--- /dev/null
+/*
+ * Copyright (c) 2016-2020, 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 "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
+
+/*-*************************************
+* Structures
+***************************************/
+typedef enum {
+ ZSTD_cwksp_alloc_objects,
+ ZSTD_cwksp_alloc_buffers,
+ ZSTD_cwksp_alloc_aligned
+} ZSTD_cwksp_alloc_phase_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_free{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.
+ *
+ * - Aligned: these buffers are used for various purposes that require 4 byte
+ * alignment, but don't require any initialization before they're used.
+ *
+ * - 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
+ * 4. 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;
+
+ int allocFailed;
+ int workspaceOversizedDuration;
+ ZSTD_cwksp_alloc_phase_e phase;
+} 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.
+ */
+MEM_STATIC size_t ZSTD_cwksp_alloc_size(size_t size) {
+#if defined (ADDRESS_SANITIZER) && !defined (ZSTD_ASAN_DONT_POISON_WORKSPACE)
+ return size + 2 * ZSTD_CWKSP_ASAN_REDZONE_SIZE;
+#else
+ return size;
+#endif
+}
+
+MEM_STATIC void ZSTD_cwksp_internal_advance_phase(
+ ZSTD_cwksp* ws, ZSTD_cwksp_alloc_phase_e phase) {
+ assert(phase >= ws->phase);
+ if (phase > ws->phase) {
+ if (ws->phase < ZSTD_cwksp_alloc_buffers &&
+ phase >= ZSTD_cwksp_alloc_buffers) {
+ ws->tableValidEnd = ws->objectEnd;
+ }
+ if (ws->phase < ZSTD_cwksp_alloc_aligned &&
+ phase >= ZSTD_cwksp_alloc_aligned) {
+ /* If unaligned allocations down from a too-large top have left us
+ * unaligned, we need to realign our alloc ptr. Technically, this
+ * can consume space that is unaccounted for in the neededSpace
+ * calculation. However, I believe this can only happen when the
+ * workspace is too large, and specifically when it is too large
+ * by a larger margin than the space that will be consumed. */
+ /* TODO: cleaner, compiler warning friendly way to do this??? */
+ ws->allocStart = (BYTE*)ws->allocStart - ((size_t)ws->allocStart & (sizeof(U32)-1));
+ if (ws->allocStart < ws->tableValidEnd) {
+ ws->tableValidEnd = ws->allocStart;
+ }
+ }
+ ws->phase = 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);
+}
+
+/**
+ * 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;
+ void* bottom = ws->tableEnd;
+ ZSTD_cwksp_internal_advance_phase(ws, phase);
+ alloc = (BYTE *)ws->allocStart - bytes;
+
+#if defined (ADDRESS_SANITIZER) && !defined (ZSTD_ASAN_DONT_POISON_WORKSPACE)
+ /* over-reserve space */
+ alloc = (BYTE *)alloc - 2 * ZSTD_CWKSP_ASAN_REDZONE_SIZE;
+#endif
+
+ 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;
+
+#if defined (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;
+ __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 sizeof(unsigned).
+ */
+MEM_STATIC void* ZSTD_cwksp_reserve_aligned(ZSTD_cwksp* ws, size_t bytes) {
+ assert((bytes & (sizeof(U32)-1)) == 0);
+ return ZSTD_cwksp_reserve_internal(ws, ZSTD_cwksp_align(bytes, sizeof(U32)), ZSTD_cwksp_alloc_aligned);
+}
+
+/**
+ * Aligned on sizeof(unsigned). 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 = ws->tableEnd;
+ void* end = (BYTE *)alloc + bytes;
+ void* 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_internal_advance_phase(ws, phase);
+ 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 defined (ADDRESS_SANITIZER) && !defined (ZSTD_ASAN_DONT_POISON_WORKSPACE)
+ __asan_unpoison_memory_region(alloc, bytes);
+#endif
+
+ 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 defined (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 defined (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;
+ __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 defined (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) {
+ 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 defined (ADDRESS_SANITIZER) && !defined (ZSTD_ASAN_DONT_POISON_WORKSPACE)
+ {
+ 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 defined (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 defined (ADDRESS_SANITIZER) && !defined (ZSTD_ASAN_DONT_POISON_WORKSPACE)
+ {
+ 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) {
+ 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;
+ 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_malloc(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);
+ return 0;
+}
+
+MEM_STATIC void ZSTD_cwksp_free(ZSTD_cwksp* ws, ZSTD_customMem customMem) {
+ void *ptr = ws->workspace;
+ DEBUGLOG(4, "cwksp: freeing workspace");
+ memset(ws, 0, sizeof(ZSTD_cwksp));
+ ZSTD_free(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 its used again).
+ */
+MEM_STATIC void ZSTD_cwksp_move(ZSTD_cwksp* dst, ZSTD_cwksp* src) {
+ *dst = *src;
+ 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 int ZSTD_cwksp_reserve_failed(const ZSTD_cwksp* ws) {
+ return ws->allocFailed;
+}
+
+/*-*************************************
+* Functions Checking Free Space
+***************************************/
+
+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 */
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