add nfc binding

Change-Id: I1ebf8e803436430490201db533c2a5a04c04295e
Signed-off-by: Loïc Collignon <loic.collignon@iot.bzh>

7 files changed, 656 insertions, 0 deletions

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
new file mode 100644
index 0000000..0c9021c
--- /dev/null
+++ b/src/CMakeLists.txt
@@ -0,0 +1,44 @@
+###########################################################################
+# Copyright 2015, 2016, 2017 IoT.bzh
+#
+# author: Loïc Collignon <loic.collignon@iot.bzh>
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+###########################################################################
+
+CMAKE_MINIMUM_REQUIRED(VERSION 3.3)
+
+PROJECT_TARGET_ADD(nfc-binding)
+
+set(NFC_BINDING_SOURCES api.c nfc-binding.c)
+
+if (USE_LIBNFC)
+	set(NFC_BINDING_SOURCES ${NFC_BINDING_SOURCES} libnfc_reader.c)
+	add_definitions(-DUSE_LIBNFC=1)
+endif()
+message(STATUS "libnfc enabled: ${USE_LIBNFC}")
+
+add_library(${TARGET_NAME} MODULE ${NFC_BINDING_SOURCES})
+target_link_libraries(${TARGET_NAME} ${link_libraries})
+
+add_custom_command(TARGET ${TARGET_NAME}
+	PRE_BUILD
+	COMMAND mkdir -p ${CMAKE_CURRENT_BINARY_DIR}/../package/htdocs
+	COMMAND cp -rv ${CMAKE_CURRENT_SOURCE_DIR}/../htdocs ${CMAKE_CURRENT_BINARY_DIR}/../package/)
+
+SET_TARGET_PROPERTIES(${TARGET_NAME} PROPERTIES
+	PREFIX "afb-"
+	LABELS "BINDING"
+	LINK_FLAGS ${BINDINGS_LINK_FLAG}
+	OUTPUT_NAME ${TARGET_NAME})
+	
diff --git a/src/api.c b/src/api.c
new file mode 100644
index 0000000..e508e86
--- /dev/null
+++ b/src/api.c
@@ -0,0 +1,63 @@
+#include "nfc-binding.h"
+
+/*
+static const struct afb_auth nfc_auths[] = {
+};
+*/
+
+static const struct afb_verb_v2 nfc_verbs[] = {
+	{
+		.verb = "subscribe",
+		.callback = verb_subscribe,
+		.auth = NULL,
+		.info = NULL,
+		.session = AFB_SESSION_NONE_V2
+	},
+	{
+		.verb = "unsubscribe",
+		.callback = verb_unsubscribe,
+		.auth = NULL,
+		.info = NULL,
+		.session = AFB_SESSION_NONE_V2
+	},
+	{
+		.verb = "list-devices",
+		.callback = verb_list_devices,
+		.auth = NULL,
+		.info = NULL,
+		.session = AFB_SESSION_NONE_V2
+	},
+	{
+		.verb = "list-devices-capabilities",
+		.callback = verb_list_devices_capabilities,
+		.auth = NULL,
+		.info = NULL,
+		.session = AFB_SESSION_NONE_V2
+	},
+	{
+		.verb = "start-polling",
+		.callback = verb_start_polling,
+		.auth = NULL,
+		.info = NULL,
+		.session = AFB_SESSION_NONE_V2
+	},	
+	{
+		.verb = "stop-polling",
+		.callback = verb_stop_polling,
+		.auth = NULL,
+		.info = NULL,
+		.session = AFB_SESSION_NONE_V2
+	},
+	{ .verb = NULL }
+};
+
+const struct afb_binding afbBindingV2 = {
+	.api = "nfc",
+	.specification = NULL,
+	.info = NULL,
+	.verbs = nfc_verbs,
+	.preinit = NULL,
+	.init = init,
+	.onevent = NULL,
+	.noconcurrency = 0
+};
diff --git a/src/libnfc_reader.c b/src/libnfc_reader.c
new file mode 100644
index 0000000..8b11f0c
--- /dev/null
+++ b/src/libnfc_reader.c
@@ -0,0 +1,366 @@
+#include "nfc-binding.h"
+
+#include <string.h>
+#include <sys/types.h>
+#include <pthread.h>
+
+// FIXME: It compile without these lines, but KDevelop complains about pthread_t being undeclared.
