#include <libkern/crypto/crypto_internal.h>
#include <libkern/crypto/md5.h>
#include <kern/debug.h>
#include <corecrypto/ccdigest.h>

static uint64_t getCount(MD5_CTX *ctx)
{
	return ( (((uint64_t)ctx->count[0])<<32) | (ctx->count[1]) );
}

static void setCount(MD5_CTX *ctx, uint64_t count)
{
	ctx->count[0]=(uint32_t)(count>>32);
	ctx->count[1]=(uint32_t)count;
}

/* Copy a ccdigest ctx into a legacy MD5 context */
static void DiToMD5(const struct ccdigest_info *di, struct ccdigest_ctx *di_ctx, MD5_CTX *md5_ctx)
{
	setCount(md5_ctx, ccdigest_nbits(di, di_ctx)/8+ccdigest_num(di, di_ctx));
	memcpy(md5_ctx->buffer, ccdigest_data(di, di_ctx), di->block_size);
	memcpy(md5_ctx->state, ccdigest_state_ccn(di, di_ctx), di->state_size);
}

/* Copy a legacy MD5 context into a ccdigest ctx  */
static void MD5ToDi(const struct ccdigest_info *di, MD5_CTX *md5_ctx, struct ccdigest_ctx *di_ctx)
{
	uint64_t count = getCount(md5_ctx);
	
	ccdigest_num(di, di_ctx)=count%di->block_size;
	ccdigest_nbits(di, di_ctx)=(count-ccdigest_num(di, di_ctx))*8;
	memcpy(ccdigest_data(di, di_ctx), md5_ctx->buffer, di->block_size);
	memcpy(ccdigest_state_ccn(di, di_ctx), md5_ctx->state, di->state_size);	
}

void MD5Init(MD5_CTX *ctx)
{
	const struct ccdigest_info *di=g_crypto_funcs->ccmd5_di;
	ccdigest_di_decl(di, di_ctx);
	
	g_crypto_funcs->ccdigest_init_fn(di, di_ctx);
	
	DiToMD5(di, di_ctx, ctx);
}

void MD5Update(MD5_CTX *ctx, const void *data, unsigned int len)
{
	const struct ccdigest_info *di=g_crypto_funcs->ccmd5_di;
	ccdigest_di_decl(di, di_ctx);
	
	MD5ToDi(di, ctx, di_ctx);
	g_crypto_funcs->ccdigest_update_fn(di, di_ctx, len, data);	
	DiToMD5(di, di_ctx, ctx);
}

void MD5Final(unsigned char digest[MD5_DIGEST_LENGTH], MD5_CTX *ctx)
{
	const struct ccdigest_info *di=g_crypto_funcs->ccmd5_di;
	ccdigest_di_decl(di, di_ctx);
	
	MD5ToDi(di, ctx, di_ctx);
	ccdigest_final(di, di_ctx, digest);
}