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glibc/stdio-common/tst-printf-binary-main.c

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Support C2X printf %b, %B C2X adds a printf %b format (see <http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2630.pdf>, accepted for C2X), for outputting integers in binary. It also has recommended practice for a corresponding %B format (like %b, but %#B starts the output with 0B instead of 0b). Add support for these formats to glibc. One existing test uses %b as an example of an unknown format, to test how glibc printf handles unknown formats; change that to %v. Use of %b and %B as user-registered format specifiers continues to work (and we already have a test that covers that, tst-printfsz.c). Note that C2X also has scanf %b support, plus support for binary constants starting 0b in strtol (base 0 and 2) and scanf %i (strtol base 0 and scanf %i coming from a previous paper that added binary integer literals). I intend to implement those features in a separate patch or patches; as discussed in the thread starting at <https://sourceware.org/pipermail/libc-alpha/2020-December/120414.html>, they will be more complicated because they involve adding extra public symbols to ensure compatibility with existing code that might not expect 0b constants to be handled by strtol base 0 and 2 and scanf %i, whereas simply adding a new format specifier poses no such compatibility concerns. Note that the actual conversion from integer to string uses existing code in _itoa.c. That code has special cases for bases 8, 10 and 16, probably so that the compiler can optimize division by an integer constant in the code for those bases. If desired such special cases could easily be added for base 2 as well, but that would be an optimization, not actually needed for these printf formats to work. Tested for x86_64 and x86. Also tested with build-many-glibcs.py for aarch64-linux-gnu with GCC mainline to make sure that the test does indeed build with GCC 12 (where format checking warnings are enabled for most of the test).
2021-11-10 15:52:21 +00:00
/* Test binary printf formats.
Update copyright dates with scripts/update-copyrights I used these shell commands: ../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright (cd ../glibc && git commit -am"[this commit message]") and then ignored the output, which consisted lines saying "FOO: warning: copyright statement not found" for each of 7061 files FOO. I then removed trailing white space from math/tgmath.h, support/tst-support-open-dev-null-range.c, and sysdeps/x86_64/multiarch/strlen-vec.S, to work around the following obscure pre-commit check failure diagnostics from Savannah. I don't know why I run into these diagnostics whereas others evidently do not. remote: *** 912-#endif remote: *** 913: remote: *** 914- remote: *** error: lines with trailing whitespace found ... remote: *** error: sysdeps/unix/sysv/linux/statx_cp.c: trailing lines
2022-01-01 18:54:23 +00:00
Copyright (C) 2021-2022 Free Software Foundation, Inc.
Support C2X printf %b, %B C2X adds a printf %b format (see <http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2630.pdf>, accepted for C2X), for outputting integers in binary. It also has recommended practice for a corresponding %B format (like %b, but %#B starts the output with 0B instead of 0b). Add support for these formats to glibc. One existing test uses %b as an example of an unknown format, to test how glibc printf handles unknown formats; change that to %v. Use of %b and %B as user-registered format specifiers continues to work (and we already have a test that covers that, tst-printfsz.c). Note that C2X also has scanf %b support, plus support for binary constants starting 0b in strtol (base 0 and 2) and scanf %i (strtol base 0 and scanf %i coming from a previous paper that added binary integer literals). I intend to implement those features in a separate patch or patches; as discussed in the thread starting at <https://sourceware.org/pipermail/libc-alpha/2020-December/120414.html>, they will be more complicated because they involve adding extra public symbols to ensure compatibility with existing code that might not expect 0b constants to be handled by strtol base 0 and 2 and scanf %i, whereas simply adding a new format specifier poses no such compatibility concerns. Note that the actual conversion from integer to string uses existing code in _itoa.c. That code has special cases for bases 8, 10 and 16, probably so that the compiler can optimize division by an integer constant in the code for those bases. If desired such special cases could easily be added for base 2 as well, but that would be an optimization, not actually needed for these printf formats to work. Tested for x86_64 and x86. Also tested with build-many-glibcs.py for aarch64-linux-gnu with GCC mainline to make sure that the test does indeed build with GCC 12 (where format checking warnings are enabled for most of the test).
2021-11-10 15:52:21 +00:00
This file is part of the GNU C Library.
The GNU C 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 2.1 of the License, or (at your option) any later version.
