#ifndef CHACHA_H_
#define CHACHA_H_ 1

#include <stdint.h>

#define TLS_CHACHA20_IV_LENGTH    12

/* ChaCha20 implementation by D. J. Bernstein
 * Public domain.
 */

#define CHACHA_MINKEYLEN    16
#define CHACHA_NONCELEN     8
#define CHACHA_NONCELEN_96  12
#define CHACHA_CTRLEN       8
#define CHACHA_CTRLEN_96    4
#define CHACHA_STATELEN     (CHACHA_NONCELEN+CHACHA_CTRLEN)
#define CHACHA_BLOCKLEN     64

#define POLY1305_MAX_AAD    32
#define POLY1305_KEYLEN     32
#define POLY1305_TAGLEN     16

#define POLY1305_BLOCK_SIZE 16

struct chacha_ctx {
	uint32_t input[16];
	uint8_t ks[CHACHA_BLOCKLEN];
	uint8_t unused;
};

/* 17 + sizeof(size_t) + 14*sizeof(unsigned long) */
struct poly1305_context {
    unsigned long r[5];
    unsigned long h[5];
    unsigned long pad[4];
    size_t leftover;
    unsigned char buffer[POLY1305_BLOCK_SIZE];
    unsigned char final;
};

void chacha_keysetup(struct chacha_ctx *x, const unsigned char *k, unsigned int kbits);
void chacha_ivsetup(struct chacha_ctx *x, const unsigned char *iv, const unsigned char *ctr);
void chacha_ivsetup_96bitnonce(struct chacha_ctx *x, const unsigned char *iv, const unsigned char *ctr);
void chacha_encrypt_bytes(struct chacha_ctx *x, const unsigned char *m, unsigned char *c, unsigned int bytes);
int poly1305_generate_key(unsigned char *key256, unsigned char *nonce, unsigned int noncelen, unsigned char *poly_key, unsigned int counter);
void chacha_ivupdate(struct chacha_ctx *x, const uint8_t *iv, const uint8_t *aad, const uint8_t *counter);
void chacha20_poly1305_key(struct chacha_ctx *ctx, unsigned char *poly1305_key);
int chacha20_poly1305_aead(struct chacha_ctx *ctx,  unsigned char *pt, unsigned int len, unsigned char *aad, unsigned int aad_len, unsigned char *poly_key, unsigned char *out);
void tls_poly1305_init(struct poly1305_context *ctx, const unsigned char key[32]);
void tls_poly1305_update(struct poly1305_context *ctx, const unsigned char *m, size_t bytes);
void tls_poly1305_finish(struct poly1305_context *ctx, unsigned char mac[16]);


#endif