xref: /lighttpd1.4/src/buffer.c (revision 84fa4b8d)
1 #include "first.h"
2 
3 #include "buffer.h"
4 
5 #include <stdlib.h>
6 #include <string.h>
7 #include "sys-time.h"   /* strftime() */
8 
9 static const char hex_chars_lc[] = "0123456789abcdef";
10 static const char hex_chars_uc[] = "0123456789ABCDEF";
11 
12 /**
13  * init the buffer
14  *
15  */
16 
17 __attribute_noinline__
18 buffer* buffer_init(void) {
19 	buffer * const b = calloc(1, sizeof(*b));
20 	force_assert(b);
21 	return b;
22 }
23 
24 buffer *buffer_init_buffer(const buffer *src) {
25 	buffer * const b = buffer_init();
26 	buffer_copy_string_len(b, BUF_PTR_LEN(src));
27 	return b;
28 }
29 
30 buffer *buffer_init_string(const char *str) {
31 	buffer * const b = buffer_init();
32 	buffer_copy_string(b, str);
33 	return b;
34 }
35 
36 void buffer_free(buffer *b) {
37 	if (NULL == b) return;
38 
39 	free(b->ptr);
40 	free(b);
41 }
42 
43 void buffer_free_ptr(buffer *b) {
44 	free(b->ptr);
45 	b->ptr = NULL;
46 	b->used = 0;
47 	b->size = 0;
48 }
49 
50 void buffer_move(buffer * restrict b, buffer * restrict src) {
51 	buffer tmp;
52 	buffer_clear(b);
53 	tmp = *src; *src = *b; *b = tmp;
54 }
55 
56 /* make sure buffer is at least "size" big + 1 for '\0'. keep old data */
57 __attribute_cold__
58 __attribute_noinline__
59 __attribute_nonnull__
60 __attribute_returns_nonnull__
61 static char* buffer_realloc(buffer * const restrict b, const size_t len) {
62     #define BUFFER_PIECE_SIZE 64uL  /*(must be power-of-2)*/
63     size_t sz = (len + 1 + BUFFER_PIECE_SIZE-1) & ~(BUFFER_PIECE_SIZE-1);
64     force_assert(sz > len);
65     if ((sz & (sz-1)) && sz < INT_MAX) {/* not power-2; huge val not expected */
66         /*(optimizer should recognize this and use ffs or clz or equivalent)*/
67         const size_t psz = sz;
68         for (sz = 256; sz < psz; sz <<= 1) ;
69     }
70 
71     b->size = sz;
72     b->ptr = realloc(b->ptr, sz);
73 
74     force_assert(NULL != b->ptr);
75     return b->ptr;
76 }
77 
78 __attribute_cold__
79 __attribute_noinline__
80 __attribute_nonnull__
81 __attribute_returns_nonnull__
82 static char* buffer_alloc_replace(buffer * const restrict b, const size_t size) {
83     /*(discard old data so realloc() does not copy)*/
84     if (NULL != b->ptr) {
85         free(b->ptr);
86         b->ptr = NULL;
87     }
88     /*(note: if size larger than one lshift, use size instead of power-2)*/
89     return buffer_realloc(b, (b->size << 1) > size ? (b->size << 1)-1 : size);
90 }
91 
92 char* buffer_string_prepare_copy(buffer * const b, const size_t size) {
93     b->used = 0;
94     return (size < b->size)
95       ? b->ptr
96       : buffer_alloc_replace(b, size);
97 }
98 
99 __attribute_cold__
100 __attribute_noinline__
101 __attribute_nonnull__
102 __attribute_returns_nonnull__
103 static char* buffer_string_prepare_append_resize(buffer * const restrict b, const size_t size) {
104     if (b->used < 2) {  /* buffer_is_blank(b) */
105         char * const s = buffer_string_prepare_copy(b, size);
106         *s = '\0'; /*(for case (1 == b->used))*/
107         return s;
108     }
109 
110     /* not empty, b->used already includes a terminating 0 */
111     /*(note: if size larger than one lshift, use size instead of power-2)*/
112     const size_t req_size = ((b->size << 1) - b->used > size)
113       ? (b->size << 1)-1
114       : b->used + size;
115 
116     /* check for overflow: unsigned overflow is defined to wrap around */
117     force_assert(req_size >= b->used);
118 
119     return buffer_realloc(b, req_size) + b->used - 1;
120 }
121 
122 char* buffer_string_prepare_append(buffer * const b, const size_t size) {
123     const uint32_t len = b->used ? b->used-1 : 0;
124     return (b->size - len >= size + 1)
125       ? b->ptr + len
126       : buffer_string_prepare_append_resize(b, size);
127 }
128 
129 /*(prefer smaller code than inlining buffer_extend in many places in buffer.c)*/
130 __attribute_noinline__
131 char*
132 buffer_extend (buffer * const b, const size_t x)
