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Diffstat (limited to 'Utilities/cmzstd/lib/compress/zstd_cwksp.h')
| -rw-r--r-- | Utilities/cmzstd/lib/compress/zstd_cwksp.h | 662 |
1 files changed, 662 insertions, 0 deletions
diff --git a/Utilities/cmzstd/lib/compress/zstd_cwksp.h b/Utilities/cmzstd/lib/compress/zstd_cwksp.h new file mode 100644 index 0000000000..2656d26ca2 --- /dev/null +++ b/Utilities/cmzstd/lib/compress/zstd_cwksp.h @@ -0,0 +1,662 @@ +/* + * Copyright (c) Yann Collet, Facebook, Inc. + * All rights reserved. + * + * This source code is licensed under both the BSD-style license (found in the + * LICENSE file in the root directory of this source tree) and the GPLv2 (found + * in the COPYING file in the root directory of this source tree). + * You may select, at your option, one of the above-listed licenses. + */ + +#ifndef ZSTD_CWKSP_H +#define ZSTD_CWKSP_H + +/*-************************************* +* Dependencies +***************************************/ +#include "../common/zstd_internal.h" + +#if defined (__cplusplus) +extern "C" { +#endif + +/*-************************************* +* Constants +***************************************/ + +/* Since the workspace is effectively its own little malloc implementation / + * arena, when we run under ASAN, we should similarly insert redzones between + * each internal element of the workspace, so ASAN will catch overruns that + * reach outside an object but that stay inside the workspace. + * + * This defines the size of that redzone. + */ +#ifndef ZSTD_CWKSP_ASAN_REDZONE_SIZE +#define ZSTD_CWKSP_ASAN_REDZONE_SIZE 128 +#endif + + +/* Set our tables and aligneds to align by 64 bytes */ +#define ZSTD_CWKSP_ALIGNMENT_BYTES 64 + +/*-************************************* +* Structures +***************************************/ +typedef enum { + ZSTD_cwksp_alloc_objects, + ZSTD_cwksp_alloc_buffers, + ZSTD_cwksp_alloc_aligned +} ZSTD_cwksp_alloc_phase_e; + +/** + * Used to describe whether the workspace is statically allocated (and will not + * necessarily ever be freed), or if it's dynamically allocated and we can + * expect a well-formed caller to free this. + */ +typedef enum { + ZSTD_cwksp_dynamic_alloc, + ZSTD_cwksp_static_alloc +} ZSTD_cwksp_static_alloc_e; + +/** + * Zstd fits all its internal datastructures into a single continuous buffer, + * so that it only needs to perform a single OS allocation (or so that a buffer + * can be provided to it and it can perform no allocations at all). This buffer + * is called the workspace. + * + * Several optimizations complicate that process of allocating memory ranges + * from this workspace for each internal datastructure: + * + * - These different internal datastructures have different setup requirements: + * + * - The static objects need to be cleared once and can then be trivially + * reused for each compression. + * + * - Various buffers don't need to be initialized at all--they are always + * written into before they're read. + * + * - The matchstate tables have a unique requirement that they don't need + * their memory to be totally cleared, but they do need the memory to have + * some bound, i.e., a guarantee that all values in the memory they've been + * allocated is less than some maximum value (which is the starting value + * for the indices that they will then use for compression). When this + * guarantee is provided to them, they can use the memory without any setup + * work. When it can't, they have to clear the area. + * + * - These buffers also have different alignment requirements. + * + * - We would like to reuse the objects in the workspace for multiple + * compressions without having to perform any expensive reallocation or + * reinitialization work. + * + * - We would like to be able to