lib/dynamic-string.c

   1 /*
   2  * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2016 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 "openvswitch/dynamic-string.h"
  19 #include <inttypes.h>
  20 #include <stdlib.h>
  21 #include <string.h>
  22 #include <time.h>
  23 #include "timeval.h"
  24 #include "util.h"
  25
  26 /* Initializes 'ds' as an empty string buffer. */
  27 void
  28 ds_init(struct ds *ds)
  29 {
  30     ds->string = NULL;
  31     ds->length = 0;
  32     ds->allocated = 0;
  33 }
  34
  35 /* Sets 'ds''s length to 0, effectively clearing any existing content.  Does
  36  * not free any memory. */
  37 void
  38 ds_clear(struct ds *ds)
  39 {
  40     ds->length = 0;
  41 }
  42
  43 /* Reduces 'ds''s length to no more than 'new_length'.  (If its length is
  44  * already 'new_length' or less, does nothing.)  */
  45 void
  46 ds_truncate(struct ds *ds, size_t new_length)
  47 {
  48     if (ds->length > new_length) {
  49         ds->length = new_length;
  50         ds->string[new_length] = '\0';
  51     }
  52 }
  53
  54 /* Ensures that at least 'min_length + 1' bytes (including space for a null
  55  * terminator) are allocated for ds->string, allocating or reallocating memory
  56  * as necessary. */
  57 void
  58 ds_reserve(struct ds *ds, size_t min_length)
  59 {
  60     if (min_length > ds->allocated || !ds->string) {
  61         ds->allocated += MAX(min_length, ds->allocated);
  62         ds->allocated = MAX(8, ds->allocated);
  63         ds->string = xrealloc(ds->string, ds->allocated + 1);
  64     }
  65 }
  66
  67 /* Appends space for 'n' bytes to the end of 'ds->string', increasing
  68  * 'ds->length' by the same amount, and returns the first appended byte.  The
  69  * caller should fill in all 'n' bytes starting at the return value. */
  70 char *
  71 ds_put_uninit(struct ds *ds, size_t n)
  72 {
  73     ds_reserve(ds, ds->length + n);
  74     ds->length += n;
  75     ds->string[ds->length] = '\0';
  76     return &ds->string[ds->length - n];
  77 }
  78
  79 void
  80 ds_put_char__(struct ds *ds, char c)
  81 {
  82     *ds_put_uninit(ds, 1) = c;
  83 }
  84
  85 /* Appends unicode code point 'uc' to 'ds' in UTF-8 encoding. */
  86 void
  87 ds_put_utf8(struct ds *ds, int uc)
  88 {
  89     if (uc <= 0x7f) {
  90         ds_put_char(ds, uc);
  91     } else if (uc <= 0x7ff) {
  92         ds_put_char(ds, 0xc0 | (uc >> 6));
  93         ds_put_char(ds, 0x80 | (uc & 0x3f));
  94     } else if (uc <= 0xffff) {
  95         ds_put_char(ds, 0xe0 | (uc >> 12));
  96         ds_put_char(ds, 0x80 | ((uc >> 6) & 0x3f));
  97         ds_put_char(ds, 0x80 | (uc & 0x3f));
  98     } else if (uc <= 0x10ffff) {
  99         ds_put_char(ds, 0xf0 | (uc >> 18));
 100         ds_put_char(ds, 0x80 | ((uc >> 12) & 0x3f));
 101         ds_put_char(ds, 0x80 | ((uc >> 6) & 0x3f));
 102         ds_put_char(ds, 0x80 | (uc & 0x3f));
 103     } else {
 104         /* Invalid code point.  Insert the Unicode general substitute
 105          * REPLACEMENT CHARACTER. */
 106         ds_put_utf8(ds, 0xfffd);
 107     }
 108 }
 109
 110 void
 111 ds_put_char_multiple(struct ds *ds, char c, size_t n)
 112 {
 113     memset(ds_put_uninit(ds, n), c, n);
 114 }
 115
 116 void
 117 ds_put_buffer(struct ds *ds, const char *s, size_t n)
 118 {
 119     memcpy(ds_put_uninit(ds, n), s, n);
 120 }
 121
 122 void
 123 ds_put_cstr(struct ds *ds, const char *s)
 124 {
 125     size_t s_len = strlen(s);
 126     memcpy(ds_put_uninit(ds, s_len), s, s_len);
 127 }
 128
 129 void
 130 ds_put_and_free_cstr(struct ds *ds, char *s)
 131 {
 132     ds_put_cstr(ds, s);
 133     free(s);
 134 }
 135
 136 void
 137 ds_put_format(struct ds *ds, const char *format, ...)
