Merge github.com:cnlohr/libsurvive

1 files changed, 256 insertions, 0 deletions

diff --git a/src/ootx_decoder.c b/src/ootx_decoder.c
new file mode 100644
index 0000000..b1815d7
--- /dev/null
+++ b/src/ootx_decoder.c
@@ -0,0 +1,256 @@
+// (C) 2017 Joshua Allen, MIT/x11 License.
+//
+//All MIT/x11 Licensed Code in this file may be relicensed freely under the GPL or LGPL licenses.
+
+/* ootx data decoder */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <zlib.h>
+#include <assert.h>
+#include "ootx_decoder.h"
+//#include "crc32.h"
+
+//char* fmt_str = "L Y HMD %d 5 1 206230 %d\n";
+
+#define MAX_BUFF_SIZE 64
+
+void (*ootx_packet_clbk)(ootx_decoder_context * ctx, ootx_packet* packet) = NULL;
+void (*ootx_bad_crc_clbk)(ootx_decoder_context * ctx, ootx_packet* packet, uint32_t crc) = NULL;
+
+void ootx_pump_bit(ootx_decoder_context *ctx, uint8_t dbit);
+
+void ootx_init_decoder_context(ootx_decoder_context *ctx) {
+	ctx->buf_offset = 0;
+	ctx->bits_written = 0;
+
+	ctx->preamble = 0XFFFFFFFF;
+	ctx->bits_processed = 0;
+	ctx->found_preamble = 0;
+
+	ctx->buffer = (uint8_t*)malloc(MAX_BUFF_SIZE);
+	ctx->payload_size = (uint16_t*)ctx->buffer;
+	*(ctx->payload_size) = 0;
+}
+
+void ootx_free_decoder_context(ootx_decoder_context *ctx) {
+	free(ctx->buffer);
+	ctx->buffer = NULL;
+	ctx->payload_size = NULL;
+}
+
+uint8_t ootx_decode_bit(uint32_t length) {
+	uint8_t t = (length - 2750) / 500; //why 2750?
+//	return ((t & 0x02)>0)?0xFF:0x00; //easier if we need to bitshift right
+	return ((t & 0x02)>>1);
+}
+
+uint8_t ootx_detect_preamble(ootx_decoder_context *ctx, uint8_t dbit) {
+	ctx->preamble <<= 1;
+//	ctx->preamble |= (0x01 & dbit);
+	ctx->preamble |= dbit;
+	if ((ctx->preamble & 0x0003ffff) == 0x00000001) return 1;
+	return 0;
+}
+
+void ootx_reset_buffer(ootx_decoder_context *ctx) {
+	ctx->buf_offset = 0;
+	ctx->buffer[ctx->buf_offset] = 0;
+	ctx->bits_written = 0;
+	*(ctx->payload_size) = 0;
+}
+
+void ootx_inc_buffer_offset(ootx_decoder_context *ctx) {
+	++(ctx->buf_offset);
+
+//	assert(ctx->buf_offset<MAX_BUFF_SIZE);
+
+	/* the buffer is going to overflow, wrap the buffer and don't write more data until the preamble is found again */
+	if(ctx->buf_offset>=MAX_BUFF_SIZE) {
+		ctx->buf_offset = 0;
+		ctx->found_preamble = 0;
+	}
+
+	ctx->buffer[ctx->buf_offset] = 0;
+}
+
+void ootx_write_to_buffer(ootx_decoder_context *ctx, uint8_t dbit) {
+	uint8_t *current_byte = ctx->buffer + ctx->buf_offset;
+
+	*current_byte <<= 1;
+//	*current_byte |= (0x01 & dbit);
+	*current_byte |= dbit;
+
+	++(ctx->bits_written);
+	if (ctx->bits_written>7) {
+		ctx->bits_written=0;
+//		printf("%d\n", *current_byte);
+		ootx_inc_buffer_offset(ctx);
+	}
+}
+
+uint8_t ootx_process_bit(ootx_decoder_context *ctx, uint32_t length) {
+	uint8_t dbit = ootx_decode_bit(length);
+	ootx_pump_bit( ctx, dbit );
+	return dbit;
+}
+
+void ootx_pump_bit(ootx_decoder_context *ctx, uint8_t dbit) {
+//	uint8_t dbit = ootx_decode_bit(length);
+	++(ctx->bits_processed);
+
+	if ( ootx_detect_preamble(ctx, dbit) ) {
+		/*	data stream can start over at any time so we must
+			always look for preamble bits */
+		//printf("Preamble found\n");
+		ootx_reset_buffer(ctx);
+		ctx->bits_processed = 0;
+		ctx->found_preamble = 1;
+	}
+	else if(ctx->bits_processed>16) {
+		//every 17th bit needs to be dropped (sync bit)
+//		printf("drop %d\n", dbit);
+		if( !dbit )
+		{
+			printf("Bad sync bit\n");
+			ootx_reset_buffer(ctx);
+		}
+		ctx->bits_processed = 0;
+	}
+	else if (ctx->found_preamble > 0)
+	{
+		/*	only write to buffer if the preamble is found.
