/* ** Two Level Segregated Fit memory allocator, version 3.1. ** Written by Matthew Conte ** http://tlsf.baisoku.org ** ** Based on the original documentation by Miguel Masmano: ** http://www.gii.upv.es/tlsf/main/docs ** ** This implementation was written to the specification ** of the document, therefore no GPL restrictions apply. ** ** Copyright (c) 2006-2016, Matthew Conte ** All rights reserved. ** ** Redistribution and use in source and binary forms, with or without ** modification, are permitted provided that the following conditions are met: ** * Redistributions of source code must retain the above copyright ** notice, this list of conditions and the following disclaimer. ** * Redistributions in binary form must reproduce the above copyright ** notice, this list of conditions and the following disclaimer in the ** documentation and/or other materials provided with the distribution. ** * Neither the name of the copyright holder nor the ** names of its contributors may be used to endorse or promote products ** derived from this software without specific prior written permission. ** ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ** ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED ** WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE ** DISCLAIMED. IN NO EVENT SHALL MATTHEW CONTE BE LIABLE FOR ANY ** DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES ** (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; ** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ** ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS ** SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include "multi_heap_config.h" #include "multi_heap.h" #include "multi_heap_internal.h" #include "heap_tlsf_config.h" #include "heap_tlsf.h" /* ** Architecture-specific bit manipulation routines. ** ** TLSF achieves O(1) cost for malloc and free operations by limiting ** the search for a free block to a free list of guaranteed size ** adequate to fulfill the request, combined with efficient free list ** queries using bitmasks and architecture-specific bit-manipulation ** routines. ** ** Most modern processors provide instructions to count leading zeroes ** in a word, find the lowest and highest set bit, etc. These ** specific implementations will be used when available, falling back ** to a reasonably efficient generic implementation. ** ** NOTE: TLSF spec relies on ffs/fls returning value 0..31. ** ffs/fls return 1-32 by default, returning 0 for error. */ static inline __attribute__((__always_inline__)) int tlsf_ffs(unsigned int word) { const unsigned int reverse = word & (~word + 1); const int bit = 32 - __builtin_clz(reverse); return bit - 1; } static inline __attribute__((__always_inline__)) int tlsf_fls(unsigned int word) { const int bit = word ? 32 - __builtin_clz(word) : 0; return bit - 1; } /* ** 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); static inline __attribute__((__always_inline__)) 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 inline __attribute__((__always_inline__)) 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 inline __attribute__((__always_inline__)) 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 inline __attribute__((__always_inline__)) size_t adjust_request_size(size_t size, size_t align) { size_t adjust = 0; if (size) { const size_t aligned = align_up(size, align); /* aligned sized must not exceed block_size_max or we'll go out of bounds on sl_bitmap */ if (aligned < block_size_max) { 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 inline __attribute__((__always_inline__)) 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) >> 2; } else { fl = tlsf_fls(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 inline __attribute__((__always_inline__)) void mapping_search(size_t size, int* fli, int* sli) { if (size >= SMALL_BLOCK_SIZE) { const size_t round = (1 << (tlsf_fls(size) - SL_INDEX_COUNT_LOG2)) - 1; size += round; } mapping_insert(size, fli, sli); } static inline __attribute__((__always_inline__)) block_header_t* search_suitable_block(control_t* control, 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 = control->sl_bitmap[fl] & (~0U << sl); if (!sl_map) { /* No block exists. Search in the next largest first-level list. */ const unsigned int fl_map = control->fl_bitmap & (~0U << (fl + 1)); if (!fl_map) { /* No free blocks available, memory has been exhausted. */ return 0; } fl = tlsf_ffs(fl_map); *fli = fl; sl_map = control->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 control->blocks[fl][sl]; } /* Remove a free block from the free list.