mirror of git://sourceware.org/git/glibc.git
Mon May 6 09:51:05 1996 Roland McGrath <roland@delasyd.gnu.ai.mit.edu>
* stdio/linewrap.c: New file. * stdio/Makefile (routines): Add linewrap. * stdio/stdio.h [__USE_GNU]: Declare line_wrap_stream, line_unwrap_stream.
This commit is contained in:
Roland McGrath
parent
cee8df033b
commit
28ca945828
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@ -1,4 +1,4 @@
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# Copyright (C) 1991, 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
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# Copyright (C) 1991, 92, 93, 94, 95, 96 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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@ -36,7 +36,7 @@ routines := \
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getdelim \
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fclose fflush \
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vdprintf vsnprintf vsprintf vasprintf vsscanf \
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memstream obstream \
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memstream obstream linewrap \
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internals sysd-stdio pipestream stdio_init libc_fatal
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aux := defs glue
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@ -0,0 +1,353 @@
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/* Word-wrapping and line-truncating streams.
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Copyright (C) 1996 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 Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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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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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If
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not, write to the Free Software Foundation, Inc., 675 Mass Ave,
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Cambridge, MA 02139, USA. */
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#include <stdio.h>
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#include <ctype.h>
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#include <string.h>
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#include <stdlib.h>
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/* We keep this data for each line-wrapping stream. */
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struct data
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{
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const size_t *lmargin, *rmargin; /* Left and right margins. */
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const size_t *wrapmargin; /* Margin to wrap to, or null to truncate. */
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size_t point; /* Current column of last chars flushed. */
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/* Original cookie and hooks from the stream. */
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void *cookie;
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void (*output) (FILE *, int);
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__io_close_fn *close;
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__io_fileno_fn *fileno;
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__io_seek_fn *seek;
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};
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/* Install our hooks into a stream. */
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static inline void
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wrap_stream (FILE *stream, struct data *d)
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{
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static void lwoutput (FILE *, int);
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static __io_close_fn lwclose;
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static __io_fileno_fn lwfileno;
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stream->__cookie = d;
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stream->__room_funcs.__output = &lwoutput;
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stream->__io_funcs.__close = &lwclose;
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stream->__io_funcs.__fileno = &lwfileno;
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stream->__io_funcs.__seek = NULL; /* Cannot seek. */
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}
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/* Restore a stream to its original state. */
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static inline void
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unwrap_stream (FILE *stream, struct data *d)
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{
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stream->__cookie = d->cookie;
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stream->__room_funcs.__output = d->output;
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stream->__io_funcs.__close = d->close;
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stream->__io_funcs.__fileno = d->fileno;
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stream->__io_funcs.__seek = d->seek;
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}
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/* Cookie io functions that might get called on a wrapped stream.
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Must pass the original cookie to the original functions. */
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static int
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lwclose (void *cookie)
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{
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struct data *d = cookie;
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return (*d->close) (d->cookie);
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}
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static int
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lwfileno (void *cookie)
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{
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struct data *d = cookie;
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return (*d->fileno) (d->cookie);
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}
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/* This function is called when STREAM must be flushed.
