Michiharu Ariza
6 years ago
commit
b999ce9bf0
17 changed files with 488 additions and 245 deletions
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/*
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* Copyright © 2019 Facebook, Inc. |
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* |
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* This is part of HarfBuzz, a text shaping library. |
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* |
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* Permission is hereby granted, without written agreement and without |
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* license or royalty fees, to use, copy, modify, and distribute this |
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* software and its documentation for any purpose, provided that the |
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* above copyright notice and the following two paragraphs appear in |
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* all copies of this software. |
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* |
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* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR |
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* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES |
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* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN |
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* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH |
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* DAMAGE. |
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* |
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* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, |
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* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND |
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* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS |
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* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO |
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* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. |
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* |
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* Facebook Author(s): Behdad Esfahbod |
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*/ |
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#ifndef HB_POOL_HH |
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#define HB_POOL_HH |
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#include "hb.hh" |
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/* Memory pool for persistent allocation of small objects. */ |
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template <typename T, unsigned ChunkLen = 16> |
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struct hb_pool_t |
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{ |
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hb_pool_t () : next (nullptr) {} |
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~hb_pool_t () { fini (); } |
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void fini () |
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{ |
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next = nullptr; |
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+ hb_iter (chunks) |
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| hb_apply ([] (chunk_t *_) { ::free (_); }) |
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; |
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chunks.fini (); |
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} |
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T* alloc () |
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{ |
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if (unlikely (!next)) |
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{ |
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if (unlikely (!chunks.alloc (chunks.length + 1))) return nullptr; |
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chunk_t *chunk = (chunk_t *) calloc (1, sizeof (chunk_t)); |
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if (unlikely (!chunk)) return nullptr; |
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chunks.push (chunk); |
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next = chunk->thread (); |
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} |
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T* obj = next; |
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next = * ((T**) next); |
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memset (obj, 0, sizeof (T)); |
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return obj; |
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} |
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void free (T* obj) |
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{ |
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* (T**) obj = next; |
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next = obj; |
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} |
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private: |
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static_assert (ChunkLen > 1, ""); |
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static_assert (sizeof (T) >= sizeof (void *), ""); |
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static_assert (alignof (T) % sizeof (void *) == 0, ""); |
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struct chunk_t |
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{ |
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T* thread () |
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{ |
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for (unsigned i = 0; i < ARRAY_LENGTH (arrayZ) - 1; i++) |
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* (T**) &arrayZ[i] = &arrayZ[i + 1]; |
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* (T**) &arrayZ[ARRAY_LENGTH (arrayZ) - 1] = nullptr; |
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return arrayZ; |
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} |
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T arrayZ[ChunkLen]; |
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}; |
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T* next; |
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hb_vector_t<chunk_t *> chunks; |
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}; |
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#endif /* HB_POOL_HH */ |
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