104 lines
2.9 KiB
C
104 lines
2.9 KiB
C
/* linebuffer.c -- read arbitrarily long lines
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Copyright (C) 1986, 1991, 1998-1999, 2001, 2003-2004, 2006-2007, 2009-2022
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Free Software Foundation, Inc.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program 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
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
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/* Written by Richard Stallman. */
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#include <config.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/types.h>
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#include "linebuffer.h"
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#include "xalloc.h"
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#if USE_UNLOCKED_IO
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# include "unlocked-io.h"
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#endif
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/* Initialize linebuffer LINEBUFFER for use. */
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void
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initbuffer (struct linebuffer *linebuffer)
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{
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memset (linebuffer, 0, sizeof *linebuffer);
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}
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struct linebuffer *
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readlinebuffer (struct linebuffer *linebuffer, FILE *stream)
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{
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return readlinebuffer_delim (linebuffer, stream, '\n');
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}
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/* Read an arbitrarily long line of text from STREAM into LINEBUFFER.
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Consider lines to be terminated by DELIMITER.
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Keep the delimiter; append DELIMITER if it's the last line of a file
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that ends in a character other than DELIMITER. Do not NUL-terminate.
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Therefore the stream can contain NUL bytes, and the length
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(including the delimiter) is returned in linebuffer->length.
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Return NULL when stream is empty. Return NULL and set errno upon
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error; callers can distinguish this case from the empty case by
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invoking ferror (stream).
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Otherwise, return LINEBUFFER. */
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struct linebuffer *
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readlinebuffer_delim (struct linebuffer *linebuffer, FILE *stream,
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char delimiter)
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{
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int c;
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char *buffer = linebuffer->buffer;
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char *p = linebuffer->buffer;
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char *end = buffer + linebuffer->size; /* Sentinel. */
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if (feof (stream))
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return NULL;
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do
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{
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c = getc (stream);
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if (c == EOF)
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{
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if (p == buffer || ferror (stream))
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return NULL;
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if (p[-1] == delimiter)
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break;
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c = delimiter;
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}
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if (p == end)
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{
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idx_t oldsize = linebuffer->size;
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buffer = xpalloc (buffer, &linebuffer->size, 1, -1, 1);
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p = buffer + oldsize;
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linebuffer->buffer = buffer;
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end = buffer + linebuffer->size;
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}
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*p++ = c;
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}
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while (c != delimiter);
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linebuffer->length = p - buffer;
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return linebuffer;
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}
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/* Free the buffer that was allocated for linebuffer LINEBUFFER. */
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void
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freebuffer (struct linebuffer *linebuffer)
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{
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free (linebuffer->buffer);
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}
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