lib/dynamic-string.c

   1 /*
   2  * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013 Nicira, Inc.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at:
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #include <config.h>
  18 #include "dynamic-string.h"
  19 #include <stdlib.h>
  20 #include <string.h>
  21 #include <time.h>
  22 #include "timeval.h"
  23 #include "util.h"
  24
  25 /* Initializes 'ds' as an empty string buffer. */
  26 void
  27 ds_init(struct ds *ds)
  28 {
  29     ds->string = NULL;
  30     ds->length = 0;
  31     ds->allocated = 0;
  32 }
  33
  34 /* Sets 'ds''s length to 0, effectively clearing any existing content.  Does
  35  * not free any memory. */
  36 void
  37 ds_clear(struct ds *ds)
  38 {
  39     ds->length = 0;
  40 }
  41
  42 /* Reduces 'ds''s length to no more than 'new_length'.  (If its length is
  43  * already 'new_length' or less, does nothing.)  */
  44 void
  45 ds_truncate(struct ds *ds, size_t new_length)
  46 {
  47     if (ds->length > new_length) {
  48         ds->length = new_length;
  49         ds->string[new_length] = '\0';
  50     }
  51 }
  52
  53 /* Ensures that at least 'min_length + 1' bytes (including space for a null
  54  * terminator) are allocated for ds->string, allocating or reallocating memory
  55  * as necessary. */
  56 void
  57 ds_reserve(struct ds *ds, size_t min_length)
  58 {
  59     if (min_length > ds->allocated || !ds->string) {
  60         ds->allocated += MAX(min_length, ds->allocated);
  61         ds->allocated = MAX(8, ds->allocated);
  62         ds->string = xrealloc(ds->string, ds->allocated + 1);
  63     }
  64 }
  65
  66 /* Appends space for 'n' bytes to the end of 'ds->string', increasing
  67  * 'ds->length' by the same amount, and returns the first appended byte.  The
  68  * caller should fill in all 'n' bytes starting at the return value. */
  69 char *
  70 ds_put_uninit(struct ds *ds, size_t n)
  71 {
  72     ds_reserve(ds, ds->length + n);
  73     ds->length += n;
  74     ds->string[ds->length] = '\0';
  75     return &ds->string[ds->length - n];
  76 }
  77
  78 void
  79 ds_put_char__(struct ds *ds, char c)
  80 {
  81     *ds_put_uninit(ds, 1) = c;
  82 }
  83
  84 /* Appends unicode code point 'uc' to 'ds' in UTF-8 encoding. */
  85 void
  86 ds_put_utf8(struct ds *ds, int uc)
  87 {
  88     if (uc <= 0x7f) {
  89         ds_put_char(ds, uc);
  90     } else if (uc <= 0x7ff) {
  91         ds_put_char(ds, 0xc0 | (uc >> 6));
  92         ds_put_char(ds, 0x80 | (uc & 0x3f));
  93     } else if (uc <= 0xffff) {
  94         ds_put_char(ds, 0xe0 | (uc >> 12));
  95         ds_put_char(ds, 0x80 | ((uc >> 6) & 0x3f));
  96         ds_put_char(ds, 0x80 | (uc & 0x3f));
  97     } else if (uc <= 0x10ffff) {
  98         ds_put_char(ds, 0xf0 | (uc >> 18));
  99         ds_put_char(ds, 0x80 | ((uc >> 12) & 0x3f));
 100         ds_put_char(ds, 0x80 | ((uc >> 6) & 0x3f));
 101         ds_put_char(ds, 0x80 | (uc & 0x3f));
 102     } else {
 103         /* Invalid code point.  Insert the Unicode general substitute
 104          * REPLACEMENT CHARACTER. */
 105         ds_put_utf8(ds, 0xfffd);
 106     }
 107 }
 108
 109 void
 110 ds_put_char_multiple(struct ds *ds, char c, size_t n)
 111 {
 112     memset(ds_put_uninit(ds, n), c, n);
 113 }
 114
 115 void
 116 ds_put_buffer(struct ds *ds, const char *s, size_t n)
 117 {
 118     memcpy(ds_put_uninit(ds, n), s, n);
 119 }
 120
 121 void
 122 ds_put_cstr(struct ds *ds, const char *s)
 123 {
 124     size_t s_len = strlen(s);
 125     memcpy(ds_put_uninit(ds, s_len), s, s_len);
 126 }
 127
 128 void
 129 ds_put_and_free_cstr(struct ds *ds, char *s)
 130 {
 131     ds_put_cstr(ds, s);
 132     free(s);
 133 }
 134
 135 void
 136 ds_put_format(struct ds *ds, const char *format, ...)
