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authorAntony Pavlov <antonynpavlov@gmail.com>2011-12-08 18:03:47 +0400
committerSascha Hauer <s.hauer@pengutronix.de>2011-12-23 11:26:42 +0100
commitd5b733a6449e6c285309880cdb65933a21ba5a76 (patch)
tree00c9416f9cf3f775a7b11c5dd334705e85e1313f /common/tlsf.c
parent81e1f6d0201a6cb15629ba81757f6acd80e01a60 (diff)
downloadbarebox-d5b733a6449e6c285309880cdb65933a21ba5a76.tar.gz
import TLSF 2.0 from http://tlsf.baisoku.org/tlsf-2.0.zip
TLSF: Two Level Segregated Fit memory allocator implementation. Written by Matthew Conte (matt@baisoku.org). Public Domain, no restrictions. Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Diffstat (limited to 'common/tlsf.c')
-rw-r--r--common/tlsf.c961
1 files changed, 961 insertions, 0 deletions
diff --git a/common/tlsf.c b/common/tlsf.c
new file mode 100644
index 0000000..02dc8d4
--- /dev/null
+++ b/common/tlsf.c
@@ -0,0 +1,961 @@
+#include <assert.h>
+#include <limits.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "tlsf.h"
+#include "tlsfbits.h"
+
+/*
+** Constants.
+*/
+
+/* Public constants: may be modified. */
+enum tlsf_public
+{
+ /* log2 of number of linear subdivisions of block sizes. */
+ SL_INDEX_COUNT_LOG2 = 5,
+};
+
+/* Private constants: do not modify. */
+enum tlsf_private
+{
+#if defined (TLSF_64BIT)
+ /* All allocation sizes and addresses are aligned to 8 bytes. */
+ ALIGN_SIZE_LOG2 = 3,
+#else
+ /* All allocation sizes and addresses are aligned to 4 bytes. */
+ ALIGN_SIZE_LOG2 = 2,
+#endif
+ ALIGN_SIZE = (1 << ALIGN_SIZE_LOG2),
+
+ /*
+ ** We support allocations of sizes up to (1 << FL_INDEX_MAX) bits.
+ ** However, because we linearly subdivide the second-level lists, and
+ ** our minimum size granularity is 4 bytes, it doesn't make sense to
+ ** create first-level lists for sizes smaller than SL_INDEX_COUNT * 4,
+ ** or (1 << (SL_INDEX_COUNT_LOG2 + 2)) bytes, as there we will be
+ ** trying to split size ranges into more slots than we have available.
+ ** Instead, we calculate the minimum threshold size, and place all
+ ** blocks below that size into the 0th first-level list.
+ */
+
+#if defined (TLSF_64BIT)
+ /*
+ ** TODO: We can increase this to support larger sizes, at the expense
+ ** of more overhead in the TLSF structure.
+ */
+ FL_INDEX_MAX = 32,
+#else
+ FL_INDEX_MAX = 30,
+#endif
+ SL_INDEX_COUNT = (1 << SL_INDEX_COUNT_LOG2),
+ FL_INDEX_SHIFT = (SL_INDEX_COUNT_LOG2 + ALIGN_SIZE_LOG2),
+ FL_INDEX_COUNT = (FL_INDEX_MAX - FL_INDEX_SHIFT + 1),
+
+ SMALL_BLOCK_SIZE = (1 << FL_INDEX_SHIFT),
+};
+
+/*
+** Cast and min/max macros.
+*/
+
+#define tlsf_cast(t, exp) ((t) (exp))
+#define tlsf_min(a, b) ((a) < (b) ? (a) : (b))
+#define tlsf_max(a, b) ((a) > (b) ? (a) : (b))
+
+/*
+** Set assert macro, if it has not been provided by the user.
+*/
+#if !defined (tlsf_assert)
+#define tlsf_assert assert
+#endif
+
+/*
+** Static assertion mechanism.