 138 {
 139     va_list args;
 140
 141     va_start(args, format);
 142     ds_put_format_valist(ds, format, args);
 143     va_end(args);
 144 }
 145
 146 void
 147 ds_put_format_valist(struct ds *ds, const char *format, va_list args_)
 148 {
 149     va_list args;
 150     size_t available;
 151     int needed;
 152
 153     va_copy(args, args_);
 154     available = ds->string ? ds->allocated - ds->length + 1 : 0;
 155     needed = vsnprintf(&ds->string[ds->length], available, format, args);
 156     va_end(args);
 157
 158     if (needed < available) {
 159         ds->length += needed;
 160     } else {
 161         ds_reserve(ds, ds->length + needed);
 162
 163         va_copy(args, args_);
 164         available = ds->allocated - ds->length + 1;
 165         needed = vsnprintf(&ds->string[ds->length], available, format, args);
 166         va_end(args);
 167
 168         ovs_assert(needed < available);
 169         ds->length += needed;
 170     }
 171 }
 172
 173 void
 174 ds_put_printable(struct ds *ds, const char *s, size_t n)
 175 {
 176     ds_reserve(ds, ds->length + n);
 177     while (n-- > 0) {
 178         unsigned char c = *s++;
 179         if (c < 0x20 || c > 0x7e || c == '\\' || c == '"') {
 180             ds_put_format(ds, "\\%03o", (int) c);
 181         } else {
 182             ds_put_char(ds, c);
 183         }
 184     }
 185 }
 186
 187 /* Writes the current time with optional millisecond resolution to 'string'
 188  * based on 'template'.
 189  * The current time is either localtime or UTC based on 'utc'. */
 190 void
 191 ds_put_strftime_msec(struct ds *ds, const char *template, long long int when,
 192                      bool utc)
 193 {
 194     struct tm_msec tm;
 195     if (utc) {
 196         gmtime_msec(when, &tm);
 197     } else {
 198         localtime_msec(when, &tm);
 199     }
 200
 201     for (;;) {
 202         size_t avail = ds->string ? ds->allocated - ds->length + 1 : 0;
 203         size_t used = strftime_msec(&ds->string[ds->length], avail, template,
 204                                     &tm);
 205         if (used) {
 206             ds->length += used;
 207             return;
 208         }
 209         ds_reserve(ds, ds->length + (avail < 32 ? 64 : 2 * avail));
 210     }
 211 }
 212
 213 /* Returns a malloc()'d string for time 'when' based on 'template', in local
 214  * time or UTC based on 'utc'. */
 215 char *
 216 xastrftime_msec(const char *template, long long int when, bool utc)
 217 {
 218     struct ds s;
 219
 220     ds_init(&s);
 221     ds_put_strftime_msec(&s, template, when, utc);
 222     return s.string;
 223 }
 224
 225 int
 226 ds_get_line(struct ds *ds, FILE *file)
 227 {
 228     ds_clear(ds);
 229     for (;;) {
 230         int c = getc(file);
 231         if (c == EOF) {
 232             return ds->length ? 0 : EOF;
 233         } else if (c == '\n') {
 234             return 0;
 235         } else {
 236             ds_put_char(ds, c);
 237         }
 238     }
 239 }
 240
 241 /* Reads a line from 'file' into 'ds', clearing anything initially in 'ds'.
 242  * Deletes comments introduced by "#" and skips lines that contains only white
 243  * space (after deleting comments).
 244  *
 245  * If 'line_numberp' is nonnull, increments '*line_numberp' by the number of
 246  * lines read from 'file'.
 247  *
 248  * Returns 0 if successful, EOF if no non-blank line was found. */
 249 int
 250 ds_get_preprocessed_line(struct ds *ds, FILE *file, int *line_numberp)
 251 {
 252     while (!ds_get_line(ds, file)) {
 253         char *line = ds_cstr(ds);
 254         char *comment;
 255
 256         if (line_numberp) {
 257             ++*line_numberp;
 258         }
 259
 260         /* Delete comments. */
 261         comment = strchr(line, '#');
 262         if (comment) {
 263             *comment = '\0';
 264         }
 265
 266         /* Return successfully unless the line is all spaces. */
 267         if (line[strspn(line, " \t\n")] != '\0') {
 268             return 0;
 269         }
 270     }
 271     return EOF;
 272 }
 273
 274 /* Reads a line from 'file' into 'ds' and does some preprocessing on it:
 275  *
 276  *    - If the line begins with #, prints it on stdout and reads the next line.
 277  *
 278  *    - Otherwise, if the line contains an # somewhere else, strips it and
 279  *      everything following it (as a comment).
 280  *
 281  *    - If (after comment removal) the line contains only white space, prints
 282  *      a blank line on stdout and reads the next line.
 283  *
 284  *    - Otherwise, returns the line to the caller.
 285  *
 286  * This is useful in some of the OVS tests, where we want to check that parsing
 287  * and then re-formatting some kind of data does not change it, but we also
 288  * want to be able to put comments in the input.
