2 * Copyright (c) Meta Platforms, Inc. and affiliates.
5 * This source code is licensed under both the BSD-style license (found in the
6 * LICENSE file in the root directory of this source tree) and the GPLv2 (found
7 * in the COPYING file in the root directory of this source tree).
8 * You may select, at your option, one of the above-listed licenses.
14 /*-*************************************
16 ***************************************/
17 #include "../common/allocations.h" /* ZSTD_customMalloc, ZSTD_customFree */
18 #include "../common/zstd_internal.h"
19 #include "../common/portability_macros.h"
21 #if defined (__cplusplus)
25 /*-*************************************
27 ***************************************/
29 /* Since the workspace is effectively its own little malloc implementation /
30 * arena, when we run under ASAN, we should similarly insert redzones between
31 * each internal element of the workspace, so ASAN will catch overruns that
32 * reach outside an object but that stay inside the workspace.
34 * This defines the size of that redzone.
36 #ifndef ZSTD_CWKSP_ASAN_REDZONE_SIZE
37 #define ZSTD_CWKSP_ASAN_REDZONE_SIZE 128
41 /* Set our tables and aligneds to align by 64 bytes */
42 #define ZSTD_CWKSP_ALIGNMENT_BYTES 64
44 /*-*************************************
46 ***************************************/
48 ZSTD_cwksp_alloc_objects,
49 ZSTD_cwksp_alloc_aligned_init_once,
50 ZSTD_cwksp_alloc_aligned,
51 ZSTD_cwksp_alloc_buffers
52 } ZSTD_cwksp_alloc_phase_e;
55 * Used to describe whether the workspace is statically allocated (and will not
56 * necessarily ever be freed), or if it's dynamically allocated and we can
57 * expect a well-formed caller to free this.
60 ZSTD_cwksp_dynamic_alloc,
61 ZSTD_cwksp_static_alloc
62 } ZSTD_cwksp_static_alloc_e;
65 * Zstd fits all its internal datastructures into a single continuous buffer,
66 * so that it only needs to perform a single OS allocation (or so that a buffer
67 * can be provided to it and it can perform no allocations at all). This buffer
68 * is called the workspace.
70 * Several optimizations complicate that process of allocating memory ranges
71 * from this workspace for each internal datastructure:
73 * - These different internal datastructures have different setup requirements:
75 * - The static objects need to be cleared once and can then be trivially
76 * reused for each compression.
78 * - Various buffers don't need to be initialized at all--they are always
79 * written into before they're read.
81 * - The matchstate tables have a unique requirement that they don't need
82 * their memory to be totally cleared, but they do need the memory to have
83 * some bound, i.e., a guarantee that all values in the memory they've been
84 * allocated is less than some maximum value (which is the starting value
85 * for the indices that they will then use for compression). When this
86 * guarantee is provided to them, they can use the memory without any setup
87 * work. When it can't, they have to clear the area.
89 * - These buffers also have different alignment requirements.
91 * - We would like to reuse the objects in the workspace for multiple
92 * compressions without having to perform any expensive reallocation or
93 * reinitialization work.
95 * - We would like to be able to efficiently reuse the workspace across
96 * multiple compressions **even when the compression parameters change** and
97 * we need to resize some of the objects (where possible).
99 * To attempt to manage this buffer, given these constraints, the ZSTD_cwksp
100 * abstraction was created. It works as follows:
104 * [ ... workspace ... ]
105 * [objects][tables ->] free space [<- buffers][<- aligned][<- init once]
107 * The various objects that live in the workspace are divided into the
108 * following categories, and are allocated separately:
110 * - Static objects: this is optionally the enclosing ZSTD_CCtx or ZSTD_CDict,
111 * so that literally everything fits in a single buffer. Note: if present,
112 * this must be the first object in the workspace, since ZSTD_customFree{CCtx,
113 * CDict}() rely on a pointer comparison to see whether one or two frees are
116 * - Fixed size objects: these are fixed-size, fixed-count objects that are
117 * nonetheless "dynamically" allocated in the workspace so that we can
118 * control how they're initialized separately from the broader ZSTD_CCtx.
