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Diffstat (limited to 'unproto.c')
| -rw-r--r-- | unproto.c | 999 |
1 files changed, 999 insertions, 0 deletions
diff --git a/unproto.c b/unproto.c new file mode 100644 index 0000000..2b2e764 --- /dev/null +++ b/unproto.c @@ -0,0 +1,999 @@ +/*++ +/* NAME +/* unproto 1 +/* SUMMARY +/* compile ANSI C with traditional UNIX C compiler +/* PACKAGE +/* unproto +/* SYNOPSIS +/* /somewhere/cpp ... +/* +/* cc cflags -E file.c | unproto >file.i; cc cflags -c file.i +/* DESCRIPTION +/* This document describes a filter that sits in between the UNIX +/* C preprocessor and the next UNIX C compiler stage, on the fly rewriting +/* ANSI-style syntax to old-style syntax. Typically, the program is +/* invoked by the native UNIX C compiler as an alternate preprocessor. +/* The unprototyper in turn invokes the native C preprocessor and +/* massages its output. Similar tricks can be used with the lint(1) +/* command. +/* +/* Language constructs that are always rewritten: +/* .TP +/* function headings, prototypes, pointer types +/* ANSI-C style function headings, function prototypes, function +/* pointer types and type casts are rewritten to old style. +/* <stdarg.h> support is provided for functions with variable-length +/* argument lists. +/* .TP +/* character and string constants +/* The \\a and \\x escape sequences are rewritten to their (three-digit) +/* octal equivalents. +/* +/* Multiple string tokens are concatenated; an arbitrary number of +/* whitespace or comment tokens may appear between successive +/* string tokens. +/* +/* Within string constants, octal escape sequences are rewritten to the +/* three-digit \\ddd form, so that string concatenation produces correct +/* results. +/* .TP +/* date and time +/* The __DATE__ and __TIME__ tokens are replaced by string constants +/* of the form "Mmm dd yyyy" and "hh:mm:ss", respectively. The result +/* is subjected to string concatenation, just like any other string +/* constant. +/* .PP +/* Language constructs that are rewritten only if the program has been +/* configured to do so: +/* .TP +/* void types +/* The unprototyper can be configured to rewrite "void *" to "char *", +/* and even to rewrite plain "void" to "int". +/* These features are configurable because many traditional UNIX C +/* compilers do not need them. +/* +/* Note: (void) argument lists are always replaced by empty ones. +/* .PP +/* ANSI C constructs that are not rewritten because the traditional +/* UNIX C preprocessor provides suitable workarounds: +/* .TP +/* const and volatile +/* Use the "-Dconst=" and/or "-Dvolatile=" preprocessor directives to +/* get rid of unimplemented keywords. +/* .TP +/* token pasting and stringizing +/* The traditional UNIX C preprocessor provides excellent alternatives. +/* For example: +/* +/* .nf +/* .ne 2 +/* #define string(bar) "bar" /* instead of: # x */ +/* #define paste(x,y) x/**\/y /* instead of: x##y */ +/* .fi +/* +/* There is a good reason why the # and ## operators are not implemented +/* in the unprototyper. +/* After program text has gone through a non-ANSI C preprocessor, all +/* information about the grouping of the operands of # and ## is lost. +/* Thus, if the unprototyper were to perform these operations, it would +/* produce correct results only in the most trivial cases. Operands +/* with embedded blanks, operands that expand to null tokens, and nested +/* use of # and/or ## would cause all kinds of obscure problems. +/* .PP +/* Unsupported ANSI features: +/* .TP +/* trigraphs and #pragmas +/* Trigraphs are useful only for systems with broken character sets. +/* If the local compiler chokes on #pragma, insert a blank before the +/* "#" character, and enclose the offending directive between #ifdef +/* and #endif. +/* SEE ALSO +/* .ad +/* .fi +/* cc(1), how to specify