--- /dev/null
+/* Word-wrapping and line-truncating streams.
+Copyright (C) 1996 Free Software Foundation, Inc.
+This file is part of the GNU C Library.
+
+The GNU C Library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public License as
+published by the Free Software Foundation; either version 2 of the
+License, or (at your option) any later version.
+
+The GNU C Library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB. If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA. */
+
+#include <stdio.h>
+#include <ctype.h>
+#include <string.h>
+#include <stdlib.h>
+
+/* We keep this data for each line-wrapping stream. */
+
+struct data
+ {
+ const size_t *lmargin, *rmargin; /* Left and right margins. */
+ const size_t *wrapmargin; /* Margin to wrap to, or null to truncate. */
+ size_t point; /* Current column of last chars flushed. */
+
+ /* Original cookie and hooks from the stream. */
+ void *cookie;
+ void (*output) (FILE *, int);
+ __io_close_fn *close;
+ __io_fileno_fn *fileno;
+ __io_seek_fn *seek;
+ };
+
+/* Install our hooks into a stream. */
+
+static inline void
+wrap_stream (FILE *stream, struct data *d)
+{
+ static void lwoutput (FILE *, int);
+ static __io_close_fn lwclose;
+ static __io_fileno_fn lwfileno;
+
+ stream->__cookie = d;
+ stream->__room_funcs.__output = &lwoutput;
+ stream->__io_funcs.__close = &lwclose;
+ stream->__io_funcs.__fileno = &lwfileno;
+ stream->__io_funcs.__seek = NULL; /* Cannot seek. */
+}
+
+/* Restore a stream to its original state. */
+
+static inline void
+unwrap_stream (FILE *stream, struct data *d)
+{
+ stream->__cookie = d->cookie;
+ stream->__room_funcs.__output = d->output;
+ stream->__io_funcs.__close = d->close;
+ stream->__io_funcs.__fileno = d->fileno;
+ stream->__io_funcs.__seek = d->seek;
+}
+\f
+/* Cookie io functions that might get called on a wrapped stream.
+ Must pass the original cookie to the original functions. */
+
+static int
+lwclose (void *cookie)
+{
+ struct data *d = cookie;
+ return (*d->close) (d->cookie);
+}
+
+static int
+lwfileno (void *cookie)
+{
+ struct data *d = cookie;
+ return (*d->fileno) (d->cookie);
+}
+\f
+/* This function is called when STREAM must be flushed.
+ C is EOF or a character to be appended to the buffer contents. */
+
+static void
+lwoutput (FILE *stream, int c)
+{
+ char *buf, *nl;
+ size_t len;
+
+ /* Extract our data and restore the stream's original cookie
+ and output function so writes we do really go out. */
+ struct data *d = stream->__cookie;
+ unwrap_stream (stream, d);
+
+ /* Scan the buffer for newlines. */
+ for (buf = stream->__buffer;
+ (buf < stream->__bufp || (c != EOF && c != '\n')) && !stream->__error)
+ {
+ size_t r;
+
+ if (d->point == 0 && d->lmargin && *d->lmargin != 0)
+ {
+ /* We are starting a new line. Print spaces to the left margin. */
+ const size_t pad = *d->lmargin;
+ if (stream->__bufp + pad < stream->__put_limit)
+ {
+ /* We can fit in them in the buffer by moving the
+ buffer text up and filling in the beginning. */
+ memmove (buf + pad, buf, stream->__bufp - buf);
+ stream->__bufp += pad; /* Compensate for bigger buffer. */
+ memset (buf, ' ', pad); /* Fill in the spaces. */
+ buf += pad; /* Don't bother searching them. */
+ }
+ else
+ {
+ /* No buffer space for spaces. Must flush. */
+ size_t i;
+ char *olimit;
+
+ len = stream->__bufp - buf;
+ olimit = stream->__put_limit;
+ stream->__bufp = stream->__put_limit = buf;
+ for (i = 0; i < pad; ++i)
+ (*d->output) (stream, ' ');
+ stream->__put_limit = olimit;
+ memcpy (stream->__bufp, buf, len);
+ stream->__bufp += len;
+ }
+ d->point = pad;
+ }
+
+ len = stream->__bufp - buf;
+ nl = memchr (buf, '\n', len);
+
+ if (!nl)
+ {
+ /* The buffer ends in a partial line. */
+
+ if (!d->rmargin ||
+ d->point + len + (c != EOF && c != '\n') <= d->rmargin)
+ {
+ /* The remaining buffer text is a partial line and fits
+ within the maximum line width. Advance point for the
+ characters to be written and stop scanning. */
+ d->point += len;
+ break;
+ }
+ else
+ /* Set the end-of-line pointer for the code below to
+ the end of the buffer. */
+ nl = stream->__bufp;
+ }
+ else if (!d->rmargin || d->point + (nl - buf) <= d->rmargin)
+ {
+ /* The buffer contains a full line that fits within the maximum
+ line width. Reset point and scan the next line. */
+ d->point = 0;
+ buf = nl + 1;
+ continue;
+ }
+
+ /* This line is too long. */
+ r = *d->rmargin;
+
+ if (! d->wrapmargin)
+ {
+ /* Truncate the line by overwriting the excess with the
+ newline and anything after it in the buffer. */
+ if (nl < stream->__bufp)
+ {
+ memcpy (buf + (r - d->point), nl, stream->__bufp - nl);
+ stream->__bufp -= buf + (r - d->point) - nl;
+ /* Reset point for the next line and start scanning it. */
+ d->point = 0;
+ buf += r + 1; /* Skip full line plus \n. */
+ }
+ else
+ {
+ /* The buffer ends with a partial line that is beyond the
+ maximum line width. Advance point for the characters
+ written, and discard those past the max from the buffer. */
+ d->point += len;
+ stream->__bufp -= d->point - r;
+ if (c != '\n')
+ /* Swallow the extra character too. */
+ c = EOF;
+ break;
+ }
+ }
+ else
+ {
+ /* Do word wrap. Go to the column just past the maximum line
+ width and scan back for the beginning of the word there.