120 * - Entropy Workspace
121 * - 2 x ZSTD_compressedBlockState_t
122 * - CDict dictionary contents
124 * - Tables: these are any of several different datastructures (hash tables,
125 * chain tables, binary trees) that all respect a common format: they are
126 * uint32_t arrays, all of whose values are between 0 and (nextSrc - base).
127 * Their sizes depend on the cparams. These tables are 64-byte aligned.
129 * - Init once: these buffers require to be initialized at least once before
130 * use. They should be used when we want to skip memory initialization
131 * while not triggering memory checkers (like Valgrind) when reading from
132 * from this memory without writing to it first.
133 * These buffers should be used carefully as they might contain data
134 * from previous compressions.
135 * Buffers are aligned to 64 bytes.
137 * - Aligned: these buffers don't require any initialization before they're
138 * used. The user of the buffer should make sure they write into a buffer
139 * location before reading from it.
140 * Buffers are aligned to 64 bytes.
142 * - Buffers: these buffers are used for various purposes that don't require
143 * any alignment or initialization before they're used. This means they can
144 * be moved around at no cost for a new compression.
148 * The various types of objects must be allocated in order, so they can be
149 * correctly packed into the workspace buffer. That order is:
152 * 2. Init once / Tables
153 * 3. Aligned / Tables
154 * 4. Buffers / Tables
156 * Attempts to reserve objects of different types out of order will fail.
169 int workspaceOversizedDuration;
170 ZSTD_cwksp_alloc_phase_e phase;
171 ZSTD_cwksp_static_alloc_e isStatic;
174 /*-*************************************
176 ***************************************/
178 MEM_STATIC size_t ZSTD_cwksp_available_space(ZSTD_cwksp* ws);
179 MEM_STATIC void* ZSTD_cwksp_initialAllocStart(ZSTD_cwksp* ws);
181 MEM_STATIC void ZSTD_cwksp_assert_internal_consistency(ZSTD_cwksp* ws) {
183 assert(ws->workspace <= ws->objectEnd);
184 assert(ws->objectEnd <= ws->tableEnd);
185 assert(ws->objectEnd <= ws->tableValidEnd);
186 assert(ws->tableEnd <= ws->allocStart);
187 assert(ws->tableValidEnd <= ws->allocStart);
188 assert(ws->allocStart <= ws->workspaceEnd);
189 assert(ws->initOnceStart <= ZSTD_cwksp_initialAllocStart(ws));
190 assert(ws->workspace <= ws->initOnceStart);
191 #if ZSTD_MEMORY_SANITIZER
193 intptr_t const offset = __msan_test_shadow(ws->initOnceStart,
194 (U8*)ZSTD_cwksp_initialAllocStart(ws) - (U8*)ws->initOnceStart);
196 #if defined(ZSTD_MSAN_PRINT)
198 __msan_print_shadow((U8*)ws->initOnceStart + offset - 8, 32);
207 * Align must be a power of 2.
209 MEM_STATIC size_t ZSTD_cwksp_align(size_t size, size_t const align) {
210 size_t const mask = align - 1;
211 assert((align & mask) == 0);
212 return (size + mask) & ~mask;
216 * Use this to determine how much space in the workspace we will consume to
217 * allocate this object. (Normally it should be exactly the size of the object,
218 * but under special conditions, like ASAN, where we pad each object, it might
221 * Since tables aren't currently redzoned, you don't need to call through this
222 * to figure out how much space you need for the matchState tables. Everything
225 * Do not use for sizing aligned buffers. Instead, use ZSTD_cwksp_aligned_alloc_size().
227 MEM_STATIC size_t ZSTD_cwksp_alloc_size(size_t size) {
230 #if ZSTD_ADDRESS_SANITIZER && !defined (ZSTD_ASAN_DONT_POISON_WORKSPACE)
231 return size + 2 * ZSTD_CWKSP_ASAN_REDZONE_SIZE;
238 * Returns an adjusted alloc size that is the nearest larger multiple of 64 bytes.
