lala

3 files changed, 246 insertions, 0 deletions

diff --git a/gsm-tvoid/src/lib/Makefile.am b/gsm-tvoid/src/lib/Makefile.am
index 2d4d7f7..8a84086 100755
--- a/gsm-tvoid/src/lib/Makefile.am
+++ b/gsm-tvoid/src/lib/Makefile.am
@@ -38,6 +38,7 @@ ourlib_LTLIBRARIES = _gsm.la
 
 # These are the source files that go into the shared library
 _gsm_la_SOURCES = 			\
+	fire_crc.			\
 	gsmstack.c			\
 	interleave.c			\
 	conv.c				\
@@ -63,6 +64,7 @@ gsm.cc gsm.py: $(LOCAL_IFILES) $(ALL_IFILES)
 
 # These headers get installed in ${prefix}/include/gnuradio
 grinclude_HEADERS =			\
+	fire_crc.h			\
 	gsm_burst.h			\
 	gsmstack.h			\
 	interleave.h			\
diff --git a/gsm-tvoid/src/lib/fire_crc.c b/gsm-tvoid/src/lib/fire_crc.c
new file mode 100644
index 0000000..ea14bcb
--- /dev/null
+++ b/gsm-tvoid/src/lib/fire_crc.c
@@ -0,0 +1,179 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2005 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 2, 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., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#include "fire_crc.h"
+#include <math.h>
+#include <iostream>
+
+#define REM(x, y)	(x) % (y)
+
+static int FC_syndrome_shift(FC_CTX *ctx, unsigned int bit);
+
+static int
+outit(int *data, int len)
+{
+	for (int i = 0; i < len; i++)
+		printf("%d ", data[i]);
+	printf("\n");
+}
+
+int
+FC_init(FC_CTX *ctx, unsigned int crc_size, unsigned int data_size)
+{
+	ctx->crc_size = crc_size;
+	ctx->data_size = data_size;
+	ctx->syn_start = 0;
+
+	return 0;
+}
+
+int
+FC_check_crc(FC_CTX *ctx, unsigned char *input_bits, unsigned char *control_data)
+{ 
+    int j,error_count = 0, error_index = 0, success_flag = 0, syn_index = 0;
+
+    ctx->syn_start = 0;
+    // reset the syndrome register
+	memset(ctx->syndrome_reg, 0, sizeof ctx->syndrome_reg);
+ //   d_syndrome_reg.clear();
+    //d_syndrome_reg.insert(d_syndrome_reg.begin(),40,0);
+
+    // shift in the data bits
+    //for (unsigned int i=0; i < 1; i++) {
+    for (unsigned int i=0; i < ctx->data_size; i++) {
+        error_count = FC_syndrome_shift(ctx, input_bits[i]);
+        control_data[i] = input_bits[i];
+    }
+
+    // shift in the crc bits
+    for (unsigned int i=0; i < ctx->crc_size; i++) {
+        error_count = FC_syndrome_shift(ctx, 1-input_bits[i+ctx->data_size]);
+    }
+
+    // Find position of error burst
+    if (error_count == 0) {
+        error_index = 0;
+    }
+    else {
+        error_index = 1;
+        error_count = FC_syndrome_shift(ctx, 0);
+        error_index += 1;
+        while (error_index < (ctx->data_size + ctx->crc_size) ) {
+            error_count = FC_syndrome_shift(ctx, 0);
+            error_index += 1;
+            if ( error_count == 0 ) break;
+        }
+    }
+
+    // Test for correctable errors
+    //printf("error_index %d\n",error_index);
+    if (error_index == 224) success_flag = 0;
+    else {
+
+        // correct index depending on the position of the error
+        if (error_index == 0) syn_index = error_index;
+        else syn_index = error_index - 1;
+        
+        // error burst lies within data bits
+        if (error_index < 184) {
+            //printf("error < bit 184,%d\n",error_index);
+            j = error_index;
+            while ( j < (error_index+12) ) {
+                if (j < 184) {
+                    control_data[j] = control_data[j] ^ 
+                       ctx->syndrome_reg[REM(ctx->syn_start+39-j+syn_index,40)];
+                }               
+                else break;
+                j = j + 1;
+            }
+        }
+        else if ( error_index > 212 ) {
+            //printf("error > bit 212,%d\n",error_index);
+            j = 0;
+            while ( j < (error_index - 212) ) {
+                control_data[j] = control_data[j] ^ 
+                      ctx->syndrome_reg[REM(ctx->syn_start+39-j-224+syn_index,40)];
+                j = j + 1;
