#include <idea.h>
#include <stdlib.h>
#include <strings.h>

#include "algs.h"
#include "alg-util.h"

typedef struct idea_state IDEA_STATE;

struct idea_state {
  IDEA_KEY key;
  unsigned char iv[8];
  int direction;
#define ENCRYPT 1
#define DECRYPT 2
  } ;

static void *enc_idea_cbc_init_enc(const void *key, const void *iv)
{
 IDEA_STATE *s;

 s = malloc(sizeof(IDEA_STATE));
 if (s == 0) return(0);
 idea_setkey_e(key,&s->key);
 bcopy(iv,&s->iv[0],8);
 s->direction = ENCRYPT;
 return(s);
}

static void *enc_idea_cbc_init_dec(const void *key, const void *iv)
{
 IDEA_STATE *s;

 s = malloc(sizeof(IDEA_STATE));
 if (s == 0) return(0);
 idea_setkey_d(key,&s->key);
 bcopy(iv,&s->iv[0],8);
 s->direction = DECRYPT;
 return(s);
}

static void enc_idea_cbc_process(void *state, const void *in, void *out, int datalen)
{
 IDEA_STATE *s;
 const unsigned char *ip;
 unsigned char *op;
 unsigned char xorbuf[8];

 s = state;
 ip = in;
 op = out;
 if (datalen & 7) abort();
 switch (s->direction)
  { case ENCRYPT:
       bcopy(&s->iv[0],&xorbuf[0],8);
       while (datalen > 0)
	{ xor_block(&xorbuf[0],ip,&xorbuf[0],8);
	  idea_crypt(&xorbuf[0],&s->key,&xorbuf[0]);
	  bcopy(&xorbuf[0],op,8);
	  ip += 8;
	  op += 8;
	  datalen -= 8;
	}
       bcopy(&xorbuf[0],&s->iv[0],8);
       break;
    case DECRYPT:
	{ unsigned char iv1[8] __attribute__((__aligned__));
	  unsigned char iv2[8] __attribute__((__aligned__));
	  bcopy(&s->iv[0],&iv1[0],8);
	  while (datalen > 0)
	   { bcopy(ip,&iv2[0],8);
	     idea_crypt(ip,&s->key,op);
	     xor_block(&iv1[0],op,op,8);
	     bcopy(&iv2[0],&iv1[0],8);
	     ip += 8;
	     op += 8;
	     datalen -= 8;
	   }
	  bcopy(&iv1[0],&s->iv[0],8);
	}
       break;
    default:
       abort();
       break;
  }
}

static void enc_idea_cbc_done(void *state)
{
 free(state);
}

ENCALG encalg_idea_cbc
 = { "idea-cbc", 8, 8, 16,
     &enc_idea_cbc_init_enc, &enc_idea_cbc_init_dec,
     &enc_idea_cbc_process,
     &enc_idea_cbc_done };