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 time 'when' to 'string' based on 'template', in local time or UTC
 187  * based on 'utc'. */
 188 void
 189 ds_put_strftime(struct ds *ds, const char *template, time_t when, bool utc)
 190 {
 191     struct tm tm;
 192     if (utc) {
 193         gmtime_r(&when, &tm);
 194     } else {
 195         localtime_r(&when, &tm);
 196     }
 197
 198     for (;;) {
 199         size_t avail = ds->string ? ds->allocated - ds->length + 1 : 0;
 200         size_t used = strftime(&ds->string[ds->length], avail, template, &tm);
 201         if (used) {
 202             ds->length += used;
 203             return;
 204         }
 205         ds_reserve(ds, ds->length + (avail < 32 ? 64 : 2 * avail));
 206     }
 207 }
 208
 209 /* Returns a malloc()'d string for time 'when' based on 'template', in local
 210  * time or UTC based on 'utc'. */
 211 char *
 212 xastrftime(const char *template, time_t when, bool utc)
 213 {
 214     struct ds s;
 215
 216     ds_init(&s);
 217     ds_put_strftime(&s, template, when, utc);
 218     return s.string;
 219 }
 220
 221 int
 222 ds_get_line(struct ds *ds, FILE *file)
 223 {
 224     ds_clear(ds);
 225     for (;;) {
 226         int c = getc(file);
 227         if (c == EOF) {
 228             return ds->length ? 0 : EOF;
 229         } else if (c == '\n') {
 230             return 0;
 231         } else {
 232             ds_put_char(ds, c);
 233         }
 234     }
 235 }
 236
 237 /* Reads a line from 'file' into 'ds', clearing anything initially in 'ds'.
 238  * Deletes comments introduced by "#" and skips lines that contains only white
 239  * space (after deleting comments).
 240  *
 241  * Returns 0 if successful, EOF if no non-blank line was found. */
 242 int
 243 ds_get_preprocessed_line(struct ds *ds, FILE *file)
 244 {
 245     while (!ds_get_line(ds, file)) {
 246         char *line = ds_cstr(ds);
 247         char *comment;
 248
 249         /* Delete comments. */
 250         comment = strchr(line, '#');
 251         if (comment) {
 252             *comment = '\0';
 253         }
 254
 255         /* Return successfully unless the line is all spaces. */
 256         if (line[strspn(line, " \t\n")] != '\0') {
 257             return 0;
 258         }
 259     }
 260     return EOF;
 261 }
 262
 263 /* Reads a line from 'file' into 'ds' and does some preprocessing on it:
 264  *
 265  *    - If the line begins with #, prints it on stdout and reads the next line.
 266  *
 267  *    - Otherwise, if the line contains an # somewhere else, strips it and
 268  *      everything following it (as a comment).
 269  *
 270  *    - If (after comment removal) the line contains only white space, prints
 271  *      a blank line on stdout and reads the next line.
 272  *
 273  *    - Otherwise, returns the line to the caller.
 274  *
 275  * This is useful in some of the OVS tests, where we want to check that parsing
 276  * and then re-formatting some kind of data does not change it, but we also
 277  * want to be able to put comments in the input.
 278  *
 279  * Returns 0 if successful, EOF if no non-blank line was found. */
 280 int
 281 ds_get_test_line(struct ds *ds, FILE *file)
 282 {
 283     for (;;) {
 284         char *s, *comment;
 285         int retval;
 286
 287         retval = ds_get_line(ds, file);
 288         if (retval) {
 289             return retval;
 290         }
 291
 292         s = ds_cstr(ds);
 293         if (*s == '#') {
 294             puts(s);
 295             continue;
 296         }
 297
 298         comment = strchr(s, '#');
 299         if (comment) {
 300             *comment = '\0';
 301         }
 302         if (s[strspn(s, " \t\n")] == '\0') {
 303             putchar('\n');
 304             continue;
 305         }
 306
 307         return 0;
 308     }
 309 }
 310
 311 char *
 312 ds_cstr(struct ds *ds)
 313 {
 314     if (!ds->string) {
 315         ds_reserve(ds, 0);
 316     }
 317     ds->string[ds->length] = '\0';
 318     return ds->string;
 319 }
 320
 321 const char *
 322 ds_cstr_ro(const struct ds *ds)
 323 {
 324     return ds_cstr(CONST_CAST(struct ds *, ds));
 325 }
 326
 327 /* Returns a null-terminated string representing the current contents of 'ds',
 328  * which the caller is expected to free with free(), then clears the contents
 329  * of 'ds'. */
 330 char *
 331 ds_steal_cstr(struct ds *ds)
 332 {
 333     char *s = ds_cstr(ds);
 334     ds_init(ds);
 335     return s;
 336 }
 337
 338 void
 339 ds_destroy(struct ds *ds)
 340 {
 341     free(ds->string);
 342 }
 343
 344 /* Swaps the content of 'a' and 'b'. */
 345 void
 346 ds_swap(struct ds *a, struct ds *b)
 347 {
 348     struct ds temp = *a;
 349     *a = *b;
 350     *b = temp;
 351 }
 352
 353 /* Writes the 'size' bytes in 'buf' to 'string' as hex bytes arranged 16 per
 354  * line.  Numeric offsets are also included, starting at 'ofs' for the first
 355  * byte in 'buf'.  If 'ascii' is true then the corresponding ASCII characters
 356  * are also rendered alongside. */
 357 void
 358 ds_put_hex_dump(struct ds *ds, const void *buf_, size_t size,
 359                 uintptr_t ofs, bool ascii)
 360 {
 361   const uint8_t *buf = buf_;
 362   const size_t per_line = 16; /* Maximum bytes per line. */
 363
 364   while (size > 0)
 365     {
 366       size_t start, end, n;
 367       size_t i;
 368
 369       /* Number of bytes on this line. */
 370       start = ofs % per_line;
 371       end = per_line;
 372       if (end - start > size)
 373         end = start + size;
 374       n = end - start;
 375
 376       /* Print line. */
 377       ds_put_format(ds, "%08jx  ", (uintmax_t) ROUND_DOWN(ofs, per_line));
 378       for (i = 0; i < start; i++)
 379         ds_put_format(ds, "   ");
 380       for (; i < end; i++)
 381         ds_put_format(ds, "%02hhx%c",
 382                 buf[i - start], i == per_line / 2 - 1? '-' : ' ');
 383       if (ascii)
 384         {
 385           for (; i < per_line; i++)
 386             ds_put_format(ds, "   ");
 387           ds_put_format(ds, "|");
 388           for (i = 0; i < start; i++)
 389             ds_put_format(ds, " ");
 390           for (; i < end; i++) {
 391               int c = buf[i - start];
 392               ds_put_char(ds, c >= 32 && c < 127 ? c : '.');
 393           }
 394           for (; i < per_line; i++)
 395             ds_put_format(ds, " ");
 396           ds_put_format(ds, "|");
 397         }
 398       ds_put_format(ds, "\n");
 399
 400       ofs += n;
 401       buf += n;
 402       size -= n;
 403     }
 404 }
 405
 406 int
 407 ds_last(const struct ds *ds)
 408 {
 409     return ds->length > 0 ? (unsigned char) ds->string[ds->length - 1] : EOF;
 410 }
 411
 412 void
 413 ds_chomp(struct ds *ds, int c)
 414 {
 415     if (ds->length > 0 && ds->string[ds->length - 1] == (char) c) {
 416         ds->string[--ds->length] = '\0';
 417     }
 418 }