#include <stdlib.h>
#include <string.h>

#include "crypto_buffer.h"


#include <stdio.h>
int crypto_buffer_init(crypto_buffer *s, int fd, operation op, u32 blocks, int type, u8 *key, u32 key_len)
{
	int ret;
	int size;

	if(blocks<3) return -1;	/* magic + info + data */

	s->fd = fd;
	s->op = op;

	if(type & BLOWFISH){
		size = BF_BLOCK_SIZE;
		ret = blowfish_setkey((struct blowfish_ctx*)&s->ctx, key, key_len, 0);
		if(type & DECRYPT){ s->cipher = blowfish_decrypt; }
		else { s->cipher = blowfish_encrypt; }
	}
	else if(type & TWOFISH){
		size = TF_BLOCK_SIZE;
		ret = twofish_setkey((struct twofish_ctx*)&s->ctx, key, key_len, 0);
		if(type & DECRYPT) { s->cipher = twofish_decrypt; }
		else {s->cipher = twofish_encrypt; }
	}
	else if(type & AES){
		size = AES_BLOCK_SIZE;
		ret = aes_setkey((struct aes_ctx*)&s->ctx, key, key_len, 0);
		if(type & DECRYPT) { s->cipher = aes_decrypt; }
		else {s->cipher = aes_encrypt; }
	}
	else if(type & DES){
		size = DES_BLOCK_SIZE;
		ret = des_setkey((struct des_ctx*)&s->ctx, key, key_len, 0);
		if(type & DECRYPT) { s->cipher = des_decrypt; }
		else {s->cipher = des_encrypt; }
	}
	else if(type & DES3_EDE){
		size = DES3_EDE_BLOCK_SIZE;
		ret = des3_ede_setkey((struct des3_ede_ctx*)&s->ctx, key, key_len, 0);
		if(type & DECRYPT) { s->cipher = des3_ede_decrypt; }
		else {s->cipher = des3_ede_encrypt; }
	}
	else return -1;
	if(ret!=0) return -1;

	if((U32_MAX / size) < blocks) return -1;

	s->block_size = size;
	s->e_len = size * blocks;		/* TODO check overflow */
	s->data_st.bytes = s->data_st.strlen = 0;
	/* clear buffer */
	s->c_buffer = malloc(size);
	if(s->c_buffer==NULL) return -1;
	s->c_ptr = s->c_buffer;
	s->c_end = s->c_buffer + size;
	/* encrypte buffer */
	s->e_buffer = malloc(s->e_len);
	if(s->e_buffer==NULL) return -1;
	memset(s->e_buffer,0x5a,size);		/* for write operation */
	s->e_data = (struct info*)(s->e_buffer + size);
	s->e_end = s->e_buffer + s->e_len;
	if(type & DECRYPT){
		s->e_ptr = s->e_buffer;
	}
	else{
		s->e_ptr = s->e_buffer + (size << 1);
		s->e_len -= (size << 1);
	}
/*
	fprintf(stderr,"e_buffer  : %x\n",s->e_buffer);
	fprintf(stderr,"e_data    : %x\n",s->e_data);
	fprintf(stderr,"e_ptr     : %x\n",s->e_ptr);
	fprintf(stderr,"e_end     : %x\n",s->e_end);
	fprintf(stderr,"length    : %d\n",s->e_len);
*/
	return ret;
}