SubGhz: add protocol MegaCode (#1204)

* SubGhz: add protocol MegaCode
* SubGhz: check for guard time injection at the end of buffer
* SubGhz: rollback samples counting in trasmitter
* SubGhz: fix subghz_file_encoder_worker incorrect pulse sequence
* Input: tune debounce interval
* SubGhz: fix spelling in subghz_file_encoder_worker_add_level_duration

Co-authored-by: Aleksandr Kutuzov <alleteam@gmail.com>

lib/subghz/protocols/megacode.h

@@ -0,0 +1,109 @@
+#pragma once
+
+#include "base.h"
+
+#define SUBGHZ_PROTOCOL_MEGACODE_NAME "MegaCode"
+
+typedef struct SubGhzProtocolDecoderMegaCode SubGhzProtocolDecoderMegaCode;
+typedef struct SubGhzProtocolEncoderMegaCode SubGhzProtocolEncoderMegaCode;
+
+extern const SubGhzProtocolDecoder subghz_protocol_megacode_decoder;
+extern const SubGhzProtocolEncoder subghz_protocol_megacode_encoder;
+extern const SubGhzProtocol subghz_protocol_megacode;
+
+/**
+ * Allocate SubGhzProtocolEncoderMegaCode.
+ * @param environment Pointer to a SubGhzEnvironment instance
+ * @return SubGhzProtocolEncoderMegaCode* pointer to a SubGhzProtocolEncoderMegaCode instance
+ */
+void* subghz_protocol_encoder_megacode_alloc(SubGhzEnvironment* environment);
+
+/**
+ * Free SubGhzProtocolEncoderMegaCode.
+ * @param context Pointer to a SubGhzProtocolEncoderMegaCode instance
+ */
+void subghz_protocol_encoder_megacode_free(void* context);
+
+/**
+ * Deserialize and generating an upload to send.
+ * @param context Pointer to a SubGhzProtocolEncoderMegaCode instance
+ * @param flipper_format Pointer to a FlipperFormat instance
+ * @return true On success
+ */
+bool subghz_protocol_encoder_megacode_deserialize(void* context, FlipperFormat* flipper_format);
+
+/**
+ * Forced transmission stop.
+ * @param context Pointer to a SubGhzProtocolEncoderMegaCode instance
+ */
+void subghz_protocol_encoder_megacode_stop(void* context);
+
+/**
+ * Getting the level and duration of the upload to be loaded into DMA.
+ * @param context Pointer to a SubGhzProtocolEncoderMegaCode instance
+ * @return LevelDuration 
+ */
+LevelDuration subghz_protocol_encoder_megacode_yield(void* context);
+
+/**
+ * Allocate SubGhzProtocolDecoderMegaCode.
+ * @param environment Pointer to a SubGhzEnvironment instance
+ * @return SubGhzProtocolDecoderMegaCode* pointer to a SubGhzProtocolDecoderMegaCode instance
+ */
+void* subghz_protocol_decoder_megacode_alloc(SubGhzEnvironment* environment);
+
+/**
+ * Free SubGhzProtocolDecoderMegaCode.
+ * @param context Pointer to a SubGhzProtocolDecoderMegaCode instance
+ */
+void subghz_protocol_decoder_megacode_free(void* context);
+
+/**
+ * Reset decoder SubGhzProtocolDecoderMegaCode.
+ * @param context Pointer to a SubGhzProtocolDecoderMegaCode instance
+ */
+void subghz_protocol_decoder_megacode_reset(void* context);
+
+/**
+ * Parse a raw sequence of levels and durations received from the air.
+ * @param context Pointer to a SubGhzProtocolDecoderMegaCode instance
+ * @param level Signal level true-high false-low
+ * @param duration Duration of this level in, us
+ */
+void subghz_protocol_decoder_megacode_feed(void* context, bool level, uint32_t duration);
+
+/**
+ * Getting the hash sum of the last randomly received parcel.
+ * @param context Pointer to a SubGhzProtocolDecoderMegaCode instance
+ * @return hash Hash sum
+ */
+uint8_t subghz_protocol_decoder_megacode_get_hash_data(void* context);
+
+/**
+ * Serialize data SubGhzProtocolDecoderMegaCode.
+ * @param context Pointer to a SubGhzProtocolDecoderMegaCode instance
+ * @param flipper_format Pointer to a FlipperFormat instance
+ * @param frequency The frequency at which the signal was received, Hz
+ * @param preset The modulation on which the signal was received, FuriHalSubGhzPreset
+ * @return true On success
+ */
+bool subghz_protocol_decoder_megacode_serialize(
+    void* context,
+    FlipperFormat* flipper_format,
+    uint32_t frequency,
+    FuriHalSubGhzPreset preset);
+
+/**
+ * Deserialize data SubGhzProtocolDecoderMegaCode.
+ * @param context Pointer to a SubGhzProtocolDecoderMegaCode instance
+ * @param flipper_format Pointer to a FlipperFormat instance
+ * @return true On success
+ */
+bool subghz_protocol_decoder_megacode_deserialize(void* context, FlipperFormat* flipper_format);
+
+/**
+ * Getting a textual representation of the received data.
+ * @param context Pointer to a SubGhzProtocolDecoderMegaCode instance
+ * @param output Resulting text
+ */
+void subghz_protocol_decoder_megacode_get_string(void* context, string_t output);