/* Locations for Bison

   Copyright (C) 2002, 2005-2015 Free Software Foundation, Inc.

   This file is part of Bison, the GNU Compiler Compiler.

   This program 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.

   This program 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/>.  */

#include <config.h>

#include "system.h"

#include <mbswidth.h>

#include <quotearg.h>

#include "complain.h"

#include "location.h"

location const empty_location = EMPTY_LOCATION_INIT;

/* If BUF is null, add BUFSIZE (which in this case must be less than

   INT_MAX) to COLUMN; otherwise, add mbsnwidth (BUF, BUFSIZE, 0) to

   COLUMN.  If an overflow occurs, or might occur but is undetectable,

   return INT_MAX.  Assume COLUMN is nonnegative.  */

static inline int

add_column_width (int column, char const *buf, size_t bufsize)

{

  size_t width;

  unsigned int remaining_columns = INT_MAX - column;

  if (buf)

    {

      if (INT_MAX / 2 <= bufsize)

        return INT_MAX;

      width = mbsnwidth (buf, bufsize, 0);

    }

  else

    width = bufsize;

  return width <= remaining_columns ? column + width : INT_MAX;

}

/* Set *LOC and adjust scanner cursor to account for token TOKEN of

   size SIZE.  */

void

location_compute (location *loc, boundary *cur, char const *token, size_t size)

{

  int line = cur->line;

  int column = cur->column;

  char const *p0 = token;

  char const *p = token;

  char const *lim = token + size;

  loc->start = *cur;

  for (p = token; p < lim; p++)

    switch (*p)

      {

      case '\n':

        line += line < INT_MAX;

        column = 1;

        p0 = p + 1;

        break;

      case '\t':

        column = add_column_width (column, p0, p - p0);

        column = add_column_width (column, NULL, 8 - ((column - 1) & 7));

        p0 = p + 1;

        break;

      default:

        break;

      }

  cur->line = line;

  cur->column = column = add_column_width (column, p0, p - p0);

  loc->end = *cur;

  if (line == INT_MAX && loc->start.line != INT_MAX)

    complain (loc, Wother, _("line number overflow"));

  if (column == INT_MAX && loc->start.column != INT_MAX)

    complain (loc, Wother, _("column number overflow"));

}

unsigned

location_print (location loc, FILE *out)

{

  unsigned res = 0;

  int end_col = 0 != loc.end.column ? loc.end.column - 1 : 0;

  res += fprintf (out, "%s",

                  quotearg_n_style (3, escape_quoting_style, loc.start.file));

  if (0 <= loc.start.line)

    {

      res += fprintf (out, ":%d", loc.start.line);

      if (0 <= loc.start.column)

        res += fprintf (out, ".%d", loc.start.column);

    }

  if (loc.start.file != loc.end.file)

    {

      res += fprintf (out, "-%s",

                      quotearg_n_style (3, escape_quoting_style,

                                        loc.end.file));

      if (0 <= loc.end.line)

        {

          res += fprintf (out, ":%d", loc.end.line);

          if (0 <= end_col)

            res += fprintf (out, ".%d", end_col);

        }

    }

  else if (0 <= loc.end.line)

    {

      if (loc.start.line < loc.end.line)

        {

          res += fprintf (out, "-%d", loc.end.line);

          if (0 <= end_col)

            res += fprintf (out, ".%d", end_col);

        }

      else if (0 <= end_col && loc.start.column < end_col)

        res += fprintf (out, "-%d", end_col);

    }

  return res;

}

/* Persistant data used by location_caret to avoid reopening and rereading the

   same file all over for each error.  */

struct caret_info

{

  FILE *source;

  size_t line;

  size_t offset;

};

static struct caret_info caret_info = { NULL, 1, 0 };

void

cleanup_caret ()

{

  if (caret_info.source)

    fclose (caret_info.source);

  caret_info.source = NULL;

  caret_info.line = 1;

  caret_info.offset = 0;

}

void

location_caret (location loc, FILE *out)

{

  /* FIXME: find a way to support multifile locations, and only open once each

     file. That would make the procedure future-proof.  */

  if (! (caret_info.source

         || (caret_info.source = fopen (loc.start.file, "r")))

      || loc.start.column == -1 || loc.start.line == -1)

    return;

  /* If the line we want to quote is seekable (the same line as the previous

     location), just seek it. If it was a previous line, we lost track of it,

     so return to the start of file.  */

  if (caret_info.line <= loc.start.line)

    fseek (caret_info.source, caret_info.offset, SEEK_SET);

  else

    {

      caret_info.line = 1;

      caret_info.offset = 0;

      fseek (caret_info.source, caret_info.offset, SEEK_SET);

    }

  /* Advance to the line's position, keeping track of the offset.  */

  while (caret_info.line < loc.start.line)

    caret_info.line += getc (caret_info.source) == '\n';

  caret_info.offset = ftell (caret_info.source);

  /* Read the actual line.  Don't update the offset, so that we keep a pointer

     to the start of the line.  */

  {

    int c = getc (caret_info.source);

    if (c != EOF)

      {

        /* Quote the file, indent by a single column.  */

        putc (' ', out);

        do

          putc (c, out);

        while ((c = getc (caret_info.source)) != EOF && c != '\n');

        putc ('\n', out);

        {

          /* The caret of a multiline location ends with the first line.  */

          size_t len = loc.start.line != loc.end.line

            ? ftell (caret_info.source) - caret_info.offset

            : loc.end.column;

          int i;

          /* Print the carets (at least one), with the same indent as above.*/

          fprintf (out, " %*s", loc.start.column - 1, "");

          for (i = loc.start.column; i == loc.start.column || i < len; ++i)

            putc ('^', out);

          }

        putc ('\n', out);

      }

  }

}

void

boundary_set_from_string (boundary *bound, char *loc_str)

{

  /* Must search in reverse since the file name field may

   * contain '.' or ':'.  */

  char *delim = strrchr (loc_str, '.');

  aver (delim);

  *delim = '\0';

  bound->column = atoi (delim+1);

  delim = strrchr (loc_str, ':');

  aver (delim);

  *delim = '\0';

  bound->line = atoi (delim+1);

  bound->file = uniqstr_new (loc_str);

}