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C is EOF or a character to be appended to the buffer contents. */
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static void
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lwoutput (FILE *stream, int c)
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{
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char *buf, *nl;
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size_t len;
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/* Extract our data and restore the stream's original cookie
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and output function so writes we do really go out. */
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struct data *d = stream->__cookie;
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unwrap_stream (stream, d);
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/* Scan the buffer for newlines. */
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for (buf = stream->__buffer;
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(buf < stream->__bufp || (c != EOF && c != '\n')) && !stream->__error)
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{
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size_t r;
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if (d->point == 0 && d->lmargin && *d->lmargin != 0)
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{
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/* We are starting a new line. Print spaces to the left margin. */
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const size_t pad = *d->lmargin;
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if (stream->__bufp + pad < stream->__put_limit)
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{
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/* We can fit in them in the buffer by moving the
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buffer text up and filling in the beginning. */
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memmove (buf + pad, buf, stream->__bufp - buf);
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stream->__bufp += pad; /* Compensate for bigger buffer. */
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memset (buf, ' ', pad); /* Fill in the spaces. */
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buf += pad; /* Don't bother searching them. */
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}
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else
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{
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/* No buffer space for spaces. Must flush. */
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size_t i;
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char *olimit;
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len = stream->__bufp - buf;
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olimit = stream->__put_limit;
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stream->__bufp = stream->__put_limit = buf;
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for (i = 0; i < pad; ++i)
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(*d->output) (stream, ' ');
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stream->__put_limit = olimit;
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memcpy (stream->__bufp, buf, len);
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stream->__bufp += len;
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}
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d->point = pad;
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}
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len = stream->__bufp - buf;
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nl = memchr (buf, '\n', len);
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if (!nl)
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{
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/* The buffer ends in a partial line. */
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if (!d->rmargin ||
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d->point + len + (c != EOF && c != '\n') <= d->rmargin)
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{
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/* The remaining buffer text is a partial line and fits
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within the maximum line width. Advance point for the
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characters to be written and stop scanning. */
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d->point += len;
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break;
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}
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else
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/* Set the end-of-line pointer for the code below to
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the end of the buffer. */
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nl = stream->__bufp;
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}
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else if (!d->rmargin || d->point + (nl - buf) <= d->rmargin)
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{
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/* The buffer contains a full line that fits within the maximum
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line width. Reset point and scan the next line. */
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d->point = 0;
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buf = nl + 1;
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continue;
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}
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/* This line is too long. */
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r = *d->rmargin;
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if (! d->wrapmargin)
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{
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/* Truncate the line by overwriting the excess with the
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newline and anything after it in the buffer. */
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if (nl < stream->__bufp)
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{
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memcpy (buf + (r - d->point), nl, stream->__bufp - nl);
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stream->__bufp -= buf + (r - d->point) - nl;
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/* Reset point for the next line and start scanning it. */
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d->point = 0;
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buf += r + 1; /* Skip full line plus \n. */
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}
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else
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{
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/* The buffer ends with a partial line that is beyond the
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maximum line width. Advance point for the characters
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written, and discard those past the max from the buffer. */
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d->point += len;
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stream->__bufp -= d->point - r;
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if (c != '\n')
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/* Swallow the extra character too. */
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c = EOF;
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break;
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}
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}
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else
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{
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/* Do word wrap. Go to the column just past the maximum line
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width and scan back for the beginning of the word there.
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Then insert a line break. */
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char *p, *nextline;
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int i;
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p = buf + (r + 1 - d->point);
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while (p >= buf && !isblank (*p))
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--p;
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nextline = p + 1; /* This will begin the next line. */
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if (nextline > buf)
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{
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/* Swallow separating blanks. */
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do
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--p;
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while (isblank (*p));
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nl = p + 1; /* The newline will replace the first blank. */
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}
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else
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{
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/* A single word that is greater than the maximum line width.
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Oh well. Put it on an overlong line by itself. */
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p = buf + (r + 1 - d->point);
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/* Find the end of the long word. */
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do
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++p;
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while (p < nl && !isblank (*p));
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if (p == nl)
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{
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/* It already ends a line. No fussing required. */
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d->point = 0;
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buf = nl + 1;
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continue;
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}
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/* We will move the newline to replace the first blank. */
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nl = p;
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/* Swallow separating blanks. */
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do
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++p;
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while (isblank (*p));
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/* The next line will start here. */
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nextline = p;
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}
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/* Temporarily reset bufp to include just the first line. */
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stream->__bufp = nl;
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if (nextline - (nl + 1) < d->wrap)
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/* The margin needs more blanks than we removed.
