/* GNU m4 -- A simple macro processor

   Copyright (C) 1989-1994, 2004-2014, 2016 Free Software Foundation,
   Inc.

   This file is part of GNU M4.

   GNU M4 is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   GNU M4 is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

/* We use <config.h> instead of "config.h" so that a compilation
   using -I. -I$srcdir will use ./config.h rather than $srcdir/config.h
   (which it would do because it found this file in $srcdir).  */

#include <config.h>

#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <stdbool.h>
#include <stdint.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>

#include "binary-io.h"
#include "clean-temp.h"
#include "cloexec.h"
#include "close-stream.h"
#include "closein.h"
#include "dirname.h"
#include "error.h"
#include "exitfail.h"
#include "filenamecat.h"
#include "obstack.h"
#include "stdio--.h"
#include "stdlib--.h"
#include "unistd--.h"
#include "verror.h"
#include "xalloc.h"
#include "xprintf.h"
#include "xvasprintf.h"

/* Canonicalize UNIX recognition macros.  */
#if defined unix || defined __unix || defined __unix__ \
  || defined _POSIX_VERSION || defined _POSIX2_VERSION \
  || defined __NetBSD__ || defined __OpenBSD__ \
  || defined __APPLE__ || defined __APPLE_CC__
# define UNIX 1
#endif

/* Canonicalize Windows recognition macros.  */
#if (defined _WIN32 || defined __WIN32__) && !defined __CYGWIN__
# define W32_NATIVE 1
#endif

/* Canonicalize OS/2 recognition macro.  */
#ifdef __EMX__
# define OS2 1
# undef UNIX
#endif

/* Used if any programmer error is detected (not possible, right?)  */
#define EXIT_INTERNAL_ERROR 2

/* Used for version mismatch, when -R detects a frozen file it can't parse.  */
#define EXIT_MISMATCH 63

/* No-op, for future gettext compatibility.  */
#define _(ARG) ARG

/* Various declarations.  */

struct string
  {
    char *string;               /* characters of the string */
    size_t length;              /* length of the string */
  };
typedef struct string STRING;

/* Memory allocation.  */
#define obstack_chunk_alloc     xmalloc
#define obstack_chunk_free      free

/* Those must come first.  */
typedef struct token_data token_data;
typedef void builtin_func (struct obstack *, int, token_data **);

/* Gnulib's stdbool doesn't work with bool bitfields.  For nicer
   debugging, use bool when we know it works, but use the more
   portable unsigned int elsewhere.  */
#if __GNUC__ > 2
typedef bool bool_bitfield;
#else
typedef unsigned int bool_bitfield;
#endif /* ! __GNUC__ */

/* Take advantage of GNU C compiler source level optimization hints,
   using portable macros.  */
#if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ > 6)
# define M4_GNUC_ATTRIBUTE(args)        __attribute__ (args)
#else
# define M4_GNUC_ATTRIBUTE(args)
#endif  /* __GNUC__ */

#define M4_GNUC_UNUSED          M4_GNUC_ATTRIBUTE ((__unused__))
#define M4_GNUC_PRINTF(fmt, arg)                        \
  M4_GNUC_ATTRIBUTE ((__format__ (__printf__, fmt, arg)))
#define M4_GNUC_NORETURN        M4_GNUC_ATTRIBUTE ((__noreturn__))
#define M4_GNUC_PURE            M4_GNUC_ATTRIBUTE ((__pure__))

/* File: m4.c  --- global definitions.  */

/* Option flags.  */
extern int sync_output;                 /* -s */
extern int debug_level;                 /* -d */
extern size_t hash_table_size;          /* -H */
extern int no_gnu_extensions;           /* -G */
extern int prefix_all_builtins;         /* -P */
extern int max_debug_argument_length;   /* -l */
extern int suppress_warnings;           /* -Q */
extern int warning_status;              /* -E */
extern int nesting_limit;               /* -L */
#ifdef ENABLE_CHANGEWORD
extern const char *user_word_regexp;    /* -W */
#endif