239 * Used to determine the number of bytes required for a given "aligned".
241 MEM_STATIC size_t ZSTD_cwksp_aligned_alloc_size(size_t size) {
242 return ZSTD_cwksp_alloc_size(ZSTD_cwksp_align(size, ZSTD_CWKSP_ALIGNMENT_BYTES));
246 * Returns the amount of additional space the cwksp must allocate
247 * for internal purposes (currently only alignment).
249 MEM_STATIC size_t ZSTD_cwksp_slack_space_required(void) {
250 /* For alignment, the wksp will always allocate an additional 2*ZSTD_CWKSP_ALIGNMENT_BYTES
251 * bytes to align the beginning of tables section and end of buffers;
253 size_t const slackSpace = ZSTD_CWKSP_ALIGNMENT_BYTES * 2;
259 * Return the number of additional bytes required to align a pointer to the given number of bytes.
260 * alignBytes must be a power of two.
262 MEM_STATIC size_t ZSTD_cwksp_bytes_to_align_ptr(void* ptr, const size_t alignBytes) {
263 size_t const alignBytesMask = alignBytes - 1;
264 size_t const bytes = (alignBytes - ((size_t)ptr & (alignBytesMask))) & alignBytesMask;
265 assert((alignBytes & alignBytesMask) == 0);
266 assert(bytes < alignBytes);
271 * Returns the initial value for allocStart which is used to determine the position from
272 * which we can allocate from the end of the workspace.
274 MEM_STATIC void* ZSTD_cwksp_initialAllocStart(ZSTD_cwksp* ws) {
275 return (void*)((size_t)ws->workspaceEnd & ~(ZSTD_CWKSP_ALIGNMENT_BYTES-1));
279 * Internal function. Do not use directly.
280 * Reserves the given number of bytes within the aligned/buffer segment of the wksp,
281 * which counts from the end of the wksp (as opposed to the object/table segment).
283 * Returns a pointer to the beginning of that space.
286 ZSTD_cwksp_reserve_internal_buffer_space(ZSTD_cwksp* ws, size_t const bytes)
288 void* const alloc = (BYTE*)ws->allocStart - bytes;
289 void* const bottom = ws->tableEnd;
290 DEBUGLOG(5, "cwksp: reserving %p %zd bytes, %zd bytes remaining",
291 alloc, bytes, ZSTD_cwksp_available_space(ws) - bytes);
292 ZSTD_cwksp_assert_internal_consistency(ws);
293 assert(alloc >= bottom);
294 if (alloc < bottom) {
295 DEBUGLOG(4, "cwksp: alloc failed!");
299 /* the area is reserved from the end of wksp.
300 * If it overlaps with tableValidEnd, it voids guarantees on values' range */
301 if (alloc < ws->tableValidEnd) {
302 ws->tableValidEnd = alloc;
304 ws->allocStart = alloc;
309 * Moves the cwksp to the next phase, and does any necessary allocations.
310 * cwksp initialization must necessarily go through each phase in order.
311 * Returns a 0 on success, or zstd error
314 ZSTD_cwksp_internal_advance_phase(ZSTD_cwksp* ws, ZSTD_cwksp_alloc_phase_e phase)
316 assert(phase >= ws->phase);
317 if (phase > ws->phase) {
318 /* Going from allocating objects to allocating initOnce / tables */
319 if (ws->phase < ZSTD_cwksp_alloc_aligned_init_once &&
320 phase >= ZSTD_cwksp_alloc_aligned_init_once) {
321 ws->tableValidEnd = ws->objectEnd;
322 ws->initOnceStart = ZSTD_cwksp_initialAllocStart(ws);
324 { /* Align the start of the tables to 64 bytes. Use [0, 63] bytes */
325 void *const alloc = ws->objectEnd;
326 size_t const bytesToAlign = ZSTD_cwksp_bytes_to_align_ptr(alloc, ZSTD_CWKSP_ALIGNMENT_BYTES);
327 void *const objectEnd = (BYTE *) alloc + bytesToAlign;
328 DEBUGLOG(5, "reserving table alignment addtl space: %zu", bytesToAlign);
329 RETURN_ERROR_IF(objectEnd > ws->workspaceEnd, memory_allocation,
330 "table phase - alignment initial allocation failed!");
331 ws->objectEnd = objectEnd;
332 ws->tableEnd = objectEnd; /* table area starts being empty */
333 if (ws->tableValidEnd < ws->tableEnd) {
334 ws->tableValidEnd = ws->tableEnd;
339 ZSTD_cwksp_assert_internal_consistency(ws);
345 * Returns whether this object/buffer/etc was allocated in this workspace.
