1/* Word-wrapping and line-truncating streams 2 Copyright (C) 1997-1999,2001,2002,2003,2005 Free Software Foundation, Inc. 3 This file is part of the GNU C Library. 4 Written by Miles Bader <miles@gnu.ai.mit.edu>. 5 6 This program is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 2, or (at your option) 9 any later version. 10 11 This program is distributed in the hope that it will be useful, 12 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 GNU General Public License for more details. 15 16 You should have received a copy of the GNU General Public License along 17 with this program; if not, write to the Free Software Foundation, 18 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ 19 20/* This package emulates glibc `line_wrap_stream' semantics for systems that 21 don't have that. */ 22 23#ifdef HAVE_CONFIG_H 24# include <config.h> 25#endif 26 27#include <stdlib.h> 28#include <string.h> 29#include <errno.h> 30#include <stdarg.h> 31#include <ctype.h> 32 33#include "argp-fmtstream.h" 34#include "argp-namefrob.h" 35 36#ifndef ARGP_FMTSTREAM_USE_LINEWRAP 37 38#ifndef isblank 39#define isblank(ch) ((ch)==' ' || (ch)=='\t') 40#endif 41 42#if defined _LIBC && defined USE_IN_LIBIO 43# include <wchar.h> 44# include <libio/libioP.h> 45# define __vsnprintf(s, l, f, a) _IO_vsnprintf (s, l, f, a) 46#endif 47 48#define INIT_BUF_SIZE 200 49#define PRINTF_SIZE_GUESS 150 50 51/* Return an argp_fmtstream that outputs to STREAM, and which prefixes lines 52 written on it with LMARGIN spaces and limits them to RMARGIN columns 53 total. If WMARGIN >= 0, words that extend past RMARGIN are wrapped by 54 replacing the whitespace before them with a newline and WMARGIN spaces. 55 Otherwise, chars beyond RMARGIN are simply dropped until a newline. 56 Returns NULL if there was an error. */ 57argp_fmtstream_t 58__argp_make_fmtstream (FILE *stream, 59 size_t lmargin, size_t rmargin, ssize_t wmargin) 60{ 61 argp_fmtstream_t fs; 62 63 fs = (struct argp_fmtstream *) malloc (sizeof (struct argp_fmtstream)); 64 if (fs != NULL) 65 { 66 fs->stream = stream; 67 68 fs->lmargin = lmargin; 69 fs->rmargin = rmargin; 70 fs->wmargin = wmargin; 71 fs->point_col = 0; 72 fs->point_offs = 0; 73 74 fs->buf = (char *) malloc (INIT_BUF_SIZE); 75 if (! fs->buf) 76 { 77 free (fs); 78 fs = 0; 79 } 80 else 81 { 82 fs->p = fs->buf; 83 fs->end = fs->buf + INIT_BUF_SIZE; 84 } 85 } 86 87 return fs; 88} 89#if 0 90/* Not exported. */ 91#ifdef weak_alias 92weak_alias (__argp_make_fmtstream, argp_make_fmtstream) 93#endif 94#endif 95 96/* Flush FS to its stream, and free it (but don't close the stream). */ 97void 98__argp_fmtstream_free (argp_fmtstream_t fs) 99{ 100 __argp_fmtstream_update (fs); 101 if (fs->p > fs->buf) 102 { 103#ifdef USE_IN_LIBIO 104 __fxprintf (fs->stream, "%.*s", (int) (fs->p - fs->buf), fs->buf); 105#else 106 fwrite_unlocked (fs->buf, 1, fs->p - fs->buf, fs->stream); 107#endif 108 } 109 free (fs->buf); 110 free (fs); 111} 112#if 0 113/* Not exported. */ 114#ifdef weak_alias 115weak_alias (__argp_fmtstream_free, argp_fmtstream_free) 116#endif 117#endif 118 119/* Process FS's buffer so that line wrapping is done from POINT_OFFS to the 120 end of its buffer. This code is mostly from glibc stdio/linewrap.c. */ 121void 122__argp_fmtstream_update (argp_fmtstream_t fs) 123{ 124 char *buf, *nl; 125 size_t len; 126 127 /* Scan the buffer for newlines. */ 128 buf = fs->buf + fs->point_offs; 129 while (buf < fs->p) 130 { 131 size_t r; 132 133 if (fs->point_col == 0 && fs->lmargin != 0) 134 { 135 /* We are starting a new line. Print spaces to the left margin. */ 136 const size_t pad = fs->lmargin; 137 if (fs->p + pad < fs->end) 138 { 139 /* We can fit in them in the buffer by moving the 140 buffer text up and filling in the beginning. */ 141 memmove (buf + pad, buf, fs->p - buf); 142 