X-Git-Url: https://git.rvb.name/rtl-433.git/blobdiff_plain/ca13278b24eb61443559bcb61e64627fba3d8823..6d15c6f967221af825cf84e3ed12b96c763b127b:/include/bitbuffer.h

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+/**
+ * Bit buffer
+ * 
+ * A two-dimensional bit buffer consisting of bytes
+ * 
+ * Copyright (C) 2015 Tommy Vestermark
+ * 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 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#ifndef INCLUDE_BITBUFFER_H_
+#define INCLUDE_BITBUFFER_H_
+
+#include <stdint.h>
+
+#define BITBUF_COLS		80		// Number of bytes in a column
+#define BITBUF_ROWS		25
+#define BITBUF_MAX_PRINT_BITS	50	// Maximum number of bits to print (in addition to hex values)
+
+typedef uint8_t bitrow_t[BITBUF_COLS];
+typedef bitrow_t bitarray_t[BITBUF_ROWS];
+
+/// Bit buffer
+typedef struct {
+	uint16_t	num_rows;	// Number of active rows
+	uint16_t	bits_per_row[BITBUF_ROWS];	// Number of active bits per row
+	bitarray_t	bb;			// The actual bits buffer
+} bitbuffer_t;
+
+
+/// Clear the content of the bitbuffer
+void bitbuffer_clear(bitbuffer_t *bits);
+
+/// Add a single bit at the end of the bitbuffer (MSB first)
+void bitbuffer_add_bit(bitbuffer_t *bits, int bit);
+
+/// Add a new row to the bitbuffer
+void bitbuffer_add_row(bitbuffer_t *bits);
+
+/// Extract (potentially unaligned) bytes from the bit buffer. Len is bits.
+void bitbuffer_extract_bytes(bitbuffer_t *bitbuffer, unsigned row,
+			     unsigned pos, uint8_t *out, unsigned len);
+
+/// Invert all bits in the bitbuffer (do not invert the empty bits)
+void bitbuffer_invert(bitbuffer_t *bits);
+
+/// Print the content of the bitbuffer
+void bitbuffer_print(const bitbuffer_t *bits);
+
+// Search the specified row of the bitbuffer, starting from bit 'start', for
+// the pattern provided. Return the location of the first match, or the end
+// of the row if no match is found.
+// The pattern starts in the high bit. For example if searching for 011011
+// the byte pointed to by 'pattern' would be 0xAC. (011011xx).
+unsigned bitbuffer_search(bitbuffer_t *bitbuffer, unsigned row, unsigned start,
+			  const uint8_t *pattern, unsigned pattern_bits_len);
+
+// Manchester decoding from one bitbuffer into another, starting at the
+// specified row and start bit. Decode at most 'max' data bits (i.e. 2*max)
+// bits from the input buffer). Return the bit position in the input row
+// (i.e. returns start + 2*outbuf->bits_per_row[0]).
+unsigned bitbuffer_manchester_decode(bitbuffer_t *inbuf, unsigned row, unsigned start,
+				     bitbuffer_t *outbuf, unsigned max);
+
+// Function to compare bitbuffer rows and count repetitions
+int compare_rows(bitbuffer_t *bits, unsigned row_a, unsigned row_b);
+unsigned count_repeats(bitbuffer_t *bits, unsigned row);
+
+/// Find a repeated row that has a minimum count of bits.
+/// Return the row index or -1.
+int bitbuffer_find_repeated_row(bitbuffer_t *bits, unsigned min_repeats, unsigned min_bits);
+
+
+/// Return a single bit from a bitrow at bit_idx position
+static inline uint8_t bitrow_get_bit(const bitrow_t bitrow, unsigned bit_idx)
+{
+	return bitrow[bit_idx >> 3] >> (7 - (bit_idx & 7)) & 1;
+}
+
+/// Return a single byte from a bitrow at bit_idx position (which may be unaligned)
+static inline uint8_t bitrow_get_byte(const bitrow_t bitrow, unsigned bit_idx)
+{
+	return ((bitrow[(bit_idx >> 3)] << (bit_idx & 7)) |
+			(bitrow[(bit_idx >> 3) + 1] >> (8 - (bit_idx & 7))));
+}
+
+#endif /* INCLUDE_BITBUFFER_H_ */