133 {
134     /* extend buffer to append x (reallocate by power-2 (or larger), if needed)
135      * (combine buffer_string_prepare_append() and buffer_commit())
136      * (future: might make buffer.h static inline func for HTTP/1.1 performance)
137      * pre-sets '\0' byte and b->used (unlike buffer_string_prepare_append())*/
138   #if 0
139     char * const s = buffer_string_prepare_append(b, x);
140     b->used += x + (0 == b->used);
141   #else
142     const uint32_t len = b->used ? b->used-1 : 0;
143     char * const s = (b->size - len >= x + 1)
144       ? b->ptr + len
145       : buffer_string_prepare_append_resize(b, x);
146     b->used = len+x+1;
147   #endif
148     s[x] = '\0';
149     return s;
150 }
151 
152 void buffer_commit(buffer *b, size_t size)
153 {
154 	size_t sz = b->used;
155 	if (0 == sz) sz = 1;
156 
157 	if (size > 0) {
158 		/* check for overflow: unsigned overflow is defined to wrap around */
159 		sz += size;
160 		force_assert(sz > size);
161 	}
162 
163 	b->used = sz;
164 	b->ptr[sz - 1] = '\0';
165 }
166 
167 void buffer_copy_string(buffer * restrict b, const char * restrict s) {
168 	buffer_copy_string_len(b, s, NULL != s ? strlen(s) : 0);
169 }
170 
171 void buffer_copy_string_len(buffer * const restrict b, const char * const restrict s, const size_t len) {
172     b->used = len + 1;
173     char * const restrict d = (len < b->size)
174       ? b->ptr
175       : buffer_alloc_replace(b, len);
176     d[len] = '\0';
177     memcpy(d, s, len);
178 }
179 
180 void buffer_append_string(buffer * restrict b, const char * restrict s) {
181 	buffer_append_string_len(b, s, NULL != s ? strlen(s) : 0);
182 }
183 
184 /**
185  * append a string to the end of the buffer
186  *
187  * the resulting buffer is terminated with a '\0'
188  * s is treated as a un-terminated string (a \0 is handled a normal character)
189  *
190  * @param b a buffer
191  * @param s the string
192  * @param s_len size of the string (without the terminating \0)
193  */
194 
195 void buffer_append_string_len(buffer * const restrict b, const char * const restrict s, const size_t len) {
196     memcpy(buffer_extend(b, len), s, len);
197 }
198 
199 void buffer_append_str2(buffer * const restrict b, const char * const s1, const size_t len1, const char * const s2, const size_t len2) {
200     char * const restrict s = buffer_extend(b, len1+len2);
201   #ifdef HAVE_MEMPCPY
202     mempcpy(mempcpy(s, s1, len1), s2, len2);
203   #else
204     memcpy(s,      s1, len1);
205     memcpy(s+len1, s2, len2);
206   #endif
207 }
208 
209 void buffer_append_str3(buffer * const restrict b, const char * const s1, const size_t len1, const char * const s2, const size_t len2, const char * const s3, const size_t len3) {
210     char * restrict s = buffer_extend(b, len1+len2+len3);
211   #ifdef HAVE_MEMPCPY
212     mempcpy(mempcpy(mempcpy(s, s1, len1), s2, len2), s3, len3);
213   #else
214     memcpy(s,         s1, len1);
215     memcpy((s+=len1), s2, len2);
216     memcpy((s+=len2), s3, len3);
217   #endif
218 }
219 
220 void buffer_append_iovec(buffer * const restrict b, const struct const_iovec * const iov, const size_t n) {
221     size_t len = 0;
222     for (size_t i = 0; i < n; ++i)
223         len += iov[i].iov_len;
224     char *s = buffer_extend(b, len);
225     for (size_t i = 0; i < n; ++i) {
226         if (0 == iov[i].iov_len) continue;
227       #ifdef HAVE_MEMPCPY
228         s = mempcpy(s, iov[i].iov_base, iov[i].iov_len);
229       #else
230         memcpy(s, iov[i].iov_base, iov[i].iov_len);
231         s += iov[i].iov_len;
232       #endif
233     }
234 }
235 
236 void buffer_append_path_len(buffer * restrict b, const char * restrict a, size_t alen) {
237     char * restrict s = buffer_string_prepare_append(b, alen+1);
238     const int aslash = (alen && a[0] == '/');
239     if (b->used > 1 && s[-1] == '/') {
240         if (aslash) {
241             ++a;
242             --alen;
243         }
244     }
245     else {
246         if (0 == b->used) b->used = 1;