The GNU C 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 the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <limits.h>
#include <stdio.h>
#include <string.h>
#include <wchar.h>
#include <libc-diag.h>
#include <support/check.h>
/* GCC does not know the %b or %B formats before GCC 12. */
DIAG_PUSH_NEEDS_COMMENT;
#if !__GNUC_PREREQ (12, 0)
DIAG_IGNORE_NEEDS_COMMENT (11, "-Wformat");
DIAG_IGNORE_NEEDS_COMMENT (11, "-Wformat-extra-args");
#endif
#define CHECK_PRINTF(EXPECTED, FMT, ...) \
do \
{ \
int ret = SNPRINTF (buf, sizeof buf / sizeof buf[0], L_(FMT), \
__VA_ARGS__); \
TEST_COMPARE_STRING_MACRO (buf, L_(EXPECTED)); \
TEST_COMPARE (ret, STRLEN (L_(EXPECTED))); \
} \
while (0)
static int
do_test (void)
{
CHAR buf[1024];
CHECK_PRINTF ("0", "%b", 0u);
CHECK_PRINTF ("0", "%B", 0u);
CHECK_PRINTF ("0", "%#b", 0u);
CHECK_PRINTF ("0", "%#B", 0u);
CHECK_PRINTF ("1", "%b", 1u);
CHECK_PRINTF ("1", "%B", 1u);
CHECK_PRINTF ("10", "%b", 2u);
CHECK_PRINTF ("10", "%B", 2u);
CHECK_PRINTF ("11", "%b", 3u);
CHECK_PRINTF ("11", "%B", 3u);
CHECK_PRINTF ("10000111011001010100001100100001", "%b", 0x87654321);
CHECK_PRINTF ("10000111011001010100001100100001", "%B", 0x87654321);
CHECK_PRINTF ("100001100100001", "%hb", (int) 0x87654321);
CHECK_PRINTF ("100001100100001", "%hB", (int) 0x87654321);
CHECK_PRINTF ("100001", "%hhb", (int) 0x87654321);
CHECK_PRINTF ("100001", "%hhB", (int) 0x87654321);
CHECK_PRINTF ("10000111011001010100001100100001", "%lb", 0x87654321ul);
CHECK_PRINTF ("10000111011001010100001100100001", "%lB", 0x87654321ul);
CHECK_PRINTF ("11111110110111001011101010011001"
"10000111011001010100001100100001", "%llb",
0xfedcba9987654321ull);
CHECK_PRINTF ("11111110110111001011101010011001"
"10000111011001010100001100100001", "%llB",
0xfedcba9987654321ull);
#if LONG_WIDTH >= 64
CHECK_PRINTF ("11111110110111001011101010011001"
"10000111011001010100001100100001", "%lb",
0xfedcba9987654321ul);
CHECK_PRINTF ("11111110110111001011101010011001"
"10000111011001010100001100100001", "%lB",
0xfedcba9987654321ul);
#endif
CHECK_PRINTF (" 1010", "%5b", 10u);
CHECK_PRINTF (" 1010", "%5B", 10u);
CHECK_PRINTF ("01010", "%05b", 10u);
CHECK_PRINTF ("01010", "%05B", 10u);
CHECK_PRINTF ("1011 ", "%-5b", 11u);
CHECK_PRINTF ("1011 ", "%-5B", 11u);
CHECK_PRINTF ("0b10011", "%#b", 19u);
CHECK_PRINTF ("0B10011", "%#B", 19u);
CHECK_PRINTF (" 0b10011", "%#10b", 19u);
CHECK_PRINTF (" 0B10011", "%#10B", 19u);
CHECK_PRINTF ("0b00010011", "%0#10b", 19u);
CHECK_PRINTF ("0B00010011", "%0#10B", 19u);
CHECK_PRINTF ("0b00010011", "%#010b", 19u);
CHECK_PRINTF ("0B00010011", "%#010B", 19u);
CHECK_PRINTF ("0b10011 ", "%#-10b", 19u);
CHECK_PRINTF ("0B10011 ", "%#-10B", 19u);
CHECK_PRINTF ("00010011", "%.8b", 19u);
CHECK_PRINTF ("00010011", "%.8B", 19u);
CHECK_PRINTF ("0b00010011", "%#.8b", 19u);
CHECK_PRINTF ("0B00010011", "%#.8B", 19u);
CHECK_PRINTF (" 00010011", "%15.8b", 19u);
CHECK_PRINTF (" 00010011", "%15.8B", 19u);
CHECK_PRINTF ("00010011 ", "%-15.8b", 19u);
CHECK_PRINTF ("00010011 ", "%-15.8B", 19u);
CHECK_PRINTF (" 0b00010011", "%#15.8b", 19u);
CHECK_PRINTF (" 0B00010011", "%#15.8B", 19u);
CHECK_PRINTF ("0b00010011 ", "%-#15.8b", 19u);
CHECK_PRINTF ("0B00010011 ", "%-#15.8B", 19u);
/* GCC diagnoses ignored flags. */
DIAG_PUSH_NEEDS_COMMENT;
DIAG_IGNORE_NEEDS_COMMENT (12, "-Wformat");
/* '0' flag ignored with '-'. */
CHECK_PRINTF ("1011 ", "%0-5b", 11u);
CHECK_PRINTF ("1011 ", "%0-5B", 11u);
CHECK_PRINTF ("0b10011 ", "%#0-10b", 19u);
CHECK_PRINTF ("0B10011 ", "%#0-10B", 19u);
/* '0' flag ignored with precision. */
CHECK_PRINTF (" 00010011", "%015.8b", 19u);
CHECK_PRINTF (" 00010011", "%015.8B", 19u);
CHECK_PRINTF (" 0b00010011", "%0#15.8b", 19u);
CHECK_PRINTF (" 0B00010011", "%0#15.8B", 19u);
DIAG_POP_NEEDS_COMMENT;
/* Test positional argument handling. */
CHECK_PRINTF ("test 1011 test2 100010001000100010001000100010001",
"%2$s %1$b %4$s %3$llb", 11u, "test", 0x111111111ull, "test2");
return 0;
}
DIAG_POP_NEEDS_COMMENT;
#include <support/test-driver.c>
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