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Output the first line so we can use the space. */
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(*d->output) (stream, '\n');
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else
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/* We can fit the newline and blanks in before
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the next word. */
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*stream->__bufp++ = '\n';
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/* Reset the counter of what has been output this line. */
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d->point = 0;
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/* Add blanks up to the wrap margin column. */
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for (i = 0; i < d->wrap; ++i)
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*stream->__bufp++ = ' ';
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/* Copy the tail of the original buffer into the current buffer
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position. */
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if (stream->__bufp != nextline)
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memcpy (stream->__bufp, nextline, buf + len - nextline);
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len -= nextline - buf;
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/* Continue the scan on the remaining lines in the buffer. */
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buf = stream->__bufp;
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/* Restore bufp to include all the remaining text. */
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stream->__bufp += len;
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}
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}
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if (!stream->__error)
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{
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(*d->output) (stream, c);
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if (c == '\n')
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d->point = 0;
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else if (c != EOF)
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++d->point;
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}
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wrap_stream (stream, d);
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}
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/* Modify STREAM so that it prefixes lines written on it with *LMARGIN
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spaces and limits them to *RMARGIN columns total. If WRAP is not null,
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words that extend past *RMARGIN are wrapped by replacing the whitespace
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before them with a newline and *WRAP spaces. Otherwise, chars beyond
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*RMARGIN are simply dropped until a newline. Returns STREAM after
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modifying it, or NULL if there was an error. The pointers passed are
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stored in the stream and so must remain valid until `line_unwrap_stream'
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is called; the values pointed to can be changed between stdio calls. */
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FILE *
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line_wrap_stream (FILE *stream, size_t *lmargin, size_t *rmargin, size_t *wrap)
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{
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struct data *d = malloc (sizeof *d);
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if (!d)
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return NULL;
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/* Ensure full setup before we start tweaking. */
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fflush (stream);
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/* Initialize our wrapping state. */
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d->point = 0;
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/* Save the original cookie and output and close hooks. */
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d->cookie = stream->__cookie;
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d->output = stream->__room_funcs.__output;
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d->close = stream->__io_funcs.__close;
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d->fileno = stream->__io_funcs.__fileno;
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/* Take over the stream. */
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wrap_stream (stream, d);
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/* Line-wrapping streams are normally line-buffered. This is not
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required, just assumed desired. The wrapping feature should continue
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to work if the stream is switched to full or no buffering. */
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stream->__linebuf = 1;
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#define ref(arg) d->arg = arg
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ref (lmargin);
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ref (rmargin);
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ref (wrap);
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#undef ref
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return stream;
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}
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/* Remove the hooks placed in STREAM by `line_wrap_stream'. */
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void
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line_unwrap_stream (FILE *stream)
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{
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struct data *d = stream->__cookie;
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unwrap_stream (stream, d);
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free (d);
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}
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#ifdef TEST
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int
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main (int argc, char **argv)
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{
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int c;
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puts ("stopme");
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line_wrap_stream (stdout, atoi (argv[1]), atoi (argv[2] ?: "-1"));
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while ((c = getchar()) != EOF) putchar (c);
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return 0;
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}
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#endif
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@ -1,4 +1,4 @@
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/* Copyright (C) 1991, 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
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/* Copyright (C) 1991, 92, 93, 94, 95, 96 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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@ -353,6 +353,22 @@ extern FILE *fmemopen __P ((__ptr_t __s, size_t __len, __const char *__modes));
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necessary. *BUFLOC and *SIZELOC are updated with the buffer's location
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and the number of characters written on fflush or fclose. */
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extern FILE *open_memstream __P ((char **__bufloc, size_t *__sizeloc));
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/* Modify STREAM so that it prefixes lines written on it with *LMARGIN
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spaces and limits them to *RMARGIN columns total. If WRAP is not null,
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words that extend past *RMARGIN are wrapped by replacing the whitespace
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before them with a newline and *WRAP spaces. Otherwise, chars beyond
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*RMARGIN are simply dropped until a newline. Returns STREAM after
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modifying it, or NULL if there was an error. The pointers passed are
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stored in the stream and so must remain valid until `line_unwrap_stream'
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is called; the values pointed to can be changed between stdio calls. */
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extern FILE *line_wrap_stream __P ((FILE *__stream,
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size_t *__lmargin, size_t *__rmargin,
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size_t *__wrap));
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/* Remove the hooks placed in STREAM by `line_wrap_stream'. */
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extern void line_unwrap_stream __P ((FILE *__stream));
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#endif
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