diff options
Diffstat (limited to 'Utilities/cmzstd/lib/compress/zstd_cwksp.h')
-rw-r--r-- | Utilities/cmzstd/lib/compress/zstd_cwksp.h | 248 |
1 files changed, 164 insertions, 84 deletions
diff --git a/Utilities/cmzstd/lib/compress/zstd_cwksp.h b/Utilities/cmzstd/lib/compress/zstd_cwksp.h index 2656d26..cc7fb1c 100644 --- a/Utilities/cmzstd/lib/compress/zstd_cwksp.h +++ b/Utilities/cmzstd/lib/compress/zstd_cwksp.h @@ -1,5 +1,5 @@ /* - * Copyright (c) Yann Collet, Facebook, Inc. + * Copyright (c) Meta Platforms, Inc. and affiliates. * All rights reserved. * * This source code is licensed under both the BSD-style license (found in the @@ -14,7 +14,9 @@ /*-************************************* * Dependencies ***************************************/ +#include "../common/allocations.h" /* ZSTD_customMalloc, ZSTD_customFree */ #include "../common/zstd_internal.h" +#include "../common/portability_macros.h" #if defined (__cplusplus) extern "C" { @@ -44,8 +46,9 @@ extern "C" { ***************************************/ typedef enum { ZSTD_cwksp_alloc_objects, - ZSTD_cwksp_alloc_buffers, - ZSTD_cwksp_alloc_aligned + ZSTD_cwksp_alloc_aligned_init_once, + ZSTD_cwksp_alloc_aligned, + ZSTD_cwksp_alloc_buffers } ZSTD_cwksp_alloc_phase_e; /** @@ -98,8 +101,8 @@ typedef enum { * * Workspace Layout: * - * [ ... workspace ... ] - * [objects][tables ... ->] free space [<- ... aligned][<- ... buffers] + * [ ... workspace ... ] + * [objects][tables ->] free space [<- buffers][<- aligned][<- init once] * * The various objects that live in the workspace are divided into the * following categories, and are allocated separately: @@ -123,9 +126,18 @@ typedef enum { * uint32_t arrays, all of whose values are between 0 and (nextSrc - base). * Their sizes depend on the cparams. These tables are 64-byte aligned. * - * - Aligned: these buffers are used for various purposes that require 4 byte - * alignment, but don't require any initialization before they're used. These - * buffers are each aligned to 64 bytes. + * - Init once: these buffers require to be initialized at least once before + * use. They should be used when we want to skip memory initialization + * while not triggering memory checkers (like Valgrind) when reading from + * from this memory without writing to it first. + * These buffers should be used carefully as they might contain data + * from previous compressions. + * Buffers are aligned to 64 bytes. + * + * - Aligned: these buffers don't require any initialization before they're + * used. The user of the buffer should make sure they write into a buffer + * location before reading from it. + * Buffers are aligned to 64 bytes. * * - Buffers: these buffers are used for various purposes that don't require * any alignment or initialization before they're used. This means they can @@ -137,8 +149,9 @@ typedef enum { * correctly packed into the workspace buffer. That order is: * * 1. Objects - * 2. Buffers - * 3. Aligned/Tables + * 2. Init once / Tables + * 3. Aligned / Tables + * 4. Buffers / Tables * * Attempts to reserve objects of different types out of order will fail. */ @@ -150,6 +163,7 @@ typedef struct { void* tableEnd; void* tableValidEnd; void* allocStart; + void* initOnceStart; BYTE allocFailed; int workspaceOversizedDuration; @@ -162,6 +176,7 @@ typedef struct { ***************************************/ MEM_STATIC size_t