/*
 * Argon2 source code package
 *
 * Written by Daniel Dinu and Dmitry Khovratovich, 2015
 *
 * This work is licensed under a Creative Commons CC0 1.0 License/Waiver.
 *
 * You should have received a copy of the CC0 Public Domain Dedication along
 * with this software. If not, see
 * <http://creativecommons.org/publicdomain/zero/1.0/>.
 */
#ifndef argon2_H
#define argon2_H

#include <limits.h>
#include <stddef.h>
#include <stdint.h>

/*
 * Argon2 input parameter restrictions
 */

/* Minimum and maximum number of lanes (degree of parallelism) */
#define ARGON2_MIN_LANES UINT32_C(1)
#define ARGON2_MAX_LANES UINT32_C(0xFFFFFF)

/* Minimum and maximum number of threads */
#define ARGON2_MIN_THREADS UINT32_C(1)
#define ARGON2_MAX_THREADS UINT32_C(0xFFFFFF)

/* Number of synchronization points between lanes per pass */
#define ARGON2_SYNC_POINTS UINT32_C(4)

/* Minimum and maximum digest size in bytes */
#define ARGON2_MIN_OUTLEN UINT32_C(16)
#define ARGON2_MAX_OUTLEN UINT32_C(0xFFFFFFFF)

/* Minimum and maximum number of memory blocks (each of BLOCK_SIZE bytes) */
#define ARGON2_MIN_MEMORY (2 * ARGON2_SYNC_POINTS) /* 2 blocks per slice */

#define ARGON2_MIN(a, b) ((a) < (b) ? (a) : (b))
/* Max memory size is half the addressing space, topping at 2^32 blocks (4 TB)
 */
#define ARGON2_MAX_MEMORY_BITS \
    ARGON2_MIN(UINT32_C(32), (sizeof(void *) * CHAR_BIT - 10 - 1))
#define ARGON2_MAX_MEMORY \
    ARGON2_MIN(UINT32_C(0xFFFFFFFF), UINT64_C(1) << ARGON2_MAX_MEMORY_BITS)

/* Minimum and maximum number of passes */
#define ARGON2_MIN_TIME UINT32_C(3)
#define ARGON2_MAX_TIME UINT32_C(0xFFFFFFFF)

/* Minimum and maximum password length in bytes */
#define ARGON2_MIN_PWD_LENGTH UINT32_C(0)
#define ARGON2_MAX_PWD_LENGTH UINT32_C(0xFFFFFFFF)

/* Minimum and maximum associated data length in bytes */
#define ARGON2_MIN_AD_LENGTH UINT32_C(0)
#define ARGON2_MAX_AD_LENGTH UINT32_C(0xFFFFFFFF)

/* Minimum and maximum salt length in bytes */
#define ARGON2_MIN_SALT_LENGTH UINT32_C(8)
#define ARGON2_MAX_SALT_LENGTH UINT32_C(0xFFFFFFFF)

/* Minimum and maximum key length in bytes */
#define ARGON2_MIN_SECRET UINT32_C(0)
#define ARGON2_MAX_SECRET UINT32_C(0xFFFFFFFF)

#define ARGON2_FLAG_CLEAR_PASSWORD (UINT32_C(1) << 0)
#define ARGON2_FLAG_CLEAR_SECRET (UINT32_C(1) << 1)
#define ARGON2_FLAG_CLEAR_MEMORY (UINT32_C(1) << 2)
#define ARGON2_DEFAULT_FLAGS (ARGON2_FLAG_CLEAR_MEMORY)

/* Error codes */
typedef enum Argon2_ErrorCodes {
    ARGON2_OK = 0,

    ARGON2_OUTPUT_PTR_NULL = -1,

    ARGON2_OUTPUT_TOO_SHORT = -2,
    ARGON2_OUTPUT_TOO_LONG  = -3,

    ARGON2_PWD_TOO_SHORT = -4,
    ARGON2_PWD_TOO_LONG  = -5,

    ARGON2_SALT_TOO_SHORT = -6,
    ARGON2_SALT_TOO_LONG  = -7,

    ARGON2_AD_TOO_SHORT = -8,
    ARGON2_AD_TOO_LONG  = -9,

    ARGON2_SECRET_TOO_SHORT = -10,
    ARGON2_SECRET_TOO_LONG  = -11,

    ARGON2_TIME_TOO_SMALL = -12,
    ARGON2_TIME_TOO_LARGE = -13,

    ARGON2_MEMORY_TOO_LITTLE = -14,
    ARGON2_MEMORY_TOO_MUCH   = -15,

    ARGON2_LANES_TOO_FEW  = -16,
    ARGON2_LANES_TOO_MANY = -17,

    ARGON2_PWD_PTR_MISMATCH    = -18, /* NULL ptr with non-zero length */
    ARGON2_SALT_PTR_MISMATCH   = -19, /* NULL ptr with non-zero length */
    ARGON2_SECRET_PTR_MISMATCH = -20, /* NULL ptr with non-zero length */
    ARGON2_AD_PTR_MISMATCH     = -21, /* NULL ptr with non-zero length */