+*/
+
+#define _tlsf_glue2(x, y) x ## y
+#define _tlsf_glue(x, y) _tlsf_glue2(x, y)
+#define tlsf_static_assert(exp) \
+ typedef char _tlsf_glue(static_assert, __LINE__) [(exp) ? 1 : -1]
+
+/* This code has been tested on 32- and 64-bit (LP/LLP) architectures. */
+tlsf_static_assert(sizeof(int) * CHAR_BIT == 32);
+tlsf_static_assert(sizeof(size_t) * CHAR_BIT >= 32);
+tlsf_static_assert(sizeof(size_t) * CHAR_BIT <= 64);
+
+/* SL_INDEX_COUNT must be <= number of bits in sl_bitmap's storage type. */
+tlsf_static_assert(sizeof(unsigned int) * CHAR_BIT >= SL_INDEX_COUNT);
+
+/* Ensure we've properly tuned our sizes. */
+tlsf_static_assert(ALIGN_SIZE == SMALL_BLOCK_SIZE / SL_INDEX_COUNT);
+
+/*
+** Data structures and associated constants.
+*/
+
+/*
+** Block header structure.
+**
+** There are several implementation subtleties involved:
+** - The prev_phys_block field is only valid if the previous block is free.
+** - The prev_phys_block field is actually stored at the end of the
+** previous block. It appears at the beginning of this structure only to
+** simplify the implementation.
+** - The next_free / prev_free fields are only valid if the block is free.
+*/
+typedef struct block_header_t
+{
+ /* Points to the previous physical block. */
+ struct block_header_t* prev_phys_block;
+
+ /* The size of this block, excluding the block header. */
+ size_t size;
+
+ /* Next and previous free blocks. */
+ struct block_header_t* next_free;
+ struct block_header_t* prev_free;
+} block_header_t;
+
+/*
+** Since block sizes are always at least a multiple of 4, the two least
+** significant bits of the size field are used to store the block status:
+** - bit 0: whether block is busy or free
+** - bit 1: whether previous block is busy or free
+*/
+static const size_t block_header_free_bit = 1 << 0;
+static const size_t block_header_prev_free_bit = 1 << 1;
+
+/*
+** The size of the block header exposed to used blocks is the size field.
+** The prev_phys_block field is stored *inside* the previous free block.
+*/
+static const size_t block_header_overhead = sizeof(size_t);
+
+/* User data starts directly after the size field in a used block. */
+static const size_t block_start_offset =
+ offsetof(block_header_t, size) + sizeof(size_t);
+
+/*
+** A free block must be large enough to store its header minus the size of
+** the prev_phys_block field, and no larger than the number of addressable
+** bits for FL_INDEX.
+*/
+static const size_t block_size_min =
+ sizeof(block_header_t) - sizeof(block_header_t*);
+static const size_t block_size_max = tlsf_cast(size_t, 1) << FL_INDEX_MAX;
+
+
+/* The TLSF pool structure. */
+typedef struct pool_t
+{
+ /* Empty lists point at this block to indicate they are free. */
+ block_header_t block_null;
+
+ /* Bitmaps for free lists. */
+ unsigned int fl_bitmap;
+ unsigned int sl_bitmap[FL_INDEX_COUNT];
+
+ /* Head of free lists. */
+ block_header_t* blocks[FL_INDEX_COUNT][SL_INDEX_COUNT];
+} pool_t;
+
+/* A type used for casting when doing pointer arithmetic. */
+typedef ptrdiff_t tlsfptr_t;
+
+/*
+** block_header_t member functions.
