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/* Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
/*
* Helper functions/wrappers for memory allocations, manipulation and
* comparison.
*/
#ifndef VBOOT_FIRMWARE_LIB_STATEFUL_UTIL_H_
#define VBOOT_FIRMWARE_LIB_STATEFUL_UTIL_H_
#include "sysincludes.h"
/* Track remaining data to be read in a buffer. */
typedef struct MemcpyState {
uint8_t *remaining_buf;
uint64_t remaining_len; /* Remaining length of the buffer. */
uint8_t overrun; /* Flag set to 1 when an overrun occurs. */
} MemcpyState;
/**
* Initialize a stateful buffer struct to point to the buffer, with the
* specified remaining length in bytes.
*/
void StatefulInit(MemcpyState *state, void *buf, uint64_t len);
/**
* Skip [len] bytes only if there's enough data to skip according to [state].
*
* On success, return a meaningless but non-NULL pointer and updates [state].
* On failure, return NULL, set state->overrun to 1.
*
* Useful for iterating through a binary blob to populate a struct. After the
* first failure (buffer overrun), successive calls will always fail.
*/
void *StatefulSkip(MemcpyState *state, uint64_t len);
/**
* Copy [len] bytes into [dst] only if there's enough data to read according
* to [state].
*
* On success, return [dst] and update [state].
* On failure, return NULL, set state->overrun to 1.
*
* Useful for iterating through a binary blob to populate a struct. After the
* first failure (buffer overrun), successive calls will always fail.
*/
void *StatefulMemcpy(MemcpyState *state, void *dst, uint64_t len);
/**
* Like StatefulMemcpy() but copies in the opposite direction, populating
* data from [src] into the buffer encapsulated in state [state].
*
* On success, return [src] and update [state].
* On failure, return NULL, set state->overrun to 1.
*
* Useful for iterating through a structure to populate a binary blob. After the
* first failure (buffer overrun), successive calls will always fail.
*/
const void *StatefulMemcpy_r(MemcpyState *state, const void *src, uint64_t len);
/**
* Like StatefulMemcpy_r() but fills a portion of the encapsulated buffer with
* a constant value.
*
* On success, return a meaningless but non-NULL pointer and updates [state].
* On failure, return NULL, set state->overrun to 1.
*
* After the first failure (buffer overrun), successive calls will always fail.
*/
const void *StatefulMemset_r(MemcpyState *state, const uint8_t val,
uint64_t len);
#endif
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