pager_flex_parse.cc

这是用python语言写的一个数字广播的信号处理工具包。利用它

/*
 * Copyright 2004,2006,2007 Free Software Foundation, Inc.
 * 
 * This file is part of GNU Radio
 * 
 * GNU Radio 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, or (at your option)
 * any later version.
 * 
 * GNU Radio 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 GNU Radio; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street,
 * Boston, MA 02110-1301, USA.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <pager_flex_parse.h>
#include <pageri_bch3221.h>
#include <gr_io_signature.h>
#include <ctype.h>
#include <iostream>
#include <iomanip>

pager_flex_parse_sptr pager_make_flex_parse(gr_msg_queue_sptr queue, float freq)
{
    return pager_flex_parse_sptr(new pager_flex_parse(queue, freq));
}

pager_flex_parse::pager_flex_parse(gr_msg_queue_sptr queue, float freq) :
    gr_sync_block("flex_parse",
    gr_make_io_signature(1, 1, sizeof(gr_int32)),
    gr_make_io_signature(0, 0, 0)),
    d_queue(queue),
    d_freq(freq)
{
    d_count = 0;
}

int pager_flex_parse::work(int noutput_items,
    gr_vector_const_void_star &input_items,
    gr_vector_void_star &output_items)
{
    const gr_int32 *in = (const gr_int32 *)input_items[0];
    
    int i = 0;
    while (i < noutput_items) {
	// Accumulate one whole frame's worth of data words (88 of them)
	d_datawords[d_count] = *in++; i++;
	if (++d_count == 88) {
	    parse_data();
	    d_count = 0;
	}
    }

    return i;
}

/* FLEX data frames (that is, 88 data words per phase recovered after sync,
   symbol decoding, dephasing, deinterleaving, error correction, and conversion
   from codewords to data words) start with a block information word containing
   indices of the page address field and page vector fields.
*/

void pager_flex_parse::parse_capcode(gr_int32 aw1, gr_int32 aw2)
{
    d_laddr = (aw1 < 0x008001L) ||
              (aw1 > 0x1E0000L) ||
	      (aw1 > 0x1E7FFEL);	
    
    if (d_laddr)
        d_capcode = aw1+((aw2^0x001FFFFF)<<15)+0x1F9000;  // Don't ask
    else
        d_capcode = aw1-0x8000;
}

void pager_flex_parse::parse_data()
{
    // Block information word is the first data word in frame
    gr_int32 biw = d_datawords[0];

    // Nothing to see here, please move along
    if (biw == 0 || biw == 0x001FFFFF)
	return;

    // Vector start index is bits 15-10
    // Address start address is bits 9-8, plus one for offset
    int voffset = (biw >> 10) & 0x3f;
    int aoffset = ((biw >> 8) & 0x03) + 1;
    
    //printf("BIW:%08X AW:%02i-%02i\n", biw, aoffset, voffset);

    // Iterate through pages and dispatch to appropriate handler
    for (int i = aoffset; i < voffset; i++) {
	int j = voffset+i-aoffset;		// Start of vector field for address @ i

	if (d_datawords[i] == 0x00000000 ||
	    d_datawords[i] == 0x001FFFFF)
	    continue;				// Idle codewords, invalid address

	parse_capcode(d_datawords[i], d_datawords[i+1]);
        if (d_laddr)
           i++;
                           
        if (d_capcode < 0)			// Invalid address, skip
          continue;        

        // Parse vector information word for address @ offset 'i'
	gr_int32 viw = d_datawords[j];
	d_type = (page_type_t)((viw >> 4) & 0x00000007);
	int mw1 = (viw >> 7) & 0x00000007F;
	int len = (viw >> 14) & 0x0000007F;

	if (is_numeric_page(d_type))
            len &= 0x07;
        int mw2 = mw1+len;
	    
	if (mw1 == 0 && mw2 == 0)
	    continue;				// Invalid VIW

	if (is_tone_page(d_type))
	    mw1 = mw2 = 0;

	if (mw1 > 87 || mw2 > 87)
	    continue;				// Invalid offsets

	d_payload.str("");
	d_payload.setf(std::ios::showpoint);
	d_payload << std::setprecision(6) << std::setw(7)
		  << d_freq/1e6 << FIELD_DELIM 
		  << std::setw(10) << d_capcode << FIELD_DELIM
		  << flex_page_desc[d_type] << FIELD_DELIM;

	if (is_alphanumeric_page(d_type))
	    parse_alphanumeric(mw1, mw2-1, j);
	else if (is_numeric_page(d_type))
	    parse_numeric(mw1, mw2, j);
	else if (is_tone_page(d_type))
	    parse_tone_only();
	else
	    parse_unknown(mw1, mw2);

	gr_message_sptr msg = gr_make_message_from_string(std::string(d_payload.str()));
	d_queue->handle(msg);
    }
}

void pager_flex_parse::parse_alphanumeric(int mw1, int mw2, int j)
{
    int frag;
    bool cont;

    if (!d_laddr) {
	frag = (d_datawords[mw1] >> 11) & 0x03;
	cont = (d_datawords[mw1] >> 10) & 0x01;
	mw1++;
    }
    else {
	frag = (d_datawords[j+1] >> 11) & 0x03;
	cont = (d_datawords[j+1] >> 10) & 0x01;
	mw2--;
    }    

    //d_payload << frag << FIELD_DELIM;
    //d_payload << cont << FIELD_DELIM;

    for (int i = mw1; i <= mw2; i++) {
	gr_int32 dw = d_datawords[i];
	unsigned char ch;
	
	if (i > mw1 || frag != 0x03) {
	    ch = dw & 0x7F;
	    if (ch != 0x03)
		d_payload << ch;
	}
	
	ch = (dw >> 7) & 0x7F;
	if (ch != 0x03)	// Fill
	    d_payload << ch;
	    	
	ch = (dw >> 14) & 0x7F;
	if (ch != 0x03)	// Fill
	    d_payload << ch;
    }
}

void pager_flex_parse::parse_numeric(int mw1, int mw2, int j)
{
    // Get first dataword from message field or from second
    // vector word if long address
    gr_int32 dw;
    if (!d_laddr) {
	dw = d_datawords[mw1];
	mw1++;
	mw2++;
    }
    else {
	dw = d_datawords[j+1];
    }

    unsigned char digit = 0;
    int count = 4;
    if (d_type == FLEX_NUMBERED_NUMERIC)
	count += 10;	// Skip 10 header bits for numbered numeric pages
    else
	count += 2;	// Otherwise skip 2
    
    for (int i = mw1; i <= mw2; i++) {
	for (int k = 0; k < 21; k++) {
	    // Shift LSB from data word into digit
	    digit = (digit >> 1) & 0x0F;
	    if (dw & 0x01)
		digit ^= 0x08;
	    dw >>= 1;
    	    if (--count == 0) {
		if (digit != 0x0C) // Fill
                    d_payload << flex_bcd[digit];
		count = 4;
	    }
	}
	
	dw = d_datawords[i];
    }
}

void pager_flex_parse::parse_tone_only()
{
}

void pager_flex_parse::parse_unknown(int mw1, int mw2)
{
}