fs->p += pad; /* Compensate for bigger buffer. */ 143 memset (buf, ' ', pad); /* Fill in the spaces. */ 144 buf += pad; /* Don't bother searching them. */ 145 } 146 else 147 { 148 /* No buffer space for spaces. Must flush. */ 149 size_t i; 150 for (i = 0; i < pad; i++) 151 { 152#ifdef USE_IN_LIBIO 153 if (_IO_fwide (fs->stream, 0) > 0) 154 putwc_unlocked (L' ', fs->stream); 155 else 156#endif 157 putc_unlocked (' ', fs->stream); 158 } 159 } 160 fs->point_col = pad; 161 } 162 163 len = fs->p - buf; 164 nl = memchr (buf, '\n', len); 165 166 if (fs->point_col < 0) 167 fs->point_col = 0; 168 169 if (!nl) 170 { 171 /* The buffer ends in a partial line. */ 172 173 if (fs->point_col + len < fs->rmargin) 174 { 175 /* The remaining buffer text is a partial line and fits 176 within the maximum line width. Advance point for the 177 characters to be written and stop scanning. */ 178 fs->point_col += len; 179 break; 180 } 181 else 182 /* Set the end-of-line pointer for the code below to 183 the end of the buffer. */ 184 nl = fs->p; 185 } 186 else if (fs->point_col + (nl - buf) < (ssize_t) fs->rmargin) 187 { 188 /* The buffer contains a full line that fits within the maximum 189 line width. Reset point and scan the next line. */ 190 fs->point_col = 0; 191 buf = nl + 1; 192 continue; 193 } 194 195 /* This line is too long. */ 196 r = fs->rmargin - 1; 197 198 if (fs->wmargin < 0) 199 { 200 /* Truncate the line by overwriting the excess with the 201 newline and anything after it in the buffer. */ 202 if (nl < fs->p) 203 { 204 memmove (buf + (r - fs->point_col), nl, fs->p - nl); 205 fs->p -= buf + (r - fs->point_col) - nl; 206 /* Reset point for the next line and start scanning it. */ 207 fs->point_col = 0; 208 buf += r + 1; /* Skip full line plus \n. */ 209 } 210 else 211 { 212 /* The buffer ends with a partial line that is beyond the 213 maximum line width. Advance point for the characters 214 written, and discard those past the max from the buffer. */ 215 fs->point_col += len; 216 fs->p -= fs->point_col - r; 217 break; 218 } 219 } 220 else 221 { 222 /* Do word wrap. Go to the column just past the maximum line 223 width and scan back for the beginning of the word there. 224 Then insert a line break. */ 225 226 char *p, *nextline; 227 int i; 228 229 p = buf + (r + 1 - fs->point_col); 230 while (p >= buf && !isblank (*p)) 231 --p; 232 nextline = p + 1; /* This will begin the next line. */ 233 234 if (nextline > buf) 235 { 236 /* Swallow separating blanks. */ 237 if (p >= buf) 238 do 239 --p; 240 while (p >= buf && isblank (*p)); 241 nl = p + 1; /* The newline will replace the first blank. */ 242 } 243 else 244 { 245 /* A single word that is greater than the maximum line width. 246 Oh well. Put it on an overlong line by itself. */ 247 p = buf + (r + 1 - fs->point_col); 248 /* Find the end of the long word. */ 249 if (p < nl) 250 do 251 ++p; 252 while (p < nl && !isblank (*p)); 253 if (p == nl) 254 { 255 /* It already ends a line. No fussing required. */ 256 fs->point_col = 0; 257 buf = nl + 1; 258 continue; 259 } 260 /* We will move the newline to replace the first blank. */ 261 nl = p; 262 /* Swallow separating blanks. */ 263 do 264 ++p; 265 while (isblank (*p)); 266 /* The next line will start here. */ 267 nextline = p; 268 } 269 270 /* Note: There are a bunch of tests below for 271 NEXTLINE == BUF + LEN + 1; this case is where NL happens to fall 272 at the end of the buffer, and NEXTLINE is in fact empty (and so 273 we need not be careful to maintain its contents). */ 274 275 if ((nextline == buf + len + 1 276 ? fs->end - nl < fs->wmargin + 1 277 : nextline - (nl + 1) < fs->wmargin) 278 && fs->p > nextline) 279 { 280 /* The margin needs more blanks than we removed. */ 281 if (fs->end - fs->p > fs->wmargin + 1) 282 /* Make some space for them. */ 283 { 284 size_t mv = fs->p - nextline; 285 memmove (nl + 1 + fs->wmargin, nextline, mv); 286 nextline = nl + 1 + fs->wmargin; 287 len = nextline + mv - buf; 288 *nl++ = '\n'; 289 } 290 else 291 /* Output the first line so we can use the space. */ 292 { 293#ifdef _LIBC 294 __fxprintf (fs->stream, "%.