forked from 0ad/0ad
110 lines
3.0 KiB
C++
110 lines
3.0 KiB
C++
/* Copyright (c) 2010 Wildfire Games
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be included
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* in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
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* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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/*
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* shared storage for strings
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*/
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#include "precompiled.h"
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#include "lib/allocators/string_pool.h"
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#include "lib/rand.h"
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StringPool::StringPool(size_t maxSize)
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{
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pool_create(&m_pool, maxSize, POOL_VARIABLE_ALLOCS);
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}
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StringPool::~StringPool()
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{
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m_map.clear();
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(void)pool_destroy(&m_pool);
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}
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const char* StringPool::UniqueCopy(const char* string)
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{
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// early out: check if it already lies in the pool
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if(Contains(string))
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return string;
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// check if equivalent to an existing string.
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//
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// rationale: the entire storage could be done via container,
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// rather than simply using it as a lookup mapping.
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// however, DynHashTbl together with Pool (see above) is more efficient.
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const char* existingString = m_map.find(string);
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if(existingString)
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return existingString;
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const size_t length = strlen(string);
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char* uniqueCopy = (char*)pool_alloc(&m_pool, length+1);
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if(!uniqueCopy)
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throw std::bad_alloc();
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memcpy((void*)uniqueCopy, string, length);
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uniqueCopy[length] = '\0';
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m_map.insert(uniqueCopy, uniqueCopy);
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return uniqueCopy;
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}
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bool StringPool::Contains(const char* string) const
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{
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return pool_contains(&m_pool, (void*)string);
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}
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const char* StringPool::RandomString() const
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{
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// there had better be names in m_pool, else this will fail.
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debug_assert(m_pool.da.pos != 0);
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again:
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const size_t start_ofs = (size_t)rand(0, (size_t)m_pool.da.pos);
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// scan back to start of string (don't scan ahead; this must
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// work even if m_pool only contains one entry).
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const char* start = (const char*)m_pool.da.base + start_ofs;
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for(size_t i = 0; i < start_ofs; i++)
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{
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if(*start == '\0')
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break;
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start--;
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}
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// skip past the '\0' we found. loop is needed because there may be
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// several if we land in padding (due to pool alignment).
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size_t chars_left = m_pool.da.pos - start_ofs;
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for(; *start == '\0'; start++)
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{
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// we had landed in padding at the end of the buffer.
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if(chars_left-- == 0)
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goto again;
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}
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return start;
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}
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