summaryrefslogtreecommitdiffstats
path: root/lib/zstd/compress/zstd_cwksp.h
diff options
context:
space:
mode:
authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
commitace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch)
treeb2d64bc10158fdd5497876388cd68142ca374ed3 /lib/zstd/compress/zstd_cwksp.h
parentInitial commit. (diff)
downloadlinux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz
linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'lib/zstd/compress/zstd_cwksp.h')
-rw-r--r--lib/zstd/compress/zstd_cwksp.h595
1 files changed, 595 insertions, 0 deletions
diff --git a/lib/zstd/compress/zstd_cwksp.h b/lib/zstd/compress/zstd_cwksp.h
new file mode 100644
index 0000000000..349fc923c3
--- /dev/null
+++ b/lib/zstd/compress/zstd_cwksp.h
@@ -0,0 +1,595 @@
+/*
+ * 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"
+
+
+/*-*************************************
+* 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;
+ return size;
+}
+
+/*
+ * 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 section.
+ *
+ * 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;
+ }
+ /* 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;
+ }
+ ws->allocStart = alloc;
+ return alloc;
+}
+
+/*
+ * 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)
+{
+ 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 objectEnd = (BYTE*)alloc + bytesToAlign;
+ DEBUGLOG(5, "reserving table alignment addtl space: %zu", bytesToAlign);
+ RETURN_ERROR_IF(objectEnd > ws->workspaceEnd, memory_allocation,
+ "table phase - alignment initial allocation failed!");
+ ws->objectEnd = objectEnd;
+ ws->tableEnd = objectEnd; /* table area starts being empty */
+ if (ws->tableValidEnd < ws->tableEnd) {
+ ws->tableValidEnd = ws->tableEnd;
+ } } }
+ 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;
+ }
+
+
+ alloc = ZSTD_cwksp_reserve_internal_buffer_space(ws, bytes);
+
+
+ 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;
+
+
+ assert((bytes & (ZSTD_CWKSP_ALIGNMENT_BYTES-1)) == 0);
+ assert(((size_t)alloc & (ZSTD_CWKSP_ALIGNMENT_BYTES-1))== 0);
+ return alloc;
+}
+
+/*
+ * 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 const roundedBytes = ZSTD_cwksp_align(bytes, sizeof(void*));
+ void* alloc = ws->objectEnd;
+ void* end = (BYTE*)alloc + roundedBytes;
+
+
+ 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 % 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(3, "cwksp: object alloc failed!");
+ ws->allocFailed = 1;
+ return NULL;
+ }
+ ws->objectEnd = end;
+ ws->tableEnd = end;
+ ws->tableValidEnd = end;
+
+
+ return alloc;
+}
+
+MEM_STATIC void ZSTD_cwksp_mark_tables_dirty(ZSTD_cwksp* ws)
+{
+ DEBUGLOG(4, "cwksp: ZSTD_cwksp_mark_tables_dirty");
+
+
+ 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!");
+
+
+ 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!");
+
+
+
+ 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;
+ }
+}
+
+
+#endif /* ZSTD_CWKSP_H */