/* Error handling.  */
extern int retcode;

extern void m4_error (int, int, const char *, ...) M4_GNUC_PRINTF(3, 4);
extern void m4_error_at_line (int, int, const char *, int,
                              const char *, ...) M4_GNUC_PRINTF(5, 6);

#define M4ERROR(Arglist) (m4_error Arglist)
#define M4ERROR_AT_LINE(Arglist) (m4_error_at_line Arglist)


/* File: debug.c  --- debugging and tracing function.  */

extern FILE *debug;

/* The value of debug_level is a bitmask of the following.  */

/* a: show arglist in trace output */
#define DEBUG_TRACE_ARGS 1
/* e: show expansion in trace output */
#define DEBUG_TRACE_EXPANSION 2
/* q: quote args and expansion in trace output */
#define DEBUG_TRACE_QUOTE 4
/* t: trace all macros -- overrides trace{on,off} */
#define DEBUG_TRACE_ALL 8
/* l: add line numbers to trace output */
#define DEBUG_TRACE_LINE 16
/* f: add file name to trace output */
#define DEBUG_TRACE_FILE 32
/* p: trace path search of include files */
#define DEBUG_TRACE_PATH 64
/* c: show macro call before args collection */
#define DEBUG_TRACE_CALL 128
/* i: trace changes of input files */
#define DEBUG_TRACE_INPUT 256
/* x: add call id to trace output */
#define DEBUG_TRACE_CALLID 512

/* V: very verbose --  print everything */
#define DEBUG_TRACE_VERBOSE 1023
/* default flags -- equiv: aeq */
#define DEBUG_TRACE_DEFAULT 7

#define DEBUG_PRINT1(Fmt, Arg1) \
  do                                                            \
    {                                                           \
      if (debug != NULL)                                        \
        xfprintf (debug, Fmt, Arg1);                            \
    }                                                           \
  while (0)

#define DEBUG_PRINT3(Fmt, Arg1, Arg2, Arg3) \
  do                                                            \
    {                                                           \
      if (debug != NULL)                                        \
        xfprintf (debug, Fmt, Arg1, Arg2, Arg3);                \
    }                                                           \
  while (0)

#define DEBUG_MESSAGE(Fmt) \
  do                                                            \
    {                                                           \
      if (debug != NULL)                                        \
        {                                                       \
          debug_message_prefix ();                              \
          xfprintf (debug, Fmt);                                \
          putc ('\n', debug);                                   \
        }                                                       \
    }                                                           \
  while (0)

#define DEBUG_MESSAGE1(Fmt, Arg1) \
  do                                                            \
    {                                                           \
      if (debug != NULL)                                        \
        {                                                       \
          debug_message_prefix ();                              \
          xfprintf (debug, Fmt, Arg1);                          \
          putc ('\n', debug);                                   \
        }                                                       \
    }                                                           \
  while (0)

#define DEBUG_MESSAGE2(Fmt, Arg1, Arg2) \
  do                                                            \
    {                                                           \
      if (debug != NULL)                                        \
        {                                                       \
          debug_message_prefix ();                              \
          xfprintf (debug, Fmt, Arg1, Arg2);                    \
          putc ('\n', debug);                                   \
        }                                                       \
    }                                                           \
  while (0)

extern void debug_init (void);
extern int debug_decode (const char *);
extern void debug_flush_files (void);
extern bool debug_set_output (const char *);
extern void debug_message_prefix (void);

extern void trace_prepre (const char *, int);
extern void trace_pre (const char *, int, int, token_data **);
extern void trace_post (const char *, int, int, const char *);

