eol.c revision 362181 
1/*
2 * eol.c :  generic eol/keyword routines
3 *
4 * ====================================================================
5 *    Licensed to the Apache Software Foundation (ASF) under one
6 *    or more contributor license agreements.  See the NOTICE file
7 *    distributed with this work for additional information
8 *    regarding copyright ownership.  The ASF licenses this file
9 *    to you under the Apache License, Version 2.0 (the
10 *    "License"); you may not use this file except in compliance
11 *    with the License.  You may obtain a copy of the License at
12 *
13 *      http://www.apache.org/licenses/LICENSE-2.0
14 *
15 *    Unless required by applicable law or agreed to in writing,
16 *    software distributed under the License is distributed on an
17 *    "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
18 *    KIND, either express or implied.  See the License for the
19 *    specific language governing permissions and limitations
20 *    under the License.
21 * ====================================================================
22 */
23
24
25
26#define APR_WANT_STRFUNC
27
28#include <apr_file_io.h>
29#include "svn_io.h"
30#include "private/svn_eol_private.h"
31#include "private/svn_dep_compat.h"
32
33char *
34svn_eol__find_eol_start(char *buf, apr_size_t len)
35{
36#if SVN_UNALIGNED_ACCESS_IS_OK
37
38  /* Scan the input one machine word at a time. */
39  for (; len > sizeof(apr_uintptr_t)
40       ; buf += sizeof(apr_uintptr_t), len -= sizeof(apr_uintptr_t))
41    {
42      /* This is a variant of the well-known strlen test: */
43      apr_uintptr_t chunk = *(const apr_uintptr_t *)buf;
44
45      /* A byte in SVN__R_TEST is \0, iff it was \r in *BUF.
46       * Similarly, SVN__N_TEST is an indicator for \n. */
47      apr_uintptr_t r_test = chunk ^ SVN__R_MASK;
48      apr_uintptr_t n_test = chunk ^ SVN__N_MASK;
49
50      /* A byte in SVN__R_TEST can only be < 0x80, iff it has been \0 before
51       * (i.e. \r in *BUF). Ditto for SVN__N_TEST. */
52      r_test |= (r_test & SVN__LOWER_7BITS_SET) + SVN__LOWER_7BITS_SET;
53      n_test |= (n_test & SVN__LOWER_7BITS_SET) + SVN__LOWER_7BITS_SET;
54
55      /* Check whether at least one of the words contains a byte <0x80
56       * (if one is detected, there was a \r or \n in CHUNK). */
57      if ((r_test & n_test & SVN__BIT_7_SET) != SVN__BIT_7_SET)
58        break;
59    }
60
61#endif
62
63  /* The remaining odd bytes will be examined the naive way: */
64  for (; len > 0; ++buf, --len)
65    {
66      if (*buf == '\n' || *buf == '\r')
67        return buf;
68    }
69
70  return NULL;
71}
72
73const char *
74svn_eol__detect_eol(char *buf, apr_size_t len, char **eolp)
75{
76  char *eol;
77
78  eol = svn_eol__find_eol_start(buf, len);
79  if (eol)
80    {
81      if (eolp)
82        *eolp = eol;
83
84      if (*eol == '\n')
85        return "\n";
86
87      /* We found a CR. */
88      ++eol;
89      if (eol == buf + len || *eol != '\n')
90        return "\r";
91      return "\r\n";
92    }
93
94  return NULL;
95}
96