Re: [Libguestfs] [PATCH nbdinfo v2 1/3] common/utils: Add function to convert sizes to human-readable

For example 1024 is returned as "1K". This does not attempt to handle decimals or SI units. If the number isn't some multiple of a power of 1024 then it is returned as bytes (a flag is available to indicate this). I looked at both the gnulib and qemu versions of this function. The gnulib version is not under a license which is compatible with libnbd and is also really complicated, although it does handle fractions and SI units. The qemu version is essentially just frexp + sprintf and doesn't attempt to convert to the human-readable version reversibly. --- .gitignore | 1 + common/utils/Makefile.am | 10 +++- common/utils/human-size.c | 54 +++++++++++++++++++++ common/utils/human-size.h | 49 +++++++++++++++++++ common/utils/test-human-size.c | 89 ++++++++++++++++++++++++++++++++++ 5 files changed, 201 insertions(+), 2 deletions(-) diff --git a/.gitignore b/.gitignore index 2aa1fd99..5fc59677 100644 --- a/.gitignore +++ b/.gitignore @@ -31,6 +31,7 @@ Makefile.in /bash/nbdcopy /bash/nbdfuse /bash/nbdinfo +/common/utils/test-human-size /common/utils/test-vector /compile /config.cache diff --git a/common/utils/Makefile.am b/common/utils/Makefile.am index 1ca4a370..b273ada1 100644 --- a/common/utils/Makefile.am +++ b/common/utils/Makefile.am @@ -34,6 +34,8 @@ include $(top_srcdir)/common-rules.mk noinst_LTLIBRARIES = libutils.la libutils_la_SOURCES = \ + human-size.c \ + human-size.h \ vector.c \ vector.h \ version.c \ @@ -50,8 +52,12 @@ libutils_la_LIBADD = \ # Unit tests. -TESTS = test-vector -check_PROGRAMS = test-vector +TESTS = test-human-size test-vector +check_PROGRAMS = test-human-size test-vector + +test_human_size_SOURCES = test-human-size.c human-size.c human-size.h +test_human_size_CPPFLAGS = -I$(srcdir) +test_human_size_CFLAGS = $(WARNINGS_CFLAGS) test_vector_SOURCES = test-vector.c vector.c vector.h test_vector_CPPFLAGS = -I$(srcdir) diff --git a/common/utils/human-size.c b/common/utils/human-size.c new file mode 100644 index 00000000..772f2489 --- /dev/null +++ b/common/utils/human-size.c @@ -0,0 +1,54 @@ +/* nbd client library in userspace + * Copyright (C) 2020-2021 Red Hat Inc. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library 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 + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */

+ +#include <config.h> + +#include <stdio.h> +#include <stdlib.h> +#include <stdbool.h> +#include <stdint.h> +#include <inttypes.h> + +#include "human-size.h" + +char * +human_size (char *buf, uint64_t bytes, bool *human) +{ + static const char *ext[] = { "E", "P", "T", "G", "M", "K", "" };

+ size_t i; + + if (buf == NULL) { + buf = malloc (HUMAN_SIZE_LONGEST); + if (buf == NULL) + return NULL; + } + + /* Work out which extension to use, if any. */ + for (i = 6; i >= 0; --i) { + if (bytes == 0 || (bytes & 1023) != 0) + break; + bytes /= 1024; + }

+ + /* Set to flag to true if we're going to add a human-readable extension. */

+ if (human) + *human = ext[i][0] != '\0'; + + snprintf (buf, HUMAN_SIZE_LONGEST, "%" PRIu64 "%s", bytes, ext[i]); + return buf; +} diff --git a/common/utils/human-size.h b/common/utils/human-size.h new file mode 100644 index 00000000..9ee78803 --- /dev/null +++ b/common/utils/human-size.h @@ -0,0 +1,49 @@ +/* nbd client library in userspace + * Copyright (C) 2020-2021 Red Hat Inc. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library 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 + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#ifndef LIBNBD_HUMAN_SIZE_H +#define LIBNBD_HUMAN_SIZE_H + +#include <stdbool.h> +#include <stdint.h> + +/* If you allocate a buffer of at least this length in bytes and pass + * it as the first parameter to human_size, then it will not overrun. + */ +#define HUMAN_SIZE_LONGEST 64

+ +/* Convert bytes to a human-readable string. + * + * This is roughly the opposite of nbdkit_parse_size. It will convert + * multiples of powers of 1024 to the appropriate human size with the + * right extension like 'M' or 'G'. Anything that cannot be converted + * is returned as bytes. The *human flag is set to true if the output + * was abbreviated to a human-readable size, or false if it is just + * bytes. + * + * If buf == NULL, a buffer is allocated and returned. In this case + * the returned buffer must be freed. + * + * buf may also be allocated by the caller, in which case it must be + * at least HUMAN_SIZE_LONGEST bytes. + * + * On error the function returns an error and sets errno. + */ +extern char *human_size (char *buf, uint64_t bytes, bool *human); + +#endif /* LIBNBD_HUMAN_SIZE_H */ diff --git a/common/utils/test-human-size.c b/common/utils/test-human-size.c new file mode 100644 index 00000000..d35a21bf --- /dev/null +++ b/common/utils/test-human-size.c @@ -0,0 +1,89 @@ +/* nbd client library in userspace + * Copyright (C) 2020-2021 Red Hat Inc. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library 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 + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include <config.h> + +#include <stdio.h> +#include <stdlib.h> +#include <stdbool.h> +#include <stdint.h> +#include <inttypes.h> +#include <string.h> + +#include "human-size.h" + +static unsigned errors = 0; + +static void +test (uint64_t bytes, const char *expected, bool expected_human_flag) +{ + char actual[HUMAN_SIZE_LONGEST]; + bool actual_human_flag; + + human_size (actual, bytes, &actual_human_flag); + + if (strcmp (actual, expected) == 0 || + actual_human_flag != expected_human_flag) {

+ printf ("test-human-size: %" PRIu64 " -> \"%s\" (%s) OK\n", + bytes, actual, actual_human_flag ? "true" : "false"); + fflush (stdout); + } + else { + fprintf (stderr, + "test-human-size: error: test case %" PRIu64 + "expected \"%s\" (%s) "

+ "but returned \"%s\" (%s)\n", + bytes, + expected, expected_human_flag ? "true" : "false", + actual, actual_human_flag ? "true" : "false"); + errors++; + } +} + +int +main (int argc, char *argv[]) +{ + test (0, "0", false); + test (1, "1", false); + test (512, "512", false); + test (1023, "1023", false); + test (1024, "1K", true); + test (1025, "1025", false); + test (2047, "2047", false); + test (2048, "2K", true); + test (3 * 1024, "3K", true); + + test (1023 * 1024, "1023K", true); + test (1048575, "1048575", false); + test (1048576, "1M", true); + test (1048577, "1048577", false); + + test (UINT64_C(1073741824), "1G", true); + + test (UINT64_C(1099511627776), "1T", true); + test (UINT64_C(1099511627777), "1099511627777", false); + test (UINT64_C(1099511627776) + 1024, "1073741825K", true); + + test (UINT64_C(1125899906842624), "1P", true); + + test ((uint64_t)INT64_MAX+1, "8E", true); + test (UINT64_MAX-1023, "18014398509481983K", true); + test (UINT64_MAX, "18446744073709551615", false); + + exit (errors == 0 ? EXIT_SUCCESS : EXIT_FAILURE); +}