a non-default C preprocessor. +/* Some versions of the lint(1) command are implemented as a shell +/* script. It should require only minor modification for integration +/* with the unprototyper. Other versions of the lint(1) command accept +/* the same command syntax as the C compiler for the specification of a +/* non-default preprocessor. Some research may be needed. +/* FILES +/* /wherever/stdarg.h, provided with the unproto filter. +/* DIAGNOSTICS +/* Problems are reported on the standard error stream. +/* A non-zero exit status means that there was a problem. +/* BUGS +/* The unprototyper should be run on preprocessed source only: +/* unexpanded macros may confuse the program. +/* +/* Declarations of (object) are misunderstood and will result in +/* syntax errors: the objects between parentheses disappear. +/* +/* Sometimes does not preserve whitespace after parentheses and commas. +/* This is a purely aesthetical matter, and the compiler should not care. +/* Whitespace within string constants is, of course, left intact. +/* +/* Does not generate explicit type casts for function-argument +/* expressions. The lack of explicit conversions between integral +/* and/or pointer argument types should not be a problem in environments +/* where sizeof(int) == sizeof(long) == sizeof(pointer). A more serious +/* problem is the lack of automatic type conversions between integral and +/* floating-point argument types. Let lint(1) be your friend. +/* AUTHOR(S) +/* Wietse Venema (wietse@wzv.win.tue.nl) +/* Eindhoven University of Technology +/* Department of Mathematics and Computer Science +/* Den Dolech 2, P.O. Box 513, 5600 MB Eindhoven, The Netherlands +/* LAST MODIFICATION +/* 93/06/18 22:29:37 +/* VERSION/RELEASE +/* 1.6 +/*--*/ + +static char unproto_sccsid[] = "@(#) unproto.c 1.6 93/06/18 22:29:37"; + +/* C library */ + +#include <sys/types.h> +#include <sys/stat.h> +#include <stdio.h> +#include <errno.h> + +extern void exit(); +extern int optind; +extern char *optarg; +extern int getopt(); + +/* Application-specific stuff */ + +#include "vstring.h" +#include "stdarg.h" +#include "token.h" +#include "error.h" +#include "symbol.h" + +/* Forward declarations. */ + +static struct token *dcl_flush(); +static void block_flush(); +static void block_dcls(); +static struct token *show_func_ptr_type(); +static struct token *show_struct_type(); +static void show_arg_name(); +static void show_type(); +static void pair_flush(); +static void check_cast(); +static void show_empty_list(); + +#define check_cast_flush(t) (check_cast(t), tok_free(t)) + +#ifdef PIPE_THROUGH_CPP +static int pipe_stdin_through_cpp(); +#endif + +/* Disable debugging printfs while preserving side effects. */ + +#ifdef DEBUG +#define DPRINTF printf +#else +#define DPRINTF (void) +#endif + +/* An attempt to make some complicated expressions a bit more readable. */ + +#define STREQ(x,y) (*(x) == *(y) && !strcmp((x),(y))) + +#define LAST_ARG_AND_EQUAL(s,c) ((s)->next && (s)->next->next == 0 \ + && (s)->head && ((s)->head == (s)->tail) \ + && (STREQ((s)->head->vstr->str, (c)))) + +#define LIST_BEGINS_WITH_STAR(s) (s->head->head && s->head->head->tokno == '*') + +#define IS_FUNC_PTR_TYPE(s) (s->tokno == TOK_LIST && s->next \ + && s->next->tokno == TOK_LIST \ + && LIST_BEGINS_WITH_STAR(s)) + +/* What to look for to detect a (void) argument list. */ + +#ifdef MAP_VOID +#define VOID_ARG "int" /* bare "void" is mapped to "int" */ +#else +#define VOID_ARG "void" /* bare "void" is left alone */ +#endif + +/* main - driver */ + +int main(argc, argv) +int argc; +char **argv; +{ + register struct token *t; +#ifdef PIPE_THROUGH_CPP /* pipe through /lib/cpp */ + int cpp_status; + int wait_pid; + int cpp_pid; + + cpp_pid = pipe_stdin_through_cpp(argv); +#endif + + sym_init(); /* prime the symbol table */ + + while (t = tok_class()) { + if (t = dcl_flush(t)) { /* try declaration */ + if (t->tokno == '{') { /* examine rejected token */ + block_flush(t); /* body */ + } else { + tok_flush(t); /* other, recover */ + } + } + } + +#ifdef PIPE_THROUGH_CPP /* pipe through /lib/cpp */ + while ((wait_pid = wait(&cpp_status)) != -1 && wait_pid != cpp_pid) + /* void */ ; + return (errcount != 0 || wait_pid != cpp_pid || cpp_status != 0); +#else + return (errcount != 0); +#endif +} + +#ifdef PIPE_THROUGH_CPP /* pipe through /lib/cpp */ + +/* pipe_stdin_through_cpp - avoid shell script overhead */ + +static int pipe_stdin_through_cpp(argv) +char **argv; +{ + int pipefds[2]; + int pid; + char **cpptr = argv; + int i; + struct stat st; + + /* + * The code that sets up the pipe requires that file descriptors 0,1,2 + * are already open. All kinds of mysterious things will happen if that + * is not the case. The following loops makes sure that descriptors 0,1,2 + * are set up properly. + */ + + for (i = 0; i < 3; i++) { + if (fstat(i, &st) == -1 && open("/dev/null", 2) != i) { + perror("open /dev/null"); + exit(1); + } + } + + /* + * With most UNIX implementations, the second non-option argument to + * /lib/cpp specifies the output file. If an output file other than + * stdout is specified, we must force /lib/cpp to write to stdout, and we + * must redirect our own standard output to the specified output file. + */ + +#define IS_OPTION(cp) ((cp)[0] == '-' && (cp)[1] != 0) + + /* Skip to first non-option argument, if any. */ + + while (*++cpptr && IS_OPTION(*cpptr)) + /* void */ ; + + /* + * Assume that the first non-option argument is the input file name. The + * next argument could be the output destination or an option (System V + * Release 2 /lib/cpp gets the options *after* the file arguments). + */ + + if (*cpptr && *++cpptr && **cpptr != '-') { + + /* + * The first non-option argument is followed by another argument that + * is not an option ("-stuff") or a hyphen ("-"). Redirect our own + * standard output before we clobber the file name. + */ + + if (freopen(*cpptr, "w", stdout) == 0) { + perror(*cpptr); + exit(1); + } + /* Clobber the file name argument so that /lib/cpp writes to stdout */ + + *cpptr = "-"; + } + /* Set up the pipe that connects /lib/cpp to our standard input. */ + + if (pipe(pipefds)) { + perror("pipe"); + exit(1); + } + switch (pid = fork()) { + case -1: /* error */ + perror("fork"); + exit(1); + /* NOTREACHED */ + case 0: /* child */ + (void) close(pipefds[0]); /* close reading end */ + (void) close(1); /* connect stdout to pipe */ + if (dup(pipefds[1]) != 1) + fatal("dup() problem"); + (void) close(pipefds[1]); /* close redundant fd */ + (void) execv(PIPE_THROUGH_CPP, argv); + perror(PIPE_THROUGH_CPP); + exit(1); + /* NOTREACHED */ + default: /* parent */ + (void) close(pipefds[1]); /* close writing end */ + (void) close(0); /* connect stdin to pipe */ + if (dup(pipefds[0]) != 0) + fatal("dup() problem"); + close(pipefds[0]); /* close redundant fd */ + return (pid); + } +} + +#endif + +/* show_arg_names - display function argument names */ + +static void show_arg_names(t) +register struct token *t; +{ + register struct token *s; + + /* Do argument names, but suppress void and rewrite trailing ... */ + + if (LAST_ARG_AND_EQUAL(t->head, VOID_ARG)) { + show_empty_list(t); /* no arguments */ + } else { + for (s = t->head; s; s = s->next) { /* foreach argument... */ + if (LAST_ARG_AND_EQUAL(s, "...")) { +#ifdef _VA_ALIST_ /* see ./stdarg.h */ + tok_show_ch(s); /* ',' */ + put_str(_VA_ALIST_); /* varargs magic */ +#endif + } else { + tok_show_ch(s); /* '(' or ',' or ')' */ + show_arg_name(s); /* extract argument name */ + } + } + } +} + +/* show_arg_types - display function argument types */ + +static void show_arg_types(t) +register struct token *t; +{ + register struct token *s; + + /* Do