| 1 | /* Output like sprintf to a buffer of specified size. |
| 2 | Also takes args differently: pass one pointer to the end |
| 3 | of the format string in addition to the format string itself. |
| 4 | Copyright (C) 1985, 2001-2011 Free Software Foundation, Inc. |
| 5 | |
| 6 | This file is part of GNU Emacs. |
| 7 | |
| 8 | GNU Emacs is free software: you can redistribute it and/or modify |
| 9 | it under the terms of the GNU General Public License as published by |
| 10 | the Free Software Foundation, either version 3 of the License, or |
| 11 | (at your option) any later version. |
| 12 | |
| 13 | GNU Emacs is distributed in the hope that it will be useful, |
| 14 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | GNU General Public License for more details. |
| 17 | |
| 18 | You should have received a copy of the GNU General Public License |
| 19 | along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */ |
| 20 | |
| 21 | /* If you think about replacing this with some similar standard C function of |
| 22 | the printf family (such as vsnprintf), please note that this function |
| 23 | supports the following Emacs-specific features: |
| 24 | |
| 25 | . For %c conversions, it produces a string with the multibyte representation |
| 26 | of the (`int') argument, suitable for display in an Emacs buffer. |
| 27 | |
| 28 | . For %s and %c, when field width is specified (e.g., %25s), it accounts for |
| 29 | the diplay width of each character, according to char-width-table. That |
| 30 | is, it does not assume that each character takes one column on display. |
| 31 | |
| 32 | . If the size of the buffer is not enough to produce the formatted string in |
| 33 | its entirety, it makes sure that truncation does not chop the last |
| 34 | character in the middle of its multibyte sequence, producing an invalid |
| 35 | sequence. |
| 36 | |
| 37 | . It accepts a pointer to the end of the format string, so the format string |
| 38 | could include embedded null characters. |
| 39 | |
| 40 | . It signals an error if the length of the formatted string is about to |
| 41 | overflow MOST_POSITIVE_FIXNUM, to avoid producing strings longer than what |
| 42 | Emacs can handle. |
| 43 | |
| 44 | OTOH, this function supports only a small subset of the standard C formatted |
| 45 | output facilities. E.g., %u and %ll are not supported, and precision is |
| 46 | ignored %s and %c conversions. (See below for the detailed documentation of |
| 47 | what is supported.) However, this is okay, as this function is supposed to |
| 48 | be called from `error' and similar functions, and thus does not need to |
| 49 | support features beyond those in `Fformat', which is used by `error' on the |
| 50 | Lisp level. */ |
| 51 | |
| 52 | /* This function supports the following %-sequences in the `format' |
| 53 | argument: |
| 54 | |
| 55 | %s means print a string argument. |
| 56 | %S is silently treated as %s, for loose compatibility with `Fformat'. |
| 57 | %d means print a `signed int' argument in decimal. |
| 58 | %o means print an `unsigned int' argument in octal. |
| 59 | %x means print an `unsigned int' argument in hex. |
| 60 | %e means print a `double' argument in exponential notation. |
| 61 | %f means print a `double' argument in decimal-point notation. |