+#ifndef _BITS_PTHREADTYPES
+typedef unsigned long int pthread_t;
+#endif
+
+#include <nfc/nfc.h>
+#include "libnfc_reader.h"
+#include "stringutils.h"
+
+extern struct afb_event on_nfc_read_event;
+
+#define MAX_NFC_DEVICE_COUNT	8
+#define MAX_NFC_MODULATIONS		8
+#define MAX_NFC_BAUDRATES 		8
+#define POLL_NUMBER				0xff
+#define POLL_PERIOD				0x05
+
+typedef struct libnfc_device_tag
+{
+	pthread_t			poller;
+	nfc_device*			device;
+	nfc_connstring		name;
+	
+	nfc_modulation*		modulations;
+	size_t				modulations_count;
+} libnfc_device;
+
+typedef struct libnfc_context_tag
+{
+	nfc_context*		context;
+	libnfc_device*		devices;
+	size_t				devices_count;
+} libnfc_context;
+
+static libnfc_context libnfc = {
+	.context			= NULL,
+	.devices			= NULL,
+	.devices_count		= 0
+};
+
+void libnfc_polling_error(int code)
+{
+	switch(code)
+	{
+	case NFC_EIO:
+		AFB_ERROR("libnfc: polling failed with NFC_EIO (%d) code: Input / output error, device may not be usable anymore without re-open it!", code);
+		break;
+	case NFC_EINVARG:
+		AFB_ERROR("libnfc: polling failed with NFC_EINVARG (%d) code: Invalid argument(s)!", code);
+		break;
+	case NFC_EDEVNOTSUPP:
+		AFB_ERROR("libnfc: polling failed with NFC_EDEVNOTSUPP (%d) code: Operation not supported by device!", code);
+		break;
+	case NFC_ENOTSUCHDEV:
+		AFB_ERROR("libnfc: polling failed with NFC_ENOTSUCHDEV (%d) code: No such device!", code);
+		break;
+	case NFC_EOVFLOW:
+		AFB_ERROR("libnfc: polling failed with NFC_EOVFLOW (%d) code: Buffer overflow!", code);
+		break;
+	case NFC_ETIMEOUT:
+		AFB_ERROR("libnfc: polling failed with NFC_ETIMEOUT (%d) code: Operation timed out!", code);
+		break;
+	case NFC_EOPABORTED:
+		AFB_ERROR("libnfc: polling failed with NFC_EOPABORTED (%d) code: Operation aborted (by user)!", code);
+		break;
+	case NFC_ENOTIMPL:
+		AFB_ERROR("libnfc: polling failed with NFC_ENOTIMPL (%d) code: Not (yet) implemented!", code);
+		break;
+	case NFC_ETGRELEASED:
+		AFB_ERROR("libnfc: polling failed with NFC_ETGRELEASED (%d) code: Target released!", code);
+		break;
+	case NFC_ERFTRANS:
+		AFB_ERROR("libnfc: polling failed with NFC_ERFTRANS (%d) code: Error while RF transmission!", code);
+		break;
+	case NFC_EMFCAUTHFAIL:
+		AFB_ERROR("libnfc: polling failed with NFC_EMFCAUTHFAIL (%d) code: MIFARE Classic: authentication failed!", code);
+		break;
+	case NFC_ESOFT:
+		AFB_ERROR("libnfc: polling failed with NFC_ESOFT (%d) code: Software error (allocation, file/pipe creation, etc.)!", code);
+		break;
+	case NFC_ECHIP:
+		AFB_ERROR("libnfc: polling failed with NFC_ECHIP (%d) code: Device's internal chip error!", code);
+		break;
+	default:
+		AFB_ERROR("libnfc: polling failed with unknown code: %d!", code);
+		break;
+	}
+}
+
+void* libnfc_reader_main(void* arg)
+{
+	libnfc_device* device;
+	nfc_target nt;
+	int polled_target_count;
+	
+	// Read datas
+	const char* mt;
+	char* field1;
+	char* field2;
