diff options
Diffstat (limited to 'argp/argp-fmtstream.c')
| -rw-r--r-- | argp/argp-fmtstream.c | 374 |
1 files changed, 374 insertions, 0 deletions
diff --git a/argp/argp-fmtstream.c b/argp/argp-fmtstream.c new file mode 100644 index 0000000000..c7203deac6 --- /dev/null +++ b/argp/argp-fmtstream.c @@ -0,0 +1,374 @@ +/* Word-wrapping and line-truncating streams + Copyright (C) 1997 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Written by Miles Bader <miles@gnu.ai.mit.edu>. + + 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., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +/* This package emulates glibc `line_wrap_stream' semantics for systems that + don't have that. */ + +#ifdef HAVE_CONFIG_H +#include <config.h> +#endif + +#include <stdlib.h> +#include <string.h> +#include <errno.h> +#include <stdarg.h> +#include <ctype.h> + +#include "argp-fmtstream.h" +#include "argp-namefrob.h" + +#ifndef ARGP_FMTSTREAM_USE_LINEWRAP + +#ifndef isblank +#define isblank(ch) ((ch)==' ' || (ch)=='\t') +#endif + +#define INIT_BUF_SIZE 200 +#define PRINTF_SIZE_GUESS 150 + +/* Return an argp_fmtstream that outputs to STREAM, and which prefixes lines + written on it with LMARGIN spaces and limits them to RMARGIN columns + total. If WMARGIN >= 0, words that extend past RMARGIN are wrapped by + replacing the whitespace before them with a newline and WMARGIN spaces. + Otherwise, chars beyond RMARGIN are simply dropped until a newline. + Returns NULL if there was an error. */ +argp_fmtstream_t +__argp_make_fmtstream (FILE *stream, + size_t lmargin, size_t rmargin, ssize_t wmargin) +{ + argp_fmtstream_t fs = malloc (sizeof (struct argp_fmtstream)); + if (fs) + { + fs->stream = stream; + + fs->lmargin = lmargin; + fs->rmargin = rmargin; + fs->wmargin = wmargin; + fs->point_col = 0; + fs->point_offs = 0; + + fs->buf = malloc (INIT_BUF_SIZE); + if (! fs->buf) + { + free (fs); + fs = 0; + } + else + { + fs->p = fs->buf; + fs->end = fs->buf + INIT_BUF_SIZE; + } + } + + return fs; +} +#ifdef weak_alias +weak_alias (__argp_make_fmtstream, argp_make_fmtstream) +#endif + +/* Flush FS to its stream, and free it (but don't close the stream). */ +void +__argp_fmtstream_free (argp_fmtstream_t fs) +{ + __argp_fmtstream_update (fs); + if (fs->p > fs->buf) + fwrite (fs->buf, 1, fs->p - fs->buf, fs->stream); + free (fs->buf); + free (fs); +} +#ifdef weak_alias +weak_alias (__argp_fmtstream_free, argp_fmtstream_free) +#endif + +/* Process FS's buffer so that line wrapping is done from POINT_OFFS to the + end of its buffer. This code is mostly from glibc stdio/linewrap.c. */ +void +__argp_fmtstream_update (argp_fmtstream_t fs) +{ + char *buf, *nl; + size_t len; + + /* Scan the buffer for newlines. */ + buf = fs->buf + fs->point_offs; + while (buf < fs->p) + { + size_t r; + + if (fs->point_col == 0 && fs->lmargin != 0) + { + /* We are starting a new line. Print spaces to the left margin. */ + const size_t pad = fs->lmargin; + if (fs->p + pad < fs->end) + { + /* We can fit in them in the buffer by moving the + buffer text up and filling in the beginning. */ + memmove (buf + pad, buf, fs->p - buf); + fs->p += 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; + for (i = 0; i < pad; i++) + putc (' ', fs->stream); + } + fs->point_col = pad; + } + + len = fs->p - buf; + nl = memchr (buf, '\n', len); + + if (fs->point_col < 0) + fs->point_col = 0; + + if (!nl) + { + /* The buffer ends in a partial line. */ + + if (fs->point_col + len < fs->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. */ + fs->point_col += len; + break; + } + else + /* Set the end-of-line pointer for the code below to + the end of the buffer. */ + nl = fs->p; + } + else if (fs->point_col + (nl - buf) < fs->rmargin) + { + /* The buffer contains a full line that fits within the maximum + line width. Reset point and scan the next line. */ + fs->point_col = 0; + buf = nl + 1; + continue; + } + + /* This line is too long. */ + r = fs->rmargin - 1; + + if (fs->wmargin < 