1 /* 2 * Copyright (c) 2010 The WebM project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 12 /* This code is in the public domain. 13 ** Version: 1.1 Author: Walt Karas 14 */ 15 16 #include "hmm_intrnl.h" 17 U(resize)18int U(resize)(U(descriptor) *desc, void *mem, U(size_aau) n) 19 { 20 U(size_aau) i; 21 head_record *next_head_ptr; 22 head_record *head_ptr = PTR_REC_TO_HEAD(mem); 23 24 /* Flag. */ 25 int next_block_free; 26 27 /* Convert n from desired block size in AAUs to BAUs. */ 28 n += HEAD_AAUS; 29 n = DIV_ROUND_UP(n, HMM_BLOCK_ALIGN_UNIT); 30 31 if (n < MIN_BLOCK_BAUS) 32 n = MIN_BLOCK_BAUS; 33 34 #ifdef HMM_AUDIT_FAIL 35 36 AUDIT_BLOCK(head_ptr) 37 38 if (!IS_BLOCK_ALLOCATED(head_ptr)) 39 HMM_AUDIT_FAIL 40 41 if (desc->avl_tree_root) 42 AUDIT_BLOCK(PTR_REC_TO_HEAD(desc->avl_tree_root)) 43 44 #endif 45 46 i = head_ptr->block_size; 47 48 next_head_ptr = 49 (head_record *) BAUS_FORWARD(head_ptr, head_ptr->block_size); 50 51 next_block_free = 52 (next_head_ptr == desc->last_freed) || 53 !IS_BLOCK_ALLOCATED(next_head_ptr); 54 55 if (next_block_free) 56 /* Block can expand into next free block. */ 57 i += BLOCK_BAUS(next_head_ptr); 58 59 if (n > i) 60 /* Not enough room for block to expand. */ 61 return(-1); 62 63 if (next_block_free) 64 { 65 #ifdef HMM_AUDIT_FAIL 66 AUDIT_BLOCK(next_head_ptr) 67 #endif 68 69 if (next_head_ptr == desc->last_freed) 70 desc->last_freed = 0; 71 else 72 U(out_of_free_collection)(desc, next_head_ptr); 73 74 next_head_ptr = 75 (head_record *) BAUS_FORWARD(head_ptr, (U(size_bau)) i); 76 } 77 78 /* Set i to number of "extra" BAUs. */ 79 i -= n; 80 81 if (i < MIN_BLOCK_BAUS) 82 /* Not enough extra BAUs to be a block on their own, so just keep them 83 ** in the block being resized. 84 */ 85 { 86 n += i; 87 i = n; 88 } 89 else 90 { 91 /* There are enough "leftover" BAUs in the next block to 92 ** form a remainder block. */ 93 94 head_record *rem_head_ptr; 95 96 rem_head_ptr = (head_record *) BAUS_FORWARD(head_ptr, n); 97 98 rem_head_ptr->previous_block_size = (U(size_bau)) n; 99 rem_head_ptr->block_size = (U(size_bau)) i; 100 101 if (desc->last_freed) 102 { 103 #ifdef HMM_AUDIT_FAIL 104 AUDIT_BLOCK(desc->last_freed) 105 #endif 106 107 U(into_free_collection)(desc, (head_record *)(desc->last_freed)); 108 109 desc->last_freed = 0; 110 } 111 112 desc->last_freed = rem_head_ptr; 113 } 114 115 head_ptr->block_size = (U(size_bau)) n; 116 next_head_ptr->previous_block_size = (U(size_bau)) i; 117 118 return(0); 119 } 120