+ Then insert a line break. */
+
+ char *p, *nextline;
+ int i;
+
+ p = buf + (r + 1 - d->point);
+ while (p >= buf && !isblank (*p))
+ --p;
+ nextline = p + 1; /* This will begin the next line. */
+
+ if (nextline > buf)
+ {
+ /* Swallow separating blanks. */
+ do
+ --p;
+ while (isblank (*p));
+ nl = p + 1; /* The newline will replace the first blank. */
+ }
+ else
+ {
+ /* A single word that is greater than the maximum line width.
+ Oh well. Put it on an overlong line by itself. */
+ p = buf + (r + 1 - d->point);
+ /* Find the end of the long word. */
+ do
+ ++p;
+ while (p < nl && !isblank (*p));
+ if (p == nl)
+ {
+ /* It already ends a line. No fussing required. */
+ d->point = 0;
+ buf = nl + 1;
+ continue;
+ }
+ /* We will move the newline to replace the first blank. */
+ nl = p;
+ /* Swallow separating blanks. */
+ do
+ ++p;
+ while (isblank (*p));
+ /* The next line will start here. */
+ nextline = p;
+ }
+
+ /* Temporarily reset bufp to include just the first line. */
+ stream->__bufp = nl;
+ if (nextline - (nl + 1) < d->wrap)
+ /* The margin needs more blanks than we removed.
+ Output the first line so we can use the space. */
+ (*d->output) (stream, '\n');
+ else
+ /* We can fit the newline and blanks in before
+ the next word. */
+ *stream->__bufp++ = '\n';
+
+ /* Reset the counter of what has been output this line. */
+ d->point = 0;
+
+ /* Add blanks up to the wrap margin column. */
+ for (i = 0; i < d->wrap; ++i)
+ *stream->__bufp++ = ' ';
+
+ /* Copy the tail of the original buffer into the current buffer
+ position. */
+ if (stream->__bufp != nextline)
+ memcpy (stream->__bufp, nextline, buf + len - nextline);
+ len -= nextline - buf;
+
+ /* Continue the scan on the remaining lines in the buffer. */
+ buf = stream->__bufp;
+
+ /* Restore bufp to include all the remaining text. */
+ stream->__bufp += len;
+ }
+ }
+
+ if (!stream->__error)
+ {
+ (*d->output) (stream, c);
+ if (c == '\n')
+ d->point = 0;
+ else if (c != EOF)
+ ++d->point;
+ }
+
+ wrap_stream (stream, d);
+}
+\f
+/* Modify STREAM so that it prefixes lines written on it with *LMARGIN
+ spaces and limits them to *RMARGIN columns total. If WRAP is not null,
+ words that extend past *RMARGIN are wrapped by replacing the whitespace
+ before them with a newline and *WRAP spaces. Otherwise, chars beyond
+ *RMARGIN are simply dropped until a newline. Returns STREAM after
+ modifying it, or NULL if there was an error. The pointers passed are
+ stored in the stream and so must remain valid until `line_unwrap_stream'
+ is called; the values pointed to can be changed between stdio calls. */
+
+FILE *
+line_wrap_stream (FILE *stream, size_t *lmargin, size_t *rmargin, size_t *wrap)
+{
+ struct data *d = malloc (sizeof *d);
+
+ if (!d)
+ return NULL;
+
+ /* Ensure full setup before we start tweaking. */
+ fflush (stream);
+
+ /* Initialize our wrapping state. */
+ d->point = 0;
+
+ /* Save the original cookie and output and close hooks. */
+ d->cookie = stream->__cookie;
+ d->output = stream->__room_funcs.__output;
+ d->close = stream->__io_funcs.__close;
+ d->fileno = stream->__io_funcs.__fileno;
+
+ /* Take over the stream. */
+ wrap_stream (stream, d);
+
+ /* Line-wrapping streams are normally line-buffered. This is not
+ required, just assumed desired. The wrapping feature should continue
+ to work if the stream is switched to full or no buffering. */
+ stream->__linebuf = 1;
+
+#define ref(arg) d->arg = arg
+ ref (lmargin);
+ ref (rmargin);
+ ref (wrap);
+#undef ref
+
+ return stream;
+}
+
+/* Remove the hooks placed in STREAM by `line_wrap_stream'. */
+
+void
+line_unwrap_stream (FILE *stream)
+{
+ struct data *d = stream->__cookie;
+ unwrap_stream (stream, d);
+ free (d);
+}
+\f
+#ifdef TEST
+int
+main (int argc, char **argv)
+{
+ int c;
+ puts ("stopme");
+ line_wrap_stream (stdout, atoi (argv[1]), atoi (argv[2] ?: "-1"));
+ while ((c = getchar()) != EOF) putchar (c);
+ return 0;
+}
+#endif
projects / platform / upstream / glibc.git / commitdiff