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Diffstat (limited to 'common/xreadline.c')
-rw-r--r-- | common/xreadline.c | 127 |
1 files changed, 127 insertions, 0 deletions
diff --git a/common/xreadline.c b/common/xreadline.c new file mode 100644 index 0000000..b17579f --- /dev/null +++ b/common/xreadline.c @@ -0,0 +1,127 @@ +/* xreadline.c - fgets replacement function + * Copyright (C) 1999, 2004 Free Software Foundation, Inc. + * + * This file is part of GnuPG. + * + * This file is free software; you can redistribute it and/or modify + * it under the terms of either + * + * - the GNU Lesser General Public License as published by the Free + * Software Foundation; either version 3 of the License, or (at + * your option) any later version. + * + * or + * + * - the GNU General Public License as published by the Free + * Software Foundation; either version 2 of the License, or (at + * your option) any later version. + * + * or both in parallel, as here. + * + * This file 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 <https://www.gnu.org/licenses/>. + */ + +#include <config.h> +#include <stdio.h> +#include <stdlib.h> +#include <errno.h> + +#include "util.h" + + +/* Same as fgets() but if the provided buffer is too short a larger + one will be allocated. This is similar to getline. A line is + considered a byte stream ending in a LF. + + If MAX_LENGTH is not NULL, it shall point to a value with the + maximum allowed allocation. + + Returns the length of the line. EOF is indicated by a line of + length zero. A truncated line is indicated by setting the value at + MAX_LENGTH to 0. If the returned value is less then 0 not enough + memory was enable and ERRNO is set accordingly. + + If a line has been truncated, the file pointer is moved forward to + the end of the line so that the next read starts with the next + line. Note that MAX_LENGTH must be re-initialzied in this case. + + Note: The returned buffer is allocated with enough extra space to + append a CR,LF,Nul + */ +ssize_t +read_line (FILE *fp, + char **addr_of_buffer, size_t *length_of_buffer, + size_t *max_length) +{ + int c; + char *buffer = *addr_of_buffer; + size_t length = *length_of_buffer; + size_t nbytes = 0; + size_t maxlen = max_length? *max_length : 0; + char *p; + + if (!buffer) + { /* No buffer given - allocate a new one. */ + length = 256; + buffer = xtrymalloc (length); + *addr_of_buffer = buffer; + if (!buffer) + { + *length_of_buffer = 0; + if (max_length) + *max_length = 0; + return -1; + } + *length_of_buffer = length; + } + + length -= 3; /* Reserve 3 bytes for CR,LF,EOL. */ + p = buffer; + while ((c = getc (fp)) != EOF) + { + if (nbytes == length) + { /* Enlarge the buffer. */ + if (maxlen && length > maxlen) /* But not beyond our limit. */ + { + /* Skip the rest of the line. */ + while (c != '\n' && (c=getc (fp)) != EOF) + ; + *p++ = '\n'; /* Always append a LF (we reserved some space). */ + nbytes++; + if (max_length) + *max_length = 0; /* Indicate truncation. */ + break; /* the while loop. */ + } + length += 3; /* Adjust for the reserved bytes. */ + length += length < 1024? 256 : 1024; + *addr_of_buffer = xtryrealloc (buffer, length); + if (!*addr_of_buffer) + { + int save_errno = errno; + xfree (buffer); + *length_of_buffer = 0; + if (max_length) + *max_length = 0; + gpg_err_set_errno (save_errno); + return -1; + } + buffer = *addr_of_buffer; + *length_of_buffer = length; + length -= 3; + p = buffer + nbytes; + } + *p++ = c; + nbytes++; + if (c == '\n') + break; + } + *p = 0; /* Make sure the line is a string. */ + + return nbytes; +} |