1/* Locations for Bison
2
3   Copyright (C) 2002, 2005-2012 Free Software Foundation, Inc.
4
5   This file is part of Bison, the GNU Compiler Compiler.
6
7   This program is free software: you can redistribute it and/or modify
8   it under the terms of the GNU General Public License as published by
9   the Free Software Foundation, either version 3 of the License, or
10   (at your option) any later version.
11
12   This program is distributed in the hope that it will be useful,
13   but WITHOUT ANY WARRANTY; without even the implied warranty of
14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15   GNU General Public License for more details.
16
17   You should have received a copy of the GNU General Public License
18   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
19
20#include <config.h>
21#include "system.h"
22
23#include <mbswidth.h>
24#include <quotearg.h>
25
26#include "complain.h"
27#include "location.h"
28
29location const empty_location = EMPTY_LOCATION_INIT;
30
31/* If BUF is null, add BUFSIZE (which in this case must be less than
32   INT_MAX) to COLUMN; otherwise, add mbsnwidth (BUF, BUFSIZE, 0) to
33   COLUMN.  If an overflow occurs, or might occur but is undetectable,
34   return INT_MAX.  Assume COLUMN is nonnegative.  */
35
36static inline int
37add_column_width (int column, char const *buf, size_t bufsize)
38{
39  size_t width;
40  unsigned int remaining_columns = INT_MAX - column;
41
42  if (buf)
43    {
44      if (INT_MAX / 2 <= bufsize)
45	return INT_MAX;
46      width = mbsnwidth (buf, bufsize, 0);
47    }
48  else
49    width = bufsize;
50
51  return width <= remaining_columns ? column + width : INT_MAX;
52}
53
54/* Set *LOC and adjust scanner cursor to account for token TOKEN of
55   size SIZE.  */
56
57void
58location_compute (location *loc, boundary *cur, char const *token, size_t size)
59{
60  int line = cur->line;
61  int column = cur->column;
62  char const *p0 = token;
63  char const *p = token;
64  char const *lim = token + size;
65
66  loc->start = *cur;
67
68  for (p = token; p < lim; p++)
69    switch (*p)
70      {
71      case '\n':
72	line += line < INT_MAX;
73	column = 1;
74	p0 = p + 1;
75	break;
76
77      case '\t':
78	column = add_column_width (column, p0, p - p0);
79	column = add_column_width (column, NULL, 8 - ((column - 1) & 7));
80	p0 = p + 1;
81	break;
82
83      default:
84	break;
85      }
86
87  cur->line = line;
88  cur->column = column = add_column_width (column, p0, p - p0);
89
90  loc->end = *cur;
91
92  if (line == INT_MAX && loc->start.line != INT_MAX)
93    warn_at (*loc, _("line number overflow"));
94  if (column == INT_MAX && loc->start.column != INT_MAX)
95    warn_at (*loc, _("column number overflow"));
96}
97
98
99/* Output to OUT the location LOC.
100   Warning: it uses quotearg's slot 3.  */
101unsigned
102location_print (FILE *out, location loc)
103{
104  unsigned res = 0;
105  int end_col = 0 != loc.end.column ? loc.end.column - 1 : 0;
106  res += fprintf (out, "%s",
107                  quotearg_n_style (3, escape_quoting_style, loc.start.file));
108  if (0 <= loc.start.line)
109    {
110      res += fprintf (out, ":%d", loc.start.line);
111      if (0 <= loc.start.column)
112        res += fprintf (out, ".%d", loc.start.column);
113    }
114  if (loc.start.file != loc.end.file)
115    {
116      res += fprintf (out, "-%s",
117                      quotearg_n_style (3, escape_quoting_style,
118                                        loc.end.file));
119      if (0 <= loc.end.line)
120        {
121          res += fprintf (out, ":%d", loc.end.line);
122          if (0 <= end_col)
123            res += fprintf (out, ".%d", end_col);
124        }
125    }
126  else if (0 <= loc.end.line)
127    {
128      if (loc.start.line < loc.end.line)
129        {
130          res += fprintf (out, "-%d", loc.end.line);
131          if (0 <= end_col)
132            res += fprintf (out, ".%d", end_col);
133        }
134      else if (0 <= end_col && loc.start.column < end_col)
135        res += fprintf (out, "-%d", end_col);
136    }
137
138  return res;
139}
140
141
142/* Persistant data used by location_caret to avoid reopening and rereading the
143   same file all over for each error.  */
144struct caret_info
145{
146  FILE *source;
147  size_t line;
148  size_t offset;
149};
150
151static struct caret_info caret_info = { NULL, 1, 0 };
152
153void
154cleanup_caret ()
155{
156  if (caret_info.source)
157    fclose (caret_info.source);
158}
159
160void
161location_caret (FILE *out, location loc)
162{
163  /* FIXME: find a way to support multifile locations, and only open once each
164     file. That would make the procedure future-proof.  */
165  if (! (caret_info.source
166         || (caret_info.source = fopen (loc.start.file, "r")))
167      || loc.start.column == -1 || loc.start.line == -1)
168    return;
169
170  /* If the line we want to quote is seekable (the same line as the previous
171     location), just seek it. If it was before, we lost track of it, so
172     return to the start of file.  */
173  if (caret_info.line <= loc.start.line)
174    fseek (caret_info.source, caret_info.offset, SEEK_SET);
175  else
176    {
177      caret_info.line = 1;
178      caret_info.offset = 0;
179      fseek (caret_info.source, caret_info.offset, SEEK_SET);
180    }
181
182  /* Advance to the line's position, keeping track of the offset.  */
183  while (caret_info.line < loc.start.line)
184    caret_info.line += fgetc (caret_info.source) == '\n';
185  caret_info.offset = ftell (caret_info.source);
186
187  /* Read the actual line.  Don't update the offset, so that we keep a pointer
188     to the start of the line.  */
189  {
190    char *buf = NULL;
191    size_t size = 0;
192    ssize_t len = getline (&buf, &size, caret_info.source);
193    if (0 < len)
194      {
195        /* The caret of a multiline location ends with the first line.  */
196        int end = loc.start.line != loc.end.line ? len : loc.end.column;
197
198        /* Quote the file, indent by a single column.  */
199        fputc (' ', out);
200        fwrite (buf, 1, len, out);
201
202        /* Print the caret, with the same indent as above.  */
203        fprintf (out, " %*s", loc.start.column - 1, "");
204        {
205          int i = loc.start.column;
206          do
207            fputc ('^', out);
208          while (++i < end);
209        }
210        fputc ('\n', out);
211      }
212    free (buf);
213  }
214}
215
216void
217boundary_set_from_string (boundary *bound, char *loc_str)
218{
219  /* Must search in reverse since the file name field may
220   * contain `.' or `:'.  */
221  char *delim = mbsrchr (loc_str, '.');
222  aver (delim);
223  *delim = '\0';
224  bound->column = atoi (delim+1);
225  delim = mbsrchr (loc_str, ':');
226  aver (delim);
227  *delim = '\0';
228  bound->line = atoi (delim+1);
229  bound->file = uniqstr_new (loc_str);
230}
231