347 MEM_STATIC int ZSTD_cwksp_owns_buffer(const ZSTD_cwksp* ws, const void* ptr)
349 return (ptr != NULL) && (ws->workspace <= ptr) && (ptr < ws->workspaceEnd);
353 * Internal function. Do not use directly.
356 ZSTD_cwksp_reserve_internal(ZSTD_cwksp* ws, size_t bytes, ZSTD_cwksp_alloc_phase_e phase)
359 if (ZSTD_isError(ZSTD_cwksp_internal_advance_phase(ws, phase)) || bytes == 0) {
363 #if ZSTD_ADDRESS_SANITIZER && !defined (ZSTD_ASAN_DONT_POISON_WORKSPACE)
364 /* over-reserve space */
365 bytes += 2 * ZSTD_CWKSP_ASAN_REDZONE_SIZE;
368 alloc = ZSTD_cwksp_reserve_internal_buffer_space(ws, bytes);
370 #if ZSTD_ADDRESS_SANITIZER && !defined (ZSTD_ASAN_DONT_POISON_WORKSPACE)
371 /* Move alloc so there's ZSTD_CWKSP_ASAN_REDZONE_SIZE unused space on
374 alloc = (BYTE *)alloc + ZSTD_CWKSP_ASAN_REDZONE_SIZE;
375 if (ws->isStatic == ZSTD_cwksp_dynamic_alloc) {
376 /* We need to keep the redzone poisoned while unpoisoning the bytes that
377 * are actually allocated. */
378 __asan_unpoison_memory_region(alloc, bytes - 2 * ZSTD_CWKSP_ASAN_REDZONE_SIZE);
387 * Reserves and returns unaligned memory.
389 MEM_STATIC BYTE* ZSTD_cwksp_reserve_buffer(ZSTD_cwksp* ws, size_t bytes)
391 return (BYTE*)ZSTD_cwksp_reserve_internal(ws, bytes, ZSTD_cwksp_alloc_buffers);
395 * Reserves and returns memory sized on and aligned on ZSTD_CWKSP_ALIGNMENT_BYTES (64 bytes).
396 * This memory has been initialized at least once in the past.
397 * This doesn't mean it has been initialized this time, and it might contain data from previous
399 * The main usage is for algorithms that might need read access into uninitialized memory.
400 * The algorithm must maintain safety under these conditions and must make sure it doesn't
401 * leak any of the past data (directly or in side channels).
403 MEM_STATIC void* ZSTD_cwksp_reserve_aligned_init_once(ZSTD_cwksp* ws, size_t bytes)
405 size_t const alignedBytes = ZSTD_cwksp_align(bytes, ZSTD_CWKSP_ALIGNMENT_BYTES);
406 void* ptr = ZSTD_cwksp_reserve_internal(ws, alignedBytes, ZSTD_cwksp_alloc_aligned_init_once);
407 assert(((size_t)ptr & (ZSTD_CWKSP_ALIGNMENT_BYTES-1))== 0);
408 if(ptr && ptr < ws->initOnceStart) {
409 /* We assume the memory following the current allocation is either:
410 * 1. Not usable as initOnce memory (end of workspace)
411 * 2. Another initOnce buffer that has been allocated before (and so was previously memset)
412 * 3. An ASAN redzone, in which case we don't want to write on it
413 * For these reasons it should be fine to not explicitly zero every byte up to ws->initOnceStart.
