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authorGravatar David Bremner <david@tethera.net>2014-03-29 14:53:17 -0300
committerGravatar David Bremner <david@tethera.net>2014-04-12 07:59:44 -0300
commit85d9219a62c23c3ff58b42a63b65390526b89b6b (patch)
treefbf5b430c91b6ffa6b2c773c86184790232b2fe1
parent3c13bc0321baaf340663779d6fce2b1f34c1c2c3 (diff)
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.
-rw-r--r--util/Makefile.local3
-rw-r--r--util/util.c24
-rw-r--r--util/util.h29
-rw-r--r--util/zlib-extra.c85
-rw-r--r--util/zlib-extra.h25
5 files changed, 165 insertions, 1 deletions
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 <string.h>
+#include <errno.h>
+
+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 <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_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 <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