431 lines
11 KiB
C
431 lines
11 KiB
C
/* Word-wrapping and line-truncating streams
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Copyright (C) 1997-2017 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Written by Miles Bader <miles@gnu.ai.mit.edu>.
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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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<http://www.gnu.org/licenses/>. */
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/* This package emulates glibc `line_wrap_stream' semantics for systems that
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don't have that. */
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include <stdarg.h>
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#include <ctype.h>
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#include <argp-fmtstream.h>
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#include "argp-namefrob.h"
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#ifndef ARGP_FMTSTREAM_USE_LINEWRAP
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#ifndef isblank
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#define isblank(ch) ((ch)==' ' || (ch)=='\t')
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#endif
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#ifdef _LIBC
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# include <wchar.h>
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# include <libio/libioP.h>
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# define __vsnprintf(s, l, f, a) _IO_vsnprintf (s, l, f, a)
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#endif
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#define INIT_BUF_SIZE 200
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#define PRINTF_SIZE_GUESS 150
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/* Return an argp_fmtstream that outputs to STREAM, and which prefixes lines
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written on it with LMARGIN spaces and limits them to RMARGIN columns
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total. If WMARGIN >= 0, words that extend past RMARGIN are wrapped by
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replacing the whitespace before them with a newline and WMARGIN spaces.
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Otherwise, chars beyond RMARGIN are simply dropped until a newline.
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Returns NULL if there was an error. */
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argp_fmtstream_t
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__argp_make_fmtstream (FILE *stream,
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size_t lmargin, size_t rmargin, ssize_t wmargin)
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{
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argp_fmtstream_t fs;
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fs = (struct argp_fmtstream *) malloc (sizeof (struct argp_fmtstream));
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if (fs != NULL)
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{
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fs->stream = stream;
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fs->lmargin = lmargin;
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fs->rmargin = rmargin;
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fs->wmargin = wmargin;
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fs->point_col = 0;
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fs->point_offs = 0;
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fs->buf = (char *) malloc (INIT_BUF_SIZE);
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if (! fs->buf)
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{
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free (fs);
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fs = 0;
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}
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else
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{
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fs->p = fs->buf;
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fs->end = fs->buf + INIT_BUF_SIZE;
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}
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}
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return fs;
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}
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#if 0
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/* Not exported. */
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#ifdef weak_alias
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weak_alias (__argp_make_fmtstream, argp_make_fmtstream)
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#endif
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#endif
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/* Flush FS to its stream, and free it (but don't close the stream). */
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void
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__argp_fmtstream_free (argp_fmtstream_t fs)
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{
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__argp_fmtstream_update (fs);
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if (fs->p > fs->buf)
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{
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#ifdef _LIBC
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__fxprintf (fs->stream, "%.*s", (int) (fs->p - fs->buf), fs->buf);
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#else
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fwrite_unlocked (fs->buf, 1, fs->p - fs->buf, fs->stream);
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#endif
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}
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free (fs->buf);
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free (fs);
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}
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#if 0
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/* Not exported. */
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#ifdef weak_alias
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weak_alias (__argp_fmtstream_free, argp_fmtstream_free)
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#endif
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#endif
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/* Process FS's buffer so that line wrapping is done from POINT_OFFS to the
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end of its buffer. This code is mostly from glibc stdio/linewrap.c. */
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void
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__argp_fmtstream_update (argp_fmtstream_t fs)
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{
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char *buf, *nl;
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size_t len;
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/* Scan the buffer for newlines. */
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buf = fs->buf + fs->point_offs;
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while (buf < fs->p)
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{
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size_t r;
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if (fs->point_col == 0 && fs->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 = fs->lmargin;
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if (fs->p + pad < fs->end)
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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, fs->p - buf);
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fs->p += 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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for (i = 0; i < pad; i++)
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{
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if (_IO_fwide (fs->stream, 0) > 0)
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putwc_unlocked (L' ', fs->stream);
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else
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putc_unlocked (' ', fs->stream);
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}
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}
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fs->point_col = pad;
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}
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len = fs->p - buf;
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nl = memchr (buf, '\n', len);
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if (fs->point_col < 0)
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fs->point_col = 0;
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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 (fs->point_col + len < fs->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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fs->point_col += 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 = fs->p;
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}
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else if (fs->point_col + (nl - buf) < (ssize_t) fs->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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fs->point_col = 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 = fs->rmargin - 1;
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if (fs->wmargin < 0)
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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 < fs->p)
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{
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memmove (buf + (r - fs->point_col), nl, fs->p - nl);
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fs->p -= buf + (r - fs->point_col) - nl;
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/* Reset point for the next line and start scanning it. */
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fs->point_col = 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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fs->point_col += len;
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fs->p -= fs->point_col - r;
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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 - fs->point_col);
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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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if (p >= buf)
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do
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--p;
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while (p >= buf && 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 - fs->point_col);
