Commit | Line | Data |
---|---|---|
24f98398 | 1 | /* Output like sprintf to a buffer of specified size. |
762b15be EZ |
2 | Also takes args differently: pass one pointer to the end |
3 | of the format string in addition to the format string itself. | |
73b0cd50 | 4 | Copyright (C) 1985, 2001-2011 Free Software Foundation, Inc. |
24f98398 JA |
5 | |
6 | This file is part of GNU Emacs. | |
7 | ||
9ec0b715 | 8 | GNU Emacs is free software: you can redistribute it and/or modify |
24f98398 | 9 | it under the terms of the GNU General Public License as published by |
9ec0b715 GM |
10 | the Free Software Foundation, either version 3 of the License, or |
11 | (at your option) any later version. | |
24f98398 JA |
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 | |
9ec0b715 | 19 | along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */ |
24f98398 | 20 | |
762b15be EZ |
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 | |
825cd63c EZ |
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. | |
825cd63c EZ |
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 | ||
94dcfacf EZ |
67 | A %-sequence may contain optional flag, width, and precision specifiers, and |
68 | a length modifier, as follows: | |
825cd63c | 69 | |
94dcfacf | 70 | %<flags><width><precision><length>character |
825cd63c | 71 | |
b71a1728 | 72 | where flags is [+ -0], width is [0-9]+, precision is .[0-9]+, and length |
f40b429d PE |
73 | is empty or l or ll. Also, %% in a format stands for a single % in the |
74 | output. A % that does not introduce a valid %-sequence causes | |
75 | undefined behavior. | |
825cd63c EZ |
76 | |
77 | The + flag character inserts a + before any positive number, while a space | |
94dcfacf EZ |
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 | |
54b8e3f7 | 86 | arguments, must immediately precede the conversion specifier, and means that |
94dcfacf | 87 | the respective argument is to be treated as `long int' or `unsigned long |
54b8e3f7 | 88 | int'. Similarly, ll (two letter ells) means to use `long long int' or |
b71a1728 PE |
89 | `unsigned long long int'; this can be used only on hosts that have |
90 | these two types. The empty length modifier means to use `int' or | |
54b8e3f7 PE |
91 | `unsigned int'. EMACS_INT arguments should use the pI macro, which |
92 | expands to whatever length modifier is needed for the target host. | |
825cd63c EZ |
93 | |
94 | The width specifier supplies a lower limit for the length of the printed | |
95 | representation. The padding, if any, normally goes on the left, but it goes | |
96 | on the right if the - flag is present. The padding character is normally a | |
97 | space, but (for numerical arguments only) it is 0 if the 0 flag is present. | |
98 | The - flag takes precedence over the 0 flag. | |
99 | ||
100 | For %e, %f, and %g sequences, the number after the "." in the precision | |
101 | specifier says how many decimal places to show; if zero, the decimal point | |
102 | itself is omitted. For %s and %S, the precision specifier is ignored. */ | |
24f98398 | 103 | |
6d291527 | 104 | #include <config.h> |
24f98398 JA |
105 | #include <stdio.h> |
106 | #include <ctype.h> | |
d7306fe6 | 107 | #include <setjmp.h> |
24f98398 | 108 | |
cf09633a | 109 | #ifdef STDC_HEADERS |
be65c2f4 PE |
110 | #include <float.h> |
111 | #endif | |
112 | ||
48236137 | 113 | #include <unistd.h> |
48236137 | 114 | |
e6c3da20 | 115 | #include <limits.h> |
e6c3da20 | 116 | |
523e9291 RS |
117 | #include "lisp.h" |
118 | ||
a0ca925c KH |
119 | /* Since we use the macro CHAR_HEAD_P, we have to include this, but |
120 | don't have to include others because CHAR_HEAD_P does not contains | |
121 | another macro. */ | |
83be827a | 122 | #include "character.h" |