0) + { + /* Truncate the line by overwriting the excess with the + newline and anything after it in the buffer. */ + if (nl < fs->p) + { + memmove (buf + (r - fs->point_col), nl, fs->p - nl); + fs->p -= buf + (r - fs->point_col) - nl; + /* Reset point for the next line and start scanning it. */ + fs->point_col = 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. */ + fs->point_col += len; + fs->p -= fs->point_col - r; + 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 - fs->point_col); + while (p >= buf && !isblank (*p)) + --p; + nextline = p + 1; /* This will begin the next line. */ + + if (nextline > buf) + { + /* Swallow separating blanks. */ + if (p > buf) + do + --p; + while (p > buf && 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 - fs->point_col); + /* 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. */ + fs->point_col = 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; + } + + if (nextline - (nl + 1) < fs->wmargin) + /* The margin needs more blanks than we removed. */ + if (fs->end - fs->p > fs->wmargin + 1) + /* Make some space for them. */ + { + size_t mv = fs->p - nextline; + memmove (nl + 1 + fs->wmargin, nextline, mv); + nextline = nl + 1 + fs->wmargin; + len = nextline + mv - buf; + *nl++ = '\n'; + } + else + /* Output the first line so we can use the space. */ + { + if (nl > fs->buf) + fwrite (fs->buf, 1, nl - fs->buf, fs->stream); + putc ('\n', fs->stream); + len += buf - fs->buf; + nl = buf = fs->buf; + } + else + /* We can fit the newline and blanks in before + the next word. */ + *nl++ = '\n'; + + if (nextline - nl >= fs->wmargin) + /* Add blanks up to the wrap margin column. */ + for (i = 0; i < fs->wmargin; ++i) + *nl++ = ' '; + else + for (i = 0; i < fs->wmargin; ++i) + putc (' ', fs->stream); + + /* Copy the tail of the original buffer into the current buffer + position. */ + if (nl != nextline) + memmove (nl, nextline, buf + len - nextline); + len -= nextline - buf; + + /* Continue the scan on the remaining lines in the buffer. */ + buf = nl; + + /* Restore bufp to include all the remaining text. */ + fs->p = nl + len; + + /* Reset the counter of what has been output this line. If wmargin + is 0, we want to avoid the lmargin getting added, so we set + point_col to a magic value of -1 in that case. */ + fs->point_col = fs->wmargin ? fs->wmargin : -1; + } + } + + /* Remember that we've scanned as far as the end of the buffer. */ + fs->point_offs = fs->p - fs->buf; +} + +/* Ensure that FS has space for AMOUNT more bytes in its buffer, either by + growing the buffer, or by flushing it. True is returned iff we succeed. */ +int +__argp_fmtstream_ensure (struct argp_fmtstream *fs, size_t amount) +{ + if (fs->end - fs->p < amount) + { + ssize_t wrote; + + /* Flush FS's buffer. */ + __argp_fmtstream_update (fs); + + wrote = fwrite (fs->buf, 1, fs->p - fs->buf, fs->stream); + if (wrote == fs->p - fs->buf) + { + fs->p = fs->buf; + fs->point_offs = 0; + } + else + { + fs->p -= wrote; + fs->point_offs -= wrote; + memmove (fs->buf, fs->buf + wrote, fs->p - fs->buf); + return 0; + } + + if (fs->end - fs->buf < amount) + /* Gotta grow the buffer. */ + { + size_t new_size = fs->end - fs->buf + amount; + char *new_buf = realloc (fs->buf, new_size); + + if (! new_buf) + { + __set_errno (ENOMEM); + return 0; + } + + fs->buf = new_buf; + fs->end = new_buf + new_size; + fs->p = fs->buf; + } + } + + return 1; +} + +ssize_t +__argp_fmtstream_printf (struct argp_fmtstream *fs, const char *fmt, ...) +{ + size_t out; + size_t size_guess = PRINTF_SIZE_GUESS; /* How much space to reserve. */ + + do + { + va_list args; + + if (! __argp_fmtstream_ensure (fs, size_guess)) + return -1; + size_guess += size_guess; + + va_start (args, fmt); + out = __vsnprintf (fs->p, fs->end - fs->p, fmt, args); + va_end (args); + } + while (out == -1); + + fs->p += out; + + return out; +} +#ifdef weak_alias +weak_alias (__argp_fmtstream_printf, argp_fmtstream_printf) +#endif + +#endif /* !ARGP_FMTSTREAM_USE_LINEWRAP */ |