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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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fs->point_col = 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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/* Note: There are a bunch of tests below for
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NEXTLINE == BUF + LEN + 1; this case is where NL happens to fall
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at the end of the buffer, and NEXTLINE is in fact empty (and so
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we need not be careful to maintain its contents). */
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if ((nextline == buf + len + 1
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? fs->end - nl < fs->wmargin + 1
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: nextline - (nl + 1) < fs->wmargin)
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&& fs->p > nextline)
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{
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/* The margin needs more blanks than we removed. */
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if (fs->end - fs->p > fs->wmargin + 1)
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/* Make some space for them. */
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{
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size_t mv = fs->p - nextline;
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memmove (nl + 1 + fs->wmargin, nextline, mv);
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nextline = nl + 1 + fs->wmargin;
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len = nextline + mv - buf;
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*nl++ = '\n';
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}
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else
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/* Output the first line so we can use the space. */
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{
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#ifdef _LIBC
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__fxprintf (fs->stream, "%.*s\n",
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(int) (nl - fs->buf), fs->buf);
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#else
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if (nl > fs->buf)
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fwrite_unlocked (fs->buf, 1, nl - fs->buf, fs->stream);
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putc_unlocked ('\n', fs->stream);
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#endif
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len += buf - fs->buf;
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nl = buf = fs->buf;
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}
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}
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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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*nl++ = '\n';
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if (nextline - nl >= fs->wmargin
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|| (nextline == buf + len + 1 && fs->end - nextline >= fs->wmargin))
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/* Add blanks up to the wrap margin column. */
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for (i = 0; i < fs->wmargin; ++i)
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*nl++ = ' ';
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else
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for (i = 0; i < fs->wmargin; ++i)
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if (_IO_fwide (fs->stream, 0) > 0)
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putwc_unlocked (L' ', fs->stream);
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else
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putc_unlocked (' ', fs->stream);
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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 (nl < nextline)
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memmove (nl, 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 = nl;
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/* Restore bufp to include all the remaining text. */
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fs->p = nl + len;
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/* Reset the counter of what has been output this line. If wmargin
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is 0, we want to avoid the lmargin getting added, so we set
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point_col to a magic value of -1 in that case. */
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fs->point_col = fs->wmargin ? fs->wmargin : -1;
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}
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}
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/* Remember that we've scanned as far as the end of the buffer. */
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fs->point_offs = fs->p - fs->buf;
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}
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/* Ensure that FS has space for AMOUNT more bytes in its buffer, either by
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growing the buffer, or by flushing it. True is returned iff we succeed. */
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int
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__argp_fmtstream_ensure (struct argp_fmtstream *fs, size_t amount)
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{
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if ((size_t) (fs->end - fs->p) < amount)
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{
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ssize_t wrote;
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/* Flush FS's buffer. */
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__argp_fmtstream_update (fs);
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#ifdef _LIBC
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__fxprintf (fs->stream, "%.*s", (int) (fs->p - fs->buf), fs->buf);
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wrote = fs->p - fs->buf;
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#else
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wrote = fwrite_unlocked (fs->buf, 1, fs->p - fs->buf, fs->stream);
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#endif
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if (wrote == fs->p - fs->buf)
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{
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fs->p = fs->buf;
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fs->point_offs = 0;
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}
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else
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{
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fs->p -= wrote;
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fs->point_offs -= wrote;
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memmove (fs->buf, fs->buf + wrote, fs->p - fs->buf);
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return 0;
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}
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if ((size_t) (fs->end - fs->buf) < amount)
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/* Gotta grow the buffer. */
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{
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size_t old_size = fs->end - fs->buf;
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size_t new_size = old_size + amount;
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char *new_buf;
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if (new_size < old_size || ! (new_buf = realloc (fs->buf, new_size)))
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{
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__set_errno (ENOMEM);
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return 0;
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}
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fs->buf = new_buf;
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fs->end = new_buf + new_size;
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fs->p = fs->buf;
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}
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}
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return 1;
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}
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ssize_t
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__argp_fmtstream_printf (struct argp_fmtstream *fs, const char *fmt, ...)
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{
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int out;
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size_t avail;
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size_t size_guess = PRINTF_SIZE_GUESS; /* How much space to reserve. */
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do
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{
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va_list args;
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if (! __argp_fmtstream_ensure (fs, size_guess))
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return -1;
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va_start (args, fmt);
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avail = fs->end - fs->p;
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out = __vsnprintf (fs->p, avail, fmt, args);
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va_end (args);
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if ((size_t) out >= avail)
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size_guess = out + 1;
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}
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while ((size_t) out >= avail);
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fs->p += out;
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return out;
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}
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#if 0
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/* Not exported. */
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#ifdef weak_alias
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weak_alias (__argp_fmtstream_printf, argp_fmtstream_printf)
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#endif
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#endif
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#endif /* !ARGP_FMTSTREAM_USE_LINEWRAP */
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