a0ca925c | 123 | |
283cdbef PE |
124 | #ifndef SIZE_MAX |
125 | # define SIZE_MAX ((size_t) -1) | |
126 | #endif | |
127 | ||
92bc9a36 DN |
128 | #ifndef DBL_MAX_10_EXP |
129 | #define DBL_MAX_10_EXP 308 /* IEEE double */ | |
130 | #endif | |
131 | ||
f4c730d3 RS |
132 | /* Generate output from a format-spec FORMAT, |
133 | terminated at position FORMAT_END. | |
f40b429d | 134 | (*FORMAT_END is not part of the format, but must exist and be readable.) |
f4c730d3 | 135 | Output goes in BUFFER, which has room for BUFSIZE chars. |
f40b429d PE |
136 | BUFSIZE must be positive. If the output does not fit, truncate it |
137 | to fit and return BUFSIZE - 1; if this truncates a multibyte | |
138 | sequence, store '\0' into the sequence's first byte. | |
825cd63c EZ |
139 | Returns the number of bytes stored into BUFFER, excluding |
140 | the terminating null byte. Output is always null-terminated. | |
1513af9e RS |
141 | String arguments are passed as C strings. |
142 | Integers are passed as C integers. */ | |
f4c730d3 | 143 | |
e6c3da20 EZ |
144 | size_t |
145 | doprnt (char *buffer, register size_t bufsize, const char *format, | |
a8fe7202 | 146 | const char *format_end, va_list ap) |
24f98398 | 147 | { |
a8fe7202 | 148 | const char *fmt = format; /* Pointer into format string */ |
24f98398 | 149 | register char *bufptr = buffer; /* Pointer into output buffer.. */ |
03383aaf | 150 | |
f4c730d3 | 151 | /* Use this for sprintf unless we need something really big. */ |
be65c2f4 | 152 | char tembuf[DBL_MAX_10_EXP + 100]; |
03383aaf | 153 | |
f4c730d3 | 154 | /* Size of sprintf_buffer. */ |
e6c3da20 | 155 | size_t size_allocated = sizeof (tembuf); |
03383aaf | 156 | |
f4c730d3 RS |
157 | /* Buffer to use for sprintf. Either tembuf or same as BIG_BUFFER. */ |
158 | char *sprintf_buffer = tembuf; | |
03383aaf | 159 | |
f4c730d3 | 160 | /* Buffer we have got with malloc. */ |
e6c3da20 | 161 | char *big_buffer = NULL; |
03383aaf | 162 | |
e6c3da20 | 163 | register size_t tem; |
7469ef5d | 164 | char *string; |
03383aaf BF |
165 | char fixed_buffer[20]; /* Default buffer for small formatting. */ |
166 | char *fmtcpy; | |
24f98398 | 167 | int minlen; |
7469ef5d | 168 | char charbuf[MAX_MULTIBYTE_LENGTH + 1]; /* Used for %c. */ |
825cd63c | 169 | USE_SAFE_ALLOCA; |
24f98398 JA |
170 | |
171 | if (format_end == 0) | |
172 | format_end = format + strlen (format); | |
173 | ||
03383aaf BF |
174 | if ((format_end - format + 1) < sizeof (fixed_buffer)) |
175 | fmtcpy = fixed_buffer; | |
176 | else | |
825cd63c | 177 | SAFE_ALLOCA (fmtcpy, char *, format_end - format + 1); |
03383aaf | 178 | |
24f98398 | 179 | bufsize--; |
03383aaf BF |
180 | |
181 | /* Loop until end of format string or buffer full. */ | |
94dcfacf | 182 | while (fmt < format_end && bufsize > 0) |
24f98398 JA |
183 | { |
184 | if (*fmt == '%') /* Check for a '%' character */ | |
185 | { | |
e6c3da20 EZ |
186 | size_t size_bound = 0; |
187 | EMACS_INT width; /* Columns occupied by STRING on display. */ | |
188 | int long_flag = 0; | |
f4c730d3 | 189 | |
24f98398 | 190 | fmt++; |
d427b66a | 191 | /* Copy this one %-spec into fmtcpy. */ |
7469ef5d | 192 | string = fmtcpy; |
24f98398 | 193 | *string++ = '%'; |
94dcfacf | 194 | while (fmt < format_end) |
24f98398 JA |
195 | { |
196 | *string++ = *fmt; | |
be65c2f4 PE |
197 | if ('0' <= *fmt && *fmt <= '9') |
198 | { | |
199 | /* Get an idea of how much space we might need. | |
200 | This might be a field width or a precision; e.g. | |
201 | %1.1000f and %1000.1f both might need 1000+ bytes. | |
202 | Parse the width or precision, checking for overflow. */ | |
e6c3da20 | 203 | size_t n = *fmt - '0'; |
94dcfacf EZ |
204 | while (fmt < format_end |
205 | && '0' <= fmt[1] && fmt[1] <= '9') | |
