From 85d9219a62c23c3ff58b42a63b65390526b89b6b Mon Sep 17 00:00:00 2001 From: David Bremner Date: Sat, 29 Mar 2014 14:53:17 -0300 Subject: util: add gz_readline 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 29c0ce6e..905f2376 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 00000000..06659b35 --- /dev/null +++ b/util/util.c @@ -0,0 +1,24 @@ +#include "util.h" +#include "error_util.h" +#include +#include + +const char * +util_error_string (util_status_t errnum) +{ + switch (errnum) { + case UTIL_SUCCESS: + return "success"; + 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 00000000..d12fadb4 --- /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 00000000..2e704457 --- /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 + */ + +#include "zlib-extra.h" +#include +#include +#include + +/* 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 00000000..aedfd48f --- /dev/null +++ b/util/zlib-extra.h @@ -0,0 +1,25 @@ +#ifndef _ZLIB_EXTRA_H +#define _ZLIB_EXTRA_H + +#include "util.h" +#include + +/* 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 -- cgit v1.2.3