commands/tar/libarchive_fe/line_reader.c

   1 /*-
   2  * Copyright (c) 2008 Tim Kientzle
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer
  10  *    in this position and unchanged.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26
  27 #include "lafe_platform.h"
  28 __FBSDID("$FreeBSD$");
  29
  30 #include <errno.h>
  31 #include <stdio.h>
  32 #include <stdlib.h>
  33 #include <string.h>
  34
  35 #include "err.h"
  36 #include "line_reader.h"
  37
  38 #if defined(_WIN32) && !defined(__CYGWIN__) && !defined(__BORLANDC__)
  39 #define strdup _strdup
  40 #endif
  41
  42 /*
  43  * Read lines from file and do something with each one.  If option_null
  44  * is set, lines are terminated with zero bytes; otherwise, they're
  45  * terminated with newlines.
  46  *
  47  * This uses a self-sizing buffer to handle arbitrarily-long lines.
  48  */
  49 struct lafe_line_reader {
  50         FILE *f;
  51         char *buff, *buff_end, *line_start, *line_end, *p;
  52         char *pathname;
  53         size_t buff_length;
  54         int nullSeparator; /* Lines separated by null, not CR/CRLF/etc. */
  55         int ret;
  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->buff = malloc(lr->buff_length);
  78         if (lr->buff == NULL)
  79                 lafe_errc(1, ENOMEM, "Can't read %s", pathname);
  80         lr->line_start = lr->line_end = lr->buff_end = lr->buff;
  81
  82         return (lr);
  83 }
  84
  85 const char *
  86 lafe_line_reader_next(struct lafe_line_reader *lr)
  87 {
  88         size_t bytes_wanted, bytes_read, new_buff_size;
  89         char *line_start, *p;
  90
  91         for (;;) {
  92                 /* If there's a line in the buffer, return it immediately. */
  93                 while (lr->line_end < lr->buff_end) {
  94                         if (lr->nullSeparator) {
  95                                 if (*lr->line_end == '\0') {
  96                                         line_start = lr->line_start;
  97                                         lr->line_start = lr->line_end + 1;
  98                                         lr->line_end = lr->line_start;
  99                                         return (line_start);
 100                                 }
 101                         } else if (*lr->line_end == '\x0a' || *lr->line_end == '\x0d') {
 102                                 *lr->line_end = '\0';
 103                                 line_start = lr->line_start;
 104                                 lr->line_start = lr->line_end + 1;
 105                                 lr->line_end = lr->line_start;
 106                                 if (line_start[0] != '\0')
 107                                         return (line_start);
 108                         }
 109                         lr->line_end++;
 110                 }
 111
 112                 /* If we're at end-of-file, process the final data. */
 113                 if (lr->f == NULL) {
 114                         /* If there's more text, return one last line. */
 115                         if (lr->line_end > lr->line_start) {
 116                                 *lr->line_end = '\0';
 117                                 line_start = lr->line_start;
 118                                 lr->line_start = lr->line_end + 1;
 119                                 lr->line_end = lr->line_start;
 120                                 return (line_start);
 121                         }
 122                         /* Otherwise, we're done. */
 123                         return (NULL);
 124                 }
 125
 126                 /* Buffer only has part of a line. */
 127                 if (lr->line_start > lr->buff) {
 128                         /* Move a leftover fractional line to the beginning. */
 129                         memmove(lr->buff, lr->line_start,
 130                             lr->buff_end - lr->line_start);
 131                         lr->buff_end -= lr->line_start - lr->buff;
 132                         lr->line_end -= lr->line_start - lr->buff;
 133                         lr->line_start = lr->buff;
 134                 } else {
 135                         /* Line is too big; enlarge the buffer. */
 136                         new_buff_size = lr->buff_length * 2;
 137                         if (new_buff_size <= lr->buff_length)
 138                                 lafe_errc(1, ENOMEM,
 139                                     "Line too long in %s", lr->pathname);
 140                         lr->buff_length = new_buff_size;
 141                         p = realloc(lr->buff, new_buff_size);
 142                         if (p == NULL)
 143                                 lafe_errc(1, ENOMEM,
 144                                     "Line too long in %s", lr->pathname);
 145                         lr->buff_end = p + (lr->buff_end - lr->buff);
 146                         lr->line_end = p + (lr->line_end - lr->buff);
 147                         lr->line_start = lr->buff = p;
 148                 }
 149
 150                 /* Get some more data into the buffer. */
 151                 bytes_wanted = lr->buff + lr->buff_length - lr->buff_end;
 152                 bytes_read = fread(lr->buff_end, 1, bytes_wanted, lr->f);
 153                 lr->buff_end += bytes_read;
 154
 155                 if (ferror(lr->f))
 156                         lafe_errc(1, errno, "Can't read %s", lr->pathname);
 157                 if (feof(lr->f)) {
 158                         if (lr->f != stdin)
 159                                 fclose(lr->f);
 160                         lr->f = NULL;
 161                 }
 162         }
 163 }
 164
 165 void
 166 lafe_line_reader_free(struct lafe_line_reader *lr)
 167 {
 168         free(lr->buff);
 169         free(lr->pathname);
 170         free(lr);
 171 }