/* Shared definitions for GNU DIFF
   Copyright (C) 1988, 1989 Free Software Foundation, Inc.

This file is part of GNU DIFF.

GNU DIFF 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 1, or (at your option)
any later version.

GNU DIFF 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 GNU DIFF; see the file COPYING.  If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */


#include <ctype.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>

#ifdef USG
#include <time.h>
#ifdef HAVE_NDIR
#include <ndir.h>
#else
#include <dirent.h>
#endif /* not HAVE_NDIR */
#include <fcntl.h>
#ifndef HAVE_DIRECT
#define direct dirent
#endif
#else /* not USG */
#include <sys/time.h>
#include <sys/dir.h>
#include <sys/file.h>
#endif

#ifdef USG
/* Define needed BSD functions in terms of sysV library.  */

#define bcopy(s,d,n)	memcpy((d),(s),(n))
#define bcmp(s1,s2,n)	memcmp((s1),(s2),(n))
#define bzero(s,n)	memset((s),0,(n))

#define dup2(f,t)	(close(t),fcntl((f),F_DUPFD,(t)))

#define vfork	fork
#define index	strchr
#define rindex	strrchr
#endif

#include <errno.h>
extern int      errno;
extern int      sys_nerr;
extern char    *sys_errlist[];

#define	EOS		(0)
#define	FALSE		(0)
#define TRUE		1

#define LINKSIZE	1024

#define min(a,b) ((a) <= (b) ? (a) : (b))
#define max(a,b) ((a) >= (b) ? (a) : (b))

#ifndef PR_FILE_NAME
#define PR_FILE_NAME "/bin/pr"
#endif

/* Support old-fashioned C compilers.  */
#if defined (__STDC__) || defined (__GNUC__)
#include "limits.h"
#else
#define INT_MAX 2147483647
#define CHAR_BIT 8
#endif

/* Support old-fashioned C compilers.  */
#if !defined (__STDC__) && !defined (__GNUC__)
#define const
#endif

/* Variables for command line options */

#ifndef GDIFF_MAIN
#define EXTERN extern
#else
#define EXTERN
#endif

enum output_style {
  /* Default output style.  */
  OUTPUT_NORMAL,
  /* Output the differences with lines of context before and after (-c).  */
  OUTPUT_CONTEXT,
  /* Output the differences as commands suitable for `ed' (-e).  */
  OUTPUT_ED,
  /* Output the diff as a forward ed script (-f).  */
  OUTPUT_FORWARD_ED,
  /* Like -f, but output a count of changed lines in each "command" (-n). */
  OUTPUT_RCS,
  /* Output merged #ifdef'd file (-D).  */
  OUTPUT_IFDEF };

EXTERN enum output_style output_style;

/* Number of lines of context to show in each set of diffs.
   This is zero when context is not to be shown.  */
EXTERN int      context;

/* Consider all files as text files (-a).
   Don't interpret codes over 0177 as implying a "binary file".  */
EXTERN int	always_text_flag;

/* Ignore changes in horizontal whitespace (-b).  */
EXTERN int      ignore_space_change_flag;

/* Ignore all horizontal whitespace (-w).  */
EXTERN int      ignore_all_space_flag;

/* Ignore changes that affect only blank lines (-B).  */
EXTERN int      ignore_blank_lines_flag;

/* Ignore changes that affect only lines matching this regexp (-I).  */
EXTERN char	*ignore_regexp;

/* Result of regex-compilation of `ignore_regexp'.  */
EXTERN struct re_pattern_buffer ignore_regexp_compiled;

/* 1 if lines may match even if their lengths are different.
   This depends on various options.  */
EXTERN int      length_varies;

/* Ignore differences in case of letters (-i).  */
EXTERN int      ignore_case_flag;

/* Regexp to identify function-header lines (-F).  */
EXTERN char	*function_regexp;

/* Result of regex-compilation of `function_regexp'.  */
EXTERN struct re_pattern_buffer function_regexp_compiled;

/* Say only whether files differ, not how (-q).  */
EXTERN int 	no_details_flag;

/* Report files compared that match (-s).
   Normally nothing is output when that happens.  */
EXTERN int      print_file_same_flag;

/* character that ends a line.  Currently this is always `\n'.  */
EXTERN char     line_end_char;

/* Output the differences with exactly 8 columns added to each line
   so that any tabs in the text line up properly (-T).  */
EXTERN int	tab_align_flag;

/* Expand tabs in the output so the text lines up properly
   despite the characters added to the front of each line (-t).  */
EXTERN int	tab_expand_flag;

/* In directory comparison, specify file to start with (-S).
   All file names less than this name are ignored.  */
EXTERN char	*dir_start_file;

/* If a file is new (appears in only one dir)
   include its entire contents (-N).
   Then `patch' would create the file with appropriate contents.  */
EXTERN int	entire_new_file_flag;

/* Pipe each file's output through pr (-l).  */
EXTERN int	paginate_flag;

/* String to use for #ifdef (-D).  */
EXTERN char *	ifdef_string;

/* String containing all the command options diff received,
   with spaces between and at the beginning but none at the end.
   If there were no options given, this string is empty.  */
EXTERN char *	switch_string;

/* Nonzero means use heuristics for better speed.  */
EXTERN int	heuristic;

/* Name of program the user invoked (for error messages).  */
EXTERN char *	program;

/* The result of comparison is an "edit script": a chain of `struct change'.
   Each `struct change' represents one place where some lines are deleted
   and some are inserted.
   