247         if (!aslash) {
248             *s++ = '/';
249             ++b->used;
250         }
251     }
252     b->used += alen;
253     s[alen] = '\0';
254     memcpy(s, a, alen);
255 }
256 
257 void
258 buffer_copy_path_len2 (buffer * const restrict b, const char * const restrict s1, size_t len1, const char * const restrict s2, size_t len2)
259 {
260     /*(similar to buffer_copy_string_len(b, s1, len1) but combined allocation)*/
261     memcpy(buffer_string_prepare_copy(b, len1+len2+1), s1, len1);
262     b->used = len1 + 1;                    /*('\0' byte will be written below)*/
263 
264     buffer_append_path_len(b, s2, len2);/*(choice: not inlined, special-cased)*/
265 }
266 
267 void buffer_append_uint_hex_lc(buffer *b, uintmax_t value) {
268 	char *buf;
269 	unsigned int shift = 0;
270 
271 	{
272 		uintmax_t copy = value;
273 		do {
274 			copy >>= 8;
275 			shift += 8; /* counting bits */
276 		} while (0 != copy);
277 	}
278 
279 	buf = buffer_extend(b, shift >> 2); /*nibbles (4 bits)*/
280 
281 	while (shift > 0) {
282 		shift -= 4;
283 		*(buf++) = hex_chars_lc[(value >> shift) & 0x0F];
284 	}
285 }
286 
287 __attribute_nonnull__
288 __attribute_returns_nonnull__
289 static char* utostr(char buf[LI_ITOSTRING_LENGTH], uintmax_t val) {
290 	char *cur = buf+LI_ITOSTRING_LENGTH;
291 	do {
292 		int mod = val % 10;
293 		val /= 10;
294 		/* prepend digit mod */
295 		*(--cur) = (char) ('0' + mod);
296 	} while (0 != val);
297 	return cur;
298 }
299 
300 __attribute_nonnull__
301 __attribute_returns_nonnull__
302 static char* itostr(char buf[LI_ITOSTRING_LENGTH], intmax_t val) {
303 	/* absolute value not defined for INTMAX_MIN, but can take absolute
304 	 * value of any negative number via twos complement cast to unsigned.
305 	 * negative sign is prepended after (now unsigned) value is converted
306 	 * to string */
307 	uintmax_t uval = val >= 0 ? (uintmax_t)val : ((uintmax_t)~val) + 1;
308 	char *cur = utostr(buf, uval);
309 	if (val < 0) *(--cur) = '-';
310 
311 	return cur;
312 }
313 
314 void buffer_append_int(buffer *b, intmax_t val) {
315 	char buf[LI_ITOSTRING_LENGTH];
316 	const char * const str = itostr(buf, val);
317 	buffer_append_string_len(b, str, buf+sizeof(buf) - str);
318 }
319 
320 void buffer_append_strftime(buffer * const restrict b, const char * const restrict format, const struct tm * const restrict tm) {
321     force_assert(NULL != format);
322     /*(localtime_r() or gmtime_r() producing tm should not have failed)*/
323     if (__builtin_expect( (NULL == tm), 0)) return;
324 
325     /*(expecting typical format strings to result in < 64 bytes needed;
326      * skipping buffer_string_space() calculation and providing fixed size)*/
327     size_t rv = strftime(buffer_string_prepare_append(b, 63), 64, format, tm);
328 
329     /* 0 (in some apis) signals the string may have been too small;
330      * but the format could also just have lead to an empty string */
331     if (__builtin_expect( (0 == rv), 0) || __builtin_expect( (rv > 63), 0)) {
332         /* unexpected; give it a second try with a larger string */
333         rv = strftime(buffer_string_prepare_append(b, 4095), 4096, format, tm);
334         if (__builtin_expect( (rv > 4095), 0))/*(input format was ridiculous)*/
335             return;
336     }
337 
338     /*buffer_commit(b, rv);*/
339     b->used += (uint32_t)rv + (0 == b->used);
340 }
341 
342 
343 size_t li_itostrn(char *buf, size_t buf_len, intmax_t val) {
344 	char p_buf[LI_ITOSTRING_LENGTH];
345 	char* const str = itostr(p_buf, val);
346 	size_t len = (size_t)(p_buf+sizeof(p_buf)-str);
347 	force_assert(len <= buf_len);
348 	memcpy(buf, str, len);
349 	return len;
350 }
351 
352 size_t li_utostrn(char *buf, size_t buf_len, uintmax_t val) {
353 	char p_buf[LI_ITOSTRING_LENGTH];
354 	char* const str = utostr(p_buf, val);
355 	size_t len = (size_t)(p_buf+sizeof(p_buf)-str);
356 	force_assert(len <= buf_len);
357 	memcpy(buf, str, len);
358 	return len;
359 }
360 
