lib/dynamic-string.c

   1 /*
   2  * Copyright (c) 2008, 2009, 2010, 2011, 2012 Nicira Networks.
   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 <assert.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         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 to 'string' based on 'template'.
 188  * The current time is either localtime or UTC based on 'utc'. */
 189 void
 190 ds_put_strftime(struct ds *ds, const char *template, bool utc)
 191 {
 192     const struct tm *tm;
 193     time_t now = time_wall();
 194     if (utc) {
 195         tm = gmtime(&now);
 196     } else {
 197         tm = localtime(&now);
 198     }
 199
 200     for (;;) {
 201         size_t avail = ds->string ? ds->allocated - ds->length + 1 : 0;
 202         size_t used = strftime(&ds->string[ds->length], avail, template, tm);
 203         if (used) {
 204             ds->length += used;
 205             return;
 206         }
 207         ds_reserve(ds, ds->length + (avail < 32 ? 64 : 2 * avail));
 208     }
 209 }
 210
 211 int
 212 ds_get_line(struct ds *ds, FILE *file)
 213 {
 214     ds_clear(ds);
 215     for (;;) {
 216         int c = getc(file);
 217         if (c == EOF) {
 218             return ds->length ? 0 : EOF;
 219         } else if (c == '\n') {
 220             return 0;
 221         } else {
 222             ds_put_char(ds, c);
 223         }
 224     }
 225 }
 226
 227 /* Reads a line from 'file' into 'ds', clearing anything initially in 'ds'.
 228  * Deletes comments introduced by "#" and skips lines that contains only white
 229  * space (after deleting comments).
 230  *
 231  * Returns 0 if successful, EOF if no non-blank line was found. */
 232 int
 233 ds_get_preprocessed_line(struct ds *ds, FILE *file)
 234 {
 235     while (!ds_get_line(ds, file)) {
 236         char *line = ds_cstr(ds);
 237         char *comment;
 238
 239         /* Delete comments. */
 240         comment = strchr(line, '#');
 241         if (comment) {
 242             *comment = '\0';
 243         }
 244
 245         /* Return successfully unless the line is all spaces. */
 246         if (line[strspn(line, " \t\n")] != '\0') {
 247             return 0;
 248         }
 249     }
 250     return EOF;
 251 }
 252
 253 char *
 254 ds_cstr(struct ds *ds)
 255 {
 256     if (!ds->string) {
 257         ds_reserve(ds, 0);
 258     }
 259     ds->string[ds->length] = '\0';
 260     return ds->string;
 261 }
 262
 263 const char *
 264 ds_cstr_ro(const struct ds *ds)
 265 {
 266     return ds_cstr((struct ds *) ds);
 267 }
 268
 269 /* Returns a null-terminated string representing the current contents of 'ds',
 270  * which the caller is expected to free with free(), then clears the contents
 271  * of 'ds'. */
 272 char *
 273 ds_steal_cstr(struct ds *ds)
 274 {
 275     char *s = ds_cstr(ds);
 276     ds_init(ds);
 277     return s;
 278 }
 279
 280 void
 281 ds_destroy(struct ds *ds)
 282 {
 283     free(ds->string);
 284 }
 285
 286 /* Swaps the content of 'a' and 'b'. */
 287 void
 288 ds_swap(struct ds *a, struct ds *b)
 289 {
 290     struct ds temp = *a;
 291     *a = *b;
 292     *b = temp;
 293 }
 294
 295 /* Writes the 'size' bytes in 'buf' to 'string' as hex bytes arranged 16 per
 296  * line.  Numeric offsets are also included, starting at 'ofs' for the first
 297  * byte in 'buf'.  If 'ascii' is true then the corresponding ASCII characters
 298  * are also rendered alongside. */
 299 void
 300 ds_put_hex_dump(struct ds *ds, const void *buf_, size_t size,
 301                 uintptr_t ofs, bool ascii)
 302 {
 303   const uint8_t *buf = buf_;
 304   const size_t per_line = 16; /* Maximum bytes per line. */
 305
 306   while (size > 0)
 307     {
 308       size_t start, end, n;
 309       size_t i;
 310
 311       /* Number of bytes on this line. */
 312       start = ofs % per_line;
 313       end = per_line;
 314       if (end - start > size)
 315         end = start + size;
 316       n = end - start;
 317
 318       /* Print line. */
 319       ds_put_format(ds, "%08jx  ", (uintmax_t) ROUND_DOWN(ofs, per_line));
 320       for (i = 0; i < start; i++)
 321         ds_put_format(ds, "   ");
 322       for (; i < end; i++)
 323         ds_put_format(ds, "%02hhx%c",
 324                 buf[i - start], i == per_line / 2 - 1? '-' : ' ');
 325       if (ascii)
 326         {
 327           for (; i < per_line; i++)
 328             ds_put_format(ds, "   ");
 329           ds_put_format(ds, "|");
 330           for (i = 0; i < start; i++)
 331             ds_put_format(ds, " ");
 332           for (; i < end; i++) {
 333               int c = buf[i - start];
 334               ds_put_char(ds, c >= 32 && c < 127 ? c : '.');
 335           }
 336           for (; i < per_line; i++)
 337             ds_put_format(ds, " ");
 338           ds_put_format(ds, "|");
 339         }
 340       ds_put_format(ds, "\n");
 341
 342       ofs += n;
 343       buf += n;
 344       size -= n;
 345     }
 346 }
 347
 348 int
 349 ds_last(const struct ds *ds)
 350 {
 351     return ds->length > 0 ? (unsigned char) ds->string[ds->length - 1] : EOF;
 352 }
 353
 354 void
 355 ds_chomp(struct ds *ds, int c)
 356 {
 357     if (ds->length > 0 && ds->string[ds->length - 1] == (char) c) {
 358         ds->string[--ds->length] = '\0';
 359     }
 360 }