| /* |
| * Copyright (c) 2010 The WebM project authors. All Rights Reserved. |
| * |
| * Use of this source code is governed by a BSD-style license |
| * that can be found in the LICENSE file in the root of the source |
| * tree. An additional intellectual property rights grant can be found |
| * in the file PATENTS. All contributing project authors may |
| * be found in the AUTHORS file in the root of the source tree. |
| */ |
| |
| |
| /* This code is in the public domain. |
| ** Version: 1.1 Author: Walt Karas |
| */ |
| |
| #include "hmm_intrnl.h" |
| |
| void U(init)(U(descriptor) *desc) |
| { |
| desc->avl_tree_root = 0; |
| desc->last_freed = 0; |
| } |
| |
| /* Remove a free block from a bin's doubly-linked list when it is not, |
| ** the first block in the bin. |
| */ |
| void U(dll_remove)( |
| /* Pointer to pointer record in the block to be removed. */ |
| ptr_record *to_remove) |
| { |
| to_remove->prev->next = to_remove->next; |
| |
| if (to_remove->next) |
| to_remove->next->prev = to_remove->prev; |
| } |
| |
| /* Put a block into the free collection of a heap. |
| */ |
| void U(into_free_collection)( |
| /* Pointer to heap descriptor. */ |
| U(descriptor) *desc, |
| /* Pointer to head record of block. */ |
| head_record *head_ptr) |
| { |
| ptr_record *ptr_rec_ptr = HEAD_TO_PTR_REC(head_ptr); |
| |
| ptr_record *bin_front_ptr = |
| U(avl_insert)((U(avl_avl) *) & (desc->avl_tree_root), ptr_rec_ptr); |
| |
| if (bin_front_ptr != ptr_rec_ptr) |
| { |
| /* The block was not inserted into the AVL tree because there is |
| ** already a bin for the size of the block. */ |
| |
| MARK_SUCCESSIVE_BLOCK_IN_FREE_BIN(head_ptr) |
| ptr_rec_ptr->self = ptr_rec_ptr; |
| |
| /* Make the block the new second block in the bin's doubly-linked |
| ** list. */ |
| ptr_rec_ptr->prev = bin_front_ptr; |
| ptr_rec_ptr->next = bin_front_ptr->next; |
| bin_front_ptr->next = ptr_rec_ptr; |
| |
| if (ptr_rec_ptr->next) |
| ptr_rec_ptr->next->prev = ptr_rec_ptr; |
| } |
| else |
| /* Block is first block in new bin. */ |
| ptr_rec_ptr->next = 0; |
| } |
| |
| /* Allocate a block from a given bin. Returns a pointer to the payload |
| ** of the removed block. The "last freed" pointer must be null prior |
| ** to calling this function. |
| */ |
| void *U(alloc_from_bin)( |
| /* Pointer to heap descriptor. */ |
| U(descriptor) *desc, |
| /* Pointer to pointer record of first block in bin. */ |
| ptr_record *bin_front_ptr, |
| /* Number of BAUs needed in the allocated block. If the block taken |
| ** from the bin is significantly larger than the number of BAUs needed, |
| ** the "extra" BAUs are split off to form a new free block. */ |
| U(size_bau) n_baus) |
| { |
| head_record *head_ptr; |
| U(size_bau) rem_baus; |
| |
| if (bin_front_ptr->next) |
| { |
| /* There are multiple blocks in this bin. Use the 2nd block in |
| ** the bin to avoid needless change to the AVL tree. |
| */ |
| |
| ptr_record *ptr_rec_ptr = bin_front_ptr->next; |
| head_ptr = PTR_REC_TO_HEAD(ptr_rec_ptr); |
| |
| #ifdef AUDIT_FAIL |
| AUDIT_BLOCK(head_ptr) |
| #endif |
