];
else if (buckets[i].empty)
return null;
i = (i + j) & mask;
}
}
void grow()
{
// If there are so many deleted entries, that growing would push us
// below the shrink threshold, we just purge deleted entries instead.
if (length * SHRINK_DEN < GROW_FAC * dim * SHRINK_NUM)
resize(dim);
else
resize(GROW_FAC * dim);
}
void shrink()
{
if (dim > INIT_NUM_BUCKETS)
resize(dim / GROW_FAC);
}
void resize(size_t ndim) pure nothrow
{
auto obuckets = buckets;
buckets = allocBuckets(ndim);
foreach (ref b; obuckets)
if (b.filled)
*findSlotInsert(b.hash) = b;
firstUsed = 0;
used -= deleted;
deleted = 0;
GC.free(obuckets.ptr); // safe to free b/c impossible to reference
}
static struct Entry
{
Key key;
Val val;
}
static struct Bucket
{
size_t hash;
Entry* entry;
@property bool empty() const
{
return hash == HASH_EMPTY;
}
@property bool deleted() const
{
return hash == HASH_DELETED;
}
@property bool filled() const
{
return cast(ptrdiff_t) hash < 0;
}
}
Bucket[] allocBuckets(size_t dim) @trusted pure nothrow
{
enum attr = GC.BlkAttr.NO_INTERIOR;
immutable sz = dim * Bucket.sizeof;
return (cast(Bucket*) GC.calloc(sz, attr))[0 .. dim];
}
Bucket[] buckets;
uint used;
uint deleted;
uint firstUsed;
}
RTInterface* rtInterface()() pure nothrow @nogc
{
static size_t aaLen(in void* pimpl) pure nothrow @nogc
{
auto aa = const(AA)(cast(const(Impl)*) pimpl);
return aa.length;
}
static void* aaGetY(void** pimpl, in void* pkey)
{
auto aa = AA(cast(Impl*)*pimpl);
auto res = &aa.getLValue(*cast(const(Key*)) pkey);
*pimpl = aa.impl; // might have changed
return res;
}
static inout(void)* aaInX(inout void* pimpl, in void* pkey)
{
auto aa = inout(AA)(cast(inout(Impl)*) pimpl);
return aa.opIn_r(*cast(const(Key*)) pkey);
}
static bool aaDelX(void* pimpl, in void* pkey)
{
auto aa = AA(cast(Impl*) pimpl);
return aa.remove(*cast(const(Key*)) pkey);
}
static immutable vtbl = RTInterface(&aaLen, &aaGetY, &aaInX, &aaDelX);
return cast(RTInterface*)&vtbl;
}
static size_t calcHash(in ref Key key)
{
return hashOf(key) | HASH_FILLED_MARK;
}
Impl* impl;
alias impl this;
}
package extern (C) void* _aaFromCoreAA(void* impl, RTInterface* rtIntf) pure nothrow;
private:
struct RTInterface
{
alias AA = void*;
size_t function(in AA aa) pure nothrow @nogc len;
void* function(AA* aa, in void* pkey) getY;
inout(void)* function(inout AA aa, in void* pkey) inX;
bool function(AA aa, in void* pkey) delX;
}
unittest
{
AA!(int, int) aa;
assert(aa.length == 0);
aa[0] = 1;
assert(aa.length == 1 && aa[0] == 1);
aa[1] = 2;
assert(aa.length == 2 && aa[1] == 2);
import core.stdc.stdio;
int[int] rtaa = aa.toBuiltinAA();
assert(rtaa.length == 2);
puts("length");
assert(rtaa[0] == 1);
assert(rtaa[1] == 2);
rtaa[2] = 3;
assert(aa[2] == 3);
}
unittest
{
auto aa = AA!(int, int)(3);
aa[0] = 0;
aa[1] = 1;
aa[2] = 2;
assert(aa.length == 3);
}
//==============================================================================
// Helper functions
//------------------------------------------------------------------------------
size_t nextpow2(in size_t n) pure nothrow @nogc
{
import core.bitop : bsr;
if (n < 2)
return 1;
return size_t(1) << bsr(n - 1) + 1;
}
pure nothrow @nogc unittest
{
// 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
foreach (const n, const pow2; [1, 1, 2, 4, 4, 8, 8, 8, 8, 16])
assert(nextpow2(n) == pow2);
}
T min(T)(T a, T b) pure nothrow @nogc
{
return a < b ? a : b;
}
T max(T)(T a, T b) pure nothrow @nogc
{
return b < a ? a : b;
}