+			if the buffer overflows, found_preamble will be cleared
+			and writing will stop. data would be corrupted, so there is no point in continuing
+		*/
+
+		ootx_write_to_buffer(ctx, dbit);
+
+		uint16_t padded_length = *(ctx->payload_size);
+		padded_length += (padded_length&0x01); //extra null byte if odd
+
+/*		int k;
+		printf( ":" );
+		for( k = 0; k < 36; k++ )
+		{
+			printf( "%02x ", ctx->buffer[k] );
+		}
+		printf( "\n" );*/
+
+		if (ctx->buf_offset >= (padded_length+6)) {
+			/*	once we have a complete ootx packet, send it out in the callback */
+			ootx_packet op;
+
+			op.length = *(ctx->payload_size);
+			op.data = ctx->buffer+2;
+			op.crc32 = *(uint32_t*)(op.data+padded_length);
+
+			uint32_t crc = crc32( 0L, Z_NULL, 0 );
+			crc = crc32( crc, op.data,op.length);
+
+			if (crc != op.crc32) {
+				if (ootx_bad_crc_clbk != NULL) ootx_bad_crc_clbk(ctx, &op,crc);
+			}
+			else if (ootx_packet_clbk != NULL) {
+				ootx_packet_clbk(ctx,&op);
+			}
+
+			ootx_reset_buffer(ctx);
+		}
+	}
+}
+
+uint8_t* get_ptr(uint8_t* data, uint8_t bytes, uint16_t* idx) {
+	uint8_t* x = data + *idx;
+	*idx += bytes;
+	return x;
+}
+
+float _half_to_float(uint8_t* data) {
+	//this will not handle infinity, NaN, or denormalized floats
+
+	uint16_t x = *(uint16_t*)data;
+	float f = 0;
+
+	uint32_t *ftmp = (uint32_t*)&f; //use the allocated floating point memory
+
+	if ((x & 0x7FFF) == 0) return f; //zero
+
+	//sign
+	*ftmp = x & 0x8000;
+	*ftmp <<= 16;
+
+	*ftmp += ((((uint32_t)(x & 0x7fff)) + 0x1c000) << 13);
+
+	return f;
+}
+
+void init_lighthouse_info_v6(lighthouse_info_v6* lhi, uint8_t* data) {
+	uint16_t idx = 0;
+	/*
+	uint16_t fw_version;//Firmware version (bit 15..6), protocol version (bit 5..0)
+	uint32_t id; //Unique identifier of the base station
+	float fcal_0_phase; //"phase" for rotor 0
+	float fcal_1_phase; //"phase" for rotor 1
+	float fcal_0_tilt; //"tilt" for rotor 0
+	float fcal_1_tilt; //"tilt" for rotor 1
+	uint8_t sys_unlock_count; //Lowest 8 bits of the rotor desynchronization counter
+	uint8_t hw_version; //Hardware version
+	float fcal_0_curve; //"curve" for rotor 0
+	float fcal_1_curve; //"curve" for rotor 1
+	int8_t accel_dir_x; //"orientation vector"
+	int8_t accel_dir_y; //"orientation vector"
+	int8_t accel_dir_z; //"orientation vector"