414 * Note that we assume here that MSAN and ASAN cannot run in the same time. */
415 ZSTD_memset(ptr, 0, MIN((size_t)((U8*)ws->initOnceStart - (U8*)ptr), alignedBytes));
416 ws->initOnceStart = ptr;
418 #if ZSTD_MEMORY_SANITIZER
419 assert(__msan_test_shadow(ptr, bytes) == -1);
425 * Reserves and returns memory sized on and aligned on ZSTD_CWKSP_ALIGNMENT_BYTES (64 bytes).
427 MEM_STATIC void* ZSTD_cwksp_reserve_aligned(ZSTD_cwksp* ws, size_t bytes)
429 void* ptr = ZSTD_cwksp_reserve_internal(ws, ZSTD_cwksp_align(bytes, ZSTD_CWKSP_ALIGNMENT_BYTES),
430 ZSTD_cwksp_alloc_aligned);
431 assert(((size_t)ptr & (ZSTD_CWKSP_ALIGNMENT_BYTES-1))== 0);
436 * Aligned on 64 bytes. These buffers have the special property that
437 * their values remain constrained, allowing us to reuse them without
440 MEM_STATIC void* ZSTD_cwksp_reserve_table(ZSTD_cwksp* ws, size_t bytes)
442 const ZSTD_cwksp_alloc_phase_e phase = ZSTD_cwksp_alloc_aligned_init_once;
447 /* We can only start allocating tables after we are done reserving space for objects at the
448 * start of the workspace */
449 if(ws->phase < phase) {
450 if (ZSTD_isError(ZSTD_cwksp_internal_advance_phase(ws, phase))) {
454 alloc = ws->tableEnd;
455 end = (BYTE *)alloc + bytes;
456 top = ws->allocStart;
458 DEBUGLOG(5, "cwksp: reserving %p table %zd bytes, %zd bytes remaining",
459 alloc, bytes, ZSTD_cwksp_available_space(ws) - bytes);
460 assert((bytes & (sizeof(U32)-1)) == 0);
461 ZSTD_cwksp_assert_internal_consistency(ws);
464 DEBUGLOG(4, "cwksp: table alloc failed!");
470 #if ZSTD_ADDRESS_SANITIZER && !defined (ZSTD_ASAN_DONT_POISON_WORKSPACE)
471 if (ws->isStatic == ZSTD_cwksp_dynamic_alloc) {
472 __asan_unpoison_memory_region(alloc, bytes);
476 assert((bytes & (ZSTD_CWKSP_ALIGNMENT_BYTES-1)) == 0);
477 assert(((size_t)alloc & (ZSTD_CWKSP_ALIGNMENT_BYTES-1))== 0);
482 * Aligned on sizeof(void*).