/* File: input.c  --- lexical definitions.  */

/* Various different token types.  */
enum token_type
{
  TOKEN_EOF,                    /* end of file */
  TOKEN_STRING,                 /* a quoted string or comment */
  TOKEN_WORD,                   /* an identifier */
  TOKEN_OPEN,                   /* ( */
  TOKEN_COMMA,                  /* , */
  TOKEN_CLOSE,                  /* ) */
  TOKEN_SIMPLE,                 /* any other single character */
  TOKEN_MACDEF                  /* a macro's definition (see "defn") */
};

/* The data for a token, a macro argument, and a macro definition.  */
enum token_data_type
{
  TOKEN_VOID,
  TOKEN_TEXT,
  TOKEN_FUNC
};

struct token_data
{
  enum token_data_type type;
  union
    {
      struct
        {
          char *text;
#ifdef ENABLE_CHANGEWORD
          char *original_text;
#endif
        }
      u_t;
      builtin_func *func;
    }
  u;
};

#define TOKEN_DATA_TYPE(Td)             ((Td)->type)
#define TOKEN_DATA_TEXT(Td)             ((Td)->u.u_t.text)
#ifdef ENABLE_CHANGEWORD
# define TOKEN_DATA_ORIG_TEXT(Td)       ((Td)->u.u_t.original_text)
#endif
#define TOKEN_DATA_FUNC(Td)             ((Td)->u.func)

typedef enum token_type token_type;
typedef enum token_data_type token_data_type;

extern void input_init (void);
extern token_type peek_token (void);
extern token_type next_token (token_data *, int *);
extern void skip_line (void);

/* push back input */
extern void push_file (FILE *, const char *, bool);
extern void push_macro (builtin_func *);
extern struct obstack *push_string_init (void);
extern const char *push_string_finish (void);
extern void push_wrapup (const char *);
extern bool pop_wrapup (void);

/* current input file, and line */
extern const char *current_file;
extern int current_line;

/* left and right quote, begin and end comment */
extern STRING bcomm;
extern STRING ecomm;
extern STRING lquote;
extern STRING rquote;

#define DEF_LQUOTE "`"
#define DEF_RQUOTE "\'"
#define DEF_BCOMM "#"
#define DEF_ECOMM "\n"

extern void set_quotes (const char *, const char *);
extern void set_comment (const char *, const char *);
#ifdef ENABLE_CHANGEWORD
extern void set_word_regexp (const char *);
#endif

/* File: output.c --- output functions.  */
extern int current_diversion;
extern int output_current_line;

extern void output_init (void);
extern void output_exit (void);
extern void output_text (const char *, int);
extern void shipout_text (struct obstack *, const char *, int, int);
extern void make_diversion (int);
extern void insert_diversion (int);
extern void insert_file (FILE *);
extern void freeze_diversions (FILE *);

/* File symtab.c  --- symbol table definitions.  */

/* Operation modes for lookup_symbol ().  */
enum symbol_lookup
{
  SYMBOL_LOOKUP,
  SYMBOL_INSERT,
  SYMBOL_DELETE,
  SYMBOL_PUSHDEF,
  SYMBOL_POPDEF
};

/* Symbol table entry.  */
struct symbol
{
  struct symbol *next;
  bool_bitfield traced : 1;
  bool_bitfield shadowed : 1;
  bool_bitfield macro_args : 1;
  bool_bitfield blind_no_args : 1;
  bool_bitfield deleted : 1;
  int pending_expansions;

  char *name;
  token_data data;
};

#define SYMBOL_NEXT(S)          ((S)->next)
#define SYMBOL_TRACED(S)        ((S)->traced)
#define SYMBOL_SHADOWED(S)      ((S)->shadowed)
#define SYMBOL_MACRO_ARGS(S)    ((S)->macro_args)
#define SYMBOL_BLIND_NO_ARGS(S) ((S)->blind_no_args)
#define SYMBOL_DELETED(S)       ((S)->deleted)
#define SYMBOL_PENDING_EXPANSIONS(S) ((S)->pending_expansions)
#define SYMBOL_NAME(S)          ((S)->name)
#define SYMBOL_TYPE(S)          (TOKEN_DATA_TYPE (&(S)->data))
#define SYMBOL_TEXT(S)          (TOKEN_DATA_TEXT (&(S)->data))
#define SYMBOL_FUNC(S)          (TOKEN_DATA_FUNC (&(S)->data))

typedef enum symbol_lookup symbol_lookup;
typedef struct symbol symbol;
typedef void hack_symbol (symbol *, void *);