| |
| U(dll_remove)(ptr_rec_ptr); |
| } |
| else |
| { |
| /* There is only one block in the bin, so it has to be removed |
| ** from the AVL tree. |
| */ |
| |
| head_ptr = PTR_REC_TO_HEAD(bin_front_ptr); |
| |
| U(avl_remove)( |
| (U(avl_avl) *) &(desc->avl_tree_root), BLOCK_BAUS(head_ptr)); |
| } |
| |
| MARK_BLOCK_ALLOCATED(head_ptr) |
| |
| rem_baus = BLOCK_BAUS(head_ptr) - n_baus; |
| |
| if (rem_baus >= MIN_BLOCK_BAUS) |
| { |
| /* Since there are enough "extra" BAUs, split them off to form |
| ** a new free block. |
| */ |
| |
| head_record *rem_head_ptr = |
| (head_record *) BAUS_FORWARD(head_ptr, n_baus); |
| |
| /* Change the next block's header to reflect the fact that the |
| ** block preceeding it is now smaller. |
| */ |
| SET_PREV_BLOCK_BAUS( |
| BAUS_FORWARD(head_ptr, head_ptr->block_size), rem_baus) |
| |
| head_ptr->block_size = n_baus; |
| |
| rem_head_ptr->previous_block_size = n_baus; |
| rem_head_ptr->block_size = rem_baus; |
| |
| desc->last_freed = rem_head_ptr; |
| } |
| |
| return(HEAD_TO_PTR_REC(head_ptr)); |
| } |
| |
| /* Take a block out of the free collection. |
| */ |
| void U(out_of_free_collection)( |
| /* Descriptor of heap that block is in. */ |
| U(descriptor) *desc, |
| /* Pointer to head of block to take out of free collection. */ |
| head_record *head_ptr) |
| { |
| ptr_record *ptr_rec_ptr = HEAD_TO_PTR_REC(head_ptr); |
| |
| if (ptr_rec_ptr->self == ptr_rec_ptr) |
| /* Block is not the front block in its bin, so all we have to |
| ** do is take it out of the bin's doubly-linked list. */ |
| U(dll_remove)(ptr_rec_ptr); |
| else |
| { |
| ptr_record *next = ptr_rec_ptr->next; |
| |
| if (next) |
| /* Block is the front block in its bin, and there is at least |
| ** one other block in the bin. Substitute the next block for |
| ** the front block. */ |
| U(avl_subst)((U(avl_avl) *) &(desc->avl_tree_root), next); |
| else |
| /* Block is the front block in its bin, but there is no other |
| ** block in the bin. Eliminate the bin. */ |
| U(avl_remove)( |
| (U(avl_avl) *) &(desc->avl_tree_root), BLOCK_BAUS(head_ptr)); |
| } |
| } |
| |
| void U(free)(U(descriptor) *desc, void *payload_ptr) |
| { |
| /* Flags if coalesce with adjacent block. */ |
| int coalesce; |
| |
| head_record *fwd_head_ptr; |
| head_record *free_head_ptr = PTR_REC_TO_HEAD(payload_ptr); |
| |
| desc->num_baus_can_shrink = 0; |
| |
| #ifdef HMM_AUDIT_FAIL |
| |
| AUDIT_BLOCK(free_head_ptr) |
| |
| /* Make sure not freeing an already free block. */ |
| if (!IS_BLOCK_ALLOCATED(free_head_ptr)) |
| HMM_AUDIT_FAIL |
| |
| if (desc->avl_tree_root) |
| /* Audit root block in AVL tree. */ |
| AUDIT_BLOCK(PTR_REC_TO_HEAD(desc->avl_tree_root)) |
| |
| #endif |
| |
| fwd_head_ptr = |
| (head_record *) BAUS_FORWARD(free_head_ptr, free_head_ptr->block_size); |
| |
| if (free_head_ptr->previous_block_size) |
| { |
| /* Coalesce with backward block if possible. */ |
| |
| head_record *bkwd_head_ptr = |
| (head_record *) BAUS_BACKWARD( |
| free_head_ptr, free_head_ptr->previous_block_size); |
| |
| #ifdef HMM_AUDIT_FAIL |