361 #define li_ntox_lc(n) ((n) <= 9 ? (n) + '0' : (n) + 'a' - 10)
362 
363 /* c (char) and n (nibble) MUST be unsigned integer types */
364 #define li_cton(c,n) \
365   (((n) = (c) - '0') <= 9 || (((n) = ((c)&0xdf) - 'A') <= 5 ? ((n) += 10) : 0))
366 
367 /* converts hex char (0-9, A-Z, a-z) to decimal.
368  * returns 0xFF on invalid input.
369  */
370 char hex2int(unsigned char hex) {
371 	unsigned char n;
372 	return li_cton(hex,n) ? (char)n : 0xFF;
373 }
374 
375 int li_hex2bin (unsigned char * const bin, const size_t binlen, const char * const hexstr, const size_t len)
376 {
377     /* validate and transform 32-byte MD5 hex string to 16-byte binary MD5,
378      * or 64-byte SHA-256 or SHA-512-256 hex string to 32-byte binary digest */
379     if (len > (binlen << 1)) return -1;
380     for (int i = 0, ilen = (int)len; i < ilen; i+=2) {
381         int hi = hexstr[i];
382         int lo = hexstr[i+1];
383         if ('0' <= hi && hi <= '9')                    hi -= '0';
384         else if ((uint32_t)(hi |= 0x20)-'a' <= 'f'-'a')hi += -'a' + 10;
385         else                                           return -1;
386         if ('0' <= lo && lo <= '9')                    lo -= '0';
387         else if ((uint32_t)(lo |= 0x20)-'a' <= 'f'-'a')lo += -'a' + 10;
388         else                                           return -1;
389         bin[(i >> 1)] = (unsigned char)((hi << 4) | lo);
390     }
391     return 0;
392 }
393 
394 
395 int buffer_eq_icase_ssn(const char * const a, const char * const b, const size_t len) {
396     for (size_t i = 0; i < len; ++i) {
397         unsigned int ca = ((unsigned char *)a)[i];
398         unsigned int cb = ((unsigned char *)b)[i];
399         if (ca != cb) {
400             ca |= 0x20;
401             cb |= 0x20;
402             if (ca != cb) return 0;
403             if (!light_islower(ca)) return 0;
404             if (!light_islower(cb)) return 0;
405         }
406     }
407     return 1;
408 }
409 
410 int buffer_eq_icase_ss(const char * const a, const size_t alen, const char * const b, const size_t blen) {
411     /* 1 = equal; 0 = not equal */ /* short string sizes expected (< INT_MAX) */
412     return (alen == blen && buffer_eq_icase_ssn(a, b, blen));
413 }
414 
415 int buffer_eq_icase_slen(const buffer * const b, const char * const s, const size_t slen) {
416     /* Note: b must be initialized, i.e. 0 != b->used; uninitialized is not eq*/
417     /* 1 = equal; 0 = not equal */ /* short string sizes expected (< INT_MAX) */
418     return (b->used == slen + 1 && buffer_eq_icase_ssn(b->ptr, s, slen));
419 }
420 
421 int buffer_eq_slen(const buffer * const b, const char * const s, const size_t slen) {
422     /* Note: b must be initialized, i.e. 0 != b->used; uninitialized is not eq*/
423     /* 1 = equal; 0 = not equal */ /* short string sizes expected (< INT_MAX) */
424     return (b->used == slen + 1 && 0 == memcmp(b->ptr, s, slen));
425 }
426 
427 
428 /**
429  * check if two buffer contain the same data
430  */
431 
432 int buffer_is_equal(const buffer *a, const buffer *b) {
433 	/* 1 = equal; 0 = not equal */
434 	return (a->used == b->used && 0 == memcmp(a->ptr, b->ptr, a->used));
435 }
436 
437 
438 void li_tohex_lc(char * const restrict buf, size_t buf_len, const char * const restrict s, size_t s_len) {
439 	force_assert(2 * s_len > s_len);
440 	force_assert(2 * s_len < buf_len);
441 
442 	for (size_t i = 0; i < s_len; ++i) {
443 		buf[2*i]   = hex_chars_lc[(s[i] >> 4) & 0x0F];
444 		buf[2*i+1] = hex_chars_lc[s[i] & 0x0F];
445 	}
446 	buf[2*s_len] = '\0';
447 }
448 
449 void li_tohex_uc(char * const restrict buf, size_t buf_len, const char * const restrict s, size_t s_len) {
450 	force_assert(2 * s_len > s_len);
451 	force_assert(2 * s_len < buf_len);
452 
453 	for (size_t i = 0; i < s_len; ++i) {
454 		buf[2*i]   = hex_chars_uc[(s[i] >> 4) & 0x0F];
455 		buf[2*i+1] = hex_chars_uc[s[i] & 0x0F];
456 	}
457 	buf[2*s_len] = '\0';
458 }
459 
460 
461 void buffer_substr_replace (buffer * const restrict b, const size_t offset,
