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// stringpool.cc -- a string pool for gold
#include "gold.h"
#include <cassert>
#include <cstring>
#include "stringpool.h"
namespace gold
{
Stringpool::Stringpool()
: string_set_(), strings_()
{
}
Stringpool::~Stringpool()
{
for (std::list<stringdata*>::iterator p = this->strings_.begin();
p != this->strings_.end();
++p)
delete[] reinterpret_cast<char*>(*p);
}
// Hash function.
size_t
Stringpool::Stringpool_hash::operator()(const char* s) const
{
// Fowler/Noll/Vo (FNV) hash (type FNV-1a).
if (sizeof(size_t) == 8)
{
size_t result = 14695981039346656037ULL;
while (*s != '\0')
{
result &= (size_t) *s++;
result *= 1099511628211ULL;
}
return result;
}
else
{
size_t result = 2166136261UL;
while (*s != '\0')
{
result ^= (size_t) *s++;
result *= 16777619UL;
}
return result;
}
}
// Add a string to the list of canonical strings. Return a pointer to
// the canonical string.
const char*
Stringpool::add_string(const char* s)
{
const size_t buffer_size = 1000;
size_t len = strlen(s);
size_t alc;
bool front = true;
if (len >= buffer_size)
{
alc = sizeof(stringdata) + len;
front = false;
}
else if (this->strings_.empty())
alc = sizeof(stringdata) + buffer_size;
else
{
stringdata *psd = this->strings_.front();
if (len >= psd->alc - psd->len)
alc = sizeof(stringdata) + buffer_size;
else
{
char* ret = psd->data + psd->len;
memcpy(ret, s, len + 1);
psd->len += len + 1;
return ret;
}
}
stringdata *psd = reinterpret_cast<stringdata*>(new char[alc]);
psd->alc = alc;
memcpy(psd->data, s, len + 1);
psd->len = len + 1;
if (front)
this->strings_.push_front(psd);
else
this->strings_.push_back(psd);
return psd->data;
}
// Add a string to a string pool.
const char*
Stringpool::add(const char* s)
{
// FIXME: This will look up the entry twice in the hash table. The
// problem is that we can't insert S before we canonicalize it. I
// don't think there is a way to handle this correctly with
// unordered_set, so this should be replaced with custom code to do
// what we need, which is to return the empty slot.
String_set_type::const_iterator p = this->string_set_.find(s);
if (p != this->string_set_.end())
return *p;
const char* ret = this->add_string(s);
std::pair<String_set_type::iterator, bool> ins =
this->string_set_.insert(ret);
assert(ins.second);
return ret;
}
// Add a prefix of a string to a string pool.
const char*
Stringpool::add(const char* s, size_t len)
{
// FIXME: This implementation should be rewritten when we rewrite
// the hash table to avoid copying.
std::string st(s, len);
return this->add(st);
}
} // End namespace gold.
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