mirror of
https://github.com/autc04/Retro68.git
synced 2024-11-24 07:31:32 +00:00
317 lines
9.9 KiB
C++
317 lines
9.9 KiB
C++
/* Copyright (C) 2012-2017 Free Software Foundation, Inc.
|
|
|
|
This file is part of GCC.
|
|
|
|
GCC is free software; you can redistribute it and/or modify
|
|
it under the terms of the GNU General Public License as published by
|
|
the Free Software Foundation; either version 3, or (at your option)
|
|
any later version.
|
|
|
|
GCC is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
GNU General Public License for more details.
|
|
|
|
Under Section 7 of GPL version 3, you are granted additional
|
|
permissions described in the GCC Runtime Library Exception, version
|
|
3.1, as published by the Free Software Foundation.
|
|
|
|
You should have received a copy of the GNU General Public License and
|
|
a copy of the GCC Runtime Library Exception along with this program;
|
|
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
#ifndef _VTV_MAP_H
|
|
#define _VTV_MAP_H 1
|
|
|
|
#include <string.h>
|
|
|
|
#ifdef __MINGW32__
|
|
#include <stdint.h>
|
|
#include "vtv_utils.h"
|
|
#else
|
|
#include <vtv_utils.h>
|
|
#endif
|
|
|
|
inline uint64_t
|
|
load8bytes (const void *p)
|
|
{
|
|
uint64_t result;
|
|
memcpy (&result, p, 8);
|
|
return result;
|
|
}
|
|
|
|
/* Insert_only_hash_map maps keys to values. The implementation is a
|
|
basic hash table with open addressing. The keys are not "owned" by
|
|
the table; it only stores pointers to keys. The key type is
|
|
specified below (see insert_only_hash_map::key_type) and is,
|
|
roughly speaking, a string of any length with the string length and
|
|
a hash code stored at the front. The code here does not compute
|
|
any hash codes, but rather uses what's given. */
|
|
|
|
template<typename T, typename Alloc>
|
|
class insert_only_hash_map
|
|
{
|
|
public:
|
|
typedef size_t size_type;
|
|
typedef T value_type;
|
|
typedef Alloc alloc_type;
|
|
enum { min_capacity = 4 };
|
|
#if HASHMAP_STATS
|
|
enum { stats = true };
|
|
#else
|
|
enum { stats = false };
|
|
#endif
|
|
|
|
/* Keys are a byte string (up to 2^32 - 1 long) plus a uint32_t
|
|
that's used as a hash code. The latter can encode arbitrary
|
|
information at the client's discretion, so, e.g., multiple keys
|
|
that are the same string still "differ" if the hash codes differ.
|
|
Keys are equal if the first 8 bytes are equal and the next n
|
|
bytes are equal. */
|
|
struct key_type
|
|
{
|
|
uint32_t n;
|
|
uint32_t hash;
|
|
char bytes[0];
|
|
|
|
bool
|
|
equals (const key_type *k) const;
|
|
};
|
|
|
|
/* Create an empty map with a reasonable number of buckets for the
|
|
expected size. Returns NULL if the allocator fails. */
|
|
|
|
static insert_only_hash_map *
|
|
create (size_type expected_size);
|
|
|
|
/* The opposite of create(). Free the memory for the given map. */
|
|
|
|
static void
|
|
destroy (insert_only_hash_map *m)
|
|
{ Alloc().dealloc (m, m->size_in_bytes_); }
|
|
|
|
/* Return a map identical to this except that *k is mapped to v.
|
|
Typcially it's done by modifying this in place, but if a resize
|
|
is necessary then this is deallocated and a new map is returned.
|
|
Requires k to be non-NULL. Does nothing and returns NULL if the
|
|
allocator fails. */
|
|
|
|
insert_only_hash_map*
|
|
put (const key_type *k, const value_type &v)
|
|
{ return this->put_internal (k, v, false); }
|
|
|
|
/* If *k is a key in this then set *v to point to the corresponding
|
|
value. Otherwise, do the equivalent of insert(k, value_type())
|
|
and, if that succeeds, set *v to point to the inserted value.