462                             const size_t len, const buffer * const restrict replace)
463 {
464     const size_t blen = buffer_clen(b);
465     const size_t rlen = buffer_clen(replace);
466 
467     if (rlen > len) {
468         buffer_extend(b, blen-len+rlen);
469         memmove(b->ptr+offset+rlen, b->ptr+offset+len, blen-offset-len);
470     }
471 
472     memcpy(b->ptr+offset, replace->ptr, rlen);
473 
474     if (rlen < len) {
475         memmove(b->ptr+offset+rlen, b->ptr+offset+len, blen-offset-len);
476         buffer_truncate(b, blen-len+rlen);
477     }
478 }
479 
480 
481 void buffer_append_string_encoded_hex_lc(buffer * const restrict b, const char * const restrict s, size_t len) {
482     unsigned char * const p = (unsigned char *)buffer_extend(b, len*2);
483     for (size_t i = 0; i < len; ++i) {
484         p[(i<<1)]   = hex_chars_lc[(s[i] >> 4) & 0x0F];
485         p[(i<<1)+1] = hex_chars_lc[(s[i])      & 0x0F];
486     }
487 }
488 
489 void buffer_append_string_encoded_hex_uc(buffer * const restrict b, const char * const restrict s, size_t len) {
490     unsigned char * const p = (unsigned char *)buffer_extend(b, len*2);
491     for (size_t i = 0; i < len; ++i) {
492         p[(i<<1)]   = hex_chars_uc[(s[i] >> 4) & 0x0F];
493         p[(i<<1)+1] = hex_chars_uc[(s[i])      & 0x0F];
494     }
495 }
496 
497 
498 /* everything except: ! ( ) * - . 0-9 A-Z _ a-z */
499 static const char encoded_chars_rel_uri_part[] = {
500 	/*
501 	0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F
502 	*/
503 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  00 -  0F control chars */
504 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  10 -  1F */
505 	1, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 0, 0, 1,  /*  20 -  2F space " # $ % & ' + , / */
506 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1,  /*  30 -  3F : ; < = > ? */
507 	1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  40 -  4F @ */
508 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0,  /*  50 -  5F [ \ ] ^ */
509 	1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  60 -  6F ` */
510 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 1,  /*  70 -  7F { | } DEL */
511 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  80 -  8F */
512 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  90 -  9F */
513 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  A0 -  AF */
514 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  B0 -  BF */
515 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  C0 -  CF */
516 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  D0 -  DF */
517 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  E0 -  EF */
518 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  F0 -  FF */
519 };
520 
521 /* everything except: ! ( ) * - . / 0-9 A-Z _ a-z */
522 static const char encoded_chars_rel_uri[] = {
523 	/*
524 	0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F
525 	*/
526 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  00 -  0F control chars */
527 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  10 -  1F */
528 	1, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0,  /*  20 -  2F space " # $ % & ' + , */
529 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1,  /*  30 -  3F : ; < = > ? */
530 	1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  40 -  4F @ */
531 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0,  /*  50 -  5F [ \ ] ^ */
532 	1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  60 -  6F ` */
533 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 1,  /*  70 -  7F { | } DEL */
534 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  80 -  8F */
535 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  90 -  9F */
536 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  A0 -  AF */
537 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  B0 -  BF */
538 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  C0 -  CF */
