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659fe9fdd1
These buffers will eventually be used instead of FILE * objects to implement printf functions. The multibyte buffer is struct __printf_buffer, the wide buffer is struct __wprintf_buffer. To enable writing type-generic code, the header files printf_buffer-char.h and printf_buffer-wchar_t.h define the Xprintf macro differently, enabling Xprintf (buffer) to stand for __printf_buffer and __wprintf_buffer as appropriate. For common cases, macros like Xprintf_buffer are provided as a more syntactically convenient shortcut. Buffer-specific flush callbacks are implemented with a switch statement instead of a function pointer, to avoid hardening issues similar to those of libio vtables. struct __printf_buffer_as_file is needed to support custom printf specifiers because the public interface for that requires passing a FILE *, which is why there is a trapdoor back from these buffers to FILE * streams. Since the immediate user of these interfaces knows when processing has finished, there is no flush callback for the end of processing, only a flush callback for the intermediate buffer flush. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
41 lines
1.4 KiB
C
41 lines
1.4 KiB
C
/* Final status reporting for struct __*printf_buffer. Generic version.
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Copyright (C) 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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#include <errno.h>
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#include <intprops.h>
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#include <stdint.h>
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int
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Xprintf_buffer_done (struct Xprintf_buffer *buf)
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{
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if (Xprintf_buffer_has_failed (buf))
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return -1;
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/* Use uintptr_t here because for sprintf, the buffer range may
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cover more than half of the address space. */
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uintptr_t written_current = buf->write_ptr - buf->write_base;
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int written_total;
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if (INT_ADD_WRAPV (buf->written, written_current, &written_total))
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{
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__set_errno (EOVERFLOW);
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return -1;
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}
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else
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return written_total;
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}
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