 289  *
 290  * Returns 0 if successful, EOF if no non-blank line was found. */
 291 int
 292 ds_get_test_line(struct ds *ds, FILE *file)
 293 {
 294     for (;;) {
 295         char *s, *comment;
 296         int retval;
 297
 298         retval = ds_get_line(ds, file);
 299         if (retval) {
 300             return retval;
 301         }
 302
 303         s = ds_cstr(ds);
 304         if (*s == '#') {
 305             puts(s);
 306             continue;
 307         }
 308
 309         comment = strchr(s, '#');
 310         if (comment) {
 311             *comment = '\0';
 312         }
 313         if (s[strspn(s, " \t\n")] == '\0') {
 314             putchar('\n');
 315             continue;
 316         }
 317
 318         return 0;
 319     }
 320 }
 321
 322 char *
 323 ds_cstr(struct ds *ds)
 324 {
 325     if (!ds->string) {
 326         ds_reserve(ds, 0);
 327     }
 328     ds->string[ds->length] = '\0';
 329     return ds->string;
 330 }
 331
 332 const char *
 333 ds_cstr_ro(const struct ds *ds)
 334 {
 335     return ds_cstr(CONST_CAST(struct ds *, ds));
 336 }
 337
 338 /* Returns a null-terminated string representing the current contents of 'ds',
 339  * which the caller is expected to free with free(), then clears the contents
 340  * of 'ds'. */
 341 char *
 342 ds_steal_cstr(struct ds *ds)
 343 {
 344     char *s = ds_cstr(ds);
 345     ds_init(ds);
 346     return s;
 347 }
 348
 349 void
 350 ds_destroy(struct ds *ds)
 351 {
 352     free(ds->string);
 353 }
 354
 355 /* Swaps the content of 'a' and 'b'. */
 356 void
 357 ds_swap(struct ds *a, struct ds *b)
 358 {
 359     struct ds temp = *a;
 360     *a = *b;
 361     *b = temp;
 362 }
 363
 364 void
 365 ds_put_hex(struct ds *ds, const void *buf_, size_t size)
 366 {
 367     const uint8_t *buf = buf_;
 368     bool printed = false;
 369     int i;
 370
 371     for (i = 0; i < size; i++) {
 372         uint8_t val = buf[i];
 373         if (val || printed) {
 374             if (!printed) {
 375                 ds_put_format(ds, "0x%"PRIx8, val);
 376             } else {
 377                 ds_put_format(ds, "%02"PRIx8, val);
 378             }
 379             printed = true;
 380         }
 381     }
 382     if (!printed) {
 383         ds_put_char(ds, '0');
 384     }
 385 }
 386
 387 /* Writes the 'size' bytes in 'buf' to 'string' as hex bytes arranged 16 per
 388  * line.  Numeric offsets are also included, starting at 'ofs' for the first
 389  * byte in 'buf'.  If 'ascii' is true then the corresponding ASCII characters
 390  * are also rendered alongside. */
 391 void
 392 ds_put_hex_dump(struct ds *ds, const void *buf_, size_t size,
 393                 uintptr_t ofs, bool ascii)
 394 {
 395     const uint8_t *buf = buf_;
 396     const size_t per_line = 16; /* Maximum bytes per line. */
 397
 398     while (size > 0) {
 399         size_t start, end, n;
 400         size_t i;
 401
 402         /* Number of bytes on this line. */
 403         start = ofs % per_line;
 404         end = per_line;
 405         if (end - start > size)
 406             end = start + size;
 407         n = end - start;
 408
 409         /* Print line. */
 410         ds_put_format(ds, "%08"PRIxMAX"  ",
 411                       (uintmax_t) ROUND_DOWN(ofs, per_line));
 412         for (i = 0; i < start; i++) {
 413             ds_put_format(ds, "   ");
 414         }
 415         for (; i < end; i++) {
 416             ds_put_format(ds, "%02x%c",
 417                           buf[i - start], i == per_line / 2 - 1? '-' : ' ');
 418         }
 419         if (ascii) {
 420             for (; i < per_line; i++)
 421                 ds_put_format(ds, "   ");
 422             ds_put_format(ds, "|");
 423             for (i = 0; i < start; i++)
 424                 ds_put_format(ds, " ");
 425             for (; i < end; i++) {
 426                 int c = buf[i - start];
 427                 ds_put_char(ds, c >= 32 && c < 127 ? c : '.');
 428             }
 429             for (; i < per_line; i++)
 430                 ds_put_format(ds, " ");
 431             ds_put_format(ds, "|");
 432         } else {
 433             ds_chomp(ds, ' ');
 434         }
 435         ds_put_format(ds, "\n");
 436
 437         ofs += n;
 438         buf += n;
 439         size -= n;
 440     }
 441 }
 442
 443 int
 444 ds_last(const struct ds *ds)
 445 {
 446     return ds->length > 0 ? (unsigned char) ds->string[ds->length - 1] : EOF;
 447 }
 448
 449 bool
 450 ds_chomp(struct ds *ds, int c)
 451 {
 452     if (ds->length > 0 && ds->string[ds->length - 1] == (char) c) {
 453         ds->string[--ds->length] = '\0';
 454         return true;
 455     } else {
 456         return false;
 457     }
 458 }
 459
 460 void
 461 ds_clone(struct ds *dst, struct ds *source)
 462 {
 463     dst->length = source->length;
 464     dst->allocated = dst->length;
 465     dst->string = xmalloc(dst->allocated + 1);
 466     memcpy(dst->string, source->string, dst->allocated + 1);
 467 }