| AUDIT_BLOCK(bkwd_head_ptr) |
| #endif |
| |
| if (bkwd_head_ptr == (head_record *)(desc->last_freed)) |
| { |
| desc->last_freed = 0; |
| coalesce = 1; |
| } |
| else if (IS_BLOCK_ALLOCATED(bkwd_head_ptr)) |
| coalesce = 0; |
| else |
| { |
| U(out_of_free_collection)(desc, bkwd_head_ptr); |
| coalesce = 1; |
| } |
| |
| if (coalesce) |
| { |
| bkwd_head_ptr->block_size += free_head_ptr->block_size; |
| SET_PREV_BLOCK_BAUS(fwd_head_ptr, BLOCK_BAUS(bkwd_head_ptr)) |
| free_head_ptr = bkwd_head_ptr; |
| } |
| } |
| |
| if (fwd_head_ptr->block_size == 0) |
| { |
| /* Block to be freed is last block before dummy end-of-chunk block. */ |
| desc->end_of_shrinkable_chunk = |
| BAUS_FORWARD(fwd_head_ptr, DUMMY_END_BLOCK_BAUS); |
| desc->num_baus_can_shrink = BLOCK_BAUS(free_head_ptr); |
| |
| if (PREV_BLOCK_BAUS(free_head_ptr) == 0) |
| /* Free block is the entire chunk, so shrinking can eliminate |
| ** entire chunk including dummy end block. */ |
| desc->num_baus_can_shrink += DUMMY_END_BLOCK_BAUS; |
| } |
| else |
| { |
| /* Coalesce with forward block if possible. */ |
| |
| #ifdef HMM_AUDIT_FAIL |
| AUDIT_BLOCK(fwd_head_ptr) |
| #endif |
| |
| if (fwd_head_ptr == (head_record *)(desc->last_freed)) |
| { |
| desc->last_freed = 0; |
| coalesce = 1; |
| } |
| else if (IS_BLOCK_ALLOCATED(fwd_head_ptr)) |
| coalesce = 0; |
| else |
| { |
| U(out_of_free_collection)(desc, fwd_head_ptr); |
| coalesce = 1; |
| } |
| |
| if (coalesce) |
| { |
| free_head_ptr->block_size += fwd_head_ptr->block_size; |
| |
| fwd_head_ptr = |
| (head_record *) BAUS_FORWARD( |
| fwd_head_ptr, BLOCK_BAUS(fwd_head_ptr)); |
| |
| SET_PREV_BLOCK_BAUS(fwd_head_ptr, BLOCK_BAUS(free_head_ptr)) |
| |
| if (fwd_head_ptr->block_size == 0) |
| { |
| /* Coalesced block to be freed is last block before dummy |
| ** end-of-chunk block. */ |
| desc->end_of_shrinkable_chunk = |
| BAUS_FORWARD(fwd_head_ptr, DUMMY_END_BLOCK_BAUS); |
| desc->num_baus_can_shrink = BLOCK_BAUS(free_head_ptr); |
| |
| if (PREV_BLOCK_BAUS(free_head_ptr) == 0) |
| /* Free block is the entire chunk, so shrinking can |
| ** eliminate entire chunk including dummy end block. */ |
| desc->num_baus_can_shrink += DUMMY_END_BLOCK_BAUS; |
| } |
| } |
| } |
| |
| if (desc->last_freed) |
| { |
| /* There is a last freed block, but it is not adjacent to the |
| ** block being freed by this call to free, so put the last |
| ** freed block into the free collection. |
| */ |
| |
| #ifdef HMM_AUDIT_FAIL |
| AUDIT_BLOCK(desc->last_freed) |
| #endif |
| |
| U(into_free_collection)(desc, (head_record *)(desc->last_freed)); |
| } |
| |
| desc->last_freed = free_head_ptr; |
| } |
| |
| void U(new_chunk)(U(descriptor) *desc, void *start, U(size_bau) n_baus) |
| { |
| #ifdef HMM_AUDIT_FAIL |
| |
| if (desc->avl_tree_root) |
| /* Audit root block in AVL tree. */ |
| AUDIT_BLOCK(PTR_REC_TO_HEAD(desc->avl_tree_root)) |
| #endif |
| |
| #undef HEAD_PTR |
| #define HEAD_PTR ((head_record *) start) |
| |
| /* Make the chunk one big free block followed by a dummy end block. |
| */ |
| |
| n_baus -= DUMMY_END_BLOCK_BAUS; |