|
|
Requires k to be non-NULL. Does nothing and returns NULL if the
|
|
allocator fails. Typically returns this, but will return a new
|
|
insert_only_hash_map if a resize occurs. If the return value is
|
|
non-NULL, *v is set and it's valid until a resize of the map that
|
|
is the return value. */
|
|
|
|
insert_only_hash_map *
|
|
find_or_add_key (const key_type *k, value_type **v);
|
|
|
|
/* Get the value corresponding to *k. Returns NULL if there is
|
|
none. Requires k to be non-NULL. The return value is valid
|
|
until any resize. */
|
|
const value_type *get (const key_type *k) const;
|
|
|
|
size_type
|
|
size () const
|
|
{ return num_entries_; }
|
|
|
|
bool
|
|
empty () const
|
|
{ return this->size () == 0; }
|
|
|
|
size_type
|
|
bucket_count () const
|
|
{ return num_buckets_; }
|
|
|
|
private:
|
|
typedef std::pair <const key_type *, value_type> bucket_type;
|
|
|
|
insert_only_hash_map *put_internal (const key_type *, const value_type &,
|
|
bool);
|
|
|
|
/* This function determines when to resize the table. */
|
|
bool
|
|
is_too_full (size_type entries) const
|
|
{ return entries > (this->bucket_count () * 0.7); }
|
|
|
|
/* Return a copy with double the number of buckets. Returns NULL if
|
|
the allocator fails. Otherwise, calls destroy (this). */
|
|
insert_only_hash_map *destructive_copy ();
|
|
|
|
/* Must be a power of 2 not less than min_capacity. */
|
|
size_type num_buckets_;
|
|
size_type num_entries_;
|
|
size_type size_in_bytes_;
|
|
bucket_type buckets[0]; /* Actual array size is num_buckets. */
|
|
};
|
|
|
|
template <typename T, typename Alloc>
|
|
insert_only_hash_map <T, Alloc> *
|
|
insert_only_hash_map <T, Alloc>::create (size_type expected_size)
|
|
{
|
|
size_t cap = min_capacity;
|
|
while (expected_size >= cap)
|
|
{
|
|
cap *= 2;
|
|
}
|
|
size_t size_in_bytes = sizeof (insert_only_hash_map <T, Alloc>)
|
|
+ cap * sizeof (bucket_type);
|
|
insert_only_hash_map <T, Alloc>* result =
|
|
static_cast <insert_only_hash_map <T, Alloc>*> (Alloc ()
|
|
.alloc (size_in_bytes));
|
|
if (result != NULL)
|
|
{
|
|
result->size_in_bytes_ = size_in_bytes;
|
|
result->num_buckets_ = cap;
|
|
result->num_entries_ = 0;
|
|
memset (result->buckets, 0, cap * sizeof (bucket_type));
|
|
}
|
|
return result;
|
|
}
|
|
|
|
template <typename T, typename Alloc>
|
|
insert_only_hash_map <T, Alloc>*
|
|
insert_only_hash_map <T, Alloc>::destructive_copy ()
|
|
{
|
|
insert_only_hash_map* copy = create (this->bucket_count ());
|
|
if (copy == NULL)
|
|
return NULL;
|
|
VTV_DEBUG_ASSERT (copy->bucket_count () == 2 * this->bucket_count ());
|
|
for (size_type i = 0; i < this->bucket_count (); i++)
|
|
if (this->buckets[i].first != NULL)
|
|
copy->put_internal (this->buckets[i].first, this->buckets[i].second,
|
|
true);
|
|
VTV_DEBUG_ASSERT (copy->size () == this->size ());
|
|
destroy (this);
|
|
return copy;
|
|
}
|
|
|
|
template <typename T, typename Alloc>
|
|
insert_only_hash_map <T, Alloc>*
|
|
insert_only_hash_map <T, Alloc>::find_or_add_key (const key_type *k,
|
|
value_type **v)
|
|
{
|
|
/* Table size is always a power of 2. */