+	char* field3;
+	char* field4;
+	struct json_object* result;
+	
+	device = (libnfc_device*)arg;
+	
+	while(device->device)
+	{
+		polled_target_count = nfc_initiator_poll_target(device->device, device->modulations, device->modulations_count, POLL_NUMBER, POLL_PERIOD, &nt);
+		switch(polled_target_count)
+		{
+			case 0:
+				AFB_INFO("libnfc: polling done with no result.");
+				break;
+				
+			case 1:
+				mt = str_nfc_modulation_type(nt.nm.nmt);
+				AFB_NOTICE("libnfc: polling done with one result of type %s.", mt);
+				switch(nt.nm.nmt)
+				{
+					case NMT_ISO14443A:
+						field1 = to_hex_string(nt.nti.nai.abtAtqa, 2);
+						field2 = to_hex_string(&nt.nti.nai.btSak, 1);
+						field3 = to_hex_string(nt.nti.nai.abtUid, nt.nti.nai.szUidLen);
+						field4 = to_hex_string(nt.nti.nai.abtAts, nt.nti.nai.szAtsLen);
+						
+						result = json_object_new_object();
+						json_object_object_add(result, "Type", json_object_new_string(mt));
+						if (field1) json_object_object_add(result, "ATQA", json_object_new_string(field1));
+						if (field2) json_object_object_add(result, "SAK", json_object_new_string(field2));
+						if (field3) json_object_object_add(result, "UID", json_object_new_string(field3));
+						if (field4) json_object_object_add(result, "ATS", json_object_new_string(field4));
+						
+						break;
+					case NMT_ISO14443B:
+						field1 = to_hex_string(nt.nti.nbi.abtPupi, 4);
+						field2 = to_hex_string(nt.nti.nbi.abtApplicationData, 4);
+						field3 = to_hex_string(nt.nti.nbi.abtProtocolInfo, 3);
+						field4 = to_hex_string(&nt.nti.nbi.ui8CardIdentifier, 1);
+						
+						result = json_object_new_object();
+						json_object_object_add(result, "Type", json_object_new_string(mt));
+						if (field1) json_object_object_add(result, "PUPI", json_object_new_string(field1));
+						if (field2) json_object_object_add(result, "Application Data", json_object_new_string(field2));
+						if (field3)json_object_object_add(result, "Protocol Info", json_object_new_string(field3));
+						if (field4)json_object_object_add(result, "Card Id", json_object_new_string(field4));
+						
+						break;
+					default:
+						AFB_WARNING("libnfc: unsupported modulation type: %s.", mt);
+						break;
+				}
+				
+				if (result)
+				{
+					AFB_NOTICE("libnfc: push tag read event=%s", json_object_to_json_string(result));
+					afb_event_push(on_nfc_read_event, result);
+				}
+				if (field1) free(field1);
+				if (field2) free(field2);
+				if (field3) free(field3);
+				if (field4) free(field4);
+				
+				break;
+				
+			default:
+				if (polled_target_count < 0)
+					libnfc_polling_error(polled_target_count);
+				else
+					AFB_WARNING("libnfc: polling done with unsupported result count: %d.", polled_target_count);
+				break;
+		}
+	}
+
+	return NULL;
+}
+
+/// @brief Start the libnfc context.
+/// @return An exit code, @c EXIT_LIBNFC_SUCCESS (zero) on success.