+	float fcal_0_gibphase; //"gibbous phase" for rotor 0 (normalized angle)
+	float fcal_1_gibphase; //"gibbous phase" for rotor 1 (normalized angle)
+	float fcal_0_gibmag; //"gibbous magnitude" for rotor 0
+	float fcal_1_gibmag; //"gibbous magnitude" for rotor 1
+	uint8_t mode_current; //Currently selected mode (default: 0=A, 1=B, 2=C)
+	uint8_t sys_faults; //"fault detect flags" (should be 0)
+	*/
+
+	lhi->fw_version = *(uint16_t*)get_ptr(data,sizeof(uint16_t),&idx);
+	lhi->id = *(uint32_t*)get_ptr(data,sizeof(uint32_t),&idx);
+	lhi->fcal_0_phase = _half_to_float( get_ptr(data,sizeof(uint16_t),&idx) );
+	lhi->fcal_1_phase = _half_to_float( get_ptr(data,sizeof(uint16_t),&idx) );
+	lhi->fcal_0_tilt = _half_to_float( get_ptr(data,sizeof(uint16_t),&idx) );
+	lhi->fcal_1_tilt = _half_to_float( get_ptr(data,sizeof(uint16_t),&idx) );
+	lhi->sys_unlock_count = *get_ptr(data,sizeof(uint8_t),&idx);
+	lhi->hw_version = *get_ptr(data,sizeof(uint8_t),&idx);
+	lhi->fcal_0_curve = _half_to_float( get_ptr(data,sizeof(uint16_t),&idx) );
+	lhi->fcal_1_curve = _half_to_float( get_ptr(data,sizeof(uint16_t),&idx) );
+	lhi->accel_dir_x = *(int8_t*)get_ptr(data,sizeof(uint8_t),&idx);
+	lhi->accel_dir_y = *(int8_t*)get_ptr(data,sizeof(uint8_t),&idx);
+	lhi->accel_dir_z = *(int8_t*)get_ptr(data,sizeof(uint8_t),&idx);
+	lhi->fcal_0_gibphase = _half_to_float( get_ptr(data,sizeof(uint16_t),&idx) );
+	lhi->fcal_1_gibphase = _half_to_float( get_ptr(data,sizeof(uint16_t),&idx) );
+	lhi->fcal_0_gibmag = _half_to_float( get_ptr(data,sizeof(uint16_t),&idx) );
+	lhi->fcal_1_gibmag = _half_to_float( get_ptr(data,sizeof(uint16_t),&idx) );
+	lhi->mode_current = *get_ptr(data,sizeof(uint8_t),&idx);
+	lhi->sys_faults = *get_ptr(data,sizeof(uint8_t),&idx);
+
+}
+
+void print_lighthouse_info_v6(lighthouse_info_v6* lhi) {
+
+	printf("\t%X\n\t%X\n\t%f\n\t%f\n\t%f\n\t%f\n\t%d\n\t%d\n\t%f\n\t%f\n\t%d\n\t%d\n\t%d\n\t%f\n\t%f\n\t%f\n\t%f\n\t%d\n\t%d\n",
+		lhi->fw_version,
+		lhi->id,
+		lhi->fcal_0_phase,
+		lhi->fcal_1_phase,
+		lhi->fcal_0_tilt,
+		lhi->fcal_1_tilt,
+		lhi->sys_unlock_count,
+		lhi->hw_version,
+		lhi->fcal_0_curve,
+		lhi->fcal_1_curve,
+		lhi->accel_dir_x,
+		lhi->accel_dir_y,
+		lhi->accel_dir_z,
+		lhi->fcal_0_gibphase,
+		lhi->fcal_1_gibphase,
+		lhi->fcal_0_gibmag,
+		lhi->fcal_1_gibmag,
+		lhi->mode_current,
+		lhi->sys_faults);
+}