contrib/libarchive/libarchive_fe/line_reader.c

   1 /*-
   2  * Copyright (c) 2008 Tim Kientzle
   3  * Copyright (c) 2010 Joerg Sonnenberger
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer
  11  *    in this position and unchanged.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
  17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  19  * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
  20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26  */
  27
  28 #include "lafe_platform.h"
  29 __FBSDID("$FreeBSD$");
  30
  31 #include <errno.h>
  32 #include <stdio.h>
  33 #include <stdlib.h>
  34 #include <string.h>
  35
  36 #include "err.h"
  37 #include "line_reader.h"
  38
  39 #if defined(_WIN32) && !defined(__CYGWIN__) && !defined(__BORLANDC__)
  40 #define strdup _strdup
  41 #endif
  42
  43 /*
  44  * Read lines from file and do something with each one.  If option_null
  45  * is set, lines are terminated with zero bytes; otherwise, they're
  46  * terminated with newlines.
  47  *
  48  * This uses a self-sizing buffer to handle arbitrarily-long lines.
  49  */
  50 struct lafe_line_reader {
  51         FILE *f;
  52         char *buff, *buff_end, *line_start, *line_end;
  53         char *pathname;
  54         size_t buff_length;
  55         int nullSeparator; /* Lines separated by null, not CR/CRLF/etc. */
  56 };
  57
  58 struct lafe_line_reader *
  59 lafe_line_reader(const char *pathname, int nullSeparator)
  60 {
  61         struct lafe_line_reader *lr;
  62
  63         lr = calloc(1, sizeof(*lr));
  64         if (lr == NULL)
  65                 lafe_errc(1, ENOMEM, "Can't open %s", pathname);
  66
  67         lr->nullSeparator = nullSeparator;
  68         lr->pathname = strdup(pathname);
  69
  70         if (strcmp(pathname, "-") == 0)
  71                 lr->f = stdin;
  72         else
  73                 lr->f = fopen(pathname, "r");
  74         if (lr->f == NULL)
  75                 lafe_errc(1, errno, "Couldn't open %s", pathname);
  76         lr->buff_length = 8192;
  77         lr->line_start = lr->line_end = lr->buff_end = lr->buff = NULL;
  78
  79         return (lr);
  80 }
  81
  82 static void
  83 lafe_line_reader_find_eol(struct lafe_line_reader *lr)
  84 {
  85
  86         lr->line_end += strcspn(lr->line_end,
  87             lr->nullSeparator ? "" : "\x0d\x0a");
  88         *lr->line_end = '\0'; /* Noop if line_end == buff_end */
  89 }
  90
  91 const char *
  92 lafe_line_reader_next(struct lafe_line_reader *lr)
  93 {
  94         size_t bytes_wanted, bytes_read, new_buff_size;
  95         char *line_start, *p;
  96
  97         for (;;) {
  98                 /* If there's a line in the buffer, return it immediately. */
  99                 while (lr->line_end < lr->buff_end) {
 100                         line_start = lr->line_start;
 101                         lr->line_start = ++lr->line_end;
 102                         lafe_line_reader_find_eol(lr);
 103
 104                         if (lr->nullSeparator || line_start[0] != '\0')
 105                                 return (line_start);
 106                 }
 107
 108                 /* If we're at end-of-file, process the final data. */
 109                 if (lr->f == NULL) {
 110                         if (lr->line_start == lr->buff_end)
 111                                 return (NULL); /* No more text */
 112                         line_start = lr->line_start;
 113                         lr->line_start = lr->buff_end;
 114                         return (line_start);
 115                 }
 116
 117                 /* Buffer only has part of a line. */
 118                 if (lr->line_start > lr->buff) {
 119                         /* Move a leftover fractional line to the beginning. */
 120                         memmove(lr->buff, lr->line_start,
 121                             lr->buff_end - lr->line_start);
 122                         lr->buff_end -= lr->line_start - lr->buff;
 123                         lr->line_end -= lr->line_start - lr->buff;
 124                         lr->line_start = lr->buff;
 125                 } else {
 126                         /* Line is too big; enlarge the buffer. */
 127                         new_buff_size = lr->buff_length * 2;
 128                         if (new_buff_size <= lr->buff_length)
 129                                 lafe_errc(1, ENOMEM,
 130                                     "Line too long in %s", lr->pathname);
 131                         lr->buff_length = new_buff_size;
 132                         /*
 133                          * Allocate one extra byte to allow terminating
 134                          * the buffer.
 135                          */
 136                         p = realloc(lr->buff, new_buff_size + 1);
 137                         if (p == NULL)
 138                                 lafe_errc(1, ENOMEM,
 139                                     "Line too long in %s", lr->pathname);
 140                         lr->buff_end = p + (lr->buff_end - lr->buff);
 141                         lr->line_end = p + (lr->line_end - lr->buff);
 142                         lr->line_start = lr->buff = p;
 143                 }
 144
 145                 /* Get some more data into the buffer. */
 146                 bytes_wanted = lr->buff + lr->buff_length - lr->buff_end;
 147                 bytes_read = fread(lr->buff_end, 1, bytes_wanted, lr->f);
 148                 lr->buff_end += bytes_read;
 149                 *lr->buff_end = '\0'; /* Always terminate buffer */
 150                 lafe_line_reader_find_eol(lr);
 151
 152                 if (ferror(lr->f))
 153                         lafe_errc(1, errno, "Can't read %s", lr->pathname);
 154                 if (feof(lr->f)) {
 155                         if (lr->f != stdin)
 156                                 fclose(lr->f);
 157                         lr->f = NULL;
 158                 }
 159         }
 160 }
 161
 162 void
 163 lafe_line_reader_free(struct lafe_line_reader *lr)
 164 {
 165         free(lr->buff);
 166         free(lr->pathname);
 167         free(lr);
 168 }