+            }
+        }
+        // for 183 < error_index < 213 error in parity alone so ignore
+        success_flag = 1;
+    }
+    return success_flag;
+}    
+
+static int 
+FC_syndrome_shift(FC_CTX *ctx, unsigned int bit)
+{
+	int error_count = 0;
+
+	if (ctx->syn_start == 0)
+		ctx->syn_start = 39;
+	else ctx->syn_start -= 1;
+
+	int temp_syndrome_reg[sizeof ctx->syndrome_reg];
+
+	memcpy(temp_syndrome_reg, ctx->syndrome_reg, sizeof temp_syndrome_reg);
+
+    //std::vector<int> temp_syndrome_reg = ctx->syndrome_reg;
+
+    temp_syndrome_reg[REM(ctx->syn_start+3,40)] = 
+                       ctx->syndrome_reg[REM(ctx->syn_start+3,40)] ^
+                       ctx->syndrome_reg[ctx->syn_start];
+    temp_syndrome_reg[REM(ctx->syn_start+17,40)] = 
+                       ctx->syndrome_reg[REM(ctx->syn_start+17,40)] ^
+                       ctx->syndrome_reg[ctx->syn_start];
+    temp_syndrome_reg[REM(ctx->syn_start+23,40)] = 
+                       ctx->syndrome_reg[REM(ctx->syn_start+23,40)] ^
+                       ctx->syndrome_reg[ctx->syn_start];
+    temp_syndrome_reg[REM(ctx->syn_start+26,40)] = 
+                       ctx->syndrome_reg[REM(ctx->syn_start+26,40)] ^
+                       ctx->syndrome_reg[ctx->syn_start];
+
+    temp_syndrome_reg[REM(ctx->syn_start+4,40)] = 
+                       ctx->syndrome_reg[REM(ctx->syn_start+4,40)] ^ bit;
+    temp_syndrome_reg[REM(ctx->syn_start+6,40)] = 
+                       ctx->syndrome_reg[REM(ctx->syn_start+6,40)] ^ bit;
+    temp_syndrome_reg[REM(ctx->syn_start+10,40)] = 
+                       ctx->syndrome_reg[REM(ctx->syn_start+10,40)] ^ bit;
+    temp_syndrome_reg[REM(ctx->syn_start+16,40)] = 
+                       ctx->syndrome_reg[REM(ctx->syn_start+16,40)] ^ bit;
+    temp_syndrome_reg[REM(ctx->syn_start+27,40)] = 
+                       ctx->syndrome_reg[REM(ctx->syn_start+27,40)] ^ bit;
+    temp_syndrome_reg[REM(ctx->syn_start+29,40)] = 
+                       ctx->syndrome_reg[REM(ctx->syn_start+29,40)] ^ bit;
+    temp_syndrome_reg[REM(ctx->syn_start+33,40)] = 
+                       ctx->syndrome_reg[REM(ctx->syn_start+33,40)] ^ bit;
+    temp_syndrome_reg[REM(ctx->syn_start+39,40)] = 
+                       ctx->syndrome_reg[REM(ctx->syn_start+39,40)] ^ bit;
+
+    temp_syndrome_reg[ctx->syn_start] = ctx->syndrome_reg[ctx->syn_start] ^ bit;
+
+	memcpy(ctx->syndrome_reg, temp_syndrome_reg, sizeof ctx->syndrome_reg);
+
+    for (unsigned int i = 0; i < 28; i++) {
+       error_count = error_count + ctx->syndrome_reg[REM(ctx->syn_start+i,40)];
+    }
+    return error_count;
+}
+ 
+
diff --git a/gsm-tvoid/src/lib/fire_crc.h b/gsm-tvoid/src/lib/fire_crc.h
new file mode 100644
index 0000000..91cdee3
--- /dev/null
+++ b/gsm-tvoid/src/lib/fire_crc.h
@@ -0,0 +1,65 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2005 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 2, 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., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+
+#ifndef INCLUDED_FIRE_CRC_H
+#define INCLUDED_FIRE_CRC_H
+
+typedef struct
+{
+	unsigned int crc_size;
+	unsigned int data_size;
+	unsigned int syn_start;
+	int syndrome_reg[40];
+} FC_CTX;
+
+int FC_init(FC_CTX *ctx, unsigned int crc_size, unsigned int data_size);
+int FC_check_crc(FC_CTX *ctx, unsigned char *input_bits, unsigned char *control_data);
+
+#if 0
+/*!
+ * \brief 
+ * \ingroup 
+ */
+
+class fire_crc 
+{
+protected:
+ 
+  unsigned int d_crc_size;
+  unsigned int d_data_size;
+  unsigned int d_syn_start;
+  std::vector<int> d_syndrome_reg;
+
+public:
+
+  fire_crc (unsigned int crc_size, unsigned int data_size);
+  ~fire_crc (); 
+  int check_crc (const std::vector<int> &input_bits,
+	         std::vector<int> &control_bits);
+  int syndrome_shift (unsigned int bit);
+  int rem (const int x, const int y);
+  
+};
+#endif
+
+#endif