483 * Note : should happen only once, at workspace first initialization
485 MEM_STATIC void* ZSTD_cwksp_reserve_object(ZSTD_cwksp* ws, size_t bytes)
487 size_t const roundedBytes = ZSTD_cwksp_align(bytes, sizeof(void*));
488 void* alloc = ws->objectEnd;
489 void* end = (BYTE*)alloc + roundedBytes;
491 #if ZSTD_ADDRESS_SANITIZER && !defined (ZSTD_ASAN_DONT_POISON_WORKSPACE)
492 /* over-reserve space */
493 end = (BYTE *)end + 2 * ZSTD_CWKSP_ASAN_REDZONE_SIZE;
497 "cwksp: reserving %p object %zd bytes (rounded to %zd), %zd bytes remaining",
498 alloc, bytes, roundedBytes, ZSTD_cwksp_available_space(ws) - roundedBytes);
499 assert((size_t)alloc % ZSTD_ALIGNOF(void*) == 0);
500 assert(bytes % ZSTD_ALIGNOF(void*) == 0);
501 ZSTD_cwksp_assert_internal_consistency(ws);
502 /* we must be in the first phase, no advance is possible */
503 if (ws->phase != ZSTD_cwksp_alloc_objects || end > ws->workspaceEnd) {
504 DEBUGLOG(3, "cwksp: object alloc failed!");
510 ws->tableValidEnd = end;
512 #if ZSTD_ADDRESS_SANITIZER && !defined (ZSTD_ASAN_DONT_POISON_WORKSPACE)
513 /* Move alloc so there's ZSTD_CWKSP_ASAN_REDZONE_SIZE unused space on
515 alloc = (BYTE*)alloc + ZSTD_CWKSP_ASAN_REDZONE_SIZE;
516 if (ws->isStatic == ZSTD_cwksp_dynamic_alloc) {
517 __asan_unpoison_memory_region(alloc, bytes);
524 MEM_STATIC void ZSTD_cwksp_mark_tables_dirty(ZSTD_cwksp* ws)
526 DEBUGLOG(4, "cwksp: ZSTD_cwksp_mark_tables_dirty");
528 #if ZSTD_MEMORY_SANITIZER && !defined (ZSTD_MSAN_DONT_POISON_WORKSPACE)
529 /* To validate that the table reuse logic is sound, and that we don't
530 * access table space that we haven't cleaned, we re-"poison" the table
531 * space every time we mark it dirty.
532 * Since tableValidEnd space and initOnce space may overlap we don't poison
533 * the initOnce portion as it break its promise. This means that this poisoning
534 * check isn't always applied fully. */
536 size_t size = (BYTE*)ws->tableValidEnd - (BYTE*)ws->objectEnd;
537 assert(__msan_test_shadow(ws->objectEnd, size) == -1);
538 if((BYTE*)ws->tableValidEnd < (BYTE*)ws->initOnceStart) {
539 __msan_poison(ws->objectEnd, size);
541 assert(ws->initOnceStart >= ws->objectEnd);
542 __msan_poison(ws->objectEnd, (BYTE*)ws->initOnceStart - (BYTE*)ws->objectEnd);
547 assert(ws->tableValidEnd >= ws->objectEnd);
548 assert(ws->tableValidEnd <= ws->allocStart);
549 ws->tableValidEnd = ws->objectEnd;
550 ZSTD_cwksp_assert_internal_consistency(ws);
553 MEM_STATIC void ZSTD_cwksp_mark_tables_clean(ZSTD_cwksp* ws) {
554 DEBUGLOG(4, "cwksp: ZSTD_cwksp_mark_tables_clean");
555 assert(ws->tableValidEnd >= ws->objectEnd);
556 assert(ws->tableValidEnd <= ws->allocStart);
557 if (ws->tableValidEnd < ws->tableEnd) {
558 ws->tableValidEnd = ws->tableEnd;
560 ZSTD_cwksp_assert_internal_consistency(ws);
564 * Zero the part of the allocated tables not already marked clean.
566 MEM_STATIC void ZSTD_cwksp_clean_tables(ZSTD_cwksp* ws) {
567 DEBUGLOG(4, "cwksp: ZSTD_cwksp_clean_tables");
568 assert(ws->tableValidEnd >= ws->objectEnd);
569 assert(ws->tableValidEnd <= ws->allocStart);
570 if (ws->tableValidEnd < ws->tableEnd) {
571 ZSTD_memset(ws->tableValidEnd, 0, (size_t)((BYTE*)ws->tableEnd - (BYTE*)ws->tableValidEnd));
573 ZSTD_cwksp_mark_tables_clean(ws);
577 * Invalidates table allocations.
578 * All other allocations remain valid.
580 MEM_STATIC void ZSTD_cwksp_clear_tables(ZSTD_cwksp* ws) {
581 DEBUGLOG(4, "cwksp: clearing tables!");
583 #if ZSTD_ADDRESS_SANITIZER && !defined (ZSTD_ASAN_DONT_POISON_WORKSPACE)
584 /* We don't do this when the workspace is statically allocated, because
585 * when that is the case, we have no capability to hook into the end of the
586 * workspace's lifecycle to unpoison the memory.