| 62 | %g means print a `double' argument in exponential notation |
| 63 | or in decimal-point notation, whichever uses fewer characters. |
| 64 | %c means print a `signed int' argument as a single character. |
| 65 | %% means produce a literal % character. |
| 66 | |
| 67 | A %-sequence may contain optional flag, width, and precision specifiers, and |
| 68 | a length modifier, as follows: |
| 69 | |
| 70 | %<flags><width><precision><length>character |
| 71 | |
| 72 | where flags is [+ -0], width is [0-9]+, precision is .[0-9]+, and length |
| 73 | is empty or l or the value of the pI macro. Also, %% in a format |
| 74 | stands for a single % in the output. A % that does not introduce a |
| 75 | valid %-sequence causes undefined behavior. |
| 76 | |
| 77 | The + flag character inserts a + before any positive number, while a space |
| 78 | inserts a space before any positive number; these flags only affect %d, %o, |
| 79 | %x, %e, %f, and %g sequences. The - and 0 flags affect the width specifier, |
| 80 | as described below. For signed numerical arguments only, the ` ' (space) |
| 81 | flag causes the result to be prefixed with a space character if it does not |
| 82 | start with a sign (+ or -). |
| 83 | |
| 84 | The l (lower-case letter ell) length modifier is a `long' data type |
| 85 | modifier: it is supported for %d, %o, and %x conversions of integral |
| 86 | arguments, must immediately precede the conversion specifier, and means that |
| 87 | the respective argument is to be treated as `long int' or `unsigned long |
| 88 | int'. Similarly, the value of the pI macro means to use EMACS_INT or |
| 89 | EMACS_UINT and the empty length modifier means `int' or `unsigned int'. |
| 90 | |
| 91 | The width specifier supplies a lower limit for the length of the printed |
| 92 | representation. The padding, if any, normally goes on the left, but it goes |
| 93 | on the right if the - flag is present. The padding character is normally a |
| 94 | space, but (for numerical arguments only) it is 0 if the 0 flag is present. |
| 95 | The - flag takes precedence over the 0 flag. |
| 96 | |
| 97 | For %e, %f, and %g sequences, the number after the "." in the precision |
| 98 | specifier says how many decimal places to show; if zero, the decimal point |
| 99 | itself is omitted. For %s and %S, the precision specifier is ignored. */ |
| 100 | |
| 101 | #include <config.h> |
| 102 | #include <stdio.h> |
| 103 | #include <ctype.h> |
| 104 | #include <setjmp.h> |
| 105 | |
| 106 | #ifdef STDC_HEADERS |
| 107 | #include <float.h> |
| 108 | #endif |
| 109 | |
| 110 | #include <unistd.h> |
| 111 | |
| 112 | #include <limits.h> |
| 113 | |
| 114 | #include "lisp.h" |
| 115 | |
| 116 | /* Since we use the macro CHAR_HEAD_P, we have to include this, but |
| 117 | don't have to include others because CHAR_HEAD_P does not contains |
| 118 | another macro. */ |
| 119 | #include "character.h" |
| 120 | |
| 121 | #ifndef DBL_MAX_10_EXP |
| 122 | #define DBL_MAX_10_EXP 308 /* IEEE double */ |
| 123 | #endif |
| 124 | |
| 125 | /* Generate output from a format-spec FORMAT, |
| 126 | terminated at position FORMAT_END. |
| 127 | (*FORMAT_END is not part of the format, but must exist and be readable.) |
