Software: Allow symbol definitions and comments in config files

README.md

@@ -2,12 +2,30 @@
 
 *This project is currently in early beta status.*
 
-The overlay64 module allows superimposing predefined texts onto an existing composite signal or onto the luminance portion of an s-video signal depending on the states of up to sixteen digital input lines. An LM1881 video sync separator IC is used to detect the vertical and horizontal sync pulses of the video signal. An Atmega1284 uses these signals to synchronize with the video signal and to superimpose text on the video display by bit-banging the corresponding characters over SPI.
+The overlay64 module allows superimposing predefined texts onto an
+existing composite signal or onto the luminance portion of an s-video
+signal depending on the states of up to sixteen digital input
+lines. An LM1881 video sync separator IC is used to detect the
+vertical and horizontal sync pulses of the video signal. An Atmega1284
+uses these signals to synchronize with the video signal and to
+superimpose text on the video display by bit-banging the corresponding
+characters over SPI.
 
-The user writes a simple configuration file that determines which texts are to be displayed for which input line states. The configuration file is converted to a binary format using the supplied commandline tool before flashing it to the Atmegas's eeprom memory via the USB interface.
+The user writes a simple configuration file that determines which
+texts are to be displayed for which input line states. The
+configuration file is converted to a binary format using the supplied
+commandline tool before flashing it to the Atmegas's eeprom memory via
+the USB interface.
 
-Possible uses include displaying the state of control lines for additional hardware installed in a homecomputer such as the Commodore 64, for example to display the currently selected kernal based on the state of the control lines for a multi-kernal adapter. 
+Possible uses include displaying the state of control lines for
+additional hardware installed in a homecomputer such as the Commodore
+64, for example to display the currently selected kernal based on the
+state of the control lines for a multi-kernal adapter.
 
-An early working prototype can be seen in [this video](https://www.youtube.com/watch?v=0exp2yM0WHM), where it displays the runtime configuration of the MixSID Stereo SID board.
+An early working prototype can be seen in [this
+video](https://www.youtube.com/watch?v=0exp2yM0WHM), where it displays
+the runtime configuration of the MixSID Stereo SID board.
 
-This repository includes the complete sourcecode of the client software, the firmware and all design files in KiCAD format. The project is licensed under the GPLv3.
+This repository includes the complete sourcecode of the client
+software, the firmware and all design files in KiCAD format. The
+project is licensed under the GPLv3.

overlay64.conf

@@ -1,3 +1,18 @@
+PRIORITY = 7
+REVERSED = 0
+NORMAL = 1
+
+MODE = 0
+STEREO = 0
+PARALLEL = 1
+
+MIXER = 1 2
+KERNAL = 3 4
+CHARSET = 5 6
+
+IO1 = 8
+IO2 = 9
+
 timeout 100
 
 control 16 manual 0 1
@@ -8,17 +23,18 @@ screen notify
 write 28 0 "LCHN     MODE    PRIORITY"
 write 28 35 "$D400 5IO    RCHN"
 
-sample 7
-       when 0
+sample PRIORITY
+       when REVERSED
        	    write 28 27 "8580"
 	    write 29 27 "6581"
 	    write 29 17 "REVERSED"	    
-       when 1
+
+       when NORMAL
        	    write 28 27 "6581"
 	    write 29 27 "8580"
 	    write 29 17 " NORMAL "
 
-sample 0 8 9
+sample MODE IO1 IO2
        when 000 write 29 35 "$D420 +++"
        when 001 write 29 35 "$D400 ---"
        when 010 write 29 35 "$D420 +-+"
@@ -28,17 +44,17 @@ sample 0 8 9
        when 110 write 29 35 "$D420 +--"
        when 111 write 29 35 "$D400 ---"
 
-sample 0
-       when 0
+sample MODE
+       when STEREO
        	    write 29 7 " STEREO "
 	    write 28 32 "RW"
 	    write 29 32 "RW"
-       when 1
+       when PARALLEL
        	    write 29 7 "PARALLEL"
 	    write 28 32 "RW"
 	    write 29 32 "WO"
 
-sample 1 2
+sample MIXER
        when 00
        	    write 29 0  "8580"
        	    write 29 48 "8580"
@@ -54,42 +70,42 @@ sample 1 2
 
 screen 
 
-sample 3 4
+sample KERNAL
     when 00 write 0 15 "KERNAL : XLINK SERVER V1"
     when 01 write 0 15 "KERNAL : JIFFYDOS V6.01 "
     when 10 write 0 15 "KERNAL : ORIGINAL REV-03"
     when 11 write 0 15 "KERNAL : UNDEFINED      "	 
 