*/ static inline __attribute__((__always_inline__)) void remove_free_block(control_t* control, 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 (control->blocks[fl][sl] == block) { control->blocks[fl][sl] = next; /* If the new head is null, clear the bitmap. */ if (next == &control->block_null) { control->sl_bitmap[fl] &= ~(1 << sl); /* If the second bitmap is now empty, clear the fl bitmap. */ if (!control->sl_bitmap[fl]) { control->fl_bitmap &= ~(1 << fl); } } } } /* Insert a free block into the free block list. */ static inline __attribute__((__always_inline__)) void insert_free_block(control_t* control, block_header_t* block, int fl, int sl) { block_header_t* current = control->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 = &control->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. */ control->blocks[fl][sl] = block; control->fl_bitmap |= (1 << fl); control->sl_bitmap[fl] |= (1 << sl); } /* Remove a given block from the free list. */ static inline __attribute__((__always_inline__)) void block_remove(control_t* control, block_header_t* block) { int fl, sl; mapping_insert(block_size(block), &fl, &sl); remove_free_block(control, block, fl, sl); } /* Insert a given block into the free list. */ static inline __attribute__((__always_inline__)) void block_insert(control_t* control, block_header_t* block) { int fl, sl; mapping_insert(block_size(block), &fl, &sl); insert_free_block(control, block, fl, sl); } static inline __attribute__((__always_inline__)) 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 inline __attribute__((__always_inline__)) block_header_t* block_split(block_header_t* block, size_t size) { /* Calculate the amount of space left in the remaining block. * REMINDER: remaining pointer's first field is `prev_phys_block` but this field is part of the * previous physical block. */ block_header_t* remaining = offset_to_block(block_to_ptr(block), size - block_header_overhead); /* `size` passed as an argument is the first block's new size, thus, the remaining block's size * is `block_size(block) - size`. However, the block's data must be precedeed by the data size. * This field is NOT part of the size, so it has to be substracted from the calculation. */ 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); /** * Here is the final outcome of this function: * * block remaining (block_ptr + size - BHO) * + + * | | * v v * +----------------------------------------------------------------------+ * |0000| |xxxxxxxxxxxxxxxxxxxxxx|xxxx| |###########################| * |0000| |xxxxxxxxxxxxxxxxxxxxxx|xxxx| |###########################| * |0000| |xxxxxxxxxxxxxxxxxxxxxx|xxxx| |###########################| * |0000| |xxxxxxxxxxxxxxxxxxxxxx|xxxx| |###########################| * +----------------------------------------------------------------------+ * | | | | * + +<------------------------->+ +<-------------------------> * BHO `size` (argument) bytes BHO `remain_size` bytes * * Where BHO = block_header_overhead, * 0: part of the memory owned by a `block`'s previous neighbour, * x: part of the memory owned by `block`. * #: part of the memory owned by `remaining`. */ return remaining; } /* Absorb a free block's storage into an adjacent previous free block. */ static inline __attribute__((__always_inline__)) 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); #ifdef MULTI_HEAP_POISONING_SLOW /* next_block header needs to be replaced with a fill pattern */ multi_heap_internal_poison_fill_region(block, sizeof(block_header_t), true /* free */); #endif return prev; } /* Merge a just-freed block with an adjacent previous free block. */ static inline __attribute__((__always_inline__)) block_header_t* block_merge_prev(control_t* control, 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(control, prev); block = block_absorb(prev, block); } return block; } /* Merge a just-freed block with an adjacent free block. */ static inline __attribute__((__always_inline__)) block_header_t* block_merge_next(control_t* control, 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(control, next); block = block_absorb(block, next); } return block; } /* Trim any trailing block space off the end of a block, return to pool. */ static inline __attribute__((__always_inline__)) void block_trim_free(control_t* control, 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(control, remaining_block); } } /* Trim any trailing block space off the end of a used block, return to pool. */ static inline __attribute__((__always_inline__)) void block_trim_used(control_t* control, 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(control, remaining_block); block_insert(control, remaining_block); } } static inline __attribute__((__always_inline__)) block_header_t* block_trim_free_leading(control_t* control, block_header_t* block, size_t size) { block_header_t* remaining_block = block; if (block_can_split(block, size)) { /* We want to split `block` in two: the first block will be freed and the * second block will be returned. */ remaining_block = block_split(block, size - block_header_overhead); /* `remaining_block` is the second block, mark its predecessor (first * block) as free. */ block_set_prev_free(remaining_block); block_link_next(block); /* Put back the first block into the free memory list. */ block_insert(control, block); } return remaining_block; } static inline __attribute__((__always_inline__)) block_header_t* block_locate_free(control_t* control, size_t size) { int fl = 0, sl = 0; block_header_t* block = 0; if (size) { mapping_search(size, &fl, &sl); /* ** mapping_search can futz with the size, so for excessively large sizes it can sometimes wind up ** with indices that are off the end of the block array. ** So, we protect against that here, since this is the only callsite of mapping_search. ** Note that we don't need to check sl, since it comes from a modulo operation that guarantees it's always in range. */ if (fl < FL_INDEX_COUNT) { block = search_suitable_block(control, &fl, &sl); } } if (block) { tlsf_assert(block_size(block) >= size); remove_free_block(control, block, fl, sl); } return block; } static inline __attribute__((__always_inline__)) void* block_prepare_used(control_t* control, block_header_t* block, size_t size) { void* p = 0; if (block) { tlsf_assert(size && "size must be non-zero"); block_trim_free(control, 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 control_construct(control_t* control) { int i, j; control->block_null.next_free = &control->block_null; control->block_null.prev_free = &control->block_null; control->fl_bitmap = 0; for (i = 0; i < FL_INDEX_COUNT; ++i) { control->sl_bitmap[i] = 0; for (j = 0; j < SL_INDEX_COUNT; ++j) { control->blocks[i][j] = &control->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; (void)used; 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(tlsf_t tlsf) { int i, j; control_t* control = tlsf_cast(control_t*, tlsf); int status = 0; /* 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 = control->fl_bitmap & (1 << i); const int sl_list = control->sl_bitmap[i]; const int sl_map = sl_list & (1 << j); const block_header_t* block = control->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 == &control->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 != &control->block_null && "block should not be null"); while (block != &control->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_pool(pool_t pool, tlsf_walker walker, void* user) { tlsf_walker pool_walker = walker ? walker : default_walker; block_header_t* block = offset_to_block(pool, -(int)block_header_overhead); while (block && !block_is_last(block)) { pool_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; } int tlsf_check_pool(pool_t pool) { /* Check that the blocks are physically correct. */ integrity_t integ = { 0, 0 }; tlsf_walk_pool(pool, integrity_walker, &integ); return integ.status; } /* ** Size of the TLSF structures in a given memory block passed to ** tlsf_create, equal to the size of a control_t */ size_t tlsf_size(void) { return sizeof(control_t); } size_t tlsf_align_size(void) { return ALIGN_SIZE; } size_t tlsf_block_size_min(void) { return block_size_min; } size_t tlsf_block_size_max(void) { return block_size_max; } /* ** Overhead of the TLSF structures in a given memory block passed to ** tlsf_add_pool, equal to the overhead of a free block and the ** sentinel block. */ size_t tlsf_pool_overhead(void) { return 2 * block_header_overhead; } size_t tlsf_alloc_overhead(void) { return block_header_overhead; } pool_t tlsf_add_pool(tlsf_t tlsf, void* mem, size_t bytes) { block_header_t* block; block_header_t* next; const size_t pool_overhead = tlsf_pool_overhead(); const size_t pool_bytes = align_down(bytes - pool_overhead, ALIGN_SIZE); if (((ptrdiff_t)mem % ALIGN_SIZE) != 0) { printf("tlsf_add_pool: Memory must be aligned by %u bytes.\n", (unsigned int)ALIGN_SIZE); return 0; } if (pool_bytes < block_size_min || pool_bytes > block_size_max) { #if defined (TLSF_64BIT) printf("tlsf_add_pool: Memory size must be between 0x%x and 0x%x00 bytes.\n", (unsigned int)(pool_overhead + block_size_min), (unsigned int)((pool_overhead + block_size_max) / 256)); #else printf("tlsf_add_pool: Memory 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; } /* ** Create the main free block. Offset the start of the block slightly ** so that the prev_phys_block field falls outside of the pool - ** it will never be used. */ block = offset_to_block(mem, -(tlsfptr_t)block_header_overhead); block_set_size(block, pool_bytes); block_set_free(block); block_set_prev_used(block); block_insert(tlsf_cast(control_t*, tlsf), block); /* Split the block to create a zero-size sentinel block. */ next = block_link_next(block); block_set_size(next, 0); block_set_used(next); block_set_prev_free(next); return mem; } void tlsf_remove_pool(tlsf_t tlsf, pool_t pool) { control_t* control = tlsf_cast(control_t*, tlsf); block_header_t* block = offset_to_block(pool, -(int)block_header_overhead); int fl = 0, sl = 0; tlsf_assert(block_is_free(block) && "block should be free"); tlsf_assert(!block_is_free(block_next(block)) && "next block should not be free"); tlsf_assert(block_size(block_next(block)) == 0 && "next block size should be zero"); mapping_insert(block_size(block), &fl, &sl); remove_free_block(control, block, fl, sl); } /* ** TLSF main interface. */ tlsf_t tlsf_create(void* mem) { #if _DEBUG if (test_ffs_fls()) { return 0; } #endif if (((tlsfptr_t)mem % ALIGN_SIZE) != 0) { printf("tlsf_create: Memory must be aligned to %u bytes.