+int libnfc_init()
+{
+	nfc_device* dev;
+	nfc_connstring connstrings[MAX_NFC_DEVICE_COUNT];
+	const nfc_modulation_type* modulations;
+	const nfc_baud_rate* baudrates;
+	size_t ref_device_count;
+	size_t device_idx;
+	size_t modulation_idx;
+	
+	nfc_init(&libnfc.context);
+	if (libnfc.context == NULL)
+	{
+		AFB_ERROR("[libnfc] Initialization failed (malloc)!");
+		return EXIT_LIBNFC_NOT_INITIALIZED;
+	}
+	
+	AFB_NOTICE("[libnfc] Using libnfc version: %s.", nfc_version());
+	
+	// Find and register devices
+	ref_device_count = nfc_list_devices(libnfc.context, connstrings, MAX_NFC_DEVICE_COUNT);
+	if (!ref_device_count)
+	{
+		AFB_ERROR("libnfc: No NFC device found!");
+		return EXIT_LIBNFC_NO_DEVICE_FOUND;
+	}
+	libnfc.devices_count = ref_device_count;
+	libnfc.devices = malloc(sizeof(libnfc_device) * libnfc.devices_count);
+	memset(libnfc.devices, 0, sizeof(libnfc_device) * libnfc.devices_count);
+	
+	for(device_idx = 0; device_idx < ref_device_count; ++device_idx)
+	{
+		AFB_NOTICE("libnfc: NFC Device found: \"%s\".", connstrings[device_idx]);
+		strcpy(libnfc.devices[device_idx].name, connstrings[device_idx]);
+		
+		// Find and register modulations
+		dev = nfc_open(libnfc.context, connstrings[device_idx]);
+		if (dev)
+		{
+			if (nfc_device_get_supported_modulation(dev, N_INITIATOR, &modulations))
+			{
+				AFB_ERROR("libnfc: Failed to get supported modulations from '%s'!", connstrings[device_idx]);
+			}
+			else
+			{
+				// Find and register modulations
+				modulation_idx = 0;
+				while(modulations[modulation_idx]) ++modulation_idx;
+				libnfc.devices[device_idx].modulations_count = modulation_idx;
+				if (modulation_idx)
+				{
+					libnfc.devices[device_idx].modulations = malloc(sizeof(nfc_modulation) * modulation_idx);
+					memset(libnfc.devices[device_idx].modulations, 0, sizeof(nfc_modulation) * modulation_idx);
+					
+					modulation_idx = 0;
+					while(modulations[modulation_idx])
+					{
+						libnfc.devices[device_idx].modulations[modulation_idx].nmt = modulations[modulation_idx];
+						if (!nfc_device_get_supported_baud_rate(dev, modulations[modulation_idx], &baudrates))
+						{
+							 // Keep only the first speed which is supposed to be the fastest
+							libnfc.devices[device_idx].modulations[modulation_idx].nbr = baudrates[0];
+						}
+						
+						AFB_NOTICE("libnfc:    - Modulation '%s' supported at '%s'."
+							, str_nfc_modulation_type(libnfc.devices[device_idx].modulations[modulation_idx].nmt)
+							, str_nfc_baud_rate(libnfc.devices[device_idx].modulations[modulation_idx].nbr));
+						++modulation_idx;
+					}
+				}
+			}
+			nfc_close(dev);
+		}
+	}
+	
+	return EXIT_LIBNFC_SUCCESS;
+}
+
+/// @brief List devices founds by libnfc.
+/// @param[in] result A json object array into which found devices are added.
+/// @return An exit code, @c EXIT_LIBNFC_SUCCESS (zero) on success.
+int libnfc_list_devices(struct json_object* result)
+{
+	struct json_object* device;
+	size_t i;
+	
+	for(i = 0; i < libnfc.devices_count; ++i)
+	{
+		device = json_object_new_object();
+		json_object_object_add(device, "source", json_object_new_string("libnfc"));
+		json_object_object_add(device, "name", json_object_new_string(libnfc.devices[i].name));
+		json_object_array_add(result, device);
+	}
+	
+	return EXIT_LIBNFC_SUCCESS;
+}
+
+int libnfc_list_devices_capabilities(struct json_object* result, struct json_object* devices)
+{
+	struct json_object* device;
+	struct json_object* mods;
+	struct json_object* mod;
+	size_t i, j;
+	
+	for(i = 0; i < libnfc.devices_count; ++i)
+	{
+		device = json_object_new_object();
+		json_object_object_add(device, "source", json_object_new_string("libnfc"));
+		json_object_object_add(device, "name", json_object_new_string(libnfc.devices[i].name));
+		mods = json_object_new_array();
+		
+		for(j = 0; j < libnfc.devices[i].modulations_count; ++j)
+		{
+			mod = json_object_new_object();