| 128 | Output goes in BUFFER, which has room for BUFSIZE chars. |
| 129 | BUFSIZE must be positive. If the output does not fit, truncate it |
| 130 | to fit and return BUFSIZE - 1; if this truncates a multibyte |
| 131 | sequence, store '\0' into the sequence's first byte. |
| 132 | Returns the number of bytes stored into BUFFER, excluding |
| 133 | the terminating null byte. Output is always null-terminated. |
| 134 | String arguments are passed as C strings. |
| 135 | Integers are passed as C integers. */ |
| 136 | |
| 137 | size_t |
| 138 | doprnt (char *buffer, register size_t bufsize, const char *format, |
| 139 | const char *format_end, va_list ap) |
| 140 | { |
| 141 | const char *fmt = format; /* Pointer into format string */ |
| 142 | register char *bufptr = buffer; /* Pointer into output buffer.. */ |
| 143 | |
| 144 | /* Use this for sprintf unless we need something really big. */ |
| 145 | char tembuf[DBL_MAX_10_EXP + 100]; |
| 146 | |
| 147 | /* Size of sprintf_buffer. */ |
| 148 | size_t size_allocated = sizeof (tembuf); |
| 149 | |
| 150 | /* Buffer to use for sprintf. Either tembuf or same as BIG_BUFFER. */ |
| 151 | char *sprintf_buffer = tembuf; |
| 152 | |
| 153 | /* Buffer we have got with malloc. */ |
| 154 | char *big_buffer = NULL; |
| 155 | |
| 156 | register size_t tem; |
| 157 | char *string; |
| 158 | char fixed_buffer[20]; /* Default buffer for small formatting. */ |
| 159 | char *fmtcpy; |
| 160 | int minlen; |
| 161 | char charbuf[MAX_MULTIBYTE_LENGTH + 1]; /* Used for %c. */ |
| 162 | USE_SAFE_ALLOCA; |
| 163 | |
| 164 | if (format_end == 0) |
| 165 | format_end = format + strlen (format); |
| 166 | |
| 167 | if ((format_end - format + 1) < sizeof (fixed_buffer)) |
| 168 | fmtcpy = fixed_buffer; |
| 169 | else |
| 170 | SAFE_ALLOCA (fmtcpy, char *, format_end - format + 1); |
| 171 | |
| 172 | bufsize--; |
| 173 | |
| 174 | /* Loop until end of format string or buffer full. */ |
| 175 | while (fmt < format_end && bufsize > 0) |
| 176 | { |
| 177 | if (*fmt == '%') /* Check for a '%' character */ |
| 178 | { |
| 179 | size_t size_bound = 0; |
| 180 | EMACS_INT width; /* Columns occupied by STRING on display. */ |
| 181 | int long_flag = 0; |
| 182 | int pIlen = sizeof pI - 1; |
| 183 | |
| 184 | fmt++; |
| 185 | /* Copy this one %-spec into fmtcpy. */ |
| 186 | string = fmtcpy; |
| 187 | *string++ = '%'; |
| 188 | while (fmt < format_end) |
| 189 | { |
| 190 | *string++ = *fmt; |
| 191 | if ('0' <= *fmt && *fmt <= '9') |
| 192 | { |
| 193 | /* Get an idea of how much space we might need. |
| 194 | This might be a field width or a precision; e.g. |
| 195 | %1.1000f and %1000.1f both might need 1000+ bytes. |
| 196 | Parse the width or precision, checking for overflow. */ |
| 197 | size_t n = *fmt - '0'; |
| 198 | while (fmt + 1 < format_end |
| 199 | && '0' <= fmt[1] && fmt[1] <= '9') |
| 200 | { |
| 201 | /* Avoid size_t overflow. Avoid int overflow too, as |
| 202 | many sprintfs mishandle widths greater than INT_MAX. |
| 203 | This test is simple but slightly conservative: e.g., |
| 204 | (INT_MAX - INT_MAX % 10) is reported as an overflow |
| 205 | even when it's not. */ |
| 206 | if (n >= min (INT_MAX, SIZE_MAX) / 10) |
| 207 | error ("Format width or precision too large"); |