-sample 5 6
+sample CHARSET
     when 00 write 1 15 "CHARSET: ORIGINAL C64  "
-    when 01 write 1 15 "CHARSET: RETROFAN SMALL"
-    when 10 write 1 15 "CHARSET: FUTURISTIC    "
+    when 01 write 1 15 "CHARSET: FUTURISTIC    "
+    when 10 write 1 15 "CHARSET: RETROFAN SMALL"    
     when 11 write 1 15 "CHARSET: ORIGINAL PET  "
 
 screen notify
 
-sample 3 4       
+sample KERNAL     
     when 00 write 0 9 "SWITCHED KERNAL TO XLINK SERVER V1"
     when 01 write 0 9 "SWITCHED KERNAL TO JIFFYDOS V6.01 "
     when 10 write 0 9 "SWITCHED KERNAL TO ORIGINAL REV-03"
     when 11 write 0 9 "UNDEFINED                         "	 
 
 screen notify
 
-sample 5 6
+sample CHARSET
     when 00 write 0 9 " SWITCHED CHARSET TO ORIGINAL C64 "
-    when 01 write 0 9 "SWITCHED CHARSET TO RETROFAN SMALL"
-    when 10 write 0 9 "  SWITCHED CHARSET TO FUTURISTIC  "
+    when 01 write 0 9 "  SWITCHED CHARSET TO FUTURISTIC  "
+    when 10 write 0 9 "SWITCHED CHARSET TO RETROFAN SMALL"	 
     when 11 write 0 9 " SWITCHED CHARSET TO ORIGINAL PET "
 
 screen notify
 
-sample 0
+sample MODE
     when 0 write 0 16 " STEREO ADDRESSING "
     when 1 write 0 16 "PARALLEL ADDRESSING"
 
 screen notify
 
-sample 7
-    when 0 write 0 17 " NORMAL PRIORITY "
-    when 1 write 0 17 "REVERSED PRIORITY"
+sample PRIORITY    
+    when REVERSED write 0 17 "REVERSED PRIORITY"
+    when NORMAL write 0 17 " NORMAL PRIORITY "	

parser.c

@@ -36,6 +36,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 volatile Config* config;
 uint16_t written = 0;
+const char *ws = " \t";
 
 static int fputcc(int ch, FILE* fp) {
   fputc(ch, fp);
@@ -93,18 +94,71 @@ static bool parseMode(char* word, uint8_t *mode) {
 
 bool Config_parse(volatile Config* self, FILE* in) {  
   bool result = true;
-  char buf[0x10000];
+  char* buffer = (char*) calloc(4096, sizeof(char));
+  char *line;
   char *word;
+  char *comment;
+  char *name;
+  char *value;
+  char *equals;
   int keyword;
+  int trailing = 0; 
   uint8_t timeout;
   Screen* screen = NULL;
-
-  fread(buf, sizeof(char), sizeof(buf), in);
-
   StringList* words = StringList_new();
-  StringList_append_quoted(words, buf, "\n\t ");
-  int i = 0;
+
+  fseek(in, 0, SEEK_SET);
+
+  int pos = 0;
+  while(fgets(buffer, 4095, in) != NULL) {
+    line = buffer;
+    pos++;
+
+    // skip leading whitespace
+    line += strspn(line, ws);
+
+    // skip empty lines and comments
+    if(line[0] == '\n' || line[0] == '\r' || line[0] == '#') continue;
+
+    // remove comment at the end of the line
+    if((comment = strstr(line, "#")) != NULL) {
+      comment[0] = '\0';
+    }
+
+    // discard newlines
+    if(line[strlen(line)-1] == '\n') {
+      line[strlen(line)-1] = '\0';
+    }
+
+    if(line[strlen(line)-1] == '\r') {
+      line[strlen(line)-1] = '\0';
+    }
+
+    // check if this command is a definition
+    if((equals = strstr(line, "=")) != NULL) {
+      name = line;
+      equals[0] = '\0';
+
+      if((trailing = strcspn(name, ws)) > 0) {
+        name[trailing] = '\0';
+      }
 
+      value = equals+1;
+      value = trim(value);
+
+      if(StringList_has_definition(name)) {
+        fprintf(stderr, "error: line %d: '%s': symbol already defined\n", pos, name);
+        return false;
+      }
+
+      StringList_add_definition(name, value);
+    }
+    else {
+      StringList_append_quoted(words, line, "\n\t ");
+    }
+  }
+
+  int i = 0;
   while(i<words->size) {
     word = StringList_get(words, i);
 

strings.c

@@ -18,6 +18,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 #include <stdlib.h>
 #include <string.h>
+#include <ctype.h>
 #include <stdbool.h>
 #include <stdio.h>
 
@@ -210,3 +211,20 @@ void StringList_free(StringList *self) {
   free(self->strings);
   free(self);
 }
+
+char* trim(char* s) 
+{
+  int len = strlen(s);
+
+  while (len && isspace(s[0]))
+  {
+    s++; len--;
+  }
+
+  while (len && isspace(s[len - 1]))
+  {
+    s[len - 1] = 0; len--;
+  }
+
+  return s;
+}

strings.h

@@ -45,4 +45,6 @@ char* StringList_last(StringList *self);
 void StringList_remove_last(StringList *self);
 void StringList_free(StringList *self);
 
+char* trim(char* s);
+
 #endif // STRINGS_H