+*/
+
+static size_t block_size(const block_header_t* block)
+{
+ return block->size & ~(block_header_free_bit | block_header_prev_free_bit);
+}
+
+static void block_set_size(block_header_t* block, size_t size)
+{
+ const size_t oldsize = block->size;
+ block->size = size | (oldsize & (block_header_free_bit | block_header_prev_free_bit));
+}
+
+static int block_is_last(const block_header_t* block)
+{
+ return 0 == block_size(block);
+}
+
+static int block_is_free(const block_header_t* block)
+{
+ return tlsf_cast(int, block->size & block_header_free_bit);
+}
+
+static void block_set_free(block_header_t* block)
+{
+ block->size |= block_header_free_bit;
+}
+
+static void block_set_used(block_header_t* block)
+{
+ block->size &= ~block_header_free_bit;
+}
+
+static int block_is_prev_free(const block_header_t* block)
+{
+ return tlsf_cast(int, block->size & block_header_prev_free_bit);
+}
+
+static void block_set_prev_free(block_header_t* block)
+{
+ block->size |= block_header_prev_free_bit;
+}
+
+static void block_set_prev_used(block_header_t* block)
+{
+ block->size &= ~block_header_prev_free_bit;
+}
+
+static block_header_t* block_from_ptr(const void* ptr)
+{
+ return tlsf_cast(block_header_t*,
+ tlsf_cast(unsigned char*, ptr) - block_start_offset);
+}
+
+static void* block_to_ptr(const block_header_t* block)
+{
+ return tlsf_cast(void*,
+ tlsf_cast(unsigned char*, block) + block_start_offset);
+}
+
+/* Return location of next block after block of given size. */
+static block_header_t* offset_to_block(const void* ptr, size_t size)
+{
+ return tlsf_cast(block_header_t*, tlsf_cast(tlsfptr_t, ptr) + size);
+}
+
+/* Return location of previous block. */
+static block_header_t* block_prev(const block_header_t* block)
+{
+ return block->prev_phys_block;
+}
+
+/* Return location of next existing block. */
+static block_header_t* block_next(const block_header_t* block)
+{
+ block_header_t* next = offset_to_block(block_to_ptr(block),
+ block_size(block) - block_header_overhead);
+ tlsf_assert(!block_is_last(block));
+ return next;
+}
+
+/* Link a new block with its physical neighbor, return the neighbor. */
+static block_header_t* block_link_next(block_header_t* block)
+{
+ block_header_t* next = block_next(block);
+ next->prev_phys_block = block;
+ return next;
+}
+
+static void block_mark_as_free(block_header_t* block)
+{
+ /* Link the block to the next block, first. */
+ block_header_t* next = block_link_next(block);
+ block_set_prev_free(next);
+ block_set_free(block);
+}
+
+static void block_mark_as_used(block_header_t* block)
+{
+ block_header_t* next = block_next(block);
+ block_set_prev_used(next);
+ block_set_used(block);
+}
+
+static size_t align_up(size_t x, size_t align)
+{
+ tlsf_assert(0 == (align & (align - 1)) && "must align to a power of two");
+ return (x + (align - 1)) & ~(align - 1);
+}
+
+static size_t align_down(size_t x, size_t align)
+{
+ tlsf_assert(0 == (align & (align - 1)) && "must align to a power of two");
+ return x - (x & (align - 1));
+}
+
+static void* align_ptr(const void* ptr, size_t align)
+{
+ const tlsfptr_t aligned =
+ (tlsf_cast(tlsfptr_t, ptr) + (align - 1)) & ~(align - 1);
+ tlsf_assert(0 == (align & (align - 1)) && "must align to a power of two");
+ return tlsf_cast(void*, aligned);
+}
+
+/*
+** Adjust an allocation size to be aligned to word size, and no smaller
+** than internal minimum.
+*/
+static size_t adjust_request_size(size_t size, size_t align)
+{
+ size_t adjust = 0;
+ if (size && size < block_size_max)
+ {
+ const size_t aligned = align_up(size, align);
+ adjust = tlsf_max(aligned, block_size_min);
+ }
+ return adjust;
+}
+
+/*
+** TLSF utility functions. In most cases, these are direct translations of
+** the documentation found in the white paper.
+*/
+
+static void mapping_insert(size_t size, int* fli, int* sli)
+{
+ int fl, sl;
+ if (size < SMALL_BLOCK_SIZE)
+ {
+ /* Store small blocks in first list. */
+ fl = 0;
+ sl = tlsf_cast(int, size) / (SMALL_BLOCK_SIZE / SL_INDEX_COUNT);
+ }
+ else
+ {
+ fl = tlsf_fls_sizet(size);
+ sl = tlsf_cast(int, size >> (fl - SL_INDEX_COUNT_LOG2)) ^ (1 << SL_INDEX_COUNT_LOG2);
+ fl -= (FL_INDEX_SHIFT - 1);
+ }
+ *fli = fl;
+ *sli = sl;
+}
+
+/* This version rounds up to the next block size (for allocations) */
+static void mapping_search(size_t size, int* fli, int* sli)
+{
+ if (size >= (1 << SL_INDEX_COUNT_LOG2))
+ {
+ const size_t round = (1 << (tlsf_fls_sizet(size) - SL_INDEX_COUNT_LOG2)) - 1;
+ size += round;
+ }
+ mapping_insert(size, fli, sli);
+}
+
+static block_header_t* search_suitable_block(pool_t* pool, int* fli, int* sli)
+{
+ int fl = *fli;
+ int sl = *sli;
+
+ /*
+ ** First, search for a block in the list associated with the given
+ ** fl/sl index.