| 208 | n = n * 10 + fmt[1] - '0'; |
| 209 | *string++ = *++fmt; |
| 210 | } |
| 211 | |
| 212 | if (size_bound < n) |
| 213 | size_bound = n; |
| 214 | } |
| 215 | else if (! (*fmt == '-' || *fmt == ' ' || *fmt == '.' |
| 216 | || *fmt == '+')) |
| 217 | break; |
| 218 | fmt++; |
| 219 | } |
| 220 | |
| 221 | if (0 < pIlen && pIlen <= format_end - fmt |
| 222 | && memcmp (fmt, pI, pIlen) == 0) |
| 223 | { |
| 224 | long_flag = 2; |
| 225 | memcpy (string, fmt + 1, pIlen); |
| 226 | string += pIlen; |
| 227 | fmt += pIlen; |
| 228 | } |
| 229 | else if (fmt < format_end && *fmt == 'l') |
| 230 | { |
| 231 | long_flag = 1; |
| 232 | *string++ = *++fmt; |
| 233 | } |
| 234 | *string = 0; |
| 235 | |
| 236 | /* Make the size bound large enough to handle floating point formats |
| 237 | with large numbers. */ |
| 238 | if (size_bound > SIZE_MAX - DBL_MAX_10_EXP - 50) |
| 239 | error ("Format width or precision too large"); |
| 240 | size_bound += DBL_MAX_10_EXP + 50; |
| 241 | |
| 242 | /* Make sure we have that much. */ |
| 243 | if (size_bound > size_allocated) |
| 244 | { |
| 245 | if (big_buffer) |
| 246 | xfree (big_buffer); |
| 247 | big_buffer = (char *) xmalloc (size_bound); |
| 248 | sprintf_buffer = big_buffer; |
| 249 | size_allocated = size_bound; |
| 250 | } |
| 251 | minlen = 0; |
| 252 | switch (*fmt++) |
| 253 | { |
| 254 | default: |
| 255 | error ("Invalid format operation %s", fmtcpy); |
| 256 | |
| 257 | /* case 'b': */ |
| 258 | case 'l': |
| 259 | case 'd': |
| 260 | { |
| 261 | int i; |
| 262 | long l; |
| 263 | |
| 264 | if (1 < long_flag) |
| 265 | { |
| 266 | EMACS_INT ll = va_arg (ap, EMACS_INT); |
| 267 | sprintf (sprintf_buffer, fmtcpy, ll); |
| 268 | } |
| 269 | else if (long_flag) |
| 270 | { |
| 271 | l = va_arg(ap, long); |
| 272 | sprintf (sprintf_buffer, fmtcpy, l); |
| 273 | } |
| 274 | else |
| 275 | { |
| 276 | i = va_arg(ap, int); |
| 277 | sprintf (sprintf_buffer, fmtcpy, i); |
| 278 | } |
| 279 | /* Now copy into final output, truncating as necessary. */ |
| 280 | string = sprintf_buffer; |
| 281 | goto doit; |
| 282 | } |
| 283 | |
| 284 | case 'o': |
| 285 | case 'x': |
| 286 | { |
| 287 | unsigned u; |
| 288 | unsigned long ul; |
| 289 | |
| 290 | if (1 < long_flag) |
| 291 | { |
| 292 | EMACS_UINT ull = va_arg (ap, EMACS_UINT); |
| 293 | sprintf (sprintf_buffer, fmtcpy, ull); |
| 294 | } |
| 295 | else if (long_flag) |
| 296 | { |
| 297 | ul = va_arg(ap, unsigned long); |
| 298 | sprintf (sprintf_buffer, fmtcpy, ul); |
| 299 | } |
| 300 | else |
| 301 | { |
| 302 | u = va_arg(ap, unsigned); |
| 303 | sprintf (sprintf_buffer, fmtcpy, u); |
| 304 | } |
| 305 | /* Now copy into final output, truncating as necessary. */ |
| 306 | string = sprintf_buffer; |
| 307 | goto doit; |
| 308 | } |
| 309 | |
| 310 | case 'f': |
| 311 | case 'e': |
| 312 | case 'g': |
| 313 | { |
| 314 | double d = va_arg(ap, double); |
| 315 | sprintf (sprintf_buffer, fmtcpy, d); |
| 316 | /* Now copy into final output, truncating as necessary. */ |
| 317 | string = sprintf_buffer; |
| 318 | goto doit; |
| 319 | } |
| 320 | |
| 321 | case 'S': |
| 322 | string[-1] = 's'; |
| 323 | case 's': |
| 324 | if (fmtcpy[1] != 's') |
| 325 | minlen = atoi (&fmtcpy[1]); |
| 326 | string = va_arg (ap, char *); |
| 327 | tem = strlen (string); |
