/* Copyright 2019 Google LLC. All Rights Reserved. This file and proprietary
   source code may only be used and distributed under the Widevine Master
   License Agreement. */

#ifndef OEMCRYPTO_TA_OEMCRYPTO_NONCE_TABLE_H_
#define OEMCRYPTO_TA_OEMCRYPTO_NONCE_TABLE_H_

#include "stdbool.h"
#include "stdint.h"

#define NONCE_TABLE_SIZE 4

typedef enum NonceTableState {
  NT_STATE_INVALID = 0x73624fe4,
  NT_STATE_VALID = 0x7fb3983a,
  NT_STATE_FLUSH_PENDING = 0x1b9654ae,
} NonceTableState;

typedef struct NonceTable {
  NonceTableState state[NONCE_TABLE_SIZE];
  uint32_t age[NONCE_TABLE_SIZE];
  uint32_t nonces[NONCE_TABLE_SIZE];
} NonceTable;

/* Adds |nonce| to the |nonce_table|. Flushes any nonces that have already been
   checked and then either adds it to the nonce table or replaces the oldest
   valid nonce in the table. */
void AddNonce(NonceTable* nonce_table, uint32_t nonce);

/* Checks the |nonce| exists in the |nonce_table|. Marks the nonce as ready to
   be flushed if it exists.
   Returns false if it does not exist in the table. */
bool CheckNonce(NonceTable* nonce_table, uint32_t nonce);

/* Verify that the nonce is not the same as any in |nonce_table|. */
bool NonceCollision(NonceTable* nonce_table, uint32_t nonce);

/* Flush any nonces that have been checked in |nonce_table|. */
void FlushNonces(NonceTable* nonce_table);

#endif  // OEMCRYPTO_TA_OEMCRYPTO_NONCE_TABLE_H_