|
|
const size_type mask = this->bucket_count () - 1;
|
|
size_type bucket_index = k->hash & mask;
|
|
size_type step = 1;
|
|
for (;;)
|
|
{
|
|
bucket_type &bucket = this->buckets[bucket_index];
|
|
if (bucket.first == NULL)
|
|
{
|
|
/* Key was not present. */
|
|
if (this->is_too_full (this->size () + 1))
|
|
{
|
|
insert_only_hash_map <T, Alloc>* result =
|
|
this->destructive_copy ();
|
|
return result == NULL
|
|
? NULL
|
|
: result->find_or_add_key (k, v);
|
|
}
|
|
else
|
|
{
|
|
bucket.first = k;
|
|
bucket.second = T ();
|
|
this->num_entries_++;
|
|
*v = &bucket.second;
|
|
return this;
|
|
}
|
|
}
|
|
else if (bucket.first->equals (k))
|
|
{
|
|
/* Key was present. */
|
|
*v = &bucket.second;
|
|
return this;
|
|
}
|
|
else
|
|
bucket_index = (bucket_index + step++) & mask;
|
|
}
|
|
}
|
|
|
|
template <typename T, typename Alloc>
|
|
insert_only_hash_map <T, Alloc>*
|
|
insert_only_hash_map <T, Alloc>::put_internal (
|
|
const insert_only_hash_map::key_type *k,
|
|
const insert_only_hash_map::value_type &v,
|
|
bool unique_key_and_resize_not_needed)
|
|
{
|
|
/* Table size is always a power of 2. */
|
|
const size_type mask = this->bucket_count () - 1;
|
|
size_type bucket_index = k->hash & mask;
|
|
size_type step = 1;
|
|
for (;;)
|
|
{
|
|
bucket_type &bucket = this->buckets[bucket_index];
|
|
if (bucket.first == NULL)
|
|
{
|
|
/* Key was not present. */
|
|
if (!unique_key_and_resize_not_needed
|
|
&& this->is_too_full (this->size () + 1))
|
|
{
|
|
insert_only_hash_map <T, Alloc>* result =
|
|
this->destructive_copy ();
|
|
return result == NULL
|
|
? NULL
|
|
: result->put_internal (k, v, true);
|
|
}
|
|
else
|
|
{
|
|
bucket.first = k;
|
|
bucket.second = v;
|
|
this->num_entries_++;
|
|
return this;
|
|
}
|
|
}
|
|
else if (!unique_key_and_resize_not_needed && bucket.first->equals (k))
|
|
{
|
|
/* Key was present. Just change the value. */
|
|
bucket.second = v;
|
|
return this;
|
|
}
|
|
else
|
|
bucket_index = (bucket_index + step++) & mask;
|
|
}
|
|
}
|
|
|
|
template <typename T, typename Alloc>
|
|
inline const typename insert_only_hash_map <T, Alloc>::value_type*
|
|
insert_only_hash_map <T, Alloc>::get (const insert_only_hash_map::key_type *k)
|
|
const
|
|
{
|
|
/* Table size is always a power of 2. */
|
|
const size_type mask = this->bucket_count () - 1;
|
|
size_type bucket_index = k->hash & mask;
|
|
size_type step = 1;
|
|
for (;;)
|
|
{
|
|
const bucket_type &bucket = this->buckets[bucket_index];
|
|
if (bucket.first == NULL)
|
|
return NULL;
|
|
else if (bucket.first->equals (k))
|
|
return &bucket.second;
|
|
else
|
|
bucket_index = (bucket_index + step++) & mask;
|
|
}
|
|
}
|
|
|
|
template <typename T, typename Alloc>
|
|
inline bool
|
|
insert_only_hash_map <T, Alloc>::key_type::equals (
|
|
const typename insert_only_hash_map <T, Alloc>::key_type *k) const
|
|
{
|
|
const char* x = reinterpret_cast <const char *> (k);
|
|
const char* y = reinterpret_cast <const char *> (this);
|
|
return (load8bytes (x) == load8bytes (y)
|
|
&& memcmp (x + 8, y + 8, this->n) == 0);
|
|
}
|
|
|
|
#endif /* _VTV_MAP_H */
|