argument types, but suppress void and trailing ... */ + + if (!LAST_ARG_AND_EQUAL(t->head, VOID_ARG)) { + for (s = t->head; s; s = s->next) { /* foreach argument... */ + if (LAST_ARG_AND_EQUAL(s, "...")) { +#ifdef _VA_DCL_ /* see ./stdarg.h */ + put_str(_VA_DCL_); /* varargs magic */ + put_nl(); /* make output look nicer */ +#endif + } else { + if (s->head != s->tail) { /* really new-style argument? */ + show_type(s); /* rewrite type info */ + put_ch(';'); + put_nl(); /* make output look nicer */ + } + } + } + } +} + +/* header_flush - rewrite new-style function heading to old style */ + +static void header_flush(t) +register struct token *t; +{ + show_arg_names(t); /* show argument names */ + put_nl(); /* make output look nicer */ + show_arg_types(t); /* show argument types */ + tok_free(t); /* discard token */ +} + +/* fpf_header_names - define func returning ptr to func, no argument types */ + +static void fpf_header_names(list) +struct token *list; +{ + register struct token *s; + register struct token *p; + + /* + * Recurse until we find the argument list. Account for the rare case + * that list is a comma-separated list (which should be a syntax error). + * Display old-style fuction argument names. + */ + + for (s = list->head; s; s = s->next) { + tok_show_ch(s); /* '(' or ',' or ')' */ + for (p = s->head; p; p = p->next) { + if (p->tokno == TOK_LIST) { + if (IS_FUNC_PTR_TYPE(p)) { /* recurse */ + fpf_header_names(p); + show_empty_list(p = p->next); + } else { /* display argument names */ + show_arg_names(p); + } + } else { /* pass through other stuff */ + tok_show(p); + } + } + } +} + +/* fpf_header_types - define func returning ptr to func, argument types only */ + +static void fpf_header_types(list) +struct token *list; +{ + register struct token *s; + register struct token *p; + + /* + * Recurse until we find the argument list. Account for the rare case + * that list is a comma-separated list (which should be a syntax error). + * Display old-style function argument types. + */ + + for (s = list->head; s; s = s->next) { + for (p = s->head; p; p = p->next) { + if (p->tokno == TOK_LIST) { + if (IS_FUNC_PTR_TYPE(p)) { /* recurse */ + fpf_header_types(p); + p = p->next; + } else { /* display argument types */ + show_arg_types(p); + } + } + } + } +} + +/* fpf_header - define function returning pointer to function */ + +static void fpf_header(l1, l2) +struct token *l1; +struct token *l2; +{ + fpf_header_names(l1); /* strip argument types */ + show_empty_list(l2); /* strip prototype */ + put_nl(); /* nicer output */ + fpf_header_types(l1); /* show argument types */ +} + +/* skip_enclosed - skip over enclosed tokens */ + +static struct token *skip_enclosed(p, stop) +register struct token *p; +register int stop; +{ + register int start = p->tokno; + + /* Always return a pointer to the last processed token, never NULL. */ + + while (p->next) { + p = p->next; + if (p->tokno == start) { + p = skip_enclosed(p, stop); /* recurse */ + } else if (p->tokno == stop) { + break; /* done */ + } + } + return (p); +} + +/* show_arg_name - extract argument name from argument type info */ + +static void show_arg_name(s) +register struct token *s; +{ + if (s->head) { + register struct token *p; + register struct token *t = 0; + + /* Find the last interesting item. */ + + for (p = s->head; p; p = p->next) { + if (p->tokno == TOK_WORD) { + t = p; /* remember last word */ + } else if (p->tokno == '{') { + p = skip_enclosed(p, '}'); /* skip structured stuff */ + } else if (p->tokno == '[') { + break; /* dimension may be a macro */ + } else if (IS_FUNC_PTR_TYPE(p)) { + t = p; /* or function pointer */ + p = p->next; + } + } + + /* Extract argument name from last interesting item. */ + + if (t) { + if (t->tokno == TOK_LIST) + show_arg_name(t->head); /* function pointer, recurse */ + else + tok_show(t); /* print last word */ + } + } +} + +/* show_type - rewrite type to old-style syntax */ + +static void show_type(s) +register struct token *s; +{ + register struct token *p; + + /* + * Rewrite (*stuff)(args) to (*stuff)(). Rewrite word(args) to word(), + * but only if the word was preceded by a word, '*' or '}'. Leave + * anything else alone. + */ + + for (p = s->head; p; p = p->next) { + if (IS_FUNC_PTR_TYPE(p)) { + p = show_func_ptr_type(p, p->next); /* function pointer type */ + } else { + register struct token *q; + register struct token *r; + + tok_show(p); /* other */ + if ((p->tokno == TOK_WORD || p->tokno == '*' || p->tokno == '}') + && (q = p->next) && q->tokno == TOK_WORD + && (r = q->next) && r->tokno == TOK_LIST) { + tok_show(q); /* show name */ + show_empty_list(p = r); /* strip args */ + } + } + } +} + +/* show_func_ptr_type - display function_pointer type using old-style syntax */ + +static struct token *show_func_ptr_type(t1, t2) +struct token *t1; +struct token *t2; +{ + register struct token *s; + + /* + * Rewrite (list1) (list2) to (list1) (). Account for the rare case that + * (list1) is a comma-separated list. That should be an error, but we do + * not want to waste any information. + */ + + for (s = t1->head; s; s = s->next) { + tok_show_ch(s); /* '(' or ',' or ')' */ + show_type(s); /* recurse */ + } + show_empty_list(t2); + return (t2); +} + +/* show_empty_list - display opening and closing parentheses (if available) */ + +static void show_empty_list(t) +register struct token *t; +{ + tok_show_ch(t->head); /* opening paren */ + if (t->tail->tokno == ')') + tok_show_ch(t->tail); /* closing paren */ +} + +/* show_struct_type - display structured type, rewrite function-pointer types */ + +static struct token *show_struct_type(p) +register struct token *p; +{ + tok_show(p); /* opening brace */ + + while (p->next) { /* XXX cannot return 0 */ + p = p->next; + if (IS_FUNC_PTR_TYPE(p)) { + p = show_func_ptr_type(p, p->next); /* function-pointer member */ + } else if (p->tokno == '{') { + p = show_struct_type(p); /* recurse */ + } else { + tok_show(p); /* other */ + if (p->tokno == '}') { + return (p); /* done */ + } + } + } + DPRINTF("/* missing '}' */"); + return (p); +} + +/* is_func_ptr_cast - recognize function-pointer type cast */ + +static int is_func_ptr_cast(t) +register struct token *t; +{ + register struct token *p; + + /* + * Examine superficial structure. Require (list1) (list2). Require that + * list1 begins with a star. + */ + + if (!IS_FUNC_PTR_TYPE(t)) + return (0); + + /* + * Make sure that there is no name in (list1). Do not worry about + * unexpected tokens, because the compiler will complain anyway. + */ + + for (p = t->head->head; p; p = p->next) { + switch (p->tokno) { + case TOK_LIST: /* recurse */ + return (is_func_ptr_cast(p)); + case TOK_WORD: /* name in list */ + return (0); + case '[': + return (1); /* dimension may be a macro */ + } + } + return (1); /* no name found */ +} + +/* check_cast - display ()-delimited, comma-separated list */ + +static void check_cast(t) +struct token *t; +{ + register struct token *s; + register struct token *p; + + /* + * Rewrite function-pointer types and function-pointer casts. Do not + * blindly rewrite (*list1)(list2) to (*list1)(). Function argument lists + * are about the only thing we can discard without provoking diagnostics + * from the compiler. + */ + + for (s = t->head; s; s = s->next) { + tok_show_ch(s); /* '(' or ',' or ')' */ + for (p = s->head; p; p = p->next) { + switch (p->tokno) { + case TOK_LIST: + if (is_func_ptr_cast(p)) { /* not: IS_FUNC_PTR_TYPE(p) */ + p = show_func_ptr_type(p, p->next); + } else { + check_cast(p); /* recurse */ + } + break; + case '{': + p = show_struct_type(p); /* rewrite func. ptr. types */ + break; + default: + tok_show(p); + break; + } + } + } +} + +/* block_dcls - on the fly rewrite decls/initializers at start of block */ + +static void block_dcls() +{ + register struct token *t; + + /* + * Away from the top level, a declaration should be preceded by type or + * storage-class information. That is why inside blocks, structs and + * unions we insist on reading one word before passing the _next_ token + * to the dcl_flush() function. + * + * Struct and union declarations look the same everywhere: we make an + * exception for these more regular constructs and pass the "struct" and + * "union" tokens to the type_dcl() function. + */ + + while (t = tok_class()) { + switch (t->tokno) { + case TOK_WSPACE: /* preserve white space */ + case '\n': /* preserve line count */ + tok_flush(t); + break; + case TOK_WORD: /* type declarations? */ + tok_flush(t); /* advance to next token */ + t = tok_class(); /* null return is ok */ + /* FALLTRHOUGH */ + case TOK_COMPOSITE: /* struct or union */ + if ((t = dcl_flush(t)) == 0) + break; + /* FALLTRHOUGH */ + default: /* end of declarations */ + DPRINTF("/* end dcls */"); + /* FALLTRHOUGH */ + case '}': /* end of block */ + tok_unget(t); + return; + } + } +} + +/* block_flush - rewrite struct, union or statement block on the fly */ + +static void block_flush(t) +register struct token *t; +{ + static int count = 0; + + tok_flush(t); + DPRINTF("/*%d*/", ++count); + + /* + * Rewrite function pointer types in declarations and function pointer + * casts in initializers at start of block. + */ + + block_dcls(); + + /* Remainder of block: only rewrite function pointer casts. */ + + while (t = tok_class()) { + if (t->tokno == TOK_LIST) { + check_cast_flush(t); + } else if (t->tokno == '{') { + block_flush(t); + } else { + tok_flush(t); + if (t->tokno == '}') { + DPRINTF("/*%d*/", count--); + return; + } + } + } + DPRINTF("/* missing '}' */"); +} + +/* pair_flush - on the fly rewrite casts in grouped stuff */ + +static void pair_flush(t, start, stop) +register struct token *t; +register int start; +register int stop; +{ + tok_flush(t); + + while (t = tok_class()) { + if (t->tokno == start) { /* recurse */ + pair_flush(t, start, stop); + } else if (t->tokno == TOK_LIST) { /* expression or cast */ + check_cast_flush(t); + } else { /* other, copy */ + tok_flush(t); + if (t->tokno == stop) { /* done */ + return; + } + } + } + DPRINTF("/* missing '%c' */", stop); +} + +/* initializer - on the fly rewrite casts in initializer */ + +static void initializer() +{ + register struct token *t; + + while (t = tok_class()) { + switch (t->tokno) { + case ',': /* list separator */ + case ';': /* list terminator */ + tok_unget(t); + return; + case TOK_LIST: /* expression or cast */ + check_cast_flush(t); + break; + case '[': /* array subscript, may nest */ + pair_flush(t, '[', ']'); + break; + case '{': /* structured data, may nest */ + pair_flush(t, '{', '}'); + break; + default: /* other, just copy */ + tok_flush(t); + break; + } + } +} + +/* func_ptr_dcl_flush - rewrite function pointer stuff */ + +static struct token *func_ptr_dcl_flush(list) +register struct token *list; +{ + register struct token *t; + register struct token *t2; + + /* + * Ignore blanks and newlines because we are too lazy to maintain more + * than one token worth of lookahead. The output routines will regenerate + * discarded newline tokens. + */ + + while (t = tok_class()) { + switch (t->tokno) { + case TOK_WSPACE: + case '\n': + tok_free(t); + break; + case TOK_LIST: + /* Function pointer or function returning pointer to function. */ + while ((t2 = tok_class()) /* skip blanks etc. */ + &&(t2->tokno == TOK_WSPACE || t2->tokno == '\n')) + tok_free(t2); + switch (t2 ? t2->tokno : 0) { + case '{': /* function heading (new) */ + fpf_header(list, t); + break; + case TOK_WORD: /* function heading (old) */ + tok_show(list); + tok_show(t); + break; + default: /* func pointer type */ + (void) show_func_ptr_type(list, t); + break; + } + tok_free(list); + tok_free(t); + if (t2) + tok_unget(t2); + return (0); + default: /* not a declaration */ + tok_unget(t); + return (list); + } + } + + /* Hit EOF; must be mistake, but do not waste any information. */ + + return (list); +} + +/* function_dcl_flush - rewrite function { heading, type declaration } */ + +static struct token *function_dcl_flush(list) +register struct token *list; +{ + register struct token *t; + + /* + * Ignore blanks and newlines because we are too lazy to maintain more + * than one token worth of lookahead. The output routines will regenerate + * ignored newline tokens. + */ + + while (t = tok_class()) { + switch (t->tokno) { + case TOK_WSPACE: + case '\n': + tok_free(t); + break; + case '{': + /* Function heading: word (list) { -> old style heading */ + header_flush(list); + tok_unget(t); + return (0); + case TOK_WORD: + /* Old-style function heading: word (list) word... */ + tok_flush(list); + tok_unget(t); + return (0); + case TOK_LIST: + /* Function pointer: word (list1) (list2) -> word (list1) () */ + tok_flush(list); + show_empty_list(t); + tok_free(t); + return (0); + case ',': + case ';': + /* Function type declaration: word (list) -> word () */ + show_empty_list(list); + tok_free(list); + tok_unget(t); + return (0); + default: + /* Something else, reject the list. */ + tok_unget(t); + return (list); + } + } + + /* Hit EOF; must be mistake, but do not waste any information. */ + + return (list); +} + +/* dcl_flush - parse declaration on the fly, return rejected token */ + +static struct token *dcl_flush(t) +register struct token *t; +{ + register int got_word; + + /* + * Away from the top level, type or storage-class information is required + * for an (extern or forward) function type declaration or a variable + * declaration. + * + * With our naive word-counting approach, this means that the caller should + * read one word before passing the next token to us. This is how we + * distinguish, for example, function declarations from function calls. + * + * An exception are structs and unions, because they look the same at any + * level. The caller should give is the "struct" or "union" token. + */ + + for (got_word = 0; t; t = tok_class()) { + switch (t->tokno) { + case TOK_WSPACE: /* advance past blanks */ + case '\n': /* advance past newline */ + case '*': /* indirection: keep trying */ + tok_flush(t); + break; + case TOK_WORD: /* word: keep trying */ + case TOK_COMPOSITE: /* struct or union */ + got_word = 1; + tok_flush(t); + break; + default: + + /* + * Function pointer types can be preceded by zero or more words + * (at least one when not at the top level). Other stuff can be + * accepted only after we have seen at least one word (two words + * when not at the top level). See also the above comment on + * structs and unions. + */ + + if (t->tokno == TOK_LIST && LIST_BEGINS_WITH_STAR(t)) { + if (t = func_ptr_dcl_flush(t)) { + return (t); /* reject token */ + } else { + got_word = 1; /* for = and [ and , and ; */ + } + } else if (got_word == 0) { + return (t); /* reject token */ + } else { + switch (t->tokno) { + case TOK_LIST: /* function type */ + if (t = function_dcl_flush(t)) + return (t); /* reject token */ + break; + case '[': /* dimension, does not nest */ + pair_flush(t, '[', ']'); + break; + case '=': /* initializer follows */ + tok_flush(t); + initializer(); /* rewrite casts */ + break; + case '{': /* struct, union, may nest */ + block_flush(t); /* use code for stmt blocks */ + break; + case ',': /* separator: keep trying */ + got_word = 0; + tok_flush(t); + break; + case ';': /* terminator: succeed */ + tok_flush(t); + return (0); + default: /* reject token */ + return (t); + } + } + } + } + return (0); /* hit EOF */ +} |