notmuch/util/zlib-extra.c
Olivier Taïbi b4f593e0e6 util: after gzgets(), Z_STREAM_END means EOF, not error
Context: I am compiling notmuch on OpenBSD which has a rather old zlib
1.2.3.  It seems that the behaviour of gzgets() changed slightly between
this version and more recent versions, but the manual does not reflect
that change.  Note that zlib's manual:
- does not specify which error code (Z_OK or Z_STREAM_END) is set when
  EOF is reached,
- does not indicate the meaning of Z_STREAM_END after gzgets(), but
  based on its meaning as a possible return value of inflate(), I would
  guess that it means EOF.

amended by db: tidy commit message
2020-04-16 07:55:23 -03:00

87 lines
2.2 KiB
C

/* zlib-extra.c - Extra or enhanced routines for compressed I/O.
*
* Copyright (c) 2014 David Bremner
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program 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/ .
*
* Author: David Bremner <david@tethera.net>
*/
#include "zlib-extra.h"
#include <talloc.h>
#include <stdio.h>
#include <string.h>
/* mimic POSIX/glibc getline, but on a zlib gzFile stream, and using talloc */
util_status_t
gz_getline (void *talloc_ctx, char **bufptr, ssize_t *bytes_read, gzFile stream)
{
char *buf = *bufptr;
unsigned int len;
size_t offset = 0;
if (buf) {
len = talloc_array_length (buf);
} else {
/* same as getdelim from gnulib */
len = 120;
buf = talloc_array (talloc_ctx, char, len);
if (buf == NULL)
return UTIL_OUT_OF_MEMORY;
}
while (1) {
if (! gzgets (stream, buf + offset, len - offset)) {
/* Null indicates EOF or error */
int zlib_status = 0;
(void) gzerror (stream, &zlib_status);
switch (zlib_status) {
case Z_STREAM_END:
case Z_OK:
/* no data read before EOF */
if (offset == 0)
return UTIL_EOF;
else
goto SUCCESS;
case Z_ERRNO:
return UTIL_ERRNO;
default:
return UTIL_GZERROR;
}
}
offset += strlen (buf + offset);
if (buf[offset - 1] == '\n')
goto SUCCESS;
len *= 2;
buf = talloc_realloc (talloc_ctx, buf, char, len);
if (buf == NULL)
return UTIL_OUT_OF_MEMORY;
}
SUCCESS:
*bufptr = buf;
*bytes_read = offset;
return UTIL_SUCCESS;
}
const char *
gz_error_string (util_status_t status, gzFile file)
{
if (status == UTIL_GZERROR)
return gzerror_str (file);
else
return util_error_string (status);
}