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Diffstat (limited to 'Marlin/src/feature/meatpack.h')
| -rw-r--r-- | Marlin/src/feature/meatpack.h | 123 |
1 files changed, 123 insertions, 0 deletions
diff --git a/Marlin/src/feature/meatpack.h b/Marlin/src/feature/meatpack.h new file mode 100644 index 0000000..2641130 --- /dev/null +++ b/Marlin/src/feature/meatpack.h @@ -0,0 +1,123 @@ +/** + * Marlin 3D Printer Firmware + * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin] + * + * Based on Sprinter and grbl. + * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <https://www.gnu.org/licenses/>. + * + */ + +/* + * MeatPack G-code Compression + * + * Algorithm & Implementation: Scott Mudge - mail@scottmudge.com + * Date: Dec. 2020 + * + * Specifically optimized for 3D printing G-Code, this is a zero-cost data compression method + * which packs ~180-190% more data into the same amount of bytes going to the CNC controller. + * As a majority of G-Code can be represented by a restricted alphabet, I performed histogram + * analysis on a wide variety of 3D printing gcode samples, and found ~93% of all gcode could + * be represented by the same 15-character alphabet. + * + * This allowed me to design a system of packing 2 8-bit characters into a single byte, assuming + * they fall within this limited 15-character alphabet. Using a 4-bit lookup table, these 8-bit + * characters can be represented by a 4-bit index. + * + * Combined with some logic to allow commingling of full-width characters outside of this 15- + * character alphabet (at the cost of an extra 8-bits per full-width character), and by stripping + * out unnecessary comments, the end result is gcode which is roughly half the original size. + * + * Why did I do this? I noticed micro-stuttering and other data-bottleneck issues while printing + * objects with high curvature, especially at high speeds. There is also the issue of the limited + * baud rate provided by Prusa's Atmega2560-based boards, over the USB serial connection. So soft- + * ware like OctoPrint would also suffer this same micro-stuttering and poor print quality issue. + * + */ +#pragma once + +#include <stdint.h> + +/** + * Commands sent to MeatPack to control its behavior. + * They are sent by first sending 2x MeatPack_CommandByte (0xFF) in sequence, + * followed by one of the command bytes below. + * Provided that 0xFF is an exceedingly rare character that is virtually never + * present in G-code naturally, it is safe to assume 2 in sequence should never + * happen naturally, and so it is used as a signal here. + * + * 0xFF *IS* used in "packed" G-code (used to denote that the next 2 characters are + * full-width), however 2 in a row will never occur, as the next 2 bytes will always + * some non-0xFF character. + */ +enum MeatPack_Command : uint8_t { + MPCommand_None = 0, + MPCommand_EnablePacking = 0xFB, + MPCommand_DisablePacking = 0xFA, + MPCommand_ResetAll = 0xF9, + MPCommand_QueryConfig = 0xF8, + MPCommand_EnableNoSpaces = 0xF7, + MPCommand_DisableNoSpaces = 0xF6 +}; + +enum MeatPack_ConfigStateBits : uint8_t { + MPConfig_Bit_Active = 0, + MPConfig_Bit_NoSpaces = 1 +}; + +class MeatPack { +private: + friend class GCodeQueue; + + // Utility definitions + static const uint8_t kCommandByte = 0b11111111, + kFirstNotPacked = 0b00001111, + kSecondNotPacked = 0b11110000, + kFirstCharIsLiteral = 0b00000001, + kSecondCharIsLiteral = 0b00000010; + + static const uint8_t kSpaceCharIdx = 11; + static const char kSpaceCharReplace = 'E'; + + static bool cmd_is_next; // A command is pending + static uint8_t state; // Configuration state + static uint8_t second_char; // Buffers a character if dealing with out-of-sequence pairs + static uint8_t cmd_count, // Counter of command bytes received (need 2) + full_char_count, // Counter for full-width characters to be received + char_out_count; // Stores number of characters to be read out. + static uint8_t char_out_buf[2]; // Output buffer for caching up to 2 characters + + // Pass in a character rx'd by SD card or serial. Automatically parses command/ctrl sequences, + // and will control state internally. + static void handle_rx_char(const uint8_t c, const serial_index_t serial_ind); + + /** + * After passing in rx'd char using above method, call this to get characters out. + * Can return from 0 to 2 characters at once. + * @param out [in] Output pointer for unpacked/processed data. + * @return Number of characters returned. Range from 0 to 2. + */ + static uint8_t get_result_char(char* const __restrict out); + + static void reset_state(); + static void report_state(); + static uint8_t unpacked_char(register const uint8_t in); + static uint8_t unpack_chars(const uint8_t pk, uint8_t* __restrict const chars_out); + static void handle_command(const MeatPack_Command c); + static void handle_output_char(const uint8_t c); + static void handle_rx_char_inner(const uint8_t c); +}; + +extern MeatPack meatpack; |