\n", (unsigned int)ALIGN_SIZE); return 0; } control_construct(tlsf_cast(control_t*, mem)); return tlsf_cast(tlsf_t, mem); } pool_t tlsf_get_pool(tlsf_t tlsf) { return tlsf_cast(pool_t, (char*)tlsf + tlsf_size()); } tlsf_t tlsf_create_with_pool(void* mem, size_t bytes) { tlsf_t tlsf = tlsf_create(mem); tlsf_add_pool(tlsf, (char*)mem + tlsf_size(), bytes - tlsf_size()); return tlsf; } void* tlsf_malloc(tlsf_t tlsf, size_t size) { control_t* control = tlsf_cast(control_t*, tlsf); size_t adjust = adjust_request_size(size, ALIGN_SIZE); block_header_t* block = block_locate_free(control, adjust); return block_prepare_used(control, block, adjust); } /** * @brief Allocate memory of at least `size` bytes where byte at `data_offset` will be aligned to `alignment`. * * This function will allocate memory pointed by `ptr`. However, the byte at `data_offset` of * this piece of memory (i.e., byte at `ptr` + `data_offset`) will be aligned to `alignment`. * This function is useful for allocating memory that will internally have a header, and the * usable memory following the header (i.e. `ptr` + `data_offset`) must be aligned. * * For example, a call to `multi_heap_aligned_alloc_impl_offs(heap, 64, 256, 20)` will return a * pointer `ptr` to free memory of minimum 64 bytes, where `ptr + 20` is aligned on `256`. * So `(ptr + 20) % 256` equals 0. * * @param tlsf TLSF structure to allocate memory from. * @param align Alignment for the returned pointer's offset. * @param size Minimum size, in bytes, of the memory to allocate INCLUDING * `data_offset` bytes. * @param data_offset Offset to be aligned on `alignment`. This can be 0, in * this case, the returned pointer will be aligned on * `alignment`. If it is not a multiple of CPU word size, * it will be aligned up to the closest multiple of it. * * @return pointer to free memory. */ void* tlsf_memalign_offs(tlsf_t tlsf, size_t align, size_t size, size_t data_offset) { control_t* control = tlsf_cast(control_t*, tlsf); const size_t adjust = adjust_request_size(size, ALIGN_SIZE); const size_t off_adjust = align_up(data_offset, 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 pool. 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) + off_adjust; /* The offset is included in both `adjust` and `gap_minimum`, so we ** need to subtract it once. */ const size_t size_with_gap = adjust_request_size(adjust + align + gap_minimum - off_adjust, align); /* ** If alignment is less than or equals base alignment, we're done. ** If we requested 0 bytes, return null, as tlsf_malloc(0) does. */ const size_t aligned_size = (adjust && align > ALIGN_SIZE) ? size_with_gap : adjust; block_header_t* block = block_locate_free(control, 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 or if there is not gap but we need one, ** offset to next aligned boundary. */ if ((gap && gap < gap_minimum) || (!gap && off_adjust)) { 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(control, block, gap - off_adjust); } } /* Preparing the block will also the trailing free memory. */ return block_prepare_used(control, block, adjust); } /** * @brief Same as `tlsf_memalign_offs` function but with a 0 offset. * The pointer returned is aligned on `align`. */ void* tlsf_memalign(tlsf_t tlsf, size_t align, size_t size) { return tlsf_memalign_offs(tlsf, align, size, 0); } void tlsf_free(tlsf_t tlsf, void* ptr) { /* Don't attempt to free a NULL pointer. */ if (ptr) { control_t* control = tlsf_cast(control_t*, tlsf); block_header_t* block = block_from_ptr(ptr); tlsf_assert(!block_is_free(block) && "block already marked as free"); block_mark_as_free(block); block = block_merge_prev(control, block); block = block_merge_next(control, block); block_insert(control, 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_t tlsf, void* ptr, size_t size) { control_t* control = tlsf_cast(control_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); tlsf_assert(!block_is_free(block) && "block already marked as free"); /* ** 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(control, block); block_mark_as_used(block); } /* Trim the resulting block and return the original pointer. */ block_trim_used(control, block, adjust); p = ptr; } } return p; }