1 files changed, 99 insertions, 0 deletions
diff --git a/bootloader/midi/sysex_tools.c b/bootloader/midi/sysex_tools.c
new file mode 100644
index 0000000..2ff8052
--- /dev/null
+++ b/bootloader/midi/sysex_tools.c
@@ -0,0 +1,99 @@
+//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_bit_packed_length(uint16_t unpacked_length){
+   uint8_t remainder = unpacked_length % 7;
+   if (remainder)
+      return (unpacked_length / 7) * 8 + remainder + 1;
+   else
+      return (unpacked_length / 7) * 8;
+}
+
+uint16_t sysex_bit_unpacked_length(uint16_t packed_length){
+   uint8_t remainder = packed_length % 8;
+   if (remainder)
+      return (packed_length / 8) * 7 + remainder - 1;
+   else
+      return (packed_length / 8) * 7;
+}
+
+uint16_t sysex_bit_pack(uint8_t *packed, const uint8_t *source, const uint16_t length){
+   uint16_t packed_full = length / 7; //number of full 8 byte sections from 7 bytes of input
+   uint16_t i,j;
+
+   //fill out the fully packed sections
+   for(i = 0; i < packed_full; i++) {
+      uint16_t packed_msb_idx = i * 8;
+      uint16_t input_start_idx = i * 7;
+      packed[packed_msb_idx] = 0;
+      for(j = 0; j < 7; j++){
+         uint8_t current = source[input_start_idx + j];
+         packed[packed_msb_idx] |= (0x80 & current) >> (1 + j);
+         packed[packed_msb_idx + 1 + j] = 0x7F & current;
+      }
+   }
+
+   //fill out the rest if there is any more
+   uint8_t remainder = length % 7;
+   if (remainder) {
+      uint16_t packed_msb_idx = packed_full * 8;
+      uint16_t input_start_idx = packed_full * 7;
+      packed[packed_msb_idx] = 0;
+      for(j = 0; j < remainder; j++){
+         uint8_t current = source[input_start_idx + j];
+         packed[packed_msb_idx] |= (0x80 & current) >> (1 + j);
+         packed[packed_msb_idx + 1 + j] = 0x7F & current;
+      }
+      return packed_msb_idx + remainder + 1;
+   } else {
+      return packed_full * 8;
+   }
+}
+
+uint16_t sysex_bit_unpack(uint8_t *unpacked, const uint8_t *source, const uint16_t length){
+   uint16_t unpacked_full = length / 8;
+   uint16_t i,j;
+
+   if (length < 2)
+      return 0;
+
+   //fill out the fully packed sections
+   for(i = 0; i < unpacked_full; i++) {
+      uint16_t packed_msb_idx = i * 8;
+      uint16_t output_start_index = i * 7;
+      for(j = 0; j < 7; j++){
+         unpacked[output_start_index + j] = 0x7F & source[packed_msb_idx + j + 1];
+         unpacked[output_start_index + j] |= (0x80 & (source[packed_msb_idx] << (1 + j)));
+      }
+   }
+   uint8_t remainder = length % 8;
+   if (remainder) {
+      uint16_t packed_msb_idx = unpacked_full * 8;
+      uint16_t output_start_index = unpacked_full * 7;
+      for(j = 0; j < (remainder - 1); j++) {
+         unpacked[output_start_index + j] = 0x7F & source[packed_msb_idx + j + 1];
+         unpacked[output_start_index + j] |= (0x80 & (source[packed_msb_idx] << (1 + j)));
+      }
+      return unpacked_full * 7 + remainder - 1;
+   } else {
+      return unpacked_full * 7;
+   }
+}
+