be65c2f4 | 206 | { |
ca2d6274 PE |
207 | /* Avoid size_t overflow. Avoid int overflow too, as |
208 | many sprintfs mishandle widths greater than INT_MAX. | |
209 | This test is simple but slightly conservative: e.g., | |
210 | (INT_MAX - INT_MAX % 10) is reported as an overflow | |
211 | even when it's not. */ | |
f76dee0c | 212 | if (n >= min (INT_MAX, SIZE_MAX) / 10) |
be65c2f4 | 213 | error ("Format width or precision too large"); |
26898943 | 214 | n = n * 10 + fmt[1] - '0'; |
be65c2f4 PE |
215 | *string++ = *++fmt; |
216 | } | |
217 | ||
218 | if (size_bound < n) | |
219 | size_bound = n; | |
220 | } | |
01769a73 | 221 | else if (*fmt == '-' || *fmt == ' ' || *fmt == '.' || *fmt == '+') |
be65c2f4 | 222 | ; |
e6c3da20 EZ |
223 | else if (*fmt == 'l') |
224 | { | |
226be1b0 | 225 | long_flag = 1 + (fmt + 1 < format_end && fmt[1] == 'l'); |
54b8e3f7 | 226 | fmt += long_flag; |
94dcfacf | 227 | break; |
e6c3da20 | 228 | } |
be65c2f4 | 229 | else |
24f98398 JA |
230 | break; |
231 | fmt++; | |
232 | } | |
94dcfacf EZ |
233 | if (fmt > format_end) |
234 | fmt = format_end; | |
24f98398 | 235 | *string = 0; |
03383aaf | 236 | |
be65c2f4 PE |
237 | /* Make the size bound large enough to handle floating point formats |
238 | with large numbers. */ | |
e6c3da20 | 239 | if (size_bound > SIZE_MAX - DBL_MAX_10_EXP - 50) |
be65c2f4 | 240 | error ("Format width or precision too large"); |
01769a73 | 241 | size_bound += DBL_MAX_10_EXP + 50; |
6e951728 | 242 | |
f4c730d3 RS |
243 | /* Make sure we have that much. */ |
244 | if (size_bound > size_allocated) | |
245 | { | |
246 | if (big_buffer) | |
94dcfacf EZ |
247 | xfree (big_buffer); |
248 | big_buffer = (char *) xmalloc (size_bound); | |
f4c730d3 RS |
249 | sprintf_buffer = big_buffer; |
250 | size_allocated = size_bound; | |
251 | } | |
24f98398 JA |
252 | minlen = 0; |
253 | switch (*fmt++) | |
254 | { | |
255 | default: | |
94dcfacf | 256 | error ("Invalid format operation %%%s%c", |
226be1b0 | 257 | "ll" + 2 - long_flag, fmt[-1]); |
24f98398 JA |
258 | |
259 | /* case 'b': */ | |
e6c3da20 | 260 | case 'l': |
24f98398 | 261 | case 'd': |
e6c3da20 EZ |
262 | { |
263 | int i; | |
264 | long l; | |
265 | ||
e810457d PE |
266 | if (1 < long_flag) |
267 | { | |
268 | #ifdef HAVE_LONG_LONG_INT | |
269 | long long ll = va_arg (ap, long long); | |
270 | sprintf (sprintf_buffer, fmtcpy, ll); | |
271 | #else | |
272 | abort (); | |
273 | #endif | |
274 | } | |
275 | else if (long_flag) | |
e6c3da20 EZ |
276 | { |
277 | l = va_arg(ap, long); | |
278 | sprintf (sprintf_buffer, fmtcpy, l); | |
279 | } | |
280 | else | |
281 | { | |
282 | i = va_arg(ap, int); | |
283 | sprintf (sprintf_buffer, fmtcpy, i); | |
284 | } | |
285 | /* Now copy into final output, truncating as necessary. */ | |
286 | string = sprintf_buffer; | |
287 | goto doit; | |
288 | } | |
289 | ||
24f98398 JA |
290 | case 'o': |
291 | case 'x': | |
e6c3da20 EZ |
292 | { |
293 | unsigned u; | |
294 | unsigned long ul; | |
295 | ||
e810457d PE |
296 | if (1 < long_flag) |
297 | { | |
298 | #ifdef HAVE_UNSIGNED_LONG_LONG_INT | |
299 | unsigned long long ull = va_arg (ap, unsigned long long); | |
300 | sprintf (sprintf_buffer, fmtcpy, ull); | |
301 | #else | |
302 | abort (); | |
303 | #endif | |
304 | } | |
305 | else if (long_flag) | |
e6c3da20 EZ |
306 | { |
307 | ul = va_arg(ap, unsigned long); | |
308 | sprintf (sprintf_buffer, fmtcpy, ul); | |
309 | } | |
310 | else | |
311 | { | |
312 | u = va_arg(ap, unsigned); | |
313 | sprintf (sprintf_buffer, fmtcpy, u); | |
314 | } | |
315 | /* Now copy into final output, truncating as necessary. */ | |
316 | string = sprintf_buffer; | |
317 | goto doit; | |
318 | } | |
24f98398 | 319 | |
f4c730d3 RS |
320 | case 'f': |
321 | case 'e': | |