ZSTD_cwksp_available_space(ZSTD_cwksp* ws); +MEM_STATIC void* ZSTD_cwksp_initialAllocStart(ZSTD_cwksp* ws); MEM_STATIC void ZSTD_cwksp_assert_internal_consistency(ZSTD_cwksp* ws) { (void)ws; @@ -171,6 +186,20 @@ MEM_STATIC void ZSTD_cwksp_assert_internal_consistency(ZSTD_cwksp* ws) { assert(ws->tableEnd <= ws->allocStart); assert(ws->tableValidEnd <= ws->allocStart); assert(ws->allocStart <= ws->workspaceEnd); + assert(ws->initOnceStart <= ZSTD_cwksp_initialAllocStart(ws)); + assert(ws->workspace <= ws->initOnceStart); +#if ZSTD_MEMORY_SANITIZER + { + intptr_t const offset = __msan_test_shadow(ws->initOnceStart, + (U8*)ZSTD_cwksp_initialAllocStart(ws) - (U8*)ws->initOnceStart); +#if defined(ZSTD_MSAN_PRINT) + if(offset!=-1) { + __msan_print_shadow((U8*)ws->initOnceStart + offset - 8, 32); + } +#endif + assert(offset==-1); + }; +#endif } /** @@ -217,14 +246,10 @@ MEM_STATIC size_t ZSTD_cwksp_aligned_alloc_size(size_t size) { * for internal purposes (currently only alignment). */ MEM_STATIC size_t ZSTD_cwksp_slack_space_required(void) { - /* For alignment, the wksp will always allocate an additional n_1=[1, 64] bytes - * to align the beginning of tables section, as well as another n_2=[0, 63] bytes - * to align the beginning of the aligned secion. - * - * n_1 + n_2 == 64 bytes if the cwksp is freshly allocated, due to tables and - * aligneds being sized in multiples of 64 bytes. + /* For alignment, the wksp will always allocate an additional 2*ZSTD_CWKSP_ALIGNMENT_BYTES + * bytes to align the beginning of tables section and end of buffers; */ - size_t const slackSpace = ZSTD_CWKSP_ALIGNMENT_BYTES; + size_t const slackSpace = ZSTD_CWKSP_ALIGNMENT_BYTES * 2; return slackSpace; } @@ -237,18 +262,28 @@ MEM_STATIC size_t ZSTD_cwksp_bytes_to_align_ptr(void* ptr, const size_t alignByt size_t const alignBytesMask = alignBytes - 1; size_t const bytes = (alignBytes - ((size_t)ptr & (alignBytesMask))) & alignBytesMask; assert((alignBytes & alignBytesMask) == 0); - assert(bytes != ZSTD_CWKSP_ALIGNMENT_BYTES); + assert(bytes < alignBytes); return bytes; } /** + * Returns the initial value for allocStart which is used to determine the position from + * which we can allocate from the end of the workspace. + */ +MEM_STATIC void* ZSTD_cwksp_initialAllocStart(ZSTD_cwksp* ws) { + return (void*)((size_t)ws->workspaceEnd & ~(ZSTD_CWKSP_ALIGNMENT_BYTES-1)); +} + +/** * Internal function. Do not use directly. - * Reserves the given number of bytes within the aligned/buffer segment of the wksp, which - * counts from the end of the wksp. (as opposed to the object/table segment) + * Reserves the given number of bytes within the aligned/buffer segment of the wksp, + * which counts from the end of the wksp (as opposed to the object/table segment). * * Returns a pointer to the beginning of that space. */ -MEM_STATIC void* ZSTD_cwksp_reserve_internal_buffer_space(ZSTD_cwksp* ws, size_t const bytes) { +MEM_STATIC void* +ZSTD_cwksp_reserve_internal_buffer_space(ZSTD_cwksp* ws, size_t const bytes) +{ void* const alloc = (BYTE*)ws->allocStart - bytes; void* const bottom = ws->tableEnd; DEBUGLOG(5, "cwksp: reserving %p %zd bytes, %zd bytes remaining", @@ -260,6 +295,8 @@ MEM_STATIC void* ZSTD_cwksp_reserve_internal_buffer_space(ZSTD_cwksp* ws, size_t ws->allocFailed = 1; return NULL; } + /* the area is reserved from the end of wksp. + * If it overlaps with tableValidEnd, it voids