| 328 | if (STRING_BYTES_BOUND < tem) |
| 329 | error ("String for %%s or %%S format is too long"); |
| 330 | width = strwidth (string, tem); |
| 331 | goto doit1; |
| 332 | |
| 333 | /* Copy string into final output, truncating if no room. */ |
| 334 | doit: |
| 335 | /* Coming here means STRING contains ASCII only. */ |
| 336 | tem = strlen (string); |
| 337 | if (STRING_BYTES_BOUND < tem) |
| 338 | error ("Format width or precision too large"); |
| 339 | width = tem; |
| 340 | doit1: |
| 341 | /* We have already calculated: |
| 342 | TEM -- length of STRING, |
| 343 | WIDTH -- columns occupied by STRING when displayed, and |
| 344 | MINLEN -- minimum columns of the output. */ |
| 345 | if (minlen > 0) |
| 346 | { |
| 347 | while (minlen > width && bufsize > 0) |
| 348 | { |
| 349 | *bufptr++ = ' '; |
| 350 | bufsize--; |
| 351 | minlen--; |
| 352 | } |
| 353 | minlen = 0; |
| 354 | } |
| 355 | if (tem > bufsize) |
| 356 | { |
| 357 | /* Truncate the string at character boundary. */ |
| 358 | tem = bufsize; |
| 359 | while (!CHAR_HEAD_P (string[tem - 1])) tem--; |
| 360 | /* If the multibyte sequence of this character is |
| 361 | too long for the space we have left in the |
| 362 | buffer, truncate before it. */ |
| 363 | if (tem > 0 |
| 364 | && BYTES_BY_CHAR_HEAD (string[tem - 1]) > bufsize) |
| 365 | tem--; |
| 366 | if (tem > 0) |
| 367 | memcpy (bufptr, string, tem); |
| 368 | bufptr[tem] = 0; |
| 369 | /* Trigger exit from the loop, but make sure we |
| 370 | return to the caller a value which will indicate |
| 371 | that the buffer was too small. */ |
| 372 | bufptr += bufsize; |
| 373 | bufsize = 0; |
| 374 | continue; |
| 375 | } |
| 376 | else |
| 377 | memcpy (bufptr, string, tem); |
| 378 | bufptr += tem; |
| 379 | bufsize -= tem; |
| 380 | if (minlen < 0) |
| 381 | { |
| 382 | while (minlen < - width && bufsize > 0) |
| 383 | { |
| 384 | *bufptr++ = ' '; |
| 385 | bufsize--; |
| 386 | minlen++; |
| 387 | } |
| 388 | minlen = 0; |
| 389 | } |
| 390 | continue; |
| 391 | |
| 392 | case 'c': |
| 393 | { |
| 394 | int chr = va_arg(ap, int); |
| 395 | tem = CHAR_STRING (chr, (unsigned char *) charbuf); |
| 396 | string = charbuf; |
| 397 | string[tem] = 0; |
| 398 | width = strwidth (string, tem); |
| 399 | if (fmtcpy[1] != 'c') |
| 400 | minlen = atoi (&fmtcpy[1]); |
| 401 | goto doit1; |
| 402 | } |
| 403 | |
| 404 | case '%': |
| 405 | fmt--; /* Drop thru and this % will be treated as normal */ |
| 406 | } |
| 407 | } |
| 408 | |
| 409 | { |
| 410 | /* Just some character; Copy it if the whole multi-byte form |
| 411 | fit in the buffer. */ |
| 412 | char *save_bufptr = bufptr; |
| 413 | |
| 414 | do { *bufptr++ = *fmt++; } |
| 415 | while (fmt < format_end && --bufsize > 0 && !CHAR_HEAD_P (*fmt)); |
| 416 | if (!CHAR_HEAD_P (*fmt)) |
| 417 | { |
| 418 | /* Truncate, but return value that will signal to caller |
| 419 | that the buffer was too small. */ |
| 420 | *save_bufptr = 0; |
| 421 | break; |
| 422 | } |
| 423 | } |
| 424 | }; |
| 425 | |
| 426 | /* If we had to malloc something, free it. */ |
| 427 | xfree (big_buffer); |
| 428 | |
| 429 | *bufptr = 0; /* Make sure our string ends with a '\0' */ |
| 430 | |
| 431 | SAFE_FREE (); |
| 432 | return bufptr - buffer; |
| 433 | } |