539 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  D0 -  DF */
540 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  E0 -  EF */
541 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  F0 -  FF */
542 };
543 
544 static const char encoded_chars_html[] = {
545 	/*
546 	0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F
547 	*/
548 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  00 -  0F control chars */
549 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  10 -  1F */
550 	0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0,  /*  20 -  2F " & ' */
551 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0,  /*  30 -  3F < > */
552 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  40 -  4F */
553 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  50 -  5F */
554 	1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  60 -  6F ` */
555 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1,  /*  70 -  7F DEL */
556 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  80 -  8F */
557 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  90 -  9F */
558 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  A0 -  AF */
559 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  B0 -  BF */
560 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  C0 -  CF */
561 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  D0 -  DF */
562 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  E0 -  EF */
563 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  F0 -  FF */
564 };
565 
566 static const char encoded_chars_minimal_xml[] = {
567 	/*
568 	0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F
569 	*/
570 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  00 -  0F control chars */
571 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  10 -  1F */
572 	0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0,  /*  20 -  2F " & ' */
573 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0,  /*  30 -  3F < > */
574 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  40 -  4F */
575 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  50 -  5F */
576 	1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  60 -  6F ` */
577 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1,  /*  70 -  7F DEL */
578 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  80 -  8F */
579 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  90 -  9F */
580 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  A0 -  AF */
581 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  B0 -  BF */
582 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  C0 -  CF */
583 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  D0 -  DF */
584 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  E0 -  EF */
585 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  F0 -  FF */
586 };
587 
588 
589 
590 void buffer_append_string_encoded(buffer * const restrict b, const char * const restrict s, size_t s_len, buffer_encoding_t encoding) {
591 	unsigned char *ds, *d;
592 	size_t d_len, ndx;
593 	const char *map = NULL;
594 
595 	if (0 == s_len) return;
596 
597 	force_assert(NULL != s);
598 
599 	switch(encoding) {
600 	case ENCODING_REL_URI:
601 		map = encoded_chars_rel_uri;
602 		break;
603 	case ENCODING_REL_URI_PART:
604 		map = encoded_chars_rel_uri_part;
605 		break;
606 	case ENCODING_HTML:
607 		map = encoded_chars_html;
608 		break;
609 	case ENCODING_MINIMAL_XML:
610 		map = encoded_chars_minimal_xml;
611 		break;
612 	}
613 
614 	force_assert(NULL != map);
615 
616 	/* count to-be-encoded-characters */
617 	for (ds = (unsigned char *)s, d_len = 0, ndx = 0; ndx < s_len; ds++, ndx++) {
618 		if (map[*ds & 0xFF]) {
619 			switch(encoding) {
620 			case ENCODING_REL_URI:
621 			case ENCODING_REL_URI_PART:
622 				d_len += 3;
623 				break;
624 			case ENCODING_HTML:
625 			case ENCODING_MINIMAL_XML:
626 				d_len += 6;
627 				break;
628 			}
629 		} else {
630 			d_len++;
631 		}
632 	}
633 
634 	d = (unsigned char*) buffer_extend(b, d_len);