588 if (ws->isStatic == ZSTD_cwksp_dynamic_alloc) {
589 size_t size = (BYTE*)ws->tableValidEnd - (BYTE*)ws->objectEnd;
590 __asan_poison_memory_region(ws->objectEnd, size);
594 ws->tableEnd = ws->objectEnd;
595 ZSTD_cwksp_assert_internal_consistency(ws);
599 * Invalidates all buffer, aligned, and table allocations.
600 * Object allocations remain valid.
602 MEM_STATIC void ZSTD_cwksp_clear(ZSTD_cwksp* ws) {
603 DEBUGLOG(4, "cwksp: clearing!");
605 #if ZSTD_MEMORY_SANITIZER && !defined (ZSTD_MSAN_DONT_POISON_WORKSPACE)
606 /* To validate that the context reuse logic is sound, and that we don't
607 * access stuff that this compression hasn't initialized, we re-"poison"
608 * the workspace except for the areas in which we expect memory reuse
609 * without initialization (objects, valid tables area and init once
612 if((BYTE*)ws->tableValidEnd < (BYTE*)ws->initOnceStart) {
613 size_t size = (BYTE*)ws->initOnceStart - (BYTE*)ws->tableValidEnd;
614 __msan_poison(ws->tableValidEnd, size);
619 #if ZSTD_ADDRESS_SANITIZER && !defined (ZSTD_ASAN_DONT_POISON_WORKSPACE)
620 /* We don't do this when the workspace is statically allocated, because
621 * when that is the case, we have no capability to hook into the end of the
622 * workspace's lifecycle to unpoison the memory.
624 if (ws->isStatic == ZSTD_cwksp_dynamic_alloc) {
625 size_t size = (BYTE*)ws->workspaceEnd - (BYTE*)ws->objectEnd;
626 __asan_poison_memory_region(ws->objectEnd, size);
630 ws->tableEnd = ws->objectEnd;
631 ws->allocStart = ZSTD_cwksp_initialAllocStart(ws);
633 if (ws->phase > ZSTD_cwksp_alloc_aligned_init_once) {
634 ws->phase = ZSTD_cwksp_alloc_aligned_init_once;
636 ZSTD_cwksp_assert_internal_consistency(ws);
639 MEM_STATIC size_t ZSTD_cwksp_sizeof(const ZSTD_cwksp* ws) {
640 return (size_t)((BYTE*)ws->workspaceEnd - (BYTE*)ws->workspace);
643 MEM_STATIC size_t ZSTD_cwksp_used(const ZSTD_cwksp* ws) {
644 return (size_t)((BYTE*)ws->tableEnd - (BYTE*)ws->workspace)
645 + (size_t)((BYTE*)ws->workspaceEnd - (BYTE*)ws->allocStart);
649 * The provided workspace takes ownership of the buffer [start, start+size).
650 * Any existing values in the workspace are ignored (the previously managed
651 * buffer, if present, must be separately freed).
