source: vendor/diffutils/2.8.1/src/context.c@ 2603

/* Context-format output routines for GNU DIFF.

   Copyright (C) 1988, 1989, 1991, 1992, 1993, 1994, 1995, 1998, 2001,
   2002 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 2, 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 this program; see the file COPYING.
   If not, write to the Free Software Foundation,
   59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

#include "diff.h"
#include <inttostr.h>
#include <regex.h>

#ifdef ST_MTIM_NSEC
# define TIMESPEC_NS(timespec) ((timespec).ST_MTIM_NSEC)
#else
# define TIMESPEC_NS(timespec) 0
#endif

size_t nstrftime (char *, size_t, char const *, struct tm const *, int, int);

static char const *find_function (char const * const *, lin);
static struct change *find_hunk (struct change *);
static void mark_ignorable (struct change *);
static void pr_context_hunk (struct change *);
static void pr_unidiff_hunk (struct change *);

/* Last place find_function started searching from.  */
static lin find_function_last_search;

/* The value find_function returned when it started searching there.  */
static lin find_function_last_match;


/* Print a label for a context diff, with a file name and date or a label.  */

static void
print_context_label (char const *mark,
                     struct file_data *inf,
                     char const *label)
{
  if (label)
    fprintf (outfile, "%s %s\n", mark, label);
  else
    {
      char buf[MAX (INT_STRLEN_BOUND (int) + 32,
                    INT_STRLEN_BOUND (time_t) + 11)];
      struct tm const *tm = localtime (&inf->stat.st_mtime);
      int nsec = TIMESPEC_NS (inf->stat.st_mtim);
      if (! (tm && nstrftime (buf, sizeof buf, time_format, tm, 0, nsec)))
        {
          long sec = inf->stat.st_mtime;
          verify (info_preserved, sizeof inf->stat.st_mtime <= sizeof sec);
          sprintf (buf, "%ld.%.9d", sec, nsec);
        }
      fprintf (outfile, "%s %s\t%s\n", mark, inf->name, buf);
    }
}

/* Print a header for a context diff, with the file names and dates.  */

void
print_context_header (struct file_data inf[], bool unidiff)
{
  if (unidiff)
    {
      print_context_label ("---", &inf[0], file_label[0]);
      print_context_label ("+++", &inf[1], file_label[1]);
    }
  else
    {
      print_context_label ("***", &inf[0], file_label[0]);
      print_context_label ("---", &inf[1], file_label[1]);
    }
}

/* Print an edit script in context format.  */

void
print_context_script (struct change *script, bool unidiff)
{
  if (ignore_blank_lines || ignore_regexp.fastmap)
    mark_ignorable (script);
  else
    {
      struct change *e;
      for (e = script; e; e = e->link)
        e->ignore = 0;
    }

  find_function_last_search = - files[0].prefix_lines;
  find_function_last_match = LIN_MAX;

  if (unidiff)
    print_script (script, find_hunk, pr_unidiff_hunk);
  else
    print_script (script, find_hunk, pr_context_hunk);
}


/* Print a pair of line numbers with a comma, translated for file FILE.
   If the second number is not greater, use the first in place of it.

   Args A and B are internal line numbers.
   We print the translated (real) line numbers.  */

static void
print_context_number_range (struct file_data const *file, lin a, lin b)
{
  long trans_a, trans_b;
  translate_range (file, a, b, &trans_a, &trans_b);

  /* We can have B <= A in the case of a range of no lines.
     In this case, we should print the line number before the range,
     which is B.

     POSIX 1003.1-2001 requires two line numbers separated by a comma
     even if the line numbers are the same.  However, this does not
     match existing practice and is surely an error in the
     specification.  */

  if (trans_b <= trans_a)
    fprintf (outfile, "%ld", trans_b);
  else
    fprintf (outfile, "%ld,%ld", trans_a, trans_b);
}

/* Print FUNCTION in a context header.  */
static void
print_context_function (FILE *out, char const *function)
{
  int i;
  putc (' ', out);
  for (i = 0; i < 40 && function[i] != '\n'; i++)
    continue;
  fwrite (function, 1, i, out);
}


/* Print a portion of an edit script in context format.
   HUNK is the beginning of the portion to be printed.
   The end is marked by a `link' that has been nulled out.

   Prints out lines from both files, and precedes each
   line with the appropriate flag-character.  */

static void
pr_context_hunk (struct change *hunk)
{
  lin first0, last0, first1, last1, i;
  char const *prefix;
  char const *function;
  FILE *out;

  /* Determine range of line numbers involved in each file.  */

  enum changes changes = analyze_hunk (hunk, &first0, &last0, &first1, &last1);
  if (! changes)
    return;

  /* Include a context's width before and after.  */

  i = - files[0].prefix_lines;
  first0 = MAX (first0 - context, i);
  first1 = MAX (first1 - context, i);
  if (last0 < files[0].valid_lines - context)
    last0 += context;
  else
    last0 = files[0].valid_lines - 1;
  if (last1 < files[1].valid_lines - context)
    last1 += context;
  else
    last1 = files[1].valid_lines - 1;

  /* If desired, find the preceding function definition line in file 0.  */
  function = 0;