+ */
+ unsigned int sl_map = pool->sl_bitmap[fl] & (~0 << sl);
+ if (!sl_map)
+ {
+ /* No block exists. Search in the next largest first-level list. */
+ const unsigned int fl_map = pool->fl_bitmap & (~0 << (fl + 1));
+ if (!fl_map)
+ {
+ /* No free blocks available, memory has been exhausted. */
+ return 0;
+ }
+
+ fl = tlsf_ffs(fl_map);
+ *fli = fl;
+ sl_map = pool->sl_bitmap[fl];
+ }
+ tlsf_assert(sl_map && "internal error - second level bitmap is null");
+ sl = tlsf_ffs(sl_map);
+ *sli = sl;
+
+ /* Return the first block in the free list. */
+ return pool->blocks[fl][sl];
+}
+
+/* Remove a free block from the free list.*/
+static void remove_free_block(pool_t* pool, block_header_t* block, int fl, int sl)
+{
+ block_header_t* prev = block->prev_free;
+ block_header_t* next = block->next_free;
+ tlsf_assert(prev && "prev_free field can not be null");
+ tlsf_assert(next && "next_free field can not be null");
+ next->prev_free = prev;
+ prev->next_free = next;
+
+ /* If this block is the head of the free list, set new head. */
+ if (pool->blocks[fl][sl] == block)
+ {
+ pool->blocks[fl][sl] = next;
+
+ /* If the new head is null, clear the bitmap. */
+ if (next == &pool->block_null)
+ {
+ pool->sl_bitmap[fl] &= ~(1 << sl);
+
+ /* If the second bitmap is now empty, clear the fl bitmap. */
+ if (!pool->sl_bitmap[fl])
+ {
+ pool->fl_bitmap &= ~(1 << fl);
+ }
+ }
+ }
+}
+
+/* Insert a free block into the free block list. */
+static void insert_free_block(pool_t* pool, block_header_t* block, int fl, int sl)
+{
+ block_header_t* current = pool->blocks[fl][sl];
+ tlsf_assert(current && "free list cannot have a null entry");
+ tlsf_assert(block && "cannot insert a null entry into the free list");
+ block->next_free = current;
+ block->prev_free = &pool->block_null;
+ current->prev_free = block;
+
+ tlsf_assert(block_to_ptr(block) == align_ptr(block_to_ptr(block), ALIGN_SIZE)
+ && "block not aligned properly");
+ /*
+ ** Insert the new block at the head of the list, and mark the first-
+ ** and second-level bitmaps appropriately.
+ */
+ pool->blocks[fl][sl] = block;
+ pool->fl_bitmap |= (1 << fl);
+ pool->sl_bitmap[fl] |= (1 << sl);
+}
+
+/* Remove a given block from the free list. */
+static void block_remove(pool_t* pool, block_header_t* block)
+{
+ int fl, sl;
+ mapping_insert(block_size(block), &fl, &sl);
+ remove_free_block(pool, block, fl, sl);
+}
+
+/* Insert a given block into the free list. */
+static void block_insert(pool_t* pool, block_header_t* block)
+{
+ int fl, sl;
+ mapping_insert(block_size(block), &fl, &sl);
+ insert_free_block(pool, block, fl, sl);
+}
+
+static int block_can_split(block_header_t* block, size_t size)
+{
+ return block_size(block) >= sizeof(block_header_t) + size;
+}
+
+/* Split a block into two, the second of which is free. */
+static block_header_t* block_split(block_header_t* block, size_t size)
+{
+ /* Calculate the amount of space left in the remaining block. */
+ block_header_t* remaining =
+ offset_to_block(block_to_ptr(block), size - block_header_overhead);
+
+ const size_t remain_size = block_size(block) - (size + block_header_overhead);
+
+ tlsf_assert(block_to_ptr(remaining) == align_ptr(block_to_ptr(remaining), ALIGN_SIZE)
+ && "remaining block not aligned properly");
+
+ tlsf_assert(block_size(block) == remain_size + size + block_header_overhead);
+ block_set_size(remaining, remain_size);
+ tlsf_assert(block_size(remaining) >= block_size_min && "block split with invalid size");
+
+ block_set_size(block, size);
+ block_mark_as_free(remaining);
+
+ return remaining;
+}
+
+/* Absorb a free block's storage into an adjacent previous free block. */
