106 lines
2.7 KiB
C++
106 lines
2.7 KiB
C++
/* Copyright (C) 2009 Wildfire Games.
|
|
* This file is part of 0 A.D.
|
|
*
|
|
* 0 A.D. 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 2 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* 0 A.D. 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.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with 0 A.D. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
/*
|
|
* shared storage for strings
|
|
*/
|
|
|
|
#include "precompiled.h"
|
|
#include "string_pool.h"
|
|
|
|
#include "lib/rand.h"
|
|
#include "lib/sysdep/cpu.h" // cpu_memcpy
|
|
|
|
|
|
StringPool::StringPool(size_t maxSize)
|
|
{
|
|
pool_create(&m_pool, maxSize, POOL_VARIABLE_ALLOCS);
|
|
}
|
|
|
|
|
|
StringPool::~StringPool()
|
|
{
|
|
m_map.clear();
|
|
(void)pool_destroy(&m_pool);
|
|
}
|
|
|
|
|
|
const char* StringPool::UniqueCopy(const char* string)
|
|
{
|
|
// early out: check if it already lies in the pool
|
|
if(Contains(string))
|
|
return string;
|
|
|
|
// check if equivalent to an existing string.
|
|
//
|
|
// rationale: the entire storage could be done via container,
|
|
// rather than simply using it as a lookup mapping.
|
|
// however, DynHashTbl together with Pool (see above) is more efficient.
|
|
const char* existingString = m_map.find(string);
|
|
if(existingString)
|
|
return existingString;
|
|
|
|
const size_t length = strlen(string);
|
|
char* uniqueCopy = (char*)pool_alloc(&m_pool, length+1);
|
|
if(!uniqueCopy)
|
|
throw std::bad_alloc();
|
|
cpu_memcpy((void*)uniqueCopy, string, length);
|
|
uniqueCopy[length] = '\0';
|
|
|
|
m_map.insert(uniqueCopy, uniqueCopy);
|
|
|
|
return uniqueCopy;
|
|
}
|
|
|
|
|
|
bool StringPool::Contains(const char* string) const
|
|
{
|
|
return pool_contains(&m_pool, (void*)string);
|
|
}
|
|
|
|
|
|
const char* StringPool::RandomString() const
|
|
{
|
|
// there had better be names in m_pool, else this will fail.
|
|
debug_assert(m_pool.da.pos != 0);
|
|
|
|
again:
|
|
const size_t start_ofs = (size_t)rand(0, (size_t)m_pool.da.pos);
|
|
|
|
// scan back to start of string (don't scan ahead; this must
|
|
// work even if m_pool only contains one entry).
|
|
const char* start = (const char*)m_pool.da.base + start_ofs;
|
|
for(size_t i = 0; i < start_ofs; i++)
|
|
{
|
|
if(*start == '\0')
|
|
break;
|
|
start--;
|
|
}
|
|
|
|
// skip past the '\0' we found. loop is needed because there may be
|
|
// several if we land in padding (due to pool alignment).
|
|
size_t chars_left = m_pool.da.pos - start_ofs;
|
|
for(; *start == '\0'; start++)
|
|
{
|
|
// we had landed in padding at the end of the buffer.
|
|
if(chars_left-- == 0)
|
|
goto again;
|
|
}
|
|
|
|
return start;
|
|
}
|