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e88b9f0e5c
vfprintf is entangled with vfwprintf (of course), __printf_fp,
__printf_fphex, __vstrfmon_l_internal, and the strfrom family of
functions. The latter use the internal snprintf functionality,
so vsnprintf is converted as well.
The simples conversion is __printf_fphex, followed by
__vstrfmon_l_internal and __printf_fp, and finally
__vfprintf_internal and __vfwprintf_internal. __vsnprintf_internal
and strfrom* are mostly consuming the new interfaces, so they
are comparatively simple.
__printf_fp is a public symbol, so the FILE *-based interface
had to preserved.
The __printf_fp rewrite does not change the actual binary-to-decimal
conversion algorithm, and digits are still not emitted directly to
the target buffer. However, the staging buffer now uses bytes
instead of wide characters, and one buffer copy is eliminated.
The changes are at least performance-neutral in my testing.
Floating point printing and snprintf improved measurably, so that
this Lua script
for i=1,5000000 do
print(i, i * math.pi)
end
runs about 5% faster for me. To preserve fprintf performance for
a simple "%d" format, this commit has some logic changes under
LABEL (unsigned_number) to avoid additional function calls. There
are certainly some very easy performance improvements here: binary,
octal and hexadecimal formatting can easily avoid the temporary work
buffer (the number of digits can be computed ahead-of-time using one
of the __builtin_clz* built-ins). Decimal formatting can use a
specialized version of _itoa_word for base 10.
The existing (inconsistent) width handling between strfmon and printf
is preserved here. __print_fp_buffer_1 would have to use
__translated_number_width to achieve ISO conformance for printf.
Test expectations in libio/tst-vtables-common.c are adjusted because
the internal staging buffer merges all virtual function calls into
one.
In general, stack buffer usage is greatly reduced, particularly for
unbuffered input streams. __printf_fp can still use a large buffer
in binary128 mode for %g, though.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
107 lines
3.7 KiB
C
107 lines
3.7 KiB
C
/* Copyright (C) 1994-2022 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>.
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As a special exception, if you link the code in this file with
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files compiled with a GNU compiler to produce an executable,
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that does not cause the resulting executable to be covered by
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the GNU Lesser General Public License. This exception does not
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however invalidate any other reasons why the executable file
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might be covered by the GNU Lesser General Public License.
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This exception applies to code released by its copyright holders
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in files containing the exception. */
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#include "libioP.h"
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#include <array_length.h>
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#include <printf.h>
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#include <printf_buffer.h>
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void
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__printf_buffer_flush_snprintf (struct __printf_buffer_snprintf *buf)
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{
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/* Record the bytes written so far, before switching buffers. */
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buf->base.written += buf->base.write_ptr - buf->base.write_base;
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if (buf->base.write_base != buf->discard)
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{
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/* We just finished writing the caller-supplied buffer. Force
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NUL termination if the string length is not zero. */
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if (buf->base.write_base != buf->base.write_end)
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buf->base.write_end[-1] = '\0';
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/* Switch to the discard buffer. */
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buf->base.write_base = buf->discard;
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buf->base.write_ptr = buf->discard;
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buf->base.write_end = array_end (buf->discard);
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}
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buf->base.write_base = buf->discard;
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buf->base.write_ptr = buf->discard;
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}
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void
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__printf_buffer_snprintf_init (struct __printf_buffer_snprintf *buf,
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char *buffer, size_t length)
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{
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__printf_buffer_init (&buf->base, buffer, length,
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__printf_buffer_mode_snprintf);
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if (length > 0)
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/* Historic behavior for trivially overlapping buffers (checked by
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the test suite). */
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*buffer = '\0';
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}
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int
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__printf_buffer_snprintf_done (struct __printf_buffer_snprintf *buf)
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{
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/* NB: Do not check for buf->base.fail here. Write the null
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terminator even in case of errors. */
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if (buf->base.write_ptr < buf->base.write_end)
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*buf->base.write_ptr = '\0';
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else if (buf->base.write_ptr > buf->base.write_base)
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/* If write_ptr == write_base, nothing has been written. No null
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termination is needed because of the early truncation in
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__printf_buffer_snprintf_init (the historic behavior).
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We might also be at the start of the discard buffer, but in
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this case __printf_buffer_flush_snprintf has already written
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the NUL terminator. */
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buf->base.write_ptr[-1] = '\0';
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return __printf_buffer_done (&buf->base);
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}
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int
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__vsnprintf_internal (char *string, size_t maxlen, const char *format,
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va_list args, unsigned int mode_flags)
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{
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struct __printf_buffer_snprintf buf;
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__printf_buffer_snprintf_init (&buf, string, maxlen);
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__printf_buffer (&buf.base, format, args, mode_flags);
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return __printf_buffer_snprintf_done (&buf);
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}
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int
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___vsnprintf (char *string, size_t maxlen, const char *format, va_list args)
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{
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return __vsnprintf_internal (string, maxlen, format, args, 0);
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}
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ldbl_weak_alias (___vsnprintf, __vsnprintf)
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ldbl_weak_alias (___vsnprintf, vsnprintf)
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