+static block_header_t* block_absorb(block_header_t* prev, block_header_t* block)
+{
+ tlsf_assert(!block_is_last(prev) && "previous block can't be last!");
+ /* Note: Leaves flags untouched. */
+ prev->size += block_size(block) + block_header_overhead;
+ block_link_next(prev);
+ return prev;
+}
+
+/* Merge a just-freed block with an adjacent previous free block. */
+static block_header_t* block_merge_prev(pool_t* pool, block_header_t* block)
+{
+ if (block_is_prev_free(block))
+ {
+ block_header_t* prev = block_prev(block);
+ tlsf_assert(prev && "prev physical block can't be null");
+ tlsf_assert(block_is_free(prev) && "prev block is not free though marked as such");
+ block_remove(pool, prev);
+ block = block_absorb(prev, block);
+ }
+
+ return block;
+}
+
+/* Merge a just-freed block with an adjacent free block. */
+static block_header_t* block_merge_next(pool_t* pool, block_header_t* block)
+{
+ block_header_t* next = block_next(block);
+ tlsf_assert(next && "next physical block can't be null");
+
+ if (block_is_free(next))
+ {
+ tlsf_assert(!block_is_last(block) && "previous block can't be last!");
+ block_remove(pool, next);
+ block = block_absorb(block, next);
+ }
+
+ return block;
+}
+
+/* Trim any trailing block space off the end of a block, return to pool. */
+static void block_trim_free(pool_t* pool, block_header_t* block, size_t size)
+{
+ tlsf_assert(block_is_free(block) && "block must be free");
+ if (block_can_split(block, size))
+ {
+ block_header_t* remaining_block = block_split(block, size);
+ block_link_next(block);
+ block_set_prev_free(remaining_block);
+ block_insert(pool, remaining_block);
+ }
+}
+
+/* Trim any trailing block space off the end of a used block, return to pool. */
+static void block_trim_used(pool_t* pool, block_header_t* block, size_t size)
+{
+ tlsf_assert(!block_is_free(block) && "block must be used");
+ if (block_can_split(block, size))
+ {
+ /* If the next block is free, we must coalesce. */
+ block_header_t* remaining_block = block_split(block, size);
+ block_set_prev_used(remaining_block);
+
+ remaining_block = block_merge_next(pool, remaining_block);
+ block_insert(pool, remaining_block);
+ }
+}
+
+static block_header_t* block_trim_free_leading(pool_t* pool, block_header_t* block, size_t size)
+{
+ block_header_t* remaining_block = block;
+ if (block_can_split(block, size))
+ {
+ /* We want the 2nd block. */
+ remaining_block = block_split(block, size - block_header_overhead);
+ block_set_prev_free(remaining_block);
+
+ block_link_next(block);
+ block_insert(pool, block);
+ }
+
+ return remaining_block;
+}
+
+static block_header_t* block_locate_free(pool_t* pool, size_t size)
+{
+ int fl = 0, sl = 0;
+ block_header_t* block = 0;
+
+ if (size)
+ {
+ mapping_search(size, &fl, &sl);
+ block = search_suitable_block(pool, &fl, &sl);
+ }
+
+ if (block)
+ {
+ tlsf_assert(block_size(block) >= size);
+ remove_free_block(pool, block, fl, sl);
+ }
+
+ return block;
+}
+
+static void* block_prepare_used(pool_t* pool, block_header_t* block, size_t size)
+{
+ void* p = 0;
+ if (block)
+ {
+ block_trim_free(pool, block, size);
+ block_mark_as_used(block);
+ p = block_to_ptr(block);
+ }
+ return p;
+}
+
+/* Clear structure and point all empty lists at the null block. */
+static void pool_construct(pool_t* pool)
+{
+ int i, j;
+
+ pool->block_null.next_free = &pool->block_null;
+ pool->block_null.prev_free = &pool->block_null;
+
+ pool->fl_bitmap = 0;
+ for (i = 0; i < FL_INDEX_COUNT; ++i)
+ {
+ pool->sl_bitmap[i] = 0;
+ for (j = 0; j < SL_INDEX_COUNT; ++j)
+ {
+ pool->blocks[i][j] = &pool->block_null;
+ }
+ }
+}
+
+/*
+** Debugging utilities.
