Initial version

Currently, we are just parsing PJL and gathering options.
More to come...

Makefile

+CC=gcc
+CFLAGS=-O2 -Wall -W -Wno-parentheses -Wstrict-prototypes -Wmissing-prototypes -Wundef -Wredundant-decls -std=gnu99
+
+all: xcpt
+
+clean:
+	rm -f `find . -name "*~" -or -name "*.[oa]" -or -name TAGS -or -name core -or -name .depend -or -name .#*`
+	rm -f xcpt

xcpt.c

+/*
+ *	CUPS Filter Generating XCPT
+ *
+ *	(c) 2016 Martin Mares <mj@ucw.cz>
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <string.h>
+
+#define PRINTF(i,j) __attribute__((format(printf,i,j)))
+#define NONRET __attribute__((noreturn))
+
+/*** Utility functions ***/
+
+static void PRINTF(1,2) NONRET bug(const char *fmt, ...)
+{
+  va_list args;
+  va_start(args, fmt);
+
+  fprintf(stderr, "ERROR: ");
+  vfprintf(stderr, fmt, args);
+  fputc('\n', stderr);
+
+  va_end(args);
+  exit(1);
+}
+
+#if 0
+static void PRINTF(1,2) error(const char *fmt, ...)
+{
+  va_list args;
+  va_start(args, fmt);
+
+  fprintf(stderr, "ERROR: ");
+  vfprintf(stderr, fmt, args);
+  fputc('\n', stderr);
+
+  va_end(args);
+}
+#endif
+
+static void PRINTF(1,2) debug(const char *fmt, ...)
+{
+  va_list args;
+  va_start(args, fmt);
+
+  fprintf(stderr, "DEBUG: ");
+  vfprintf(stderr, fmt, args);
+  fputc('\n', stderr);
+
+  va_end(args);
+}
+
+static char *xstrdup(const char *x)
+{
+  char *p = strdup(x);
+  if (!p)
+    bug("Out of memory");
+  return p;
+}
+
+/*** Options ***/
+
+#define OPTIONS \
+	O(LANGUAGE, "?") \
+	O(MEDIASIZE, "A4")
+
+enum option {
+#define O(name, val) OPT_##name,
+  OPTIONS
+#undef O
+  OPT_MAX
+};
+
+const char *opt_names[] = {
+#define O(name, val) #name,
+  OPTIONS
+#undef O
+};
+
+char *opt[] = {
+#define O(name, val) [OPT_##name] = val,
+  OPTIONS
+#undef O
+};
+
+static void set_option(char *key, char *val)
+{
+  for (int i=0; i<OPT_MAX; i++)
+    if (!strcmp(opt_names[i], key))
+      {
+	opt[i] = xstrdup(val);
+	return;
+      }
+  debug("SET: Unrecognized option <%s>\n", key);
+}
+
+/*** PJL parser ***/
+
+#define LINESIZE 256
+
+static char *skip_spaces(char *p)
+{
+  while (*p == ' ' || *p == '\t')
+    p++;
+  return p;
+}
+
+static int my_toupper(int c)
+{
+  if (c >= 'a' && c <= 'z')
+    return c - 32;
+  else
+    return c;
+}
+
+static char *token_buf;
+
+static char *get_token(char **pp)
+{
+  char *token_start = token_buf;
+  char *tok = token_start;
+  char *p = skip_spaces(*pp);
+  if (!*p)
+    return NULL;
+  int c = my_toupper(*p);
+  if (c >= 'A' && c <= 'Z' || c >= '0' && c <= '9')
+    {
+      while (c >= 'A' && c <= 'Z' || c >= '0' && c <= '9')
+	{
+	  *tok++ = c;
+	  c = my_toupper(*++p);
+	}
+    }
+  else
+    *tok++ = *p++;
+  *tok++ = 0;
+  *pp = skip_spaces(p);
+  token_buf = tok;
+  return token_start;
+}
+
+static void parse_pjl(void)
+{
+  static const char uel[] = "\e%-12345X";
+  for (int i=0; uel[i]; i++)
+    if (getchar() != uel[i])
+      bug("PJL error: No UEL found (pos %u)", i);
+
+  char line[LINESIZE], tokens[2*LINESIZE];
+  for (;;)
+    {
+      int i = 0;
+      for (;;)
+	{
+	  int c = getchar();
+	  if (c < 0)
+	    bug("PJL error: Premature EOF");
+	  if (i < 4 && c != "@PJL"[i])
+	    bug("PJL error: Unrecognized line");
+	  if (c == '\r')
+	    continue;
+	  if (c == '\n')
+	    {
+	      line[i] = 0;
+	      break;
+	    }
+	  if (i >= LINESIZE-1)
+	    bug("PJL error: Line too long");
+	  line[i++] = c;
+	}
+
+      debug("PJL: %s", line);
+      char *p = line+1;
+      token_buf = tokens;
+      char *t;
+      if (!(t = get_token(&p)) || strcasecmp(t, "PJL"))
+	bug("PJL error: Malformed line");
+      if (!(t = get_token(&p)))
+	continue;
+
+      if (!strcasecmp(t, "ENTER"))
+	{
+	  char *t2 = get_token(&p);
+	  if (t2 && !strcasecmp(t2, "LANGUAGE"))
+	    {
+	      char *t3 = get_token(&p);
+	      if (t3 && !strcasecmp(t3, "="))
+		{
+		  set_option("LANGUAGE", p);
+		  break;
+		}
+	    }
+	}
+
+      if (!strcasecmp(t, "SET"))
+	{
+	  char *t2 = get_token(&p);
+	  if (t2)
+	    {
+	      char *t3 = get_token(&p);
+	      if (t3 && !strcasecmp(t3, "="))
+		{
+		  if (*p == '"')
+		    {
+		      *p++ = 0;
+		      char *q = p;
+		      while (*q && *q != '"')
+			q++;
+		      if (*q)
+			*q = 0;
+		    }
+		  set_option(t2, p);
+		}
+	    }
+	}
+    }
+}
+
+int main(int argc, const char **argv)
+{
+  if (argc < 5)
+    {
+      fprintf(stderr, "Usage: xcpt <job> <user> <title> <num-copies> [<options>]\n");
+      return 1;
+    }
+
+  (void) argv; // FIXME
+
+  parse_pjl();
+
+  for (int i=0; i<OPT_MAX; i++)
+    debug("Option %s=<%s>\n", opt_names[i], opt[i]);
+
+  return 0;
+}