modified project structure and added logic to main function

Makefile

@@ -0,0 +1,51 @@
+CC := gcc
+CCFLAG := -Wall -O2 -std=c99
+DBGFLAG := -g
+CCOBJFLAG := $(CCFLAG) -c
+
+BIN_PATH := bin
+OBJ_PATH := obj
+SRC_PATH := src
+DBG_PATH := debug
+
+TARGET_NAME := m17enc
+TARGET := $(BIN_PATH)/$(TARGET_NAME)
+TARGET_DEBUG := $(DBG_PATH)/$(TARGET_NAME)
+MAIN_SRC := src/M17_RF_streamgen.c
+
+SRC := $(foreach x, $(SRC_PATH), $(wildcard $(addprefix $(x)/*,.c*)))
+OBJ := $(addprefix $(OBJ_PATH)/, $(addsuffix .o, $(notdir $(basename $(SRC)))))
+OBJ_DEBUG := $(addprefix $(DBG_PATH)/, $(addsuffix .o, $(notdir $(basename $(SRC)))))
+
+DISTCLEAN_LIST := $(OBJ) $(OBJ_DEBUG)
+CLEAN_LIST := $(TARGET) $(TARGET_DEBUG) $(DISTCLEAN_LIST)
+
+default: all
+
+$(TARGET): $(OBJ)
+	$(CC) $(CCFLAG) -o $@ $?
+
+$(OBJ_PATH)/%.o: $(SRC_PATH)/%.c*
+	$(CC) $(CCOBJFLAG) -o $@ $<
+
+$(DBG_PATH)/%.o: $(SRC_PATH)/%.c*
+	$(CC) $(CCOBJFLAG) $(DBGFLAG) -o $@ $<
+
+$(TARGET_DEBUG): $(OBJ_DEBUG)
+	$(CC) $(CCFLAG) $(DBGFLAG) $? -o $@
+
+.PHONY: all
+all: $(TARGET)
+
+.PHONY: debug
+debug: $(TARGET_DEBUG)
+
+.PHONY: clean
+clean:
+	@echo CLEAN $(CLEAN_LIST)
+	@rm -f $(CLEAN_LIST)
+
+.PHONY: distclean
+distclean:
+	@echo CLEAN $(DISTCLEAN_LIST)
+	@rm -f $(DISTCLEAN_LIST)

README.md

@@ -4,3 +4,20 @@ Generates an M17 RF stream for Codec2-encoded speech files ('c2enc' output).
 **M17_RF_streamgen.c** - main program. Just a sketch right now.
 
 **dummy.c** - can generate a pseudorandom bitstream with legitimate sync patterns. This can be used to check receivers.
+
+# Installation
+
+```
+make
+```
+
+# Nomenclature
+
+# Example
+This example records local audio and generates a M17-compliant RF stream into
+a file. Codec2 and SoX need to be installed.
+
+```
+rec -t raw -r 8000 --buffer 2048 -e signed-integer -b 16 -c 1 - | \
+c2enc 3200 - - | m17enc DL1FROM DL1TO - out.raw
+```

src/M17_RF_streamgen.c

@@ -2,6 +2,7 @@
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
+#include <unistd.h>
 
 #define LEAD_PREAM				40				//first (lead) preamble length in ms
 
@@ -39,6 +40,7 @@ uint8_t type_2[500];						//type-2 unpacked bits
 uint8_t type_3[384];
 uint8_t type_4[384];
 FILE	*f_out;
+FILE *f_in;
 
 //Takes an ASCII callsign in a null terminated char* and encodes it using base 40.
 //Returns -1 (all Fs) if the provided callsign is longer than 9 characters, which
@@ -165,15 +167,16 @@ int main(int argc, char *argv[])
 	uint16_t type=(1<<0)|(0b10<<1); //type indicator - stream, voice, codec2 3200bps, no encryption
 	uint8_t nonce[16]={0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0};
 
-	if(argc==4)
+	if(argc==5)
 	{
-		dest_addr.val=encode_callsign_base40(argv[2]);
+                // link setup
-		src_addr.val=encode_callsign_base40(argv[3]);
+		dest_addr.val=encode_callsign_base40(argv[1]);
+		src_addr.val=encode_callsign_base40(argv[2]);
 		
 		printf("DEST\t0x%012llX\n", dest_addr.val);
 		printf("SRC \t0x%012llX\n", src_addr.val);
 		
-		f_out=fopen(argv[1], "wb");
+		f_out=fopen(argv[4], "wb");
 		
 		//preamble
 		for(uint16_t i=0; i<(LEAD_PREAM*9600)/1000; i++)
@@ -207,13 +210,41 @@ int main(int argc, char *argv[])
 		//convolutionally encode type-1 to type-2
 		;
 
+                // frames
+                if(!strcmp(argv[3], "-"))
+                {
+                        f_in = stdin;
+                } else {
+                        f_in = fopen(argv[1], "rb");
+
+                        if(f_in == NULL)
+                        {
+                                printf("No valid input data to work with\n");
+
+                                return 1;
+                        }
+                }
+
+                uint8_t payload[16];
+                size_t bytes = 0;
+
+                while(1)
+                {
+                        bytes = fread(payload, 1, 16, f_in);
+                        fwrite(payload, 1, 16, f_out);
+
+                        if(bytes < 16)
+                                if(feof(f_in)) break;
+                }
+
+                fclose(f_in);
                 fclose(f_out);
 
 		return 0;
 	}
 	else
 	{
-		printf("Not enough params\n");
+		printf("Invalid number of params\n");
 		
 		return 1;
 	}