+			json_object_object_add(mod, "modulation", json_object_new_string(str_nfc_modulation_type(libnfc.devices[i].modulations[j].nmt)));
+			json_object_object_add(mod, "baudrate", json_object_new_string(str_nfc_baud_rate(libnfc.devices[i].modulations[j].nbr)));
+			json_object_array_add(mods, mod);
+		}
+		
+		json_object_object_add(device, "modulations", mods);
+		json_object_array_add(result, device);
+	}
+	
+	return EXIT_LIBNFC_SUCCESS;
+}
+
+int libnfc_start_polling(struct json_object* result, struct json_object* devices)
+{
+	struct json_object* device;
+	size_t i;
+	int r;
+	
+	for(i = 0; i < libnfc.devices_count; ++i)
+	{
+		device = json_object_new_object();
+		json_object_object_add(device, "source", json_object_new_string("libnfc"));
+		json_object_object_add(device, "name", json_object_new_string(libnfc.devices[i].name));
+		if (libnfc.devices[i].device)
+		{
+			json_object_object_add(device, "status", json_object_new_string("already polling"));
+			AFB_NOTICE("libnfc: Device '%s' is already polling.", libnfc.devices[i].name);
+		}
+		else
+		{
+			libnfc.devices[i].device = nfc_open(libnfc.context, libnfc.devices[i].name);
+			if (libnfc.devices[i].device)
+			{
+				if (nfc_initiator_init(libnfc.devices[i].device) < 0)
+				{
+					nfc_close(libnfc.devices[i].device);
+					libnfc.devices[i].device = NULL;
+					json_object_object_add(device, "status", json_object_new_string("failed to set initiator mode"));
+					AFB_ERROR("libnfc: nfc_initiator_init failedfor device '%s'!", libnfc.devices[i].name);
+				}
+				else
+				{
+					r = pthread_create(&libnfc.devices[i].poller, NULL, libnfc_reader_main, (void*)&libnfc.devices[i]);
+					if (r)
+					{
+						nfc_close(libnfc.devices[i].device);
+						libnfc.devices[i].device = NULL;
+						json_object_object_add(device, "status", json_object_new_string("failed to create the polling thread"));
+						AFB_ERROR("libnfc: pthread_create failed!");
+					}
+					else
+					{
+						json_object_object_add(device, "status", json_object_new_string("polling"));
+						AFB_NOTICE("libnfc: Polling the device '%s'.", libnfc.devices[i].name);
+					}
+				}
+			}
+			else
+			{
+				json_object_object_add(device, "status", json_object_new_string("failed to open device"));
+				AFB_ERROR("libnfc: Failed to open device '%s'!", libnfc.devices[i].name);
+			}
+		}
+		json_object_array_add(result, device);
+	}
+	
+	return EXIT_LIBNFC_SUCCESS;
+}
diff --git a/src/libnfc_reader.h b/src/libnfc_reader.h
new file mode 100644
index 0000000..1209fda
--- /dev/null
+++ b/src/libnfc_reader.h
@@ -0,0 +1,12 @@
+#pragma once
+
+#include <json-c/json.h>
+
+#define EXIT_LIBNFC_SUCCESS				0
+#define EXIT_LIBNFC_NOT_INITIALIZED		1
+#define EXIT_LIBNFC_NO_DEVICE_FOUND		2
+
+int libnfc_init();
+int libnfc_list_devices(struct json_object* result);
+int libnfc_list_devices_capabilities(struct json_object* result, struct json_object* devices);
+int libnfc_start_polling(struct json_object* result, struct json_object* devices);
diff --git a/src/nfc-binding.c b/src/nfc-binding.c
new file mode 100644
index 0000000..3d96cbb
--- /dev/null
+++ b/src/nfc-binding.c
@@ -0,0 +1,113 @@
+#include "nfc-binding.h"
+
+#if USE_LIBNFC == 1
+#include "libnfc_reader.h"
+#endif
+
+struct afb_event on_nfc_read_event;
+
+/// @brief Binding's initialization.
+/// @return Exit code, zero on success, non-zero otherwise.
+int init()
+{
+	on_nfc_read_event = afb_daemon_make_event("on-nfc-read");
+	if (!afb_event_is_valid(on_nfc_read_event))
+	{
+		AFB_ERROR("Failed to create a valid event!");
+		return 1;
+	}
+	
+#if USE_LIBNFC == 1
+	if (libnfc_init())
+	{
+		AFB_ERROR("Failed start libnfc reader!");
+		return 2;
+	}
+#endif
+	
+	return 0;
+}
+
+/// @brief Get a list of devices.
+/// @param[in] req The query.
+void verb_subscribe(struct afb_req req)
+{
+	if (afb_req_subscribe(req, on_nfc_read_event)) afb_req_fail(req, NULL, "Subscription failure!");
+	else afb_req_success(req, NULL, "Subscription success!");
+}
+
+/// @brief Get a list of devices.