 137 {
 138     va_list args;
 139
 140     va_start(args, format);
 141     ds_put_format_valist(ds, format, args);
 142     va_end(args);
 143 }
 144
 145 void
 146 ds_put_format_valist(struct ds *ds, const char *format, va_list args_)
 147 {
 148     va_list args;
 149     size_t available;
 150     int needed;
 151
 152     va_copy(args, args_);
 153     available = ds->string ? ds->allocated - ds->length + 1 : 0;
 154     needed = vsnprintf(&ds->string[ds->length], available, format, args);
 155     va_end(args);
 156
 157     if (needed < available) {
 158         ds->length += needed;
 159     } else {
 160         ds_reserve(ds, ds->length + needed);
 161
 162         va_copy(args, args_);
 163         available = ds->allocated - ds->length + 1;
 164         needed = vsnprintf(&ds->string[ds->length], available, format, args);
 165         va_end(args);
 166
 167         ovs_assert(needed < available);
 168         ds->length += needed;
 169     }
 170 }
 171
 172 void
 173 ds_put_printable(struct ds *ds, const char *s, size_t n)
 174 {
 175     ds_reserve(ds, ds->length + n);
 176     while (n-- > 0) {
 177         unsigned char c = *s++;
 178         if (c < 0x20 || c > 0x7e || c == '\\' || c == '"') {
 179             ds_put_format(ds, "\\%03o", (int) c);
 180         } else {
 181             ds_put_char(ds, c);
 182         }
 183     }
 184 }
 185
 186 /* Writes the current time with optional millisecond resolution to 'string'
 187  * based on 'template'.
 188  * The current time is either localtime or UTC based on 'utc'. */
 189 void
 190 ds_put_strftime_msec(struct ds *ds, const char *template, long long int when,
 191                      bool utc)
 192 {
 193     struct tm_msec tm;
 194     if (utc) {
 195         gmtime_msec(when, &tm);
 196     } else {
 197         localtime_msec(when, &tm);
 198     }
 199
 200     for (;;) {
 201         size_t avail = ds->string ? ds->allocated - ds->length + 1 : 0;
 202         size_t used = strftime_msec(&ds->string[ds->length], avail, template,
 203                                     &tm);
 204         if (used) {
 205             ds->length += used;
 206             return;
 207         }
 208         ds_reserve(ds, ds->length + (avail < 32 ? 64 : 2 * avail));
 209     }
 210 }
 211
 212 /* Returns a malloc()'d string for time 'when' based on 'template', in local
 213  * time or UTC based on 'utc'. */
 214 char *
 215 xastrftime_msec(const char *template, long long int when, bool utc)
 216 {
 217     struct ds s;
 218
 219     ds_init(&s);
 220     ds_put_strftime_msec(&s, template, when, utc);
 221     return s.string;
 222 }
 223
 224 int
 225 ds_get_line(struct ds *ds, FILE *file)
 226 {
 227     ds_clear(ds);
 228     for (;;) {
 229         int c = getc(file);
 230         if (c == EOF) {
 231             return ds->length ? 0 : EOF;
 232         } else if (c == '\n') {
 233             return 0;
 234         } else {
 235             ds_put_char(ds, c);
 236         }
 237     }
 238 }
 239
 240 /* Reads a line from 'file' into 'ds', clearing anything initially in 'ds'.
 241  * Deletes comments introduced by "#" and skips lines that contains only white
 242  * space (after deleting comments).
 243  *
 244  * If 'line_numberp' is nonnull, increments '*line_numberp' by the number of
 245  * lines read from 'file'.
 246  *
 247  * Returns 0 if successful, EOF if no non-blank line was found. */
 248 int
 249 ds_get_preprocessed_line(struct ds *ds, FILE *file, int *line_numberp)
 250 {
 251     while (!ds_get_line(ds, file)) {
 252         char *line = ds_cstr(ds);
 253         char *comment;
 254
 255         if (line_numberp) {
 256             ++*line_numberp;
 257         }
 258
 259         /* Delete comments. */
 260         comment = strchr(line, '#');
 261         if (comment) {
 262             *comment = '\0';
 263         }
 264
 265         /* Return successfully unless the line is all spaces. */
 266         if (line[strspn(line, " \t\n")] != '\0') {
 267             return 0;
 268         }
 269     }
 270     return EOF;
 271 }
 272
 273 /* Reads a line from 'file' into 'ds' and does some preprocessing on it:
 274  *
 275  *    - If the line begins with #, prints it on stdout and reads the next line.
 276  *
 277  *    - Otherwise, if the line contains an # somewhere else, strips it and
 278  *      everything following it (as a comment).
 279  *
 280  *    - If (after comment removal) the line contains only white space, prints
 281  *      a blank line on stdout and reads the next line.
 282  *
 283  *    - Otherwise, returns the line to the caller.
