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 U(size_aau) i; 20 head_record *next_head_ptr; 21 head_record *head_ptr = PTR_REC_TO_HEAD(mem); 22 23 /* Flag. */ 24 int next_block_free; 25 26 /* Convert n from desired block size in AAUs to BAUs. */ 27 n += HEAD_AAUS; 28 n = DIV_ROUND_UP(n, HMM_BLOCK_ALIGN_UNIT); 29 30 if (n < MIN_BLOCK_BAUS) 31 n = MIN_BLOCK_BAUS; 32 33 #ifdef HMM_AUDIT_FAIL 34 35 AUDIT_BLOCK(head_ptr) 36 37 if (!IS_BLOCK_ALLOCATED(head_ptr)) 38 HMM_AUDIT_FAIL 39 40 if (desc->avl_tree_root) 41 AUDIT_BLOCK(PTR_REC_TO_HEAD(desc->avl_tree_root)) 42 43 #endif 44 45 i = head_ptr->block_size; 46 47 next_head_ptr = 48 (head_record *) BAUS_FORWARD(head_ptr, head_ptr->block_size); 49 50 next_block_free = 51 (next_head_ptr == desc->last_freed) || 52 !IS_BLOCK_ALLOCATED(next_head_ptr); 53 54 if (next_block_free) 55 /* Block can expand into next free block. */ 56 i += BLOCK_BAUS(next_head_ptr); 57 58 if (n > i) 59 /* Not enough room for block to expand. */ 60 return(-1); 61 62 if (next_block_free) { 63 #ifdef HMM_AUDIT_FAIL 64 AUDIT_BLOCK(next_head_ptr) 65 #endif 66 67 if (next_head_ptr == desc->last_freed) 68 desc->last_freed = 0; 69 else 70 U(out_of_free_collection)(desc, next_head_ptr); 71 72 next_head_ptr = 73 (head_record *) BAUS_FORWARD(head_ptr, (U(size_bau)) i); 74 } 75 76 /* Set i to number of "extra" BAUs. */ 77 i -= n; 78 79 if (i < MIN_BLOCK_BAUS) 80 /* Not enough extra BAUs to be a block on their own, so just keep them 81 ** in the block being resized. 82 */ 83 { 84 n += i; 85 i = n; 86 } else { 87 /* There are enough "leftover" BAUs in the next block to 88 ** form a remainder block. */ 89 90 head_record *rem_head_ptr; 91 92 rem_head_ptr = (head_record *) BAUS_FORWARD(head_ptr, n); 93 94 rem_head_ptr->previous_block_size = (U(size_bau)) n; 95 rem_head_ptr->block_size = (U(size_bau)) i; 96 97 if (desc->last_freed) { 98 #ifdef HMM_AUDIT_FAIL 99 AUDIT_BLOCK(desc->last_freed) 100 #endif 101 102 U(into_free_collection)(desc, (head_record *)(desc->last_freed)); 103 104 desc->last_freed = 0; 105 } 106 107 desc->last_freed = rem_head_ptr; 108 } 109 110 head_ptr->block_size = (U(size_bau)) n; 111 next_head_ptr->previous_block_size = (U(size_bau)) i; 112 113 return(0); 114 } 115