/*************************************************************************/
/*  hashing_context.cpp                                                  */
/*************************************************************************/
/*                       This file is part of:                           */
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/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md).   */
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#include "hashing_context.h"

#include "core/crypto/crypto_core.h"

Error HashingContext::start(HashType p_type) {
	ERR_FAIL_COND_V(ctx != NULL, ERR_ALREADY_IN_USE);
	_create_ctx(p_type);
	ERR_FAIL_COND_V(ctx == NULL, ERR_UNAVAILABLE);
	switch (type) {
		case HASH_MD5:
			return ((CryptoCore::MD5Context *)ctx)->start();
		case HASH_SHA1:
			return ((CryptoCore::SHA1Context *)ctx)->start();
		case HASH_SHA256:
			return ((CryptoCore::SHA256Context *)ctx)->start();
	}
	return ERR_UNAVAILABLE;
}

Error HashingContext::update(PoolByteArray p_chunk) {
	ERR_FAIL_COND_V(ctx == NULL, ERR_UNCONFIGURED);
	size_t len = p_chunk.size();
	ERR_FAIL_COND_V(len == 0, FAILED);
	PoolByteArray::Read r = p_chunk.read();
	switch (type) {
		case HASH_MD5:
			return ((CryptoCore::MD5Context *)ctx)->update(&r[0], len);
		case HASH_SHA1:
			return ((CryptoCore::SHA1Context *)ctx)->update(&r[0], len);
		case HASH_SHA256:
			return ((CryptoCore::SHA256Context *)ctx)->update(&r[0], len);
	}
	return ERR_UNAVAILABLE;
}

PoolByteArray HashingContext::finish() {
	ERR_FAIL_COND_V(ctx == NULL, PoolByteArray());
	PoolByteArray out;
	Error err = FAILED;
	switch (type) {
		case HASH_MD5:
			out.resize(16);
			err = ((CryptoCore::MD5Context *)ctx)->finish(out.write().ptr());
			break;
		case HASH_SHA1:
			out.resize(20);
			err = ((CryptoCore::SHA1Context *)ctx)->finish(out.write().ptr());
			break;
		case HASH_SHA256:
			out.resize(32);
			err = ((CryptoCore::SHA256Context *)ctx)->finish(out.write().ptr());
			break;
	}
	_delete_ctx();
	ERR_FAIL_COND_V(err != OK, PoolByteArray());
	return out;
}

void HashingContext::_create_ctx(HashType p_type) {
	type = p_type;
	switch (type) {
		case HASH_MD5:
			ctx = memnew(CryptoCore::MD5Context);
			break;
		case HASH_SHA1:
			ctx = memnew(CryptoCore::SHA1Context);
			break;
		case HASH_SHA256:
			ctx = memnew(CryptoCore::SHA256Context);
			break;
		default:
			ctx = NULL;
	}
}

void HashingContext::_delete_ctx() {

	switch (type) {
		case HASH_MD5:
			memdelete((CryptoCore::MD5Context *)ctx);
			break;
		case HASH_SHA1:
			memdelete((CryptoCore::SHA1Context *)ctx);
			break;
		case HASH_SHA256:
			memdelete((CryptoCore::SHA256Context *)ctx);
			break;
	}
	ctx = NULL;
}

void HashingContext::_bind_methods() {
	ClassDB::bind_method(D_METHOD("start", "type"), &HashingContext::start);
	ClassDB::bind_method(D_METHOD("update", "chunk"), &HashingContext::update);
	ClassDB::bind_method(D_METHOD("finish"), &HashingContext::finish);
	BIND_ENUM_CONSTANT(HASH_MD5);
	BIND_ENUM_CONSTANT(HASH_SHA1);
	BIND_ENUM_CONSTANT(HASH_SHA256);
}

HashingContext::HashingContext() {
	ctx = NULL;
}

HashingContext::~HashingContext() {
	if (ctx != NULL)
		_delete_ctx();
}