*s\n", 295 (int) (nl - fs->buf), fs->buf); 296#else 297 if (nl > fs->buf) 298 fwrite_unlocked (fs->buf, 1, nl - fs->buf, fs->stream); 299 putc_unlocked ('\n', fs->stream); 300#endif 301 302 len += buf - fs->buf; 303 nl = buf = fs->buf; 304 } 305 } 306 else 307 /* We can fit the newline and blanks in before 308 the next word. */ 309 *nl++ = '\n'; 310 311 if (nextline - nl >= fs->wmargin 312 || (nextline == buf + len + 1 && fs->end - nextline >= fs->wmargin)) 313 /* Add blanks up to the wrap margin column. */ 314 for (i = 0; i < fs->wmargin; ++i) 315 *nl++ = ' '; 316 else 317 for (i = 0; i < fs->wmargin; ++i) 318#ifdef USE_IN_LIBIO 319 if (_IO_fwide (fs->stream, 0) > 0) 320 putwc_unlocked (L' ', fs->stream); 321 else 322#endif 323 putc_unlocked (' ', fs->stream); 324 325 /* Copy the tail of the original buffer into the current buffer 326 position. */ 327 if (nl < nextline) 328 memmove (nl, nextline, buf + len - nextline); 329 len -= nextline - buf; 330 331 /* Continue the scan on the remaining lines in the buffer. */ 332 buf = nl; 333 334 /* Restore bufp to include all the remaining text. */ 335 fs->p = nl + len; 336 337 /* Reset the counter of what has been output this line. If wmargin 338 is 0, we want to avoid the lmargin getting added, so we set 339 point_col to a magic value of -1 in that case. */ 340 fs->point_col = fs->wmargin ? fs->wmargin : -1; 341 } 342 } 343 344 /* Remember that we've scanned as far as the end of the buffer. */ 345 fs->point_offs = fs->p - fs->buf; 346} 347 348/* Ensure that FS has space for AMOUNT more bytes in its buffer, either by 349 growing the buffer, or by flushing it. True is returned iff we succeed. */ 350int 351__argp_fmtstream_ensure (struct argp_fmtstream *fs, size_t amount) 352{ 353 if ((size_t) (fs->end - fs->p) < amount) 354 { 355 ssize_t wrote; 356 357 /* Flush FS's buffer. */ 358 __argp_fmtstream_update (fs); 359 360#ifdef _LIBC 361 __fxprintf (fs->stream, "%.*s", (int) (fs->p - fs->buf), fs->buf); 362 wrote = fs->p - fs->buf; 363#else 364 wrote = fwrite_unlocked (fs->buf, 1, fs->p - fs->buf, fs->stream); 365#endif 366 if (wrote == fs->p - fs->buf) 367 { 368 fs->p = fs->buf; 369 fs->point_offs = 0; 370 } 371 else 372 { 373 fs->p -= wrote; 374 fs->point_offs -= wrote; 375 memmove (fs->buf, fs->buf + wrote, fs->p - fs->buf); 376 return 0; 377 } 378 379 if ((size_t) (fs->end - fs->buf) < amount) 380 /* Gotta grow the buffer. */ 381 { 382 size_t old_size = fs->end - fs->buf; 383 size_t new_size = old_size + amount; 384 char *new_buf; 385 386 if (new_size < old_size || ! (new_buf = realloc (fs->buf, new_size))) 387 { 388 __set_errno (ENOMEM); 389 return 0; 390 } 391 392 fs->buf = new_buf; 393 fs->end = new_buf + new_size; 394 fs->p = fs->buf; 395 } 396 } 397 398 return 1; 399} 400 401ssize_t 402__argp_fmtstream_printf (struct argp_fmtstream *fs, const char *fmt, ...) 403{ 404 int out; 405 size_t avail; 406 size_t size_guess = PRINTF_SIZE_GUESS; /* How much space to reserve. */ 407 408 do 409 { 410 va_list args; 411 412 if (! __argp_fmtstream_ensure (fs, size_guess)) 413 return -1; 414 415 va_start (args, fmt); 416 avail = fs->end - fs->p; 417 out = __vsnprintf (fs->p, avail, fmt, args); 418 va_end (args); 419 if ((size_t) out >= avail) 420 size_guess = out + 1; 421 } 422 while ((size_t) out >= avail); 423 424 fs->p += out; 425 426 return out; 427} 428#if 0 429/* Not exported. */ 430#ifdef weak_alias 431weak_alias (__argp_fmtstream_printf, argp_fmtstream_printf) 432#endif 433#endif 434 435#endif /* !ARGP_FMTSTREAM_USE_LINEWRAP */ 436