[Patch v7 2/6] util: add gz_readline
Tomi Ollila
tomi.ollila at iki.fi
Sun Apr 6 03:21:29 PDT 2014
On Sat, Apr 05 2014, David Bremner <david at tethera.net> wrote:
> The idea is to provide a more or less drop in replacement for readline
> to read from zlib/gzip streams. Take the opportunity to replace
> malloc with talloc.
> ---
> util/Makefile.local | 3 +-
> util/util.c | 24 +++++++++++++++
> util/util.h | 29 ++++++++++++++++++
> util/zlib-extra.c | 85 +++++++++++++++++++++++++++++++++++++++++++++++++++++
> util/zlib-extra.h | 25 ++++++++++++++++
> 5 files changed, 165 insertions(+), 1 deletion(-)
> create mode 100644 util/util.c
> create mode 100644 util/util.h
> create mode 100644 util/zlib-extra.c
> create mode 100644 util/zlib-extra.h
>
> diff --git a/util/Makefile.local b/util/Makefile.local
> index 29c0ce6..905f237 100644
> --- a/util/Makefile.local
> +++ b/util/Makefile.local
> @@ -4,7 +4,8 @@ dir := util
> extra_cflags += -I$(srcdir)/$(dir)
>
> libutil_c_srcs := $(dir)/xutil.c $(dir)/error_util.c $(dir)/hex-escape.c \
> - $(dir)/string-util.c $(dir)/talloc-extra.c
> + $(dir)/string-util.c $(dir)/talloc-extra.c $(dir)/zlib-extra.c \
> + $(dir)/util.c
>
> libutil_modules := $(libutil_c_srcs:.c=.o)
>
> diff --git a/util/util.c b/util/util.c
> new file mode 100644
> index 0000000..3bd305d
> --- /dev/null
> +++ b/util/util.c
> @@ -0,0 +1,24 @@
> +#include "util.h"
> +#include "error_util.h"
> +#include <string.h>
> +#include <errno.h>
> +
> +const char *
> +util_error_string (util_status_t errnum)
> +{
> + switch (errnum) {
> + case UTIL_SUCCESS:
> + return "none";
The series gets OK from me. This "none" could be amended to "success" to be
'consistent' with libc strerror(0) -- which returns 'Success'.
Tomi
> + case UTIL_OUT_OF_MEMORY:
> + return "out of memory";
> + case UTIL_EOF:
> + return "end of file";
> + case UTIL_ERRNO:
> + return strerror (errno);
> + case UTIL_GZERROR:
> + /* we lack context to be more informative here */
> + return "zlib error";
> + default:
> + INTERNAL_ERROR("unexpected error status %d", errnum);
> + }
> +}
> diff --git a/util/util.h b/util/util.h
> new file mode 100644
> index 0000000..d12fadb
> --- /dev/null
> +++ b/util/util.h
> @@ -0,0 +1,29 @@
> +#ifndef _UTIL_H
> +#define _UTIL_H
> +
> +typedef enum util_status {
> + /**
> + * No error occurred.
> + */
> + UTIL_SUCCESS = 0,
> + /**
> + * Out of memory.
> + */
> + UTIL_OUT_OF_MEMORY,
> + /**
> + * End of stream reached while attempting to read.
> + */
> + UTIL_EOF,
> + /**
> + * Low level error occured, consult errno.
> + */
> + UTIL_ERRNO,
> + /**
> + * Zlib error occured, call gzerror for details.
> + */
> + UTIL_GZERROR
> +} util_status_t;
> +
> +const char *
> +util_error_string (util_status_t status);
> +#endif
> diff --git a/util/zlib-extra.c b/util/zlib-extra.c
> new file mode 100644
> index 0000000..cb34845
> --- /dev/null
> +++ b/util/zlib-extra.c
> @@ -0,0 +1,85 @@
> +/* 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 http://www.gnu.org/licenses/ .
> + *
> + * Author: David Bremner <david at 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_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 (file, NULL);
> + else
> + return util_error_string (status);
> +}
> diff --git a/util/zlib-extra.h b/util/zlib-extra.h
> new file mode 100644
> index 0000000..dbaa0b9
> --- /dev/null
> +++ b/util/zlib-extra.h
> @@ -0,0 +1,25 @@
> +#ifndef _ZLIB_EXTRA_H
> +#define _ZLIB_EXTRA_H
> +
> +#include "util.h"
> +#include <zlib.h>
> +
> +/* Like getline, but read from a gzFile. Allocation is with talloc.
> + * Returns:
> + *
> + * UTIL_SUCCESS, UTIL_OUT_OF_MEMORY, UTIL_ERRNO, UTIL_GZERROR
> + * Consult util.h for description
> + *
> + * UTIL_EOF End of file encountered before
> + * any characters read
> + */
> +util_status_t
> +gz_getline (void *ctx, char **lineptr, ssize_t *bytes_read, gzFile stream);
> +
> +/* return a suitable error string based on the return status
> + * from gz_readline
> + */
> +
> +const char *
> +gz_error_string (util_status_t status, gzFile stream);
> +#endif
> --
> 1.9.0
>
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