 284  *
 285  * This is useful in some of the OVS tests, where we want to check that parsing
 286  * and then re-formatting some kind of data does not change it, but we also
 287  * want to be able to put comments in the input.
 288  *
 289  * Returns 0 if successful, EOF if no non-blank line was found. */
 290 int
 291 ds_get_test_line(struct ds *ds, FILE *file)
 292 {
 293     for (;;) {
 294         char *s, *comment;
 295         int retval;
 296
 297         retval = ds_get_line(ds, file);
 298         if (retval) {
 299             return retval;
 300         }
 301
 302         s = ds_cstr(ds);
 303         if (*s == '#') {
 304             puts(s);
 305             continue;
 306         }
 307
 308         comment = strchr(s, '#');
 309         if (comment) {
 310             *comment = '\0';
 311         }
 312         if (s[strspn(s, " \t\n")] == '\0') {
 313             putchar('\n');
 314             continue;
 315         }
 316
 317         return 0;
 318     }
 319 }
 320
 321 char *
 322 ds_cstr(struct ds *ds)
 323 {
 324     if (!ds->string) {
 325         ds_reserve(ds, 0);
 326     }
 327     ds->string[ds->length] = '\0';
 328     return ds->string;
 329 }
 330
 331 const char *
 332 ds_cstr_ro(const struct ds *ds)
 333 {
 334     return ds_cstr(CONST_CAST(struct ds *, ds));
 335 }
 336
 337 /* Returns a null-terminated string representing the current contents of 'ds',
 338  * which the caller is expected to free with free(), then clears the contents
 339  * of 'ds'. */
 340 char *
 341 ds_steal_cstr(struct ds *ds)
 342 {
 343     char *s = ds_cstr(ds);
 344     ds_init(ds);
 345     return s;
 346 }
 347
 348 void
 349 ds_destroy(struct ds *ds)
 350 {
 351     free(ds->string);
 352 }
 353
 354 /* Swaps the content of 'a' and 'b'. */
 355 void
 356 ds_swap(struct ds *a, struct ds *b)
 357 {
 358     struct ds temp = *a;
 359     *a = *b;
 360     *b = temp;
 361 }
 362
 363 /* Writes the 'size' bytes in 'buf' to 'string' as hex bytes arranged 16 per
 364  * line.  Numeric offsets are also included, starting at 'ofs' for the first
 365  * byte in 'buf'.  If 'ascii' is true then the corresponding ASCII characters
 366  * are also rendered alongside. */
 367 void
 368 ds_put_hex_dump(struct ds *ds, const void *buf_, size_t size,
 369                 uintptr_t ofs, bool ascii)
 370 {
 371     const uint8_t *buf = buf_;
 372     const size_t per_line = 16; /* Maximum bytes per line. */
 373
 374     while (size > 0) {
 375         size_t start, end, n;
 376         size_t i;
 377
 378         /* Number of bytes on this line. */
 379         start = ofs % per_line;
 380         end = per_line;
 381         if (end - start > size)
 382             end = start + size;
 383         n = end - start;
 384
 385         /* Print line. */
 386         ds_put_format(ds, "%08jx  ", (uintmax_t) ROUND_DOWN(ofs, per_line));
 387         for (i = 0; i < start; i++) {
 388             ds_put_format(ds, "   ");
 389         }
 390         for (; i < end; i++) {
 391             ds_put_format(ds, "%02hhx%c",
 392                           buf[i - start], i == per_line / 2 - 1? '-' : ' ');
 393         }
 394         if (ascii) {
 395             for (; i < per_line; i++)
 396                 ds_put_format(ds, "   ");
 397             ds_put_format(ds, "|");
 398             for (i = 0; i < start; i++)
 399                 ds_put_format(ds, " ");
 400             for (; i < end; i++) {
 401                 int c = buf[i - start];
 402                 ds_put_char(ds, c >= 32 && c < 127 ? c : '.');
 403             }
 404             for (; i < per_line; i++)
 405                 ds_put_format(ds, " ");
 406             ds_put_format(ds, "|");
 407         } else {
 408             ds_chomp(ds, ' ');
 409         }
 410         ds_put_format(ds, "\n");
 411
 412         ofs += n;
 413         buf += n;
 414         size -= n;
 415     }
 416 }
 417
 418 int
 419 ds_last(const struct ds *ds)
 420 {
 421     return ds->length > 0 ? (unsigned char) ds->string[ds->length - 1] : EOF;
 422 }
 423
 424 void
 425 ds_chomp(struct ds *ds, int c)
 426 {
 427     if (ds->length > 0 && ds->string[ds->length - 1] == (char) c) {
 428         ds->string[--ds->length] = '\0';
 429     }
 430 }