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-rw-r--r--quantum/api/api_sysex.c60
-rw-r--r--quantum/config_common.h2
2 files changed, 46 insertions, 16 deletions
diff --git a/quantum/api/api_sysex.c b/quantum/api/api_sysex.c
index a4a554e764..868f854b92 100644
--- a/quantum/api/api_sysex.c
+++ b/quantum/api/api_sysex.c
@@ -1,4 +1,6 @@
#include "api_sysex.h"
+#include "sysex_tools.h"
+#include "print.h"
void send_bytes_sysex(uint8_t message_type, uint8_t data_type, uint8_t * bytes, uint16_t length) {
// SEND_STRING("\nTX: ");
@@ -6,24 +8,50 @@ void send_bytes_sysex(uint8_t message_type, uint8_t data_type, uint8_t * bytes,
// send_byte(bytes[i]);
// SEND_STRING(" ");
// }
- uint8_t * precode = malloc(sizeof(uint8_t) * (length + 2));
- precode[0] = message_type;
- precode[1] = data_type;
- memcpy(precode + 2, bytes, length);
- uint8_t * encoded = malloc(sizeof(uint8_t) * (sysex_encoded_length(length + 2)));
- uint16_t encoded_length = sysex_encode(encoded, precode, length + 2);
- uint8_t * array = malloc(sizeof(uint8_t) * (encoded_length + 5));
- array[0] = 0xF0;
- array[1] = 0x00;
- array[2] = 0x00;
- array[3] = 0x00;
- array[encoded_length + 4] = 0xF7;
- memcpy(array + 4, encoded, encoded_length);
- midi_send_array(&midi_device, encoded_length + 5, array);
+ if (length > API_SYSEX_MAX_SIZE) {
+ xprintf("Sysex msg too big %d %d %d", message_type, data_type, length);
+ return;
+ }
+
+
+ // The buffer size required is calculated as the following
+ // API_SYSEX_MAX_SIZE is the maximum length
+ // In addition to that we have a two byte message header consisting of the message_type and data_type
+ // This has to be encoded with an additional overhead of one byte for every starting 7 bytes
+ // We just add one extra byte in case it's not divisible by 7
+ // Then we have an unencoded header consisting of 4 bytes
+ // Plus a one byte terminator
+ const unsigned message_header = 2;
+ const unsigned unencoded_message = API_SYSEX_MAX_SIZE + message_header;
+ const unsigned encoding_overhead = unencoded_message / 7 + 1;
+ const unsigned encoded_size = unencoded_message + encoding_overhead;
+ const unsigned unencoded_header = 4;
+ const unsigned terminator = 1;
+ const unsigned buffer_size = encoded_size + unencoded_header + terminator;
+ uint8_t buffer[encoded_size + unencoded_header + terminator];
+ // The unencoded header
+ buffer[0] = 0xF0;
+ buffer[1] = 0x00;
+ buffer[2] = 0x00;
+ buffer[3] = 0x00;
+
+ // We copy the message to the end of the array, this way we can do an inplace encoding, using the same
+ // buffer for both input and output
+ const unsigned message_size = length + message_header;
+ uint8_t* unencoded_start = buffer + buffer_size - message_size;
+ uint8_t* ptr = unencoded_start;
+ *(ptr++) = message_type;
+ *(ptr++) = data_type;
+ memcpy(ptr, bytes, length);
+
+ unsigned encoded_length = sysex_encode(buffer + unencoded_header, unencoded_start, message_size);
+ unsigned final_size = unencoded_header + encoded_length + terminator;
+ buffer[final_size - 1] = 0xF7;
+ midi_send_array(&midi_device, final_size, buffer);
// SEND_STRING("\nTD: ");
// for (uint8_t i = 0; i < encoded_length + 5; i++) {
- // send_byte(array[i]);
+ // send_byte(buffer[i]);
// SEND_STRING(" ");
// }
-} \ No newline at end of file
+}
diff --git a/quantum/config_common.h b/quantum/config_common.h
index 17c11faeb6..4bdb2065d9 100644
--- a/quantum/config_common.h
+++ b/quantum/config_common.h
@@ -80,4 +80,6 @@
# endif
#endif
+#define API_SYSEX_MAX_SIZE 32
+
#endif