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https://github.com/espressif/tlsf.git
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1ca1da2407
- the control_t structure should not be available to the user so it was moved to tlsf.c. In addition bitfields are now used in control_t when possible which reduces the size of the structure from 56 bytes to 36 bytes. - fix an assert message to place it in the tlsf_assert - add comment about the index count log2 field in control_t
128 lines
3.4 KiB
C
128 lines
3.4 KiB
C
/*
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* SPDX-FileCopyrightText: 2006-2016 Matthew Conte
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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#pragma once
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#include <stddef.h>
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#include <assert.h>
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#if defined(__cplusplus)
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extern "C" {
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#endif
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/*
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** Constants definition for poisoning.
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** These defines are used as 3rd argument of tlsf_poison_fill_region() for readability purposes.
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*/
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#define POISONING_AFTER_FREE true
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#define POISONING_AFTER_MALLOC !POISONING_AFTER_FREE
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/*
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** Cast and min/max macros.
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*/
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#define tlsf_cast(t, exp) ((t) (exp))
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#define tlsf_min(a, b) ((a) < (b) ? (a) : (b))
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#define tlsf_max(a, b) ((a) > (b) ? (a) : (b))
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/*
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** Set assert macro, if it has not been provided by the user.
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*/
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#if !defined (tlsf_assert)
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#define tlsf_assert assert
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#endif
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enum tlsf_config
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{
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/* All allocation sizes and addresses are aligned to 4 bytes. */
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ALIGN_SIZE_LOG2 = 2,
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ALIGN_SIZE = (1 << ALIGN_SIZE_LOG2),
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};
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/*
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** Data structures and associated constants.
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*/
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/* A type used for casting when doing pointer arithmetic. */
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typedef ptrdiff_t tlsfptr_t;
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typedef struct block_header_t
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{
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/* Points to the previous physical block. */
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struct block_header_t* prev_phys_block;
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/* The size of this block, excluding the block header. */
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size_t size;
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/* Next and previous free blocks. */
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struct block_header_t* next_free;
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struct block_header_t* prev_free;
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} block_header_t;
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/*
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** Since block sizes are always at least a multiple of 4, the two least
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** significant bits of the size field are used to store the block status:
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** - bit 0: whether block is busy or free
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** - bit 1: whether previous block is busy or free
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*/
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static const size_t block_header_free_bit = 1 << 0;
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static const size_t block_header_prev_free_bit = 1 << 1;
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/*
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** The size of the block header exposed to used blocks is the size field.
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** The prev_phys_block field is stored *inside* the previous free block.
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*/
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static const size_t block_header_overhead = sizeof(size_t);
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/* User data starts directly after the size field in a used block. */
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static const size_t block_start_offset =
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offsetof(block_header_t, size) + sizeof(size_t);
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/*
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** A free block must be large enough to store its header minus the size of
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** the prev_phys_block field, and no larger than the number of addressable
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** bits for FL_INDEX.
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*/
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static const size_t block_size_min =
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sizeof(block_header_t) - sizeof(block_header_t*);
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/* The TLSF control structure. */
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typedef struct control_t
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{
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/* Empty lists point at this block to indicate they are free. */
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block_header_t block_null;
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/* Local parameter for the pool. Given the maximum
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* value of each field, all the following parameters
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* can fit on 4 bytes when using bitfields
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*/
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unsigned int fl_index_count : 5; // 5 cumulated bits
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unsigned int fl_index_shift : 3; // 8 cumulated bits
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unsigned int fl_index_max : 6; // 14 cumulated bits
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unsigned int sl_index_count : 6; // 20 cumulated bits
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/* log2 of number of linear subdivisions of block sizes. Larger
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** values require more memory in the control structure. Values of
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** 4 or 5 are typical.
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*/
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unsigned int sl_index_count_log2 : 3; // 23 cumulated bits
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unsigned int small_block_size : 8; // 31 cumulated bits
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/* size of the metadata ( size of control block,
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* sl_bitmap and blocks )
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*/
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size_t size;
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/* Bitmaps for free lists. */
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unsigned int fl_bitmap;
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unsigned int *sl_bitmap;
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/* Head of free lists. */
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block_header_t** blocks;
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} control_t;
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#if defined(__cplusplus)
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};
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#endif
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