    ARGON2_MEMORY_ALLOCATION_ERROR = -22,

    ARGON2_FREE_MEMORY_CBK_NULL     = -23,
    ARGON2_ALLOCATE_MEMORY_CBK_NULL = -24,

    ARGON2_INCORRECT_PARAMETER = -25,
    ARGON2_INCORRECT_TYPE      = -26,

    ARGON2_OUT_PTR_MISMATCH = -27,

    ARGON2_THREADS_TOO_FEW  = -28,
    ARGON2_THREADS_TOO_MANY = -29,

    ARGON2_MISSING_ARGS = -30,

    ARGON2_ENCODING_FAIL = -31,

    ARGON2_DECODING_FAIL = -32,

    ARGON2_THREAD_FAIL = -33,

    ARGON2_DECODING_LENGTH_FAIL = -34,

    ARGON2_VERIFY_MISMATCH = -35
} argon2_error_codes;

/* Argon2 external data structures */

/*
 * Context: structure to hold Argon2 inputs:
 * output array and its length,
 * password and its length,
 * salt and its length,
 * secret and its length,
 * associated data and its length,
 * number of passes, amount of used memory (in KBytes, can be rounded up a bit)
 * number of parallel threads that will be run.
 * All the parameters above affect the output hash value.
 * Additionally, two function pointers can be provided to allocate and
 * deallocate the memory (if NULL, memory will be allocated internally).
 * Also, three flags indicate whether to erase password, secret as soon as they
 * are pre-hashed (and thus not needed anymore), and the entire memory
 *****
 * Simplest situation: you have output array out[8], password is stored in
 * pwd[32], salt is stored in salt[16], you do not have keys nor associated
 *data.
 * You need to spend 1 GB of RAM and you run 5 passes of Argon2 with 4 parallel
 *lanes.
 * You want to erase the password, but you're OK with last pass not being
 *erased.
 * You want to use the default memory allocator.
 * Then you initialize:
 * Argon2_Context(out,8,pwd,32,salt,16,NULL,0,NULL,0,5,1<<20,4,4,NULL,NULL,true,false,false,false).
 */
typedef struct Argon2_Context {
    uint8_t *out;    /* output array */
    uint32_t outlen; /* digest length */

    uint8_t *pwd;    /* password array */
    uint32_t pwdlen; /* password length */

    uint8_t *salt;    /* salt array */
    uint32_t saltlen; /* salt length */

    uint8_t *secret;    /* key array */
    uint32_t secretlen; /* key length */

    uint8_t *ad;    /* associated data array */
    uint32_t adlen; /* associated data length */

    uint32_t t_cost;  /* number of passes */
    uint32_t m_cost;  /* amount of memory requested (KB) */
    uint32_t lanes;   /* number of lanes */
    uint32_t threads; /* maximum number of threads */

    uint32_t flags; /* array of bool options */
} argon2_context;

/* Argon2 primitive type */
typedef enum Argon2_type { Argon2_i = 1 } argon2_type;

/*
 * Function that performs memory-hard hashing with certain degree of parallelism
 * @param  context  Pointer to the Argon2 internal structure
 * @return Error code if smth is wrong, ARGON2_OK otherwise
 */
int argon2_ctx(argon2_context *context, argon2_type type);

/**
 * Hashes a password with Argon2i, producing an encoded hash
 * @param t_cost Number of iterations
 * @param m_cost Sets memory usage to m_cost kibibytes
 * @param parallelism Number of threads and compute lanes
 * @param pwd Pointer to password
 * @param pwdlen Password size in bytes
 * @param salt Pointer to salt
 * @param saltlen Salt size in bytes
 * @param hashlen Desired length of the hash in bytes
 * @param encoded Buffer where to write the encoded hash
 * @param encodedlen Size of the buffer (thus max size of the encoded hash)
 * @pre   Different parallelism levels will give different results
 * @pre   Returns ARGON2_OK if successful
 */
int argon2i_hash_encoded(const uint32_t t_cost, const uint32_t m_cost,
                         const uint32_t parallelism, const void *pwd,
                         const size_t pwdlen, const void *salt,
                         const size_t saltlen, const size_t hashlen,
                         char *encoded, const size_t encodedlen);

/**
 * Hashes a password with Argon2i, producing a raw hash
 * @param t_cost Number of iterations
 * @param m_cost Sets memory usage to m_cost kibibytes
 * @param parallelism Number of threads and compute lanes
 * @param pwd Pointer to password
 * @param pwdlen Password size in bytes
 * @param salt Pointer to salt
 * @param saltlen Salt size in bytes
 * @param hash Buffer where to write the raw hash
 * @param hashlen Desired length of the hash in bytes
 * @pre   Different parallelism levels will give different results
 * @pre   Returns ARGON2_OK if successful
 */
int argon2i_hash_raw(const uint32_t t_cost, const uint32_t m_cost,
                     const uint32_t parallelism, const void *pwd,
                     const size_t pwdlen, const void *salt,
                     const size_t saltlen, void *hash, const size_t hashlen);

/* generic function underlying the above ones */
int argon2_hash(const uint32_t t_cost, const uint32_t m_cost,
                const uint32_t parallelism, const void *pwd,
                const size_t pwdlen, const void *salt, const size_t saltlen,
                void *hash, const size_t hashlen, char *encoded,
                const size_t encodedlen, argon2_type type);

/**
 * Verifies a password against an encoded string
 * Encoded string is restricted as in validate_inputs()
 * @param encoded String encoding parameters, salt, hash
 * @param pwd Pointer to password
 * @pre   Returns ARGON2_OK if successful
 */
int argon2i_verify(const char *encoded, const void *pwd, const size_t pwdlen);

/* generic function underlying the above ones */
int argon2_verify(const char *encoded, const void *pwd, const size_t pwdlen,
                  argon2_type type);
#endif