+*/
+
+typedef struct integrity_t
+{
+ int prev_status;
+ int status;
+} integrity_t;
+
+#define tlsf_insist(x) { tlsf_assert(x); if (!(x)) { status--; } }
+
+static void integrity_walker(void* ptr, size_t size, int used, void* user)
+{
+ block_header_t* block = block_from_ptr(ptr);
+ integrity_t* integ = tlsf_cast(integrity_t*, user);
+ const int this_prev_status = block_is_prev_free(block) ? 1 : 0;
+ const int this_status = block_is_free(block) ? 1 : 0;
+ const size_t this_block_size = block_size(block);
+
+ int status = 0;
+ tlsf_insist(integ->prev_status == this_prev_status && "prev status incorrect");
+ tlsf_insist(size == this_block_size && "block size incorrect");
+
+ integ->prev_status = this_status;
+ integ->status += status;
+}
+
+int tlsf_check_heap(tlsf_pool tlsf)
+{
+ int i, j;
+
+ pool_t* pool = tlsf_cast(pool_t*, tlsf);
+ int status = 0;
+
+ /* Check that the blocks are physically correct. */
+ integrity_t integ = { 0, 0 };
+ tlsf_walk_heap(tlsf, integrity_walker, &integ);
+ status = integ.status;
+
+ /* Check that the free lists and bitmaps are accurate. */
+ for (i = 0; i < FL_INDEX_COUNT; ++i)
+ {
+ for (j = 0; j < SL_INDEX_COUNT; ++j)
+ {
+ const int fl_map = pool->fl_bitmap & (1 << i);
+ const int sl_list = pool->sl_bitmap[i];
+ const int sl_map = sl_list & (1 << j);
+ const block_header_t* block = pool->blocks[i][j];
+
+ /* Check that first- and second-level lists agree. */
+ if (!fl_map)
+ {
+ tlsf_insist(!sl_map && "second-level map must be null");
+ }
+
+ if (!sl_map)
+ {
+ tlsf_insist(block == &pool->block_null && "block list must be null");
+ continue;
+ }
+
+ /* Check that there is at least one free block. */
+ tlsf_insist(sl_list && "no free blocks in second-level map");
+ tlsf_insist(block != &pool->block_null && "block should not be null");
+
+ while (block != &pool->block_null)
+ {
+ int fli, sli;
+ tlsf_insist(block_is_free(block) && "block should be free");
+ tlsf_insist(!block_is_prev_free(block) && "blocks should have coalesced");
+ tlsf_insist(!block_is_free(block_next(block)) && "blocks should have coalesced");
+ tlsf_insist(block_is_prev_free(block_next(block)) && "block should be free");
+ tlsf_insist(block_size(block) >= block_size_min && "block not minimum size");
+
+ mapping_insert(block_size(block), &fli, &sli);
+ tlsf_insist(fli == i && sli == j && "block size indexed in wrong list");
+ block = block->next_free;
+ }
+ }
+ }
+
+ return status;
+}
+
+#undef tlsf_insist
+
+static void default_walker(void* ptr, size_t size, int used, void* user)
+{
+ (void)user;
+ printf("\t%p %s size: %x (%p)\n", ptr, used ? "used" : "free", (unsigned int)size, block_from_ptr(ptr));
+}
+
+void tlsf_walk_heap(tlsf_pool pool, tlsf_walker walker, void* user)
+{
+ tlsf_walker heap_walker = walker ? walker : default_walker;
+ block_header_t* block =
+ offset_to_block(pool, sizeof(pool_t) - block_header_overhead);
+
+ while (block && !block_is_last(block))
+ {
+ heap_walker(
+ block_to_ptr(block),
+ block_size(block),
+ !block_is_free(block),
+ user);
+ block = block_next(block);
+ }
+}
+
+size_t tlsf_block_size(void* ptr)
+{
+ size_t size = 0;
+ if (ptr)
+ {
+ const block_header_t* block = block_from_ptr(ptr);
+ size = block_size(block);
+ }
+ return size;
+}
+
+/*
+** Overhead of the TLSF structures in a given memory block passed to
+** tlsf_create, equal to the size of a pool_t plus overhead of the initial
+** free block and the sentinel block.