#define HASHMAX 509             /* default, overridden by -Hsize */

extern symbol **symtab;

extern void free_symbol (symbol *sym);
extern void symtab_init (void);
extern symbol *lookup_symbol (const char *, symbol_lookup);
extern void hack_all_symbols (hack_symbol *, void *);

/* File: macro.c  --- macro expansion.  */

extern int expansion_level;

extern void expand_input (void);
extern void call_macro (symbol *, int, token_data **, struct obstack *);

/* File: builtin.c  --- builtins.  */

struct builtin
{
  const char *name;
  bool_bitfield gnu_extension : 1;
  bool_bitfield groks_macro_args : 1;
  bool_bitfield blind_if_no_args : 1;
  builtin_func *func;
};

struct predefined
{
  const char *unix_name;
  const char *gnu_name;
  const char *func;
};

typedef struct builtin builtin;
typedef struct predefined predefined;
struct re_pattern_buffer;
struct re_registers;

/* The default sequence detects multi-digit parameters (obsolete after
   1.4.x), and any use of extended arguments with the default ${}
   syntax (new in 2.0).  */
#define DEFAULT_MACRO_SEQUENCE "\\$\\({[^}]*}\\|[0-9][0-9]+\\)"

extern void builtin_init (void);
extern void define_builtin (const char *, const builtin *, symbol_lookup);
extern void set_macro_sequence (const char *);
extern void free_macro_sequence (void);
extern void define_user_macro (const char *, const char *, symbol_lookup);
extern void undivert_all (void);
extern void expand_user_macro (struct obstack *, symbol *, int, token_data **);
extern void m4_placeholder (struct obstack *, int, token_data **);
extern void init_pattern_buffer (struct re_pattern_buffer *,
                                 struct re_registers *);
extern const char *ntoa (int32_t, int);

extern const builtin *find_builtin_by_addr (builtin_func *);
extern const builtin *find_builtin_by_name (const char *);

/* File: path.c  --- path search for include files.  */

extern void include_init (void);
extern void include_env_init (void);
extern void add_include_directory (const char *);
extern FILE *m4_path_search (const char *, char **);

/* File: eval.c  --- expression evaluation.  */

extern bool evaluate (const char *, int32_t *);

/* File: format.c  --- printf like formatting.  */

extern void expand_format (struct obstack *, int, token_data **);

/* File: freeze.c --- frozen state files.  */

extern void produce_frozen_state (const char *);
extern void reload_frozen_state (const char *);

/* Debugging the memory allocator.  */

#ifdef WITH_DMALLOC
# define DMALLOC_FUNC_CHECK
# include <dmalloc.h>
#endif

/* Other debug stuff.  */

#ifdef DEBUG
# define DEBUG_INCL   1
# define DEBUG_INPUT  1
# define DEBUG_MACRO  1
# define DEBUG_OUTPUT 1
# define DEBUG_STKOVF 1
# define DEBUG_SYM    1
#endif

/* Convert a possibly-signed character to an unsigned character.  This is
   a bit safer than casting to unsigned char, since it catches some type
   errors that the cast doesn't.  */
#if HAVE_INLINE
static inline unsigned char to_uchar (char ch) { return ch; }
#else
# define to_uchar(C) ((unsigned char) (C))
#endif

/* Avoid negative logic when comparing two strings.  */
#define STREQ(a, b) (strcmp (a, b) == 0)