+/// @param[in] req The query.
+void verb_unsubscribe(struct afb_req req)
+{
+	if (afb_req_unsubscribe(req, on_nfc_read_event)) afb_req_fail(req, NULL, "Unsubscription failure!");
+	else afb_req_success(req, NULL, "Unsubscription success!");
+}
+
+/// @brief Get a list of devices.
+/// @param[in] req The query.
+void verb_list_devices(struct afb_req req)
+{
+	struct json_object* result;
+	
+	result = json_object_new_array();
+
+#if USE_LIBNFC == 1
+	if (libnfc_list_devices(result))
+	{
+		afb_req_fail(req, "Failed to get devices list from libnfc!", NULL);
+		return;
+	}
+#endif
+	
+	afb_req_success(req, result, NULL);
+}
+
+/// @brief Get a list of devices capabilities.
+/// @param[in] req The query.
+void verb_list_devices_capabilities(struct afb_req req)
+{
+	struct json_object* result;
+	struct json_object* arg;
+	
+	arg = afb_req_json(req);
+	
+	result = json_object_new_array();
+
+#if USE_LIBNFC == 1
+	if (libnfc_list_devices_capabilities(result, arg))
+	{
+		afb_req_fail(req, "Failed to get devices list from libnfc!", NULL);
+		return;
+	}
+#endif
+	
+	afb_req_success(req, result, NULL);
+}
+
+/// @brief Start polling.
+/// @param[in] req The query.
+void verb_start_polling(struct afb_req req)
+{
+	struct json_object* result;
+	struct json_object* arg;
+	
+	arg = afb_req_json(req);
+	
+	result = json_object_new_array();
+
+#if USE_LIBNFC == 1
+	if (libnfc_start_polling(result, arg))
+	{
+		afb_req_fail(req, "Failed to get devices list from libnfc!", NULL);
+		return;
+	}
+#endif
+	
+	afb_req_success(req, result, NULL);
+}
+
+void verb_stop_polling(struct afb_req req)
+{
+	afb_req_fail(req, "Not implemented yet!", NULL);
+}
diff --git a/src/nfc-binding.h b/src/nfc-binding.h
new file mode 100644
index 0000000..a4fcfb4
--- /dev/null
+++ b/src/nfc-binding.h
@@ -0,0 +1,17 @@
+#pragma once
+
+#include <json-c/json.h>
+
+#define AFB_BINDING_VERSION 2
+#include <afb/afb-binding.h>
+
+// Initializations
+int init();
+
+// Verbs
+void verb_subscribe(struct afb_req req);
+void verb_unsubscribe(struct afb_req req);
+void verb_list_devices(struct afb_req req);
+void verb_list_devices_capabilities(struct afb_req req);
+void verb_start_polling(struct afb_req req);
+void verb_stop_polling(struct afb_req req);
diff --git a/src/stringutils.h b/src/stringutils.h
new file mode 100644
index 0000000..824d09d
--- /dev/null
+++ b/src/stringutils.h
@@ -0,0 +1,41 @@
+#pragma once
+
+#include <stdlib.h>
+
+/**
+ * @brief Get a hexadecimal string representation from memory buffer.
+ * @param[in] src Buffer's pointer.
+ * @param[in] sz Buffer's size.
+ * @return A pointer to the result string. Caller is responsible for the result lifetime.
+ */
+static inline char* to_hex_string(const void* src, long unsigned int sz)
+{
+	static const char lookup[] =
+	{
+		'0', '1', '2', '3',
+		'4', '5', '6', '7',
+		'8', '9', 'a', 'b',
+		'c', 'd', 'e', 'f'
+	};
+
+	const char* source;
+	char* result;
+	long unsigned int i;
+
+	result = NULL;
+	if (src && sz)
+	{
+		source = (const char*)src;
+		result = (char*)malloc(sz * 2 + 1);
+		if (result)
+		{
+			result[sz * 2] = 0;
+			for (i = 0; i < sz; ++i)
+			{
+				result[i * 2] = lookup[(source[i] & 0xf0) >> 4];
+				result[i * 2 + 1] = lookup[source[i] & 0x0f];
+			}
+		}
+	}
+	return result;
+}