| |
| HEAD_PTR->previous_block_size = 0; |
| HEAD_PTR->block_size = n_baus; |
| |
| U(into_free_collection)(desc, HEAD_PTR); |
| |
| /* Set up the dummy end block. */ |
| start = BAUS_FORWARD(start, n_baus); |
| HEAD_PTR->previous_block_size = n_baus; |
| HEAD_PTR->block_size = 0; |
| |
| #undef HEAD_PTR |
| } |
| |
| #ifdef HMM_AUDIT_FAIL |
| |
| /* Function that does audit fail actions defined my preprocessor symbol, |
| ** and returns a dummy integer value. |
| */ |
| int U(audit_block_fail_dummy_return)(void) |
| { |
| HMM_AUDIT_FAIL |
| |
| /* Dummy return. */ |
| return(0); |
| } |
| |
| #endif |
| |
| /* AVL Tree instantiation. */ |
| |
| #ifdef HMM_AUDIT_FAIL |
| |
| /* The AVL tree generic package passes an ACCESS of 1 when it "touches" |
| ** a child node for the first time during a particular operation. I use |
| ** this feature to audit only one time (per operation) the free blocks |
| ** that are tree nodes. Since the root node is not a child node, it has |
| ** to be audited directly. |
| */ |
| |
| /* The pain you feel while reading these macros will not be in vain. It |
| ** will remove all doubt from you mind that C++ inline functions are |
| ** a very good thing. |
| */ |
| |
| #define AVL_GET_LESS(H, ACCESS) \ |
| (((ACCESS) ? AUDIT_BLOCK_AS_EXPR(PTR_REC_TO_HEAD(H)) : 0), (H)->self) |
| #define AVL_GET_GREATER(H, ACCESS) \ |
| (((ACCESS) ? AUDIT_BLOCK_AS_EXPR(PTR_REC_TO_HEAD(H)) : 0), (H)->prev) |
| |
| #else |
| |
| #define AVL_GET_LESS(H, ACCESS) ((H)->self) |
| #define AVL_GET_GREATER(H, ACCESS) ((H)->prev) |
| |
| #endif |
| |
| #define AVL_SET_LESS(H, LH) (H)->self = (LH); |
| #define AVL_SET_GREATER(H, GH) (H)->prev = (GH); |
| |
| /* high bit of high bit of |
| ** block_size previous_block_size balance factor |
| ** ----------- ------------------- -------------- |
| ** 0 0 n/a (block allocated) |
| ** 0 1 1 |
| ** 1 0 -1 |
| ** 1 1 0 |
| */ |
| |
| #define AVL_GET_BALANCE_FACTOR(H) \ |
| ((((head_record *) (PTR_REC_TO_HEAD(H)))->block_size & \ |
| HIGH_BIT_BAU_SIZE) ? \ |
| (((head_record *) (PTR_REC_TO_HEAD(H)))->previous_block_size & \ |
| HIGH_BIT_BAU_SIZE ? 0 : -1) : 1) |
| |
| #define AVL_SET_BALANCE_FACTOR(H, BF) \ |
| { \ |
| register head_record *p = \ |
| (head_record *) PTR_REC_TO_HEAD(H); \ |
| register int bal_f = (BF); \ |
| \ |
| if (bal_f <= 0) \ |
| p->block_size |= HIGH_BIT_BAU_SIZE; \ |
| else \ |
| p->block_size &= ~HIGH_BIT_BAU_SIZE; \ |
| if (bal_f >= 0) \ |
| p->previous_block_size |= HIGH_BIT_BAU_SIZE; \ |
| else \ |
| p->previous_block_size &= ~HIGH_BIT_BAU_SIZE; \ |
| } |
| |
| #define COMPARE_KEY_KEY(K1, K2) ((K1) == (K2) ? 0 : ((K1) > (K2) ? 1 : -1)) |
| |
| #define AVL_COMPARE_KEY_NODE(K, H) \ |
| COMPARE_KEY_KEY(K, BLOCK_BAUS(PTR_REC_TO_HEAD(H))) |
| |
| #define AVL_COMPARE_NODE_NODE(H1, H2) \ |
| COMPARE_KEY_KEY(BLOCK_BAUS(PTR_REC_TO_HEAD(H1)), \ |
| BLOCK_BAUS(PTR_REC_TO_HEAD(H2))) |
| |
| #define AVL_NULL ((ptr_record *) 0) |
| |
| #define AVL_IMPL_MASK \ |
| ( AVL_IMPL_INSERT | AVL_IMPL_SEARCH | AVL_IMPL_REMOVE | AVL_IMPL_SUBST ) |
| |
| #include "cavl_impl.h" |
