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Diffstat (limited to 'src/test/ao_fec_test.c')
| -rw-r--r-- | src/test/ao_fec_test.c | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/src/test/ao_fec_test.c b/src/test/ao_fec_test.c new file mode 100644 index 00000000..c7509728 --- /dev/null +++ b/src/test/ao_fec_test.c @@ -0,0 +1,198 @@ +/* + * Copyright © 2012 Keith Packard <keithp@keithp.com> + * + * 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; version 2 of the License. + * + * This program 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 this program; if not, write to the Free Software Foundation, Inc., + * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. + */ + +#include <ao_fec.h> +#include <stdlib.h> +#include <stdio.h> +#include <stdlib.h> +#include <math.h> +#include <string.h> + +#ifndef RANDOM_MAX +#define RANDOM_MAX 0x7fffffff +#endif + +static double +rand_real(void) { + return (double) random() / (double) RANDOM_MAX; +} + +static double +gaussian_random(double mean, double dev) +{ + static int save_x_valid = 0; + static double save_x; + double x; + + if (save_x_valid) + { + x = save_x; + save_x_valid = 0; + } + else + { + double w; + double normal_x1, normal_x2; + + do { + normal_x1 = 2 * rand_real () - 1; + normal_x2 = 2 * rand_real () - 1; + w = normal_x1*normal_x1 + normal_x2*normal_x2; + } while (w >= 1 || w < 1E-30); + + w = sqrt(log(w)*(-2./w)); + + /* + * normal_x1 and normal_x2 are independent normally + * distributed variates + */ + + x = normal_x1 * w; + /* save normal_x2 for next call */ + save_x = normal_x2 * w; + save_x_valid = 1; + } + return x * dev + mean; +} + +#define PREPARE_LEN(input_len) ((input_len) + AO_FEC_PREPARE_EXTRA) +#define ENCODE_LEN(input_len) (PREPARE_LEN(input_len) * 2) +#define DECODE_LEN(input_len) ((input_len) + AO_FEC_PREPARE_EXTRA) +#define EXPAND_LEN(input_len) (ENCODE_LEN(input_len) * 8) + +static int +ao_expand(uint8_t *bits, int bits_len, uint8_t *bytes) +{ + int i, bit; + uint8_t b; + + for (i = 0; i < bits_len; i++) { + b = bits[i]; + for (bit = 7; bit >= 0; bit--) + *bytes++ = ((b >> bit) & 1) * 0xff; + } + + return bits_len * 8; +} + +static int +ao_fuzz (uint8_t *in, int in_len, uint8_t *out, double dev) +{ + int i; + int errors = 0; + + for (i = 0; i < in_len; i++) { + double error = gaussian_random(0, dev); + uint8_t byte = in[i]; + + if (error > 0) { + if (error > 0xff) + error = 0xff; + if (error >= 0x80) + errors++; + if (byte < 0x80) + byte += error; + else + byte -= error; + } + out[i] = byte; + } + return errors; +} + +static uint8_t +ao_random_data(uint8_t *out, uint8_t out_len) +{ + uint8_t len = random() % (out_len + 1); + uint8_t i; + + for (i = 0; i < len; i++) + out[i] = random(); + return len; +} + + +int +main(int argc, char **argv) +{ + int trial; + + uint8_t original[120]; + uint8_t original_len; + + uint8_t encode[ENCODE_LEN(sizeof(original))]; + int encode_len; + + uint8_t transmit[EXPAND_LEN(sizeof(original))]; + int transmit_len; + + uint8_t receive[EXPAND_LEN(sizeof(original))]; + int receive_len, receive_errors; + + uint8_t decode[DECODE_LEN(sizeof(original))]; + int decode_len; + + int errors = 0; + int error; + + srandom(0); + for (trial = 0; trial < 10000; trial++) { + + /* Compute some random data */ + original_len = ao_random_data(original, sizeof(original)); + + /* Encode it */ + encode_len = ao_fec_encode(original, original_len, encode); + + /* Expand from 1-bit-per-symbol to 1-byte-per-symbol */ + transmit_len = ao_expand(encode, encode_len, transmit); + + /* Add gaussian noise to the signal */ + receive_errors = ao_fuzz(transmit, transmit_len, receive, 0x30); + receive_len = transmit_len; + + /* Decode it */ + decode_len = ao_fec_decode(receive, receive_len, decode); + + /* Check to see if we received the right data */ + error = 0; + + if (decode_len < original_len + 2) { + printf ("len mis-match\n"); + error++; + } + + if (!ao_fec_check_crc(decode, original_len)) { + printf ("crc mis-match\n"); + error++; + } + + if (memcmp(original, decode, original_len) != 0) { + printf ("data mis-match\n"); + error++; + } + if (error) { + printf ("Errors: %d\n", receive_errors); + ao_fec_dump_bytes(original, original_len, "Input"); + ao_fec_dump_bytes(decode, original_len, "Decode"); + errors += error; + } + } + return errors; +} + + |