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-rw-r--r--filter.c181
1 files changed, 103 insertions, 78 deletions
diff --git a/filter.c b/filter.c
index f0c27da..40c8cf2 100644
--- a/filter.c
+++ b/filter.c
@@ -1,15 +1,5 @@
/* filter - postprocessing of flex output through filters */
-/* Copyright (c) 1990 The Regents of the University of California. */
-/* All rights reserved. */
-
-/* This code is derived from software contributed to Berkeley by */
-/* Vern Paxson. */
-
-/* The United States Government has rights in this work pursuant */
-/* to contract no. DE-AC03-76SF00098 between the United States */
-/* Department of Energy and the University of California. */
-
/* This file is part of flex. */
/* Redistribution and use in source and binary forms, with or without */
@@ -231,21 +221,11 @@ int filter_tee_header (struct filter *chain)
const int readsz = 512;
char *buf;
- int to_cfd;
- FILE *to_c, *to_h;
+ int to_cfd = -1;
+ FILE *to_c = NULL, *to_h = NULL;
+ bool write_header;
- fprintf (stderr, "filter_tee()\n");
- fflush (stderr);
-
- if (!chain->extra) {
- /* No header file was specified, so we become a transparent
- * filter.
- */
- fprintf (stderr, "\texeclp(cat)\n");
- fflush (stderr);
- execlp ("cat", "cat", NULL);
- flexfatal (_("exec failed"));
- }
+ write_header = (chain->extra != NULL);
/* Store a copy of the stdout pipe, which is already piped to C file
* through the running chain. Then create a new pipe to the H file as
@@ -254,45 +234,64 @@ int filter_tee_header (struct filter *chain)
if ((to_cfd = dup (1)) == -1)
flexfatal (_("dup(1) failed"));
+ to_c = fdopen (to_cfd, "w");
- if (freopen ((char *) chain->extra, "w", stdout) == NULL)
- flexfatal (_("freopen(headerfilename) failed"));
-
- filter_apply_chain (chain->next);
+ if (write_header) {
+ if (freopen ((char *) chain->extra, "w", stdout) == NULL)
+ flexfatal (_("freopen(headerfilename) failed"));
- to_c = fdopen (to_cfd, "w");
- to_h = stdout;
+ filter_apply_chain (chain->next);
+ to_h = stdout;
+ }
/* Now to_c is a pipe to the C branch, and to_h is a pipe to the H branch.
*/
- fprintf (stderr, "\tpid(%d): to_c=%d, to_h=%d\n",
- getpid (), fileno (to_c), fileno (to_h));
- fflush (stderr);
+ if (write_header) {
+ fputs ("m4_changecom`'m4_dnl\n", to_h);
+ fputs ("m4_changequote`'m4_dnl\n", to_h);
+ fputs ("m4_changequote([[,]])[[]]m4_dnl\n", to_h);
+ fputs ("m4_define( [[M4_YY_IN_HEADER]],[[]])m4_dnl\n",
+ to_h);
+ fprintf (to_h, "#ifndef %sHEADER_H\n", prefix);
+ fprintf (to_h, "#define %sHEADER_H 1\n", prefix);
+ fprintf (to_h, "#define %sIN_HEADER 1\n\n", prefix);
+ fprintf (to_h,
+ "m4_define( [[M4_YY_OUTFILE_NAME]],[[%s]])m4_dnl\n",
+ headerfilename ? headerfilename : "<stdout>");
+
+ }
- fputs ("m4_changequote`'m4_dnl\n", to_h);
- fputs ("m4_changequote([[,]])[[]]m4_dnl\n", to_h);
- fputs ("m4_define( [[M4_YY_IN_HEADER]],[[]])m4_dnl\n", to_h);
- fprintf (to_h, "#ifndef %sHEADER_H\n", prefix);
- fprintf (to_h, "#define %sHEADER_H 1\n", prefix);
- fprintf (to_h, "#define %sIN_HEADER 1\n\n", prefix);
+ fputs ("m4_changecom`'m4_dnl\n", to_c);
+ fputs ("m4_changequote`'m4_dnl\n", to_c);
+ fputs ("m4_changequote([[,]])[[]]m4_dnl\n", to_c);
+ fprintf (to_c, "m4_define( [[M4_YY_OUTFILE_NAME]],[[%s]])m4_dnl\n",
+ outfilename ? outfilename : "<stdout>");
buf = (char *) flex_alloc (readsz);
