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/* Copyright (c) 2011 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_UTILITY_H_
#define VBOOT_FIRMWARE_LIB_UTILITY_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 /* VBOOT_FIRMWARE_LIB_UTILITY_H_ */
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