322 | case 'g': | |
323 | { | |
6a8033e1 KR |
324 | double d = va_arg(ap, double); |
325 | sprintf (sprintf_buffer, fmtcpy, d); | |
e6c3da20 | 326 | /* Now copy into final output, truncating as necessary. */ |
7469ef5d | 327 | string = sprintf_buffer; |
f4c730d3 RS |
328 | goto doit; |
329 | } | |
330 | ||
24f98398 JA |
331 | case 'S': |
332 | string[-1] = 's'; | |
333 | case 's': | |
24f98398 JA |
334 | if (fmtcpy[1] != 's') |
335 | minlen = atoi (&fmtcpy[1]); | |
7469ef5d | 336 | string = va_arg (ap, char *); |
e267324c | 337 | tem = strlen (string); |
e6c3da20 EZ |
338 | if (tem > MOST_POSITIVE_FIXNUM) |
339 | error ("String for %%s or %%S format is too long"); | |
a0ca925c | 340 | width = strwidth (string, tem); |
1513af9e RS |
341 | goto doit1; |
342 | ||
24f98398 JA |
343 | /* Copy string into final output, truncating if no room. */ |
344 | doit: | |
a0ca925c | 345 | /* Coming here means STRING contains ASCII only. */ |
e6c3da20 EZ |
346 | tem = strlen (string); |
347 | if (tem > MOST_POSITIVE_FIXNUM) | |
348 | error ("Format width or precision too large"); | |
349 | width = tem; | |
35a65fce | 350 | doit1: |
a0ca925c KH |
351 | /* We have already calculated: |
352 | TEM -- length of STRING, | |
353 | WIDTH -- columns occupied by STRING when displayed, and | |
354 | MINLEN -- minimum columns of the output. */ | |
24f98398 JA |
355 | if (minlen > 0) |
356 | { | |
a0ca925c | 357 | while (minlen > width && bufsize > 0) |
24f98398 JA |
358 | { |
359 | *bufptr++ = ' '; | |
360 | bufsize--; | |
361 | minlen--; | |
362 | } | |
363 | minlen = 0; | |
364 | } | |
365 | if (tem > bufsize) | |
a0ca925c KH |
366 | { |
367 | /* Truncate the string at character boundary. */ | |
368 | tem = bufsize; | |
a50545d9 | 369 | while (!CHAR_HEAD_P (string[tem - 1])) tem--; |
72af86bd | 370 | memcpy (bufptr, string, tem); |
a0ca925c KH |
371 | /* We must calculate WIDTH again. */ |
372 | width = strwidth (bufptr, tem); | |
373 | } | |
374 | else | |
72af86bd | 375 | memcpy (bufptr, string, tem); |
24f98398 JA |
376 | bufptr += tem; |
377 | bufsize -= tem; | |
378 | if (minlen < 0) | |
379 | { | |
a0ca925c | 380 | while (minlen < - width && bufsize > 0) |
24f98398 JA |
381 | { |
382 | *bufptr++ = ' '; | |
383 | bufsize--; | |
384 | minlen++; | |
385 | } | |
386 | minlen = 0; | |
387 | } | |
388 | continue; | |
389 | ||
390 | case 'c': | |
6a8033e1 | 391 | { |
e6c3da20 EZ |
392 | int chr = va_arg(ap, int); |
393 | tem = CHAR_STRING (chr, (unsigned char *) charbuf); | |
6a8033e1 KR |
394 | string = charbuf; |
395 | string[tem] = 0; | |
396 | width = strwidth (string, tem); | |
397 | if (fmtcpy[1] != 'c') | |
398 | minlen = atoi (&fmtcpy[1]); | |
399 | goto doit1; | |
400 | } | |
24f98398 JA |
401 | |
402 | case '%': | |
403 | fmt--; /* Drop thru and this % will be treated as normal */ | |
404 | } | |
405 | } | |
a0ca925c KH |
406 | |
407 | { | |
408 | /* Just some character; Copy it if the whole multi-byte form | |
409 | fit in the buffer. */ | |
410 | char *save_bufptr = bufptr; | |
411 | ||
412 | do { *bufptr++ = *fmt++; } | |
94dcfacf | 413 | while (fmt < format_end && --bufsize > 0 && !CHAR_HEAD_P (*fmt)); |
a50545d9 | 414 | if (!CHAR_HEAD_P (*fmt)) |
a0ca925c | 415 | { |
d178f871 EZ |
416 | /* Truncate, but return value that will signal to caller |
417 | that the buffer was too small. */ | |
418 | *save_bufptr = 0; | |
a0ca925c KH |
419 | break; |
420 | } | |
421 | } | |
24f98398 JA |
422 | }; |
423 | ||
f4c730d3 | 424 | /* If we had to malloc something, free it. */ |
70fdbb46 | 425 | xfree (big_buffer); |
f4c730d3 | 426 | |
e6c3da20 | 427 | *bufptr = 0; /* Make sure our string ends with a '\0' */ |
825cd63c EZ |
428 | |
429 | SAFE_FREE (); | |
24f98398 JA |
430 | return bufptr - buffer; |
431 | } |