summaryrefslogtreecommitdiff
path: root/src/buffer.c
blob: a89c82e36d5e5a053843eb6a84676d1b7f38d8ee (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
#include <stdarg.h>
#include <string.h>
#include <assert.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>

#include "config.h"
#include "cmark_ctype.h"
#include "buffer.h"

/* Used as default value for cmark_strbuf->ptr so that people can always
 * assume ptr is non-NULL and zero terminated even for new cmark_strbufs.
 */
unsigned char cmark_strbuf__initbuf[1];

#ifndef MIN
#define MIN(x, y) ((x < y) ? x : y)
#endif

void cmark_strbuf_init(cmark_strbuf *buf, bufsize_t initial_size) {
  buf->asize = 0;
  buf->size = 0;
  buf->ptr = cmark_strbuf__initbuf;

  if (initial_size > 0)
    cmark_strbuf_grow(buf, initial_size);
}

void cmark_strbuf_overflow_err() {
  fprintf(stderr, "String buffer overflow");
  abort();
}

static inline void S_strbuf_grow_by(cmark_strbuf *buf, size_t add) {
  size_t target_size = (size_t)buf->size + add;

  if (target_size < add            /* Integer overflow. */
      || target_size > BUFSIZE_MAX /* Truncation overflow. */
      ) {
    cmark_strbuf_overflow_err();
    return; /* unreachable */
  }

  if ((bufsize_t)target_size >= buf->asize)
    cmark_strbuf_grow(buf, (bufsize_t)target_size);
}

void cmark_strbuf_grow(cmark_strbuf *buf, bufsize_t target_size) {
  unsigned char *new_ptr;

  if (target_size < buf->asize)
    return;

  if (buf->asize == 0) {
    new_ptr = NULL;
  } else {
    new_ptr = buf->ptr;
  }

  /* Oversize the buffer by 50% to guarantee amortized linear time
   * complexity on append operations. */
  size_t new_size = (size_t)target_size + (size_t)target_size / 2;

  /* Account for terminating null byte. */
  new_size += 1;

  /* round allocation up to multiple of 8 */
  new_size = (new_size + 7) & ~7;

  if (new_size < (size_t)target_size /* Integer overflow. */
      || new_size > BUFSIZE_MAX      /* Truncation overflow. */
      ) {
    if (target_size >= BUFSIZE_MAX) {
      /* No space for terminating null byte. */
      cmark_strbuf_overflow_err();
      return; /* unreachable */
    }
    /* Oversize by the maximum possible amount. */
    new_size = BUFSIZE_MAX;
  }

  new_ptr = (unsigned char *)realloc(new_ptr, new_size);

  if (!new_ptr) {
    perror("realloc in cmark_strbuf_grow");
    abort();
  }

  buf->asize = (bufsize_t)new_size;
  buf->ptr = new_ptr;
}

bufsize_t cmark_strbuf_len(const cmark_strbuf *buf) { return buf->size; }

void cmark_strbuf_free(cmark_strbuf *buf) {
  if (!buf)
    return;

  if (buf->ptr != cmark_strbuf__initbuf)
    free(buf->ptr);

  cmark_strbuf_init(buf, 0);
}

void cmark_strbuf_clear(cmark_strbuf *buf) {
  buf->size = 0;

  if (buf->asize > 0)
    buf->ptr[0] = '\0';
}

void cmark_strbuf_set(cmark_strbuf *buf, const unsigned char *data,
                      bufsize_t len) {
  if (len <= 0 || data == NULL) {
    cmark_strbuf_clear(buf);
  } else {
    if (data != buf->ptr) {
      if (len >= buf->asize)
        cmark_strbuf_grow(buf, len);
      memmove(buf->ptr, data, len);
    }
    buf->size = len;
    buf->ptr[buf->size] = '\0';
  }
}

void cmark_strbuf_sets(cmark_strbuf *buf, const char *string) {
  cmark_strbuf_set(buf, (const unsigned char *)string,
                   string ? cmark_strbuf_safe_strlen(string) : 0);
}

void cmark_strbuf_putc(cmark_strbuf *buf, int c) {
  S_strbuf_grow_by(buf, 1);
  buf->ptr[buf->size++] = (unsigned char)(c & 0xFF);
  buf->ptr[buf->size] = '\0';
}

void cmark_strbuf_put(cmark_strbuf *buf, const unsigned char *data,
                      bufsize_t len) {
  if (len <= 0)
    return;

