1 files changed, 97 insertions, 0 deletions
diff --git a/quantum/midi/sysex_tools.c b/quantum/midi/sysex_tools.c
new file mode 100644
index 0000000000..c9a9d03285
--- /dev/null
+++ b/quantum/midi/sysex_tools.c
@@ -0,0 +1,97 @@
+// midi for embedded chips,
+// Copyright 2010 Alex Norman
+//
+// This file is part of avr-midi.
+//
+// avr-midi 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.
+//
+// avr-midi 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 avr-midi.  If not, see <http://www.gnu.org/licenses/>.
+
+#include "sysex_tools.h"
+
+uint16_t sysex_encoded_length(uint16_t decoded_length) {
+    uint8_t remainder = decoded_length % 7;
+    if (remainder)
+        return (decoded_length / 7) * 8 + remainder + 1;
+    else
+        return (decoded_length / 7) * 8;
+}
+
+uint16_t sysex_decoded_length(uint16_t encoded_length) {
+    uint8_t remainder = encoded_length % 8;
+    if (remainder)
+        return (encoded_length / 8) * 7 + remainder - 1;
+    else
+        return (encoded_length / 8) * 7;
+}
+
+uint16_t sysex_encode(uint8_t *encoded, const uint8_t *source, const uint16_t length) {
+    uint16_t encoded_full = length / 7; // number of full 8 byte sections from 7 bytes of input
+    uint16_t i, j;
+
+    // fill out the fully encoded sections
+    for (i = 0; i < encoded_full; i++) {
+        uint16_t encoded_msb_idx = i * 8;
+        uint16_t input_start_idx = i * 7;
+        encoded[encoded_msb_idx] = 0;
+        for (j = 0; j < 7; j++) {
+            uint8_t current = source[input_start_idx + j];
+            encoded[encoded_msb_idx] |= (0x80 & current) >> (1 + j);
+            encoded[encoded_msb_idx + 1 + j] = 0x7F & current;
+        }
+    }
+
+    // fill out the rest if there is any more
+    uint8_t remainder = length % 7;
+    if (remainder) {
+        uint16_t encoded_msb_idx = encoded_full * 8;
+        uint16_t input_start_idx = encoded_full * 7;
+        encoded[encoded_msb_idx] = 0;
+        for (j = 0; j < remainder; j++) {
+            uint8_t current = source[input_start_idx + j];
+            encoded[encoded_msb_idx] |= (0x80 & current) >> (1 + j);
+            encoded[encoded_msb_idx + 1 + j] = 0x7F & current;
+        }
+        return encoded_msb_idx + remainder + 1;
+    } else {
+        return encoded_full * 8;
+    }
+}
+
+uint16_t sysex_decode(uint8_t *decoded, const uint8_t *source, const uint16_t length) {
+    uint16_t decoded_full = length / 8;
+    uint16_t i, j;
+
+    if (length < 2) return 0;
+
+    // fill out the fully encoded sections
+    for (i = 0; i < decoded_full; i++) {
+        uint16_t encoded_msb_idx    = i * 8;
+        uint16_t output_start_index = i * 7;
+        for (j = 0; j < 7; j++) {
+            decoded[output_start_index + j] = 0x7F & source[encoded_msb_idx + j + 1];
+            decoded[output_start_index + j] |= (0x80 & (source[encoded_msb_idx] << (1 + j)));
+        }
+    }
+    uint8_t remainder = length % 8;
+    if (remainder) {
+        uint16_t encoded_msb_idx    = decoded_full * 8;
+        uint16_t output_start_index = decoded_full * 7;
+        for (j = 0; j < (remainder - 1); j++) {
+            decoded[output_start_index + j] = 0x7F & source[encoded_msb_idx + j + 1];
+            decoded[output_start_index + j] |= (0x80 & (source[encoded_msb_idx] << (1 + j)));
+        }
+        return decoded_full * 7 + remainder - 1;
+    } else {
+        return decoded_full * 7;
+    }
+}