653 MEM_STATIC void ZSTD_cwksp_init(ZSTD_cwksp* ws, void* start, size_t size, ZSTD_cwksp_static_alloc_e isStatic) {
654 DEBUGLOG(4, "cwksp: init'ing workspace with %zd bytes", size);
655 assert(((size_t)start & (sizeof(void*)-1)) == 0); /* ensure correct alignment */
656 ws->workspace = start;
657 ws->workspaceEnd = (BYTE*)start + size;
658 ws->objectEnd = ws->workspace;
659 ws->tableValidEnd = ws->objectEnd;
660 ws->initOnceStart = ZSTD_cwksp_initialAllocStart(ws);
661 ws->phase = ZSTD_cwksp_alloc_objects;
662 ws->isStatic = isStatic;
663 ZSTD_cwksp_clear(ws);
664 ws->workspaceOversizedDuration = 0;
665 ZSTD_cwksp_assert_internal_consistency(ws);
668 MEM_STATIC size_t ZSTD_cwksp_create(ZSTD_cwksp* ws, size_t size, ZSTD_customMem customMem) {
669 void* workspace = ZSTD_customMalloc(size, customMem);
670 DEBUGLOG(4, "cwksp: creating new workspace with %zd bytes", size);
671 RETURN_ERROR_IF(workspace == NULL, memory_allocation, "NULL pointer!");
672 ZSTD_cwksp_init(ws, workspace, size, ZSTD_cwksp_dynamic_alloc);
676 MEM_STATIC void ZSTD_cwksp_free(ZSTD_cwksp* ws, ZSTD_customMem customMem) {
677 void *ptr = ws->workspace;
678 DEBUGLOG(4, "cwksp: freeing workspace");
679 #if ZSTD_MEMORY_SANITIZER && !defined(ZSTD_MSAN_DONT_POISON_WORKSPACE)
680 if (ptr != NULL && customMem.customFree != NULL) {
681 __msan_unpoison(ptr, ZSTD_cwksp_sizeof(ws));
684 ZSTD_memset(ws, 0, sizeof(ZSTD_cwksp));
685 ZSTD_customFree(ptr, customMem);
689 * Moves the management of a workspace from one cwksp to another. The src cwksp
690 * is left in an invalid state (src must be re-init()'ed before it's used again).
692 MEM_STATIC void ZSTD_cwksp_move(ZSTD_cwksp* dst, ZSTD_cwksp* src) {
694 ZSTD_memset(src, 0, sizeof(ZSTD_cwksp));
697 MEM_STATIC int ZSTD_cwksp_reserve_failed(const ZSTD_cwksp* ws) {
698 return ws->allocFailed;
701 /*-*************************************
702 * Functions Checking Free Space
703 ***************************************/
705 /* ZSTD_alignmentSpaceWithinBounds() :
706 * Returns if the estimated space needed for a wksp is within an acceptable limit of the
707 * actual amount of space used.
709 MEM_STATIC int ZSTD_cwksp_estimated_space_within_bounds(const ZSTD_cwksp *const ws, size_t const estimatedSpace) {
710 /* We have an alignment space between objects and tables between tables and buffers, so we can have up to twice
711 * the alignment bytes difference between estimation and actual usage */
712 return (estimatedSpace - ZSTD_cwksp_slack_space_required()) <= ZSTD_cwksp_used(ws) &&
713 ZSTD_cwksp_used(ws) <= estimatedSpace;
717 MEM_STATIC size_t ZSTD_cwksp_available_space(ZSTD_cwksp* ws) {
718 return (size_t)((BYTE*)ws->allocStart - (BYTE*)ws->tableEnd);
721 MEM_STATIC int ZSTD_cwksp_check_available(ZSTD_cwksp* ws, size_t additionalNeededSpace) {
722 return ZSTD_cwksp_available_space(ws) >= additionalNeededSpace;
725 MEM_STATIC int ZSTD_cwksp_check_too_large(ZSTD_cwksp* ws, size_t additionalNeededSpace) {
726 return ZSTD_cwksp_check_available(
727 ws, additionalNeededSpace * ZSTD_WORKSPACETOOLARGE_FACTOR);
730 MEM_STATIC int ZSTD_cwksp_check_wasteful(ZSTD_cwksp* ws, size_t additionalNeededSpace) {
731 return ZSTD_cwksp_check_too_large(ws, additionalNeededSpace)
732 && ws->workspaceOversizedDuration > ZSTD_WORKSPACETOOLARGE_MAXDURATION;
735 MEM_STATIC void ZSTD_cwksp_bump_oversized_duration(
736 ZSTD_cwksp* ws, size_t additionalNeededSpace) {
737 if (ZSTD_cwksp_check_too_large(ws, additionalNeededSpace)) {
738 ws->workspaceOversizedDuration++;
740 ws->workspaceOversizedDuration = 0;
744 #if defined (__cplusplus)
748 #endif /* ZSTD_CWKSP_H */