/**

 * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.

 * All rights reserved.

 *

 * This source code is licensed under the BSD-style license found in the

 * LICENSE file in the root directory of https://github.com/facebook/zstd.

 * An additional grant of patent rights can be found in the PATENTS file in the

 * same directory.

 *

 * This program is free software; you can redistribute it and/or modify it under

 * the terms of the GNU General Public License version 2 as published by the

 * Free Software Foundation. This program is dual-licensed; you may select

 * either version 2 of the GNU General Public License ("GPL") or BSD license

 * ("BSD").

 */

/*-*************************************

*  Dependencies

***************************************/

#include "error_private.h"

#include "zstd_internal.h" /* declaration of ZSTD_isError, ZSTD_getErrorName, ZSTD_getErrorCode, ZSTD_getErrorString, ZSTD_versionNumber */

#include <linux/kernel.h>

/*=**************************************************************

*  Custom allocator

****************************************************************/

#define stack_push(stack, size)                                 \

  ({                                                      \

    void *const ptr = ZSTD_PTR_ALIGN((stack)->ptr); \

    (stack)->ptr = (char *)ptr + (size);            \

    (stack)->ptr <= (stack)->end ? ptr : NULL;      \

  })

ZSTD_customMem ZSTD_initStack(void *workspace, size_t workspaceSize)

{

  ZSTD_customMem stackMem = {ZSTD_stackAlloc, ZSTD_stackFree, workspace};

  ZSTD_stack *stack = (ZSTD_stack *)workspace;

  /* Verify preconditions */

  if (!workspace || workspaceSize < sizeof(ZSTD_stack) || workspace != ZSTD_PTR_ALIGN(workspace)) {

    ZSTD_customMem error = {NULL, NULL, NULL};

    return error;

  }

  /* Initialize the stack */

  stack->ptr = workspace;

  stack->end = (char *)workspace + workspaceSize;

  stack_push(stack, sizeof(ZSTD_stack));

  return stackMem;

}

void *ZSTD_stackAllocAll(void *opaque, size_t *size)

{

  ZSTD_stack *stack = (ZSTD_stack *)opaque;

  *size = (BYTE const *)stack->end - (BYTE *)ZSTD_PTR_ALIGN(stack->ptr);

  return stack_push(stack, *size);

}

void *ZSTD_stackAlloc(void *opaque, size_t size)

{

  ZSTD_stack *stack = (ZSTD_stack *)opaque;

  return stack_push(stack, size);

}

void ZSTD_stackFree(void *opaque, void *address)

{

  (void)opaque;

  (void)address;

}

void *ZSTD_malloc(size_t size, ZSTD_customMem customMem) { return customMem.customAlloc(customMem.opaque, size); }

void ZSTD_free(void *ptr, ZSTD_customMem customMem)

{

  if (ptr != NULL)

    customMem.customFree(customMem.opaque, ptr);

}