while (fgets (buf, readsz, stdin)) {
fputs (buf, to_c);
- fputs (buf, to_h);
+ if (write_header)
+ fputs (buf, to_h);
}
- fprintf (to_h, "\n");
- fprintf (to_h, "#undef %sIN_HEADER\n", prefix);
- fprintf (to_h, "#endif /* %sHEADER_H */\n", prefix);
- fputs ("m4_undefine( [[M4_YY_IN_HEADER]])m4_dnl\n", to_h);
+ if (write_header) {
+ fprintf (to_h, "\n");
+
+ /* write a fake line number. It will get fixed by the linedir filter. */
+ fprintf (to_h, "#line 4000 \"M4_YY_OUTFILE_NAME\"\n");
+
+ fprintf (to_h, "#undef %sIN_HEADER\n", prefix);
+ fprintf (to_h, "#endif /* %sHEADER_H */\n", prefix);
+ fputs ("m4_undefine( [[M4_YY_IN_HEADER]])m4_dnl\n", to_h);
+
+ fflush (to_h);
+ fclose (to_h);
+ }
fflush (to_c);
fclose (to_c);
- fflush (to_h);
- fclose (to_h);
while (wait (0) > 0) ;
@@ -300,12 +299,19 @@ int filter_tee_header (struct filter *chain)
return 0;
}
+/** Adjust the line numbers in the #line directives of the generated scanner.
+ * After the m4 expansion, the line numbers are incorrect since the m4 macros
+ * can add or remove lines. This only adjusts line numbers for generated code,
+ * not user code. This also happens to be a good place to squeeze multiple
+ * blank lines into a single blank line.
+ */
int filter_fix_linedirs (struct filter *chain)
{
char *buf;
const int readsz = 512;
- int lineno=1;
- bool in_gen = true;/* in generated code */
+ int lineno = 1;
+ bool in_gen = true; /* in generated code */
+ bool last_was_blank = false;
if (!chain)
return 0;
@@ -314,40 +320,59 @@ int filter_fix_linedirs (struct filter *chain)
while (fgets (buf, readsz, stdin)) {
- regmatch_t m[10];
-
+ regmatch_t m[10];
+
+ /* Check for #line directive. */
if (buf[0] == '#'
&& regexec (&regex_linedir, buf, 3, m, 0) == 0) {
-
- int num;
- char * fname;
-
- /* extract the line number and filename */
- num = regmatch_strtol(&m[1], buf, NULL, 0);
- fname = regmatch_dup(&m[2], buf);
-
- if ( strcmp(fname, outfilename?outfilename:"") ==0
- || strcmp(fname, headerfilename?headerfilename:"") ==0
- ){
- /* Adjust the line directives. */
- in_gen = true;
- fprintf(stdout, "#line %d \"%s\"\n", lineno+1, fname);
- free(fname);
-
- }
- else{
- /* it's a #line directive for code we didn't write */
- in_gen= false;
- fputs (buf, stdout);
- }
+
+ int num;
+ char *fname;
+
+ /* extract the line number and filename */
+ num = regmatch_strtol (&m[1], buf, NULL, 0);
+ fname = regmatch_dup (&m[2], buf);
+
+ if (strcmp
+ (fname, outfilename ? outfilename : "<stdout>")
+ == 0
+ || strcmp (fname,
+ headerfilename ? headerfilename :
+ "<stdout>") == 0) {
+ /* Adjust the line directives. */
+ in_gen = true;
+ sprintf (buf, "#line %d \"%s\"\n",
+ lineno + 1, fname);
+ free (fname);
+
+ }
+ else {
+ /* it's a #line directive for code we didn't write */
+ in_gen = false;
+ }
+
+ last_was_blank = false;
}
- else{
- /* It's just a regular line of code. */
- fputs(buf, stdout);
- }
- lineno++;
+
+ /* squeeze blank lines from generated code */
+ else if (in_gen
+ && regexec (&regex_blank_line, buf, 0, NULL,
+ 0) == 0) {
+ if (last_was_blank)
+ continue;
+ else
+ last_was_blank = true;
+ }
+
+ else {
+ /* it's a line of normal, non-empty code. */
+ last_was_blank = false;
+ }
+
+ fputs (buf, stdout);
+ lineno++;
}
- fflush(stdout);
+ fflush (stdout);
return 0;
}
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