view dev/efr-sid-insert.c @ 585:3c6bf0d26ee7 default tip

TW-TS-005 reader: fix maximum line length bug TW-TS-005 section 4.1 states: The maximum allowed length of each line is 80 characters, not including the OS-specific newline encoding. The implementation of this line length limit in the TW-TS-005 hex file reader function in the present suite was wrong, such that lines of the full maximum length could not be read. Fix it. Note that this bug affects comment lines too, not just actual RTP payloads. Neither Annex A nor Annex B features an RTP payload format that goes to the maximum of 40 bytes, but if a comment line goes to the maximum allowed length of 80 characters not including the terminating newline, the bug will be triggered, necessitating the present fix.
author Mychaela Falconia <falcon@freecalypso.org>
date Tue, 25 Feb 2025 07:49:28 +0000
parents 3b5958f28a40
children
line wrap: on
line source

/*
 * We need to implement a function that inserts the 95 bit wide SID
 * codeword into the frame, and we would like to do it more efficiently
 * than calling a "set bit" function for each of the 95 bits.  This
 * program will produce a more efficient solution.
 */

#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>

static const uint8_t SID_codeword_bit_idx[95] =
{
     45,  46,  48,  49,  50,  51,  52,  53,  54,  55,
     56,  57,  58,  59,  60,  61,  62,  63,  64,  65,
     66,  67,  68,  94,  95,  96,  98,  99, 100, 101,
    102, 103, 104, 105, 106, 107, 108, 109, 110, 111,
    112, 113, 114, 115, 116, 117, 118, 148, 149, 150,
    151, 152, 153, 154, 155, 156, 157, 158, 159, 160,
    161, 162, 163, 164, 165, 166, 167, 168, 169, 170,
    171, 196, 197, 198, 199, 200, 201, 202, 203, 204,
    205, 206, 207, 208, 209, 212, 213, 214, 215, 216,
    217, 218, 219, 220, 221
};

static void set_bit(uint8_t *frame, unsigned bitnum)
{
	unsigned bytenum = bitnum >> 3;
	unsigned bit_in_byte = 7 - (bitnum & 7);
	unsigned bitmask = 1 << bit_in_byte;

	frame[bytenum] |= bitmask;
}

main(argc, argv)
	char **argv;
{
	uint8_t bytes[31];
	unsigned n;

	memset(bytes, 0, 31);
	for (n = 0; n < 95; n++)
		set_bit(bytes, SID_codeword_bit_idx[n] + 4);
	for (n = 0; n < 31; n++)
		if (bytes[n])
			printf("\tframe[%u] |= 0x%02X;\n", n, bytes[n]);
	exit(0);
}