  S_strbuf_grow_by(buf, len);
  memmove(buf->ptr + buf->size, data, len);
  buf->size += len;
  buf->ptr[buf->size] = '\0';
}

void cmark_strbuf_puts(cmark_strbuf *buf, const char *string) {
  cmark_strbuf_put(buf, (const unsigned char *)string,
                   cmark_strbuf_safe_strlen(string));
}

void cmark_strbuf_copy_cstr(char *data, bufsize_t datasize,
                            const cmark_strbuf *buf) {
  bufsize_t copylen;

  assert(buf);
  if (!data || datasize <= 0)
    return;

  data[0] = '\0';

  if (buf->size == 0 || buf->asize <= 0)
    return;

  copylen = buf->size;
  if (copylen > datasize - 1)
    copylen = datasize - 1;
  memmove(data, buf->ptr, copylen);
  data[copylen] = '\0';
}

void cmark_strbuf_swap(cmark_strbuf *buf_a, cmark_strbuf *buf_b) {
  cmark_strbuf t = *buf_a;
  *buf_a = *buf_b;
  *buf_b = t;
}

unsigned char *cmark_strbuf_detach(cmark_strbuf *buf) {
  unsigned char *data = buf->ptr;

  if (buf->asize == 0) {
    /* return an empty string */
    return (unsigned char *)calloc(1, 1);
  }

  cmark_strbuf_init(buf, 0);
  return data;
}

int cmark_strbuf_cmp(const cmark_strbuf *a, const cmark_strbuf *b) {
  int result = memcmp(a->ptr, b->ptr, MIN(a->size, b->size));
  return (result != 0) ? result
                       : (a->size < b->size) ? -1 : (a->size > b->size) ? 1 : 0;
}

bufsize_t cmark_strbuf_strchr(const cmark_strbuf *buf, int c, bufsize_t pos) {
  if (pos >= buf->size)
    return -1;
  if (pos < 0)
    pos = 0;

  const unsigned char *p =
      (unsigned char *)memchr(buf->ptr + pos, c, buf->size - pos);
  if (!p)
    return -1;

  return (bufsize_t)(p - (const unsigned char *)buf->ptr);
}

bufsize_t cmark_strbuf_strrchr(const cmark_strbuf *buf, int c, bufsize_t pos) {
  if (pos < 0 || buf->size == 0)
    return -1;
  if (pos >= buf->size)
    pos = buf->size - 1;

  for (bufsize_t i = pos; i >= 0; i--) {
    if (buf->ptr[i] == (unsigned char)c)
      return i;
  }

  return -1;
}

void cmark_strbuf_truncate(cmark_strbuf *buf, bufsize_t len) {
  if (len < 0)
    len = 0;

  if (len < buf->size) {
    buf->size = len;
    buf->ptr[buf->size] = '\0';
  }
}

void cmark_strbuf_drop(cmark_strbuf *buf, bufsize_t n) {
  if (n > 0) {
    if (n > buf->size)
      n = buf->size;
    buf->size = buf->size - n;
    if (buf->size)
      memmove(buf->ptr, buf->ptr + n, buf->size);

    buf->ptr[buf->size] = '\0';
  }
}

void cmark_strbuf_rtrim(cmark_strbuf *buf) {
  if (!buf->size)
    return;

  while (buf->size > 0) {
    if (!cmark_isspace(buf->ptr[buf->size - 1]))
      break;

    buf->size--;
  }

  buf->ptr[buf->size] = '\0';
}

void cmark_strbuf_trim(cmark_strbuf *buf) {
  bufsize_t i = 0;

  if (!buf->size)
    return;

  while (i < buf->size && cmark_isspace(buf->ptr[i]))
    i++;

  cmark_strbuf_drop(buf, i);

  cmark_strbuf_rtrim(buf);
}

// Destructively modify string, collapsing consecutive
// space and newline characters into a single space.
void cmark_strbuf_normalize_whitespace(cmark_strbuf *s) {
  bool last_char_was_space = false;
  bufsize_t r, w;

  for (r = 0, w = 0; r < s->size; ++r) {
    if (cmark_isspace(s->ptr[r])) {
      if (!last_char_was_space) {
        s->ptr[w++] = ' ';
        last_char_was_space = true;
      }
    } else {
      s->ptr[w++] = s->ptr[r];
      last_char_was_space = false;
    }
  }

  cmark_strbuf_truncate(s, w);
}

// Destructively unescape a string: remove backslashes before punctuation chars.
extern void cmark_strbuf_unescape(cmark_strbuf *buf) {
  bufsize_t r, w;

  for (r = 0, w = 0; r < buf->size; ++r) {
    if (buf->ptr[r] == '\\' && cmark_ispunct(buf->ptr[r + 1]))
      r++;

    buf->ptr[w++] = buf->ptr[r];
  }

  cmark_strbuf_truncate(buf, w);
}