   LINE0 and LINE1 are the first affected lines in the two files (origin 0).
   DELETED is the number of lines deleted here from file 0.
   INSERTED is the number of lines inserted here in file 1.

   If DELETED is 0 then LINE0 is the number of the line before
   which the insertion was done; vice versa for INSERTED and LINE1.  */

struct change
{
  struct change *link;		/* Previous or next edit command  */
  int inserted;			/* # lines of file 1 changed here.  */
  int deleted;			/* # lines of file 0 changed here.  */
  int line0;			/* Line number of 1st deleted line.  */
  int line1;			/* Line number of 1st inserted line.  */
  char ignore;			/* Flag used in context.c */
};

/* Structures that describe the input files.  */

/* Data on one line of text.  */

struct line_def {
    char        *text;
    int         length;
    unsigned	hash;
};

/* Data on one input file being compared.  */

struct file_data {
    int             desc;	/* File descriptor  */
    char           *name;	/* File name  */
    struct stat     stat;	/* File status from fstat()  */
    int             dir_p;	/* 1 if file is a directory  */

    /* Buffer in which text of file is read.  */
    char *	    buffer;
    /* Allocated size of buffer.  */
    int		    bufsize;
    /* Number of valid characters now in the buffer. */
    int		    buffered_chars;

    /* Array of data on analyzed lines of this chunk of this file.  */
    struct line_def *linbuf;

    /* Allocated size of linbuf array (# of elements).  */
    int		    linbufsize;

    /* Number of elements of linbuf containing valid data. */
    int		    buffered_lines;

    /* Pointer to end of prefix of this file to ignore when hashing. */
    char *prefix_end;

    /* Count of lines in the prefix. */
    int prefix_lines;

    /* Pointer to start of suffix of this file to ignore when hashing. */
    char *suffix_begin;

    /* Count of lines in the suffix. */
    int suffix_lines;

    /* Vector, indexed by line number, containing an equivalence code for
       each line.  It is this vector that is actually compared with that
       of another file to generate differences. */
    int		   *equivs;

    /* Vector, like the previous one except that
       the elements for discarded lines have been squeezed out.  */
    int		   *undiscarded;

    /* Vector mapping virtual line numbers (not counting discarded lines)
       to real ones (counting those lines).  Both are origin-0.  */
    int		   *realindexes;

    /* Total number of nondiscarded lines. */
    int		    nondiscarded_lines;

    /* Vector, indexed by real origin-0 line number,
       containing 1 for a line that is an insertion or a deletion.
       The results of comparison are stored here.  */
    char	   *changed_flag;

    /* 1 if file ends in a line with no final newline. */
    int		    missing_newline;

    /* 1 more than the maximum equivalence value used for this or its
       sibling file. */
    int equiv_max;

    /* Table translating diff's internal line numbers 
       to actual line numbers in the file.
       This is needed only when some lines have been discarded.
       The allocated size is always linbufsize
       and the number of valid elements is buffered_lines.  */
    int		   *ltran;
};

/* info on symlink stuff */
struct link_data {
    char	   buf[LINKSIZE];
    int		   size;
};

/* Describe the two files currently being compared.  */

struct file_data files[2];

/* Queue up one-line messages to be printed at the end,
   when -l is specified.  Each message is recorded with a `struct msg'.  */

struct msg
{
  struct msg *next;
  char *format;
  char *arg1;
  char *arg2;
};

/* Head of the chain of queues messages.  */

EXTERN struct msg *msg_chain;

/* Tail of the chain of queues messages.  */

EXTERN struct msg *msg_chain_end;

/* Stdio stream to output diffs to.  */

EXTERN FILE *outfile;

/* Declare various functions.  */

#ifdef __STDC__
#define VOID void
#else
#define VOID char
#endif
VOID *xmalloc ();
VOID *xrealloc ();
char *concat ();
void free ();
char *rindex ();
char *index ();

void analyze_hunk ();
void error ();
void fatal ();
void message ();
void perror_with_name ();
void pfatal_with_name ();
void print_1_line ();
void print_message_queue ();
void print_script ();
