mirror of git://sourceware.org/git/glibc.git
123 lines
4.2 KiB
C
123 lines
4.2 KiB
C
/* Multibyte printf buffers writing data to a FILE * stream.
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Copyright (C) 2022-2024 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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#include <printf_buffer_to_file.h>
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#include <assert.h>
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#include <array_length.h>
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#include <libio/libioP.h>
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/* Switch to the file buffer if possible. If the file has write_ptr
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== write_end, use the stage buffer instead. */
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void
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__printf_buffer_to_file_switch (struct __printf_buffer_to_file *buf)
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{
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if (buf->fp->_IO_write_ptr < buf->fp->_IO_write_end)
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{
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/* buf->fp has a buffer associated with it, so write directly to
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it from now on. */
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buf->base.write_ptr = buf->fp->_IO_write_ptr;
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buf->base.write_end = buf->fp->_IO_write_end;
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}
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else
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{
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/* Use the staging area if no buffer is available in buf->fp. */
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buf->base.write_ptr = buf->stage;
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buf->base.write_end = array_end (buf->stage);
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}
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buf->base.write_base = buf->base.write_ptr;
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}
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void
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__printf_buffer_flush_to_file (struct __printf_buffer_to_file *buf)
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{
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/* The bytes in the buffer are always consumed. */
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buf->base.written += buf->base.write_ptr - buf->base.write_base;
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if (buf->base.write_end == array_end (buf->stage))
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{
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/* If the stage buffer is used, make a copy into the file. The
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stage buffer is always consumed fully, even if just partially
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written, to ensure that the file stream has all the data. */
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size_t count = buf->base.write_ptr - buf->stage;
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if ((size_t) _IO_sputn (buf->fp, buf->stage, count) != count)
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{
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__printf_buffer_mark_failed (&buf->base);
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return;
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}
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/* buf->fp may have a buffer now. */
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__printf_buffer_to_file_switch (buf);
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return;
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}
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else if (buf->base.write_end == buf->stage + 1)
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{
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/* Special one-character buffer case. This is used to avoid
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flush-only overflow below. */
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if (buf->base.write_ptr == buf->base.write_end)
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{
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if (__overflow (buf->fp, (unsigned char) *buf->stage) == EOF)
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{
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__printf_buffer_mark_failed (&buf->base);
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return;
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}
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__printf_buffer_to_file_switch (buf);
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}
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/* Else there is nothing to write. */
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return;
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}
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/* We have written directly into the buf->fp buffer. */
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assert (buf->base.write_end == buf->fp->_IO_write_end);
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/* Mark the bytes as written. */
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buf->fp->_IO_write_ptr = buf->base.write_ptr;
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if (buf->base.write_ptr == buf->base.write_end)
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{
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/* The buffer in buf->fp has been filled. This should just call
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__overflow (buf->fp, EOF), but flush-only overflow is obscure
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and not always correctly implemented. See bug 28949. Be
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conservative and switch to a one-character buffer instead, to
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obtain one more character for a regular __overflow call. */
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buf->base.write_ptr = buf->stage;
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buf->base.write_end = buf->stage + 1;
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}
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/* The bytes in the file stream were already marked as written above. */
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buf->base.write_base = buf->base.write_ptr;
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}
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void
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__printf_buffer_to_file_init (struct __printf_buffer_to_file *buf, FILE *fp)
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{
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__printf_buffer_init (&buf->base, buf->stage, array_length (buf->stage),
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__printf_buffer_mode_to_file);
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buf->fp = fp;
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__printf_buffer_to_file_switch (buf);
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}
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int
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__printf_buffer_to_file_done (struct __printf_buffer_to_file *buf)
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{
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if (__printf_buffer_has_failed (&buf->base))
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return -1;
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__printf_buffer_flush_to_file (buf);
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return __printf_buffer_done (&buf->base);
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}
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