+*/
+size_t tlsf_overhead()
+{
+ const size_t pool_overhead = sizeof(pool_t) + 2 * block_header_overhead;
+ return pool_overhead;
+}
+
+/*
+** TLSF main interface. Right out of the white paper.
+*/
+
+tlsf_pool tlsf_create(void* mem, size_t bytes)
+{
+ block_header_t* block;
+ block_header_t* next;
+
+ const size_t pool_overhead = tlsf_overhead();
+ const size_t pool_bytes = align_down(bytes - pool_overhead, ALIGN_SIZE);
+ pool_t* pool = tlsf_cast(pool_t*, mem);
+
+#if _DEBUG
+ /* Verify ffs/fls work properly. */
+ int rv = 0;
+ rv += (tlsf_ffs(0) == -1) ? 0 : 0x1;
+ rv += (tlsf_fls(0) == -1) ? 0 : 0x2;
+ rv += (tlsf_ffs(1) == 0) ? 0 : 0x4;
+ rv += (tlsf_fls(1) == 0) ? 0 : 0x8;
+ rv += (tlsf_ffs(0x80000000) == 31) ? 0 : 0x10;
+ rv += (tlsf_ffs(0x80008000) == 15) ? 0 : 0x20;
+ rv += (tlsf_fls(0x80000008) == 31) ? 0 : 0x40;
+ rv += (tlsf_fls(0x7FFFFFFF) == 30) ? 0 : 0x80;
+
+#if defined (TLSF_64BIT)
+ rv += (tlsf_fls_sizet(0x80000000) == 31) ? 0 : 0x100;
+ rv += (tlsf_fls_sizet(0x100000000) == 32) ? 0 : 0x200;
+ rv += (tlsf_fls_sizet(0xffffffffffffffff) == 63) ? 0 : 0x400;
+ if (rv)
+ {
+ printf("tlsf_create: %x ffs/fls tests failed!\n", rv);
+ return 0;
+ }
+#endif
+#endif
+
+ if (pool_bytes < block_size_min || pool_bytes > block_size_max)
+ {
+#if defined (TLSF_64BIT)
+ printf("tlsf_create: Pool size must be at least %d bytes.\n",
+ (unsigned int)(pool_overhead + block_size_min));
+#else
+ printf("tlsf_create: Pool size must be between %u and %u bytes.\n",
+ (unsigned int)(pool_overhead + block_size_min),
+ (unsigned int)(pool_overhead + block_size_max));
+#endif
+ return 0;
+ }
+
+ /* Construct a valid pool object. */
+ pool_construct(pool);
+
+ /*
+ ** Create the main free block. Offset the start of the block slightly
+ ** so that the prev_phys_block field falls inside of the pool
+ ** structure - it will never be used.
+ */
+ block = offset_to_block(
+ tlsf_cast(void*, pool), sizeof(pool_t) - block_header_overhead);
+ block_set_size(block, pool_bytes);
+ block_set_free(block);
+ block_set_prev_used(block);
+ block_insert(pool, block);
+
+ /* Split the block to create a zero-size pool sentinel block. */
+ next = block_link_next(block);
+ block_set_size(next, 0);
+ block_set_used(next);
+ block_set_prev_free(next);
+
+ return tlsf_cast(tlsf_pool, pool);
+}
+
+void tlsf_destroy(tlsf_pool pool)
+{
+ /* Nothing to do. */
+ pool = pool;
+}
+
+void* tlsf_malloc(tlsf_pool tlsf, size_t size)
+{
+ pool_t* pool = tlsf_cast(pool_t*, tlsf);
+ const size_t adjust = adjust_request_size(size, ALIGN_SIZE);
+ block_header_t* block = block_locate_free(pool, adjust);
+ return block_prepare_used(pool, block, adjust);
+}
+
+void* tlsf_memalign(tlsf_pool tlsf, size_t align, size_t size)
+{
+ pool_t* pool = tlsf_cast(pool_t*, tlsf);
+ const size_t adjust = adjust_request_size(size, ALIGN_SIZE);
+
+ /*
+ ** We must allocate an additional minimum block size bytes so that if
+ ** our free block will leave an alignment gap which is smaller, we can
+ ** trim a leading free block and release it back to the heap. We must
+ ** do this because the previous physical block is in use, therefore
+ ** the prev_phys_block field is not valid, and we can't simply adjust
+ ** the size of that block.