guarantees on values' range */ if (alloc < ws->tableValidEnd) { ws->tableValidEnd = alloc; } @@ -269,39 +306,32 @@ MEM_STATIC void* ZSTD_cwksp_reserve_internal_buffer_space(ZSTD_cwksp* ws, size_t /** * Moves the cwksp to the next phase, and does any necessary allocations. + * cwksp initialization must necessarily go through each phase in order. * Returns a 0 on success, or zstd error */ -MEM_STATIC size_t ZSTD_cwksp_internal_advance_phase( - ZSTD_cwksp* ws, ZSTD_cwksp_alloc_phase_e phase) { +MEM_STATIC size_t +ZSTD_cwksp_internal_advance_phase(ZSTD_cwksp* ws, ZSTD_cwksp_alloc_phase_e phase) +{ assert(phase >= ws->phase); if (phase > ws->phase) { - /* Going from allocating objects to allocating buffers */ - if (ws->phase < ZSTD_cwksp_alloc_buffers && - phase >= ZSTD_cwksp_alloc_buffers) { + /* Going from allocating objects to allocating initOnce / tables */ + if (ws->phase < ZSTD_cwksp_alloc_aligned_init_once && + phase >= ZSTD_cwksp_alloc_aligned_init_once) { ws->tableValidEnd = ws->objectEnd; - } + ws->initOnceStart = ZSTD_cwksp_initialAllocStart(ws); - /* Going from allocating buffers to allocating aligneds/tables */ - if (ws->phase < ZSTD_cwksp_alloc_aligned && - phase >= ZSTD_cwksp_alloc_aligned) { - { /* Align the start of the "aligned" to 64 bytes. Use [1, 64] bytes. */ - size_t const bytesToAlign = - ZSTD_CWKSP_ALIGNMENT_BYTES - ZSTD_cwksp_bytes_to_align_ptr(ws->allocStart, ZSTD_CWKSP_ALIGNMENT_BYTES); - DEBUGLOG(5, "reserving aligned alignment addtl space: %zu", bytesToAlign); - ZSTD_STATIC_ASSERT((ZSTD_CWKSP_ALIGNMENT_BYTES & (ZSTD_CWKSP_ALIGNMENT_BYTES - 1)) == 0); /* power of 2 */ - RETURN_ERROR_IF(!ZSTD_cwksp_reserve_internal_buffer_space(ws, bytesToAlign), - memory_allocation, "aligned phase - alignment initial allocation failed!"); - } { /* Align the start of the tables to 64 bytes. Use [0, 63] bytes */ - void* const alloc = ws->objectEnd; + void *const alloc = ws->objectEnd; size_t const bytesToAlign = ZSTD_cwksp_bytes_to_align_ptr(alloc, ZSTD_CWKSP_ALIGNMENT_BYTES); - void* const end = (BYTE*)alloc + bytesToAlign; + void *const objectEnd = (BYTE *) alloc + bytesToAlign; DEBUGLOG(5, "reserving table alignment addtl space: %zu", bytesToAlign); - RETURN_ERROR_IF(end > ws->workspaceEnd, memory_allocation, + RETURN_ERROR_IF(objectEnd > ws->workspaceEnd, memory_allocation, "table phase - alignment initial allocation failed!"); - ws->objectEnd = end; - ws->tableEnd = end; - ws->tableValidEnd = end; + ws->objectEnd = objectEnd; + ws->tableEnd = objectEnd; /* table area starts being empty */ + if (ws->tableValidEnd < ws->tableEnd) { + ws->tableValidEnd = ws->tableEnd; + } } } ws->phase = phase; @@ -313,15 +343,17 @@ MEM_STATIC size_t ZSTD_cwksp_internal_advance_phase( /** * Returns whether this object/buffer/etc was allocated in this workspace. */ -MEM_STATIC int ZSTD_cwksp_owns_buffer(const ZSTD_cwksp* ws, const void* ptr) { - return (ptr != NULL) && (ws->workspace <= ptr) && (ptr <= ws->workspaceEnd); +MEM_STATIC int ZSTD_cwksp_owns_buffer(const ZSTD_cwksp* ws, const void* ptr) +{ + return (ptr != NULL) && (ws->workspace <= ptr) && (ptr < ws->workspaceEnd); } /** * Internal function. Do not use directly. */ -MEM_STATIC void* ZSTD_cwksp_reserve_internal( - ZSTD_cwksp* ws, size_t bytes, ZSTD_cwksp_alloc_phase_e phase) { +MEM_STATIC void* +ZSTD_cwksp_reserve_internal(ZSTD_cwksp* ws, size_t bytes, ZSTD_cwksp_alloc_phase_e