efficiently reuse the workspace across + * multiple compressions **even when the compression parameters change** and + * we need to resize some of the objects (where possible). + * + * To attempt to manage this buffer, given these constraints, the ZSTD_cwksp + * abstraction was created. It works as follows: + * + * Workspace Layout: + * + * [ ... workspace ... ] + * [objects][tables ... ->] free space [<- ... aligned][<- ... buffers] + * + * The various objects that live in the workspace are divided into the + * following categories, and are allocated separately: + * + * - Static objects: this is optionally the enclosing ZSTD_CCtx or ZSTD_CDict, + * so that literally everything fits in a single buffer. Note: if present, + * this must be the first object in the workspace, since ZSTD_customFree{CCtx, + * CDict}() rely on a pointer comparison to see whether one or two frees are + * required. + * + * - Fixed size objects: these are fixed-size, fixed-count objects that are + * nonetheless "dynamically" allocated in the workspace so that we can + * control how they're initialized separately from the broader ZSTD_CCtx. + * Examples: + * - Entropy Workspace + * - 2 x ZSTD_compressedBlockState_t + * - CDict dictionary contents + * + * - Tables: these are any of several different datastructures (hash tables, + * chain tables, binary trees) that all respect a common format: they are + * 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. + * + * - Buffers: these buffers are used for various purposes that don't require + * any alignment or initialization before they're used. This means they can + * be moved around at no cost for a new compression. + * + * Allocating Memory: + * + * The various types of objects must be allocated in order, so they can be + * correctly packed into the workspace buffer. That order is: + * + * 1. Objects + * 2. Buffers + * 3. Aligned/Tables + * + * Attempts to reserve objects of different types out of order will fail. + */ +typedef struct { + void* workspace; + void* workspaceEnd; + + void* objectEnd; + void* tableEnd; + void* tableValidEnd; + void* allocStart; + + BYTE allocFailed; + int workspaceOversizedDuration; + ZSTD_cwksp_alloc_phase_e phase; + ZSTD_cwksp_static_alloc_e isStatic; +} ZSTD_cwksp; + +/*-************************************* +* Functions +***************************************/ + +MEM_STATIC size_t ZSTD_cwksp_available_space(ZSTD_cwksp* ws); + +MEM_STATIC void ZSTD_cwksp_assert_internal_consistency(ZSTD_cwksp* ws) { + (void)ws; + assert(ws->workspace <= ws->objectEnd); + assert(ws->objectEnd <= ws->tableEnd); + assert(ws->objectEnd <= ws->tableValidEnd); + assert(ws->tableEnd <= ws->allocStart); + assert(ws->tableValidEnd <= ws->allocStart); + assert(ws->allocStart <= ws->workspaceEnd); +} + +/** + * Align must be a power of 2. + */ +MEM_STATIC size_t ZSTD_cwksp_align(size_t size, size_t const align) { + size_t const mask = align - 1; + assert((align & mask) == 0); + return (size + mask) & ~mask; +} + +/** + * Use this to determine how much space in the workspace we will consume to + * allocate this object. (Normally it should be exactly the size of the object, + * but under special conditions, like ASAN, where we pad each object, it might + * be larger.) + * + * Since tables aren't currently redzoned, you don't need to call through this + * to figure out how much space you need for the matchState tables. Everything + * else is though. + * + * Do not use for sizing aligned buffers. Instead, use ZSTD_cwksp_aligned_alloc_size(). + */ +MEM_STATIC size_t ZSTD_cwksp_alloc_size(size_t size) { + if (size == 0) + return 0; +#if ZSTD_ADDRESS_SANITIZER && !defined (ZSTD_ASAN_DONT_POISON_WORKSPACE) + return size + 2 * ZSTD_CWKSP_ASAN_REDZONE_SIZE; +#else + return size; +#endif +} + +/** + * Returns an adjusted alloc size that is the nearest larger multiple of 64 bytes. + * Used to determine the number of bytes required for a given "aligned". + */ +MEM_STATIC size_t ZSTD_cwksp_aligned_alloc_size(size_t size) { + return ZSTD_cwksp_alloc_size(ZSTD_cwksp_align(size, ZSTD_CWKSP_ALIGNMENT_BYTES)); +} + +/** + * Returns the amount of additional space the cwksp must allocate + * 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. + */ + size_t const slackSpace = ZSTD_CWKSP_ALIGNMENT_BYTES; + return slackSpace; +} + + +/** + * Return the number of additional bytes required to align a pointer to the given number of bytes. + * alignBytes must be a power of two. + */ +MEM_STATIC size_t ZSTD_cwksp_bytes_to_align_ptr(void* ptr, const size_t alignBytes) { + 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); + return bytes; +} + +/** + * 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) + * + * 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) { + void* const alloc = (BYTE*)ws->allocStart - bytes; + void* const bottom = ws->tableEnd; + DEBUGLOG(5, "cwksp: reserving %p %zd bytes, %zd bytes remaining", + alloc, bytes, ZSTD_cwksp_available_space(ws) - bytes); + ZSTD_cwksp_assert_internal_consistency(ws); + assert(alloc >= bottom); + if (alloc < bottom) { + DEBUGLOG(4, "cwksp: alloc failed!"); + ws->allocFailed = 1; + return NULL; + } + if (alloc < ws->tableValidEnd) { + ws->tableValidEnd = alloc; + } + ws->allocStart = alloc; + return alloc; +} + +/** + * Moves the cwksp to the next phase, and does any necessary allocations. + * 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) { + 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) { + ws->tableValidEnd = ws->objectEnd; + } + + /* 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; + size_t const bytesToAlign = ZSTD_cwksp_bytes_to_align_ptr(alloc, ZSTD_CWKSP_ALIGNMENT_BYTES); + void* const end = (BYTE*)alloc + bytesToAlign; + DEBUGLOG(5, "reserving table alignment addtl space: %zu", bytesToAlign); + RETURN_ERROR_IF(end > ws->workspaceEnd, memory_allocation, + "table phase - alignment initial allocation failed!"); + ws->objectEnd = end; + ws->tableEnd = end; + ws->tableValidEnd = end; + } + } + ws->phase = phase; + ZSTD_cwksp_assert_internal_consistency(ws); + } + return 0; +} + +/** + * 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); +} + +/** + * 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) { + void* alloc; + if (ZSTD_isError(ZSTD_cwksp_internal_advance_phase(ws, phase)) || bytes == 0) { + return NULL; + } + +#if ZSTD_ADDRESS_SANITIZER && !defined (ZSTD_ASAN_DONT_POISON_WORKSPACE) + /* over-reserve space */ + bytes += 2 * ZSTD_CWKSP_ASAN_REDZONE_SIZE; +#endif + + alloc = ZSTD_cwksp_reserve_internal_buffer_space(ws, 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. */ + if (alloc) { + alloc = (BYTE *)alloc + ZSTD_CWKSP_ASAN_REDZONE_SIZE; + if (ws->isStatic == ZSTD_cwksp_dynamic_alloc) { + __asan_unpoison_memory_region(alloc, bytes); + } + } +#endif + + return alloc; +} + +/** + * Reserves and returns unaligned memory. + */ +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). + */ +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); + return ptr; +} + +/** + * Aligned on 64 bytes. These buffers have the special property that + * 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; + void* alloc; + void* end; + void* top; + + if (ZSTD_isError(ZSTD_cwksp_internal_advance_phase(ws, phase))) { + return NULL; + } + alloc = ws->tableEnd; + end = (BYTE *)alloc + bytes; + top = ws->allocStart; + + DEBUGLOG(5, "cwksp: reserving %p table %zd bytes, %zd bytes remaining", + alloc, bytes, ZSTD_cwksp_available_space(ws) - bytes); + assert((bytes & (sizeof(U32)-1)) == 0); + ZSTD_cwksp_assert_internal_consistency(ws); + assert(end <= top); + if (end > top) { + DEBUGLOG(4, "cwksp: table alloc failed!"); + ws->allocFailed = 1; + return NULL; + } + ws->tableEnd = end; + +#if ZSTD_ADDRESS_SANITIZER && !defined (ZSTD_ASAN_DONT_POISON_WORKSPACE) + if (ws->isStatic == ZSTD_cwksp_dynamic_alloc) { + __asan_unpoison_memory_region(alloc, bytes); + } +#endif + + assert((bytes & (ZSTD_CWKSP_ALIGNMENT_BYTES-1)) == 0); + assert(((size_t)alloc & (ZSTD_CWKSP_ALIGNMENT_BYTES-1))== 0); + return alloc; +} + +/** + * Aligned on sizeof(void*). + */ +MEM_STATIC void* ZSTD_cwksp_reserve_object(ZSTD_cwksp* ws, size_t bytes) { + size_t roundedBytes = ZSTD_cwksp_align(bytes, sizeof(void*)); + void* alloc = ws->objectEnd; + void* end = (BYTE*)alloc + roundedBytes; + +#if ZSTD_ADDRESS_SANITIZER && !defined (ZSTD_ASAN_DONT_POISON_WORKSPACE) + /* over-reserve space */ + end = (BYTE *)end + 2 * ZSTD_CWKSP_ASAN_REDZONE_SIZE; +#endif + + DEBUGLOG(5, + "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); + 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!"); + ws->allocFailed = 1; + return NULL; + } + ws->objectEnd = end; + ws->tableEnd = end; + ws->tableValidEnd = end; + +#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; + if (ws->isStatic == ZSTD_cwksp_dynamic_alloc) { + __asan_unpoison_memory_region(alloc, bytes); + } +#endif + + return alloc; +} + +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. */ + { + size_t size = (BYTE*)ws->tableValidEnd - (BYTE*)ws->objectEnd; + assert(__msan_test_shadow(ws->objectEnd, size) == -1); + __msan_poison(ws->objectEnd, size); + } +#endif + + assert(ws->tableValidEnd >= ws->objectEnd); + assert(ws->tableValidEnd <= ws->allocStart); + ws->tableValidEnd = ws->objectEnd; + ZSTD_cwksp_assert_internal_consistency(ws); +} + +MEM_STATIC void ZSTD_cwksp_mark_tables_clean(ZSTD_cwksp* ws) { + DEBUGLOG(4, "cwksp: ZSTD_cwksp_mark_tables_clean"); + assert(ws->tableValidEnd >= ws->objectEnd); + assert(ws->tableValidEnd <= ws->allocStart); + if (ws->tableValidEnd < ws->tableEnd) { + ws->tableValidEnd = ws->tableEnd; + } + ZSTD_cwksp_assert_internal_consistency(ws); +} + +/** + * Zero the part of the allocated tables not already marked clean. + */ +MEM_STATIC void ZSTD_cwksp_clean_tables(ZSTD_cwksp* ws) { + DEBUGLOG(4, "cwksp: ZSTD_cwksp_clean_tables"); + 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_cwksp_mark_tables_clean(ws); +} + +/** + * Invalidates table allocations. + * All other allocations remain valid. + */ +MEM_STATIC void ZSTD_cwksp_clear_tables(ZSTD_cwksp* ws) { + DEBUGLOG(4, "cwksp: clearing tables!"); + +#if ZSTD_ADDRESS_SANITIZER && !defined (ZSTD_ASAN_DONT_POISON_WORKSPACE) + /* We don't do this when the workspace is statically allocated, because + * when that is the case, we have no capability to hook into the end of the + * workspace's lifecycle to unpoison the memory. + */ + if (ws->isStatic == ZSTD_cwksp_dynamic_alloc) { + size_t size = (BYTE*)ws->tableValidEnd - (BYTE*)ws->objectEnd; + __asan_poison_memory_region(ws->objectEnd, size); + } +#endif + + ws->tableEnd = ws->objectEnd; + ZSTD_cwksp_assert_internal_consistency(ws); +} + +/** + * Invalidates all buffer, aligned, and table allocations. + * Object allocations remain valid. + */ +MEM_STATIC void ZSTD_cwksp_clear(ZSTD_cwksp* ws) { + DEBUGLOG(4, "cwksp: clearing!"); + +#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. */ + { + size_t size = (BYTE*)ws->workspaceEnd - (BYTE*)ws->tableValidEnd; + __msan_poison(ws->tableValidEnd, size); + } +#endif + +#if ZSTD_ADDRESS_SANITIZER && !defined (ZSTD_ASAN_DONT_POISON_WORKSPACE) + /* We don't do this when the workspace is statically allocated, because + * when that is the case, we have no capability to hook into the end of the + * workspace's lifecycle to unpoison the memory. + */ + if (ws->isStatic == ZSTD_cwksp_dynamic_alloc) { + size_t size = (BYTE*)ws->workspaceEnd - (BYTE*)ws->objectEnd; + __asan_poison_memory_region(ws->objectEnd, size); + } +#endif + + ws->tableEnd = ws->objectEnd; + ws->allocStart = ws->workspaceEnd; + ws->allocFailed = 0; + if (ws->phase > ZSTD_cwksp_alloc_buffers) { + ws->phase = ZSTD_cwksp_alloc_buffers; + } + ZSTD_cwksp_assert_internal_consistency(ws); +} + +/** + * The provided workspace takes ownership of the buffer [start, start+size). + * Any existing values in the workspace are ignored (the previously managed + * buffer, if present, must be separately freed). + */ +MEM_STATIC void ZSTD_cwksp_init(ZSTD_cwksp* ws, void* start, size_t size, ZSTD_cwksp_static_alloc_e isStatic) { + DEBUGLOG(4, "cwksp: init'ing workspace with %zd bytes", size); + assert(((size_t)start & (sizeof(void*)-1)) == 0); /* ensure correct alignment */ + ws->workspace = start; + ws->workspaceEnd = (BYTE*)start + size; + ws->objectEnd = ws->workspace; + ws->tableValidEnd = ws->objectEnd; + ws->phase = ZSTD_cwksp_alloc_objects; + ws->isStatic = isStatic; + ZSTD_cwksp_clear(ws); + ws->workspaceOversizedDuration = 0; + ZSTD_cwksp_assert_internal_consistency(ws); +} + +MEM_STATIC size_t ZSTD_cwksp_create(ZSTD_cwksp* ws, size_t size, ZSTD_customMem customMem) { + void* workspace = ZSTD_customMalloc(size, customMem); + DEBUGLOG(4, "cwksp: creating new workspace with %zd bytes", size); + RETURN_ERROR_IF(workspace == NULL, memory_allocation, "NULL pointer!"); + ZSTD_cwksp_init(ws, workspace, size, ZSTD_cwksp_dynamic_alloc); + return 0; +} + +MEM_STATIC void ZSTD_cwksp_free(ZSTD_cwksp* ws, ZSTD_customMem customMem) { + void *ptr = ws->workspace; + DEBUGLOG(4, "cwksp: freeing workspace"); + ZSTD_memset(ws, 0, sizeof(ZSTD_cwksp)); + ZSTD_customFree(ptr, customMem); +} + +/** + * Moves the management of a workspace from one cwksp to another. The src cwksp + * is left in an invalid state (src must be re-init()'ed before it's used again). + */ +MEM_STATIC void ZSTD_cwksp_move(ZSTD_cwksp* dst, ZSTD_cwksp* src) { + *dst = *src; + ZSTD_memset(src, 0, sizeof(ZSTD_cwksp)); +} + +MEM_STATIC size_t ZSTD_cwksp_sizeof(const ZSTD_cwksp* ws) { + return (size_t)((BYTE*)ws->workspaceEnd - (BYTE*)ws->workspace); +} + +MEM_STATIC size_t ZSTD_cwksp_used(const ZSTD_cwksp* ws) { + return (size_t)((BYTE*)ws->tableEnd - (BYTE*)ws->workspace) + + (size_t)((BYTE*)ws->workspaceEnd - (BYTE*)ws->allocStart); +} + +MEM_STATIC int ZSTD_cwksp_reserve_failed(const ZSTD_cwksp* ws) { + return ws->allocFailed; +} + +/*-************************************* +* Functions Checking Free Space +***************************************/ + +/* ZSTD_alignmentSpaceWithinBounds() : + * 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 size_t ZSTD_cwksp_available_space(ZSTD_cwksp* ws) { + return (size_t)((BYTE*)ws->allocStart - (BYTE*)ws->tableEnd); +} + +MEM_STATIC int ZSTD_cwksp_check_available(ZSTD_cwksp* ws, size_t additionalNeededSpace) { + return ZSTD_cwksp_available_space(ws) >= additionalNeededSpace; +} + +MEM_STATIC int ZSTD_cwksp_check_too_large(ZSTD_cwksp* ws, size_t additionalNeededSpace) { + return ZSTD_cwksp_check_available( + ws, additionalNeededSpace * ZSTD_WORKSPACETOOLARGE_FACTOR); +} + +MEM_STATIC int ZSTD_cwksp_check_wasteful(ZSTD_cwksp* ws, size_t additionalNeededSpace) { + return ZSTD_cwksp_check_too_large(ws, additionalNeededSpace) + && ws->workspaceOversizedDuration > ZSTD_WORKSPACETOOLARGE_MAXDURATION; +} + +MEM_STATIC void ZSTD_cwksp_bump_oversized_duration( + ZSTD_cwksp* ws, size_t additionalNeededSpace) { + if (ZSTD_cwksp_check_too_large(ws, additionalNeededSpace)) { + ws->workspaceOversizedDuration++; + } else { + ws->workspaceOversizedDuration = 0; + } +} + +#if defined (__cplusplus) +} +#endif + +#endif /* ZSTD_CWKSP_H */ |