+ */
+ const size_t gap_minimum = sizeof(block_header_t);
+ const size_t size_with_gap = adjust_request_size(adjust + align + gap_minimum, align);
+
+ /* If alignment is less than or equals base alignment, we're done. */
+ const size_t aligned_size = (align <= ALIGN_SIZE) ? adjust : size_with_gap;
+
+ block_header_t* block = block_locate_free(pool, aligned_size);
+
+ /* This can't be a static assert. */
+ tlsf_assert(sizeof(block_header_t) == block_size_min + block_header_overhead);
+
+ if (block)
+ {
+ void* ptr = block_to_ptr(block);
+ void* aligned = align_ptr(ptr, align);
+ size_t gap = tlsf_cast(size_t,
+ tlsf_cast(tlsfptr_t, aligned) - tlsf_cast(tlsfptr_t, ptr));
+
+ /* If gap size is too small, offset to next aligned boundary. */
+ if (gap && gap < gap_minimum)
+ {
+ const size_t gap_remain = gap_minimum - gap;
+ const size_t offset = tlsf_max(gap_remain, align);
+ const void* next_aligned = tlsf_cast(void*,
+ tlsf_cast(tlsfptr_t, aligned) + offset);
+
+ aligned = align_ptr(next_aligned, align);
+ gap = tlsf_cast(size_t,
+ tlsf_cast(tlsfptr_t, aligned) - tlsf_cast(tlsfptr_t, ptr));
+ }
+
+ if (gap)
+ {
+ tlsf_assert(gap >= gap_minimum && "gap size too small");
+ block = block_trim_free_leading(pool, block, gap);
+ }
+ }
+
+ return block_prepare_used(pool, block, adjust);
+}
+
+void tlsf_free(tlsf_pool tlsf, void* ptr)
+{
+ /* Don't attempt to free a NULL pointer. */
+ if (ptr)
+ {
+ pool_t* pool = tlsf_cast(pool_t*, tlsf);
+ block_header_t* block = block_from_ptr(ptr);
+ block_mark_as_free(block);
+ block = block_merge_prev(pool, block);
+ block = block_merge_next(pool, block);
+ block_insert(pool, block);
+ }
+}
+
+/*
+** The TLSF block information provides us with enough information to
+** provide a reasonably intelligent implementation of realloc, growing or
+** shrinking the currently allocated block as required.
+**
+** This routine handles the somewhat esoteric edge cases of realloc:
+** - a non-zero size with a null pointer will behave like malloc
+** - a zero size with a non-null pointer will behave like free
+** - a request that cannot be satisfied will leave the original buffer
+** untouched
+** - an extended buffer size will leave the newly-allocated area with
+** contents undefined
+*/
+void* tlsf_realloc(tlsf_pool tlsf, void* ptr, size_t size)
+{
+ pool_t* pool = tlsf_cast(pool_t*, tlsf);
+ void* p = 0;
+
+ /* Zero-size requests are treated as free. */
+ if (ptr && size == 0)
+ {
+ tlsf_free(tlsf, ptr);
+ }
+ /* Requests with NULL pointers are treated as malloc. */
+ else if (!ptr)
+ {
+ p = tlsf_malloc(tlsf, size);
+ }
+ else
+ {
+ block_header_t* block = block_from_ptr(ptr);
+ block_header_t* next = block_next(block);
+
+ const size_t cursize = block_size(block);
+ const size_t combined = cursize + block_size(next) + block_header_overhead;
+ const size_t adjust = adjust_request_size(size, ALIGN_SIZE);
+
+ /*
+ ** If the next block is used, or when combined with the current
+ ** block, does not offer enough space, we must reallocate and copy.
+ */
+ if (adjust > cursize && (!block_is_free(next) || adjust > combined))
+ {
+ p = tlsf_malloc(tlsf, size);
+ if (p)
+ {
+ const size_t minsize = tlsf_min(cursize, size);
+ memcpy(p, ptr, minsize);
+ tlsf_free(tlsf, ptr);
+ }
+ }
+ else
+ {
+ /* Do we need to expand to the next block? */
+ if (adjust > cursize)
+ {
+ block_merge_next(pool, block);
+ block_mark_as_used(block);
+ }
+
+ /* Trim the resulting block and return the original pointer. */
+ block_trim_used(pool, block, adjust);
+ p = ptr;
+ }
+ }
+
+ return p;
+}