phase) +{ void* alloc; if (ZSTD_isError(ZSTD_cwksp_internal_advance_phase(ws, phase)) || bytes == 0) { return NULL; @@ -340,7 +372,9 @@ MEM_STATIC void* ZSTD_cwksp_reserve_internal( if (alloc) { alloc = (BYTE *)alloc + ZSTD_CWKSP_ASAN_REDZONE_SIZE; if (ws->isStatic == ZSTD_cwksp_dynamic_alloc) { - __asan_unpoison_memory_region(alloc, bytes); + /* We need to keep the redzone poisoned while unpoisoning the bytes that + * are actually allocated. */ + __asan_unpoison_memory_region(alloc, bytes - 2 * ZSTD_CWKSP_ASAN_REDZONE_SIZE); } } #endif @@ -351,14 +385,46 @@ MEM_STATIC void* ZSTD_cwksp_reserve_internal( /** * Reserves and returns unaligned memory. */ -MEM_STATIC BYTE* ZSTD_cwksp_reserve_buffer(ZSTD_cwksp* ws, size_t bytes) { +MEM_STATIC BYTE* ZSTD_cwksp_reserve_buffer(ZSTD_cwksp* ws, size_t bytes) +{ return (BYTE*)ZSTD_cwksp_reserve_internal(ws, bytes, ZSTD_cwksp_alloc_buffers); } /** * Reserves and returns memory sized on and aligned on ZSTD_CWKSP_ALIGNMENT_BYTES (64 bytes). + * This memory has been initialized at least once in the past. + * This doesn't mean it has been initialized this time, and it might contain data from previous + * operations. + * The main usage is for algorithms that might need read access into uninitialized memory. + * The algorithm must maintain safety under these conditions and must make sure it doesn't + * leak any of the past data (directly or in side channels). + */ +MEM_STATIC void* ZSTD_cwksp_reserve_aligned_init_once(ZSTD_cwksp* ws, size_t bytes) +{ + size_t const alignedBytes = ZSTD_cwksp_align(bytes, ZSTD_CWKSP_ALIGNMENT_BYTES); + void* ptr = ZSTD_cwksp_reserve_internal(ws, alignedBytes, ZSTD_cwksp_alloc_aligned_init_once); + assert(((size_t)ptr & (ZSTD_CWKSP_ALIGNMENT_BYTES-1))== 0); + if(ptr && ptr < ws->initOnceStart) { + /* We assume the memory following the current allocation is either: + * 1. Not usable as initOnce memory (end of workspace) + * 2. Another initOnce buffer that has been allocated before (and so was previously memset) + * 3. An ASAN redzone, in which case we don't want to write on it + * For these reasons it should be fine to not explicitly zero every byte up to ws->initOnceStart. + * Note that we assume here that MSAN and ASAN cannot run in the same time. */ + ZSTD_memset(ptr, 0, MIN((size_t)((U8*)ws->initOnceStart - (U8*)ptr), alignedBytes)); + ws->initOnceStart = ptr; + } +#if ZSTD_MEMORY_SANITIZER + assert(__msan_test_shadow(ptr, bytes) == -1); +#endif + return ptr; +} + +/** + * Reserves and returns memory sized on and aligned on ZSTD_CWKSP_ALIGNMENT_BYTES (64 bytes). */ -MEM_STATIC void* ZSTD_cwksp_reserve_aligned(ZSTD_cwksp* ws, size_t bytes) { +MEM_STATIC void* ZSTD_cwksp_reserve_aligned(ZSTD_cwksp* ws, size_t bytes) +{ void* ptr = ZSTD_cwksp_reserve_internal(ws, ZSTD_cwksp_align(bytes, ZSTD_CWKSP_ALIGNMENT_BYTES), ZSTD_cwksp_alloc_aligned); assert(((size_t)ptr & (ZSTD_CWKSP_ALIGNMENT_BYTES-1))== 0); @@ -370,14 +436,19 @@ MEM_STATIC void* ZSTD_cwksp_reserve_aligned(ZSTD_cwksp* ws, size_t bytes) { * their values remain constrained, allowing us to re-use them without * memset()-ing them. */ -MEM_STATIC void* ZSTD_cwksp_reserve_table(ZSTD_cwksp* ws, size_t bytes) { - const ZSTD_cwksp_alloc_phase_e phase = ZSTD_cwksp_alloc_aligned; +MEM_STATIC void* ZSTD_cwksp_reserve_table(ZSTD_cwksp* ws, size_t bytes) +{ + const ZSTD_cwksp_alloc_phase_e phase = ZSTD_cwksp_alloc_aligned_init_once; void* alloc; void* end; void* top; - if (ZSTD_isError(ZSTD_cwksp_internal_advance_phase(ws, phase))) { - return NULL; + /* We can only start allocating tables after we are done reserving space for objects at the + * start of the workspace */ + if(ws->phase < phase) { + if (ZSTD_isError(ZSTD_cwksp_internal_advance_phase(ws, phase))) { + return NULL; + } } alloc = ws->tableEnd; end = (BYTE *)alloc + bytes; @@ -408,9 +479,11 @@ MEM_STATIC void* ZSTD_cwksp_reserve_table(ZSTD_cwksp* ws, size_t bytes) { /** * Aligned on sizeof(void*). + * Note : should happen only once, at workspace first initialization */ -MEM_STATIC void* ZSTD_cwksp_reserve_object(ZSTD_cwksp* ws, size_t bytes) { - size_t roundedBytes = ZSTD_cwksp_align(bytes, sizeof(void*)); +MEM_STATIC void* ZSTD_cwksp_reserve_object(ZSTD_cwksp* ws, size_t bytes) +{ + size_t const roundedBytes = ZSTD_cwksp_align(bytes, sizeof(void*)); void* alloc = ws->objectEnd; void* end = (BYTE*)alloc + roundedBytes; @@ -419,15 +492,15 @@ MEM_STATIC void* ZSTD_cwksp_reserve_object(ZSTD_cwksp* ws, size_t bytes) { end = (BYTE *)end + 2 * ZSTD_CWKSP_ASAN_REDZONE_SIZE; #endif - DEBUGLOG(5, + DEBUGLOG(4, "cwksp: reserving %p object %zd bytes (rounded to %zd), %zd bytes remaining", alloc, bytes, roundedBytes, ZSTD_cwksp_available_space(ws) - roundedBytes); - assert(((size_t)alloc & (sizeof(void*)-1)) == 0); - assert((bytes & (sizeof(void*)-1)) == 0); + assert((size_t)alloc % ZSTD_ALIGNOF(void*) == 0); + assert(bytes % ZSTD_ALIGNOF(void*) == 0); ZSTD_cwksp_assert_internal_consistency(ws); /* we must be in the first phase, no advance is possible */ if (ws->phase != ZSTD_cwksp_alloc_objects || end > ws->workspaceEnd) { - DEBUGLOG(4, "cwksp: object alloc failed!"); + DEBUGLOG(3, "cwksp: object alloc failed!"); ws->allocFailed = 1; return NULL; } @@ -438,7 +511,7 @@ MEM_STATIC void* ZSTD_cwksp_reserve_object(ZSTD_cwksp* ws, size_t bytes) { #if ZSTD_ADDRESS_SANITIZER && !defined (ZSTD_ASAN_DONT_POISON_WORKSPACE) /* Move alloc so there's ZSTD_CWKSP_ASAN_REDZONE_SIZE unused space on * either size. */ - alloc = (BYTE *)alloc + ZSTD_CWKSP_ASAN_REDZONE_SIZE; + alloc = (BYTE*)alloc + ZSTD_CWKSP_ASAN_REDZONE_SIZE; if (ws->isStatic == ZSTD_cwksp_dynamic_alloc) { __asan_unpoison_memory_region(alloc, bytes); } @@ -447,17 +520,26 @@ MEM_STATIC void* ZSTD_cwksp_reserve_object(ZSTD_cwksp* ws, size_t bytes) { return alloc; } -MEM_STATIC void ZSTD_cwksp_mark_tables_dirty(ZSTD_cwksp* ws) { +MEM_STATIC void ZSTD_cwksp_mark_tables_dirty(ZSTD_cwksp* ws) +{ DEBUGLOG(4, "cwksp: ZSTD_cwksp_mark_tables_dirty"); #if ZSTD_MEMORY_SANITIZER && !defined (ZSTD_MSAN_DONT_POISON_WORKSPACE) /* To validate that the table re-use logic is sound, and that we don't * access table space that we haven't cleaned, we re-"poison" the table - * space every time we mark it dirty. */ + * space every time we mark it dirty. + * Since tableValidEnd space and initOnce space may overlap we don't poison + * the initOnce portion as it break its promise. This means that this poisoning + * check isn't always applied fully. */ { size_t size = (BYTE*)ws->tableValidEnd - (BYTE*)ws->objectEnd; assert(__msan_test_shadow(ws->objectEnd, size) == -1); - __msan_poison(ws->objectEnd, size); + if((BYTE*)ws->tableValidEnd < (BYTE*)ws->initOnceStart) { + __msan_poison(ws->objectEnd, size); + } else { + assert(ws->initOnceStart >= ws->objectEnd); + __msan_poison(ws->objectEnd, (BYTE*)ws->initOnceStart - (BYTE*)ws->objectEnd); + } } #endif @@ -485,7 +567,7 @@ MEM_STATIC void ZSTD_cwksp_clean_tables(ZSTD_cwksp* ws) { assert(ws->tableValidEnd >= ws->objectEnd); assert(ws->tableValidEnd <= ws->allocStart); if (ws->tableValidEnd < ws->tableEnd) { - ZSTD_memset(ws->tableValidEnd, 0, (BYTE*)ws->tableEnd - (BYTE*)ws->tableValidEnd); + ZSTD_memset(ws->tableValidEnd, 0, (size_t)((BYTE*)ws->tableEnd - (BYTE*)ws->tableValidEnd)); } ZSTD_cwksp_mark_tables_clean(ws); } @@ -522,11 +604,14 @@ MEM_STATIC void ZSTD_cwksp_clear(ZSTD_cwksp* ws) { #if ZSTD_MEMORY_SANITIZER && !defined (ZSTD_MSAN_DONT_POISON_WORKSPACE) /* To validate that the context re-use logic is sound, and that we don't * access stuff that this compression hasn't initialized, we re-"poison" - * the workspace (or at least the non-static, non-table parts of it) - * every time we start a new compression. */ + * the workspace except for the areas in which we expect memory re-use + * without initialization (objects, valid tables area and init once + * memory). */ { - size_t size = (BYTE*)ws->workspaceEnd - (BYTE*)ws->tableValidEnd; - __msan_poison(ws->tableValidEnd, size); + if((BYTE*)ws->tableValidEnd < (BYTE*)ws->initOnceStart) { + size_t size = (BYTE*)ws->initOnceStart - (BYTE*)ws->tableValidEnd; + __msan_poison(ws->tableValidEnd, size); + } } #endif @@ -542,10 +627,10 @@ MEM_STATIC void ZSTD_cwksp_clear(ZSTD_cwksp* ws) { #endif ws->tableEnd = ws->objectEnd; - ws->allocStart = ws->workspaceEnd; + ws->allocStart = ZSTD_cwksp_initialAllocStart(ws); ws->allocFailed = 0; - if (ws->phase > ZSTD_cwksp_alloc_buffers) { - ws->phase = ZSTD_cwksp_alloc_buffers; + if (ws->phase > ZSTD_cwksp_alloc_aligned_init_once) { + ws->phase = ZSTD_cwksp_alloc_aligned_init_once; } ZSTD_cwksp_assert_internal_consistency(ws); } @@ -562,6 +647,7 @@ MEM_STATIC void ZSTD_cwksp_init(ZSTD_cwksp* ws, void* start, size_t size, ZSTD_c ws->workspaceEnd = (BYTE*)start + size; ws->objectEnd = ws->workspace; ws->tableValidEnd = ws->objectEnd; + ws->initOnceStart = ZSTD_cwksp_initialAllocStart(ws); ws->phase = ZSTD_cwksp_alloc_objects; ws->isStatic = isStatic; ZSTD_cwksp_clear(ws); @@ -614,17 +700,11 @@ MEM_STATIC int ZSTD_cwksp_reserve_failed(const ZSTD_cwksp* ws) { * Returns if the estimated space needed for a wksp is within an acceptable limit of the * actual amount of space used. */ -MEM_STATIC int ZSTD_cwksp_estimated_space_within_bounds(const ZSTD_cwksp* const ws, - size_t const estimatedSpace, int resizedWorkspace) { - if (resizedWorkspace) { - /* Resized/newly allocated wksp should have exact bounds */ - return ZSTD_cwksp_used(ws) == estimatedSpace; - } else { - /* Due to alignment, when reusing a workspace, we can actually consume 63 fewer or more bytes - * than estimatedSpace. See the comments in zstd_cwksp.h for details. - */ - return (ZSTD_cwksp_used(ws) >= estimatedSpace - 63) && (ZSTD_cwksp_used(ws) <= estimatedSpace + 63); - } +MEM_STATIC int ZSTD_cwksp_estimated_space_within_bounds(const ZSTD_cwksp *const ws, size_t const estimatedSpace) { + /* We have an alignment space between objects and tables between tables and buffers, so we can have up to twice + * the alignment bytes difference between estimation and actual usage */ + return (estimatedSpace - ZSTD_cwksp_slack_space_required()) <= ZSTD_cwksp_used(ws) && + ZSTD_cwksp_used(ws) <= estimatedSpace; } |