635 
636 	if (d_len == s_len) { /*(short-circuit; nothing to encoded)*/
637 		memcpy(d, s, s_len);
638 		return;
639 	}
640 
641 	for (ds = (unsigned char *)s, d_len = 0, ndx = 0; ndx < s_len; ds++, ndx++) {
642 		if (map[*ds & 0xFF]) {
643 			switch(encoding) {
644 			case ENCODING_REL_URI:
645 			case ENCODING_REL_URI_PART:
646 				d[d_len++] = '%';
647 				d[d_len++] = hex_chars_uc[((*ds) >> 4) & 0x0F];
648 				d[d_len++] = hex_chars_uc[(*ds) & 0x0F];
649 				break;
650 			case ENCODING_HTML:
651 			case ENCODING_MINIMAL_XML:
652 				d[d_len++] = '&';
653 				d[d_len++] = '#';
654 				d[d_len++] = 'x';
655 				d[d_len++] = hex_chars_uc[((*ds) >> 4) & 0x0F];
656 				d[d_len++] = hex_chars_uc[(*ds) & 0x0F];
657 				d[d_len++] = ';';
658 				break;
659 			}
660 		} else {
661 			d[d_len++] = *ds;
662 		}
663 	}
664 }
665 
666 void buffer_append_string_c_escaped(buffer * const restrict b, const char * const restrict s, size_t s_len) {
667 	unsigned char *ds, *d;
668 	size_t d_len, ndx;
669 
670 	if (0 == s_len) return;
671 
672 	/* count to-be-encoded-characters */
673 	for (ds = (unsigned char *)s, d_len = 0, ndx = 0; ndx < s_len; ds++, ndx++) {
674 		if ((*ds < 0x20) /* control character */
675 				|| (*ds >= 0x7f)) { /* DEL + non-ASCII characters */
676 			switch (*ds) {
677 			case '\t':
678 			case '\r':
679 			case '\n':
680 				d_len += 2;
681 				break;
682 			default:
683 				d_len += 4; /* \xCC */
684 				break;
685 			}
686 		} else {
687 			d_len++;
688 		}
689 	}
690 
691 	d = (unsigned char*) buffer_extend(b, d_len);
692 
693 	if (d_len == s_len) { /*(short-circuit; nothing to encoded)*/
694 		memcpy(d, s, s_len);
695 		return;
696 	}
697 
698 	for (ds = (unsigned char *)s, d_len = 0, ndx = 0; ndx < s_len; ds++, ndx++) {
699 		if ((*ds < 0x20) /* control character */
700 				|| (*ds >= 0x7f)) { /* DEL + non-ASCII characters */
701 			d[d_len++] = '\\';
702 			switch (*ds) {
703 			case '\t':
704 				d[d_len++] = 't';
705 				break;
706 			case '\r':
707 				d[d_len++] = 'r';
708 				break;
709 			case '\n':
710 				d[d_len++] = 'n';
711 				break;
712 			default:
713 				d[d_len++] = 'x';
714 				d[d_len++] = hex_chars_lc[((*ds) >> 4) & 0x0F];
715 				d[d_len++] = hex_chars_lc[(*ds) & 0x0F];
716 				break;
717 			}
718 		} else {
719 			d[d_len++] = *ds;
720 		}
721 	}
722 }
723 
724 
725 /* decodes url-special-chars inplace.
726  * replaces non-printable characters with '_'
727  * (If this is used on a portion of query string, then query string should be
728  *  split on '&', and '+' replaced with ' ' before calling this routine)
729  */
730 
731 void buffer_urldecode_path(buffer * const b) {
732     const size_t len = buffer_clen(b);
733     char *src = len ? memchr(b->ptr, '%', len) : NULL;
734     if (NULL == src) return;
735 
736     char *dst = src;
737     do {
738         /* *src == '%' */
739         unsigned char high = hex2int(*(src + 1));
740         unsigned char low = hex2int(*(src + 2));
741         if (0xFF != high && 0xFF != low) {
742             high = (high << 4) | low;   /* map ctrls to '_' */
743             *dst = (high >= 32 && high != 127) ? high : '_';
744             src += 2;
745         } /* else ignore this '%'; leave as-is and move on */
746 
747         while ((*++dst = *++src) != '%' && *src) ;
748     } while (*src);
749     b->used = (dst - b->ptr) + 1;
750 }
751 
752 int buffer_is_valid_UTF8(const buffer *b) {
753     /* https://www.w3.org/International/questions/qa-forms-utf-8 */
754     const unsigned char *c = (unsigned char *)b->ptr;
755     while (*c) {
756 
757         /*(note: includes ctrls)*/
758         if (                         c[0] <  0x80 ) { ++c;  continue; }
759 
760         if (         0xc2 <= c[0] && c[0] <= 0xdf
761             &&       0x80 <= c[1] && c[1] <= 0xbf ) { c+=2; continue; }
762 
763         if ( (   (   0xe0 == c[0]
764                   && 0xa0 <= c[1] && c[1] <= 0xbf)
765               || (   0xe1 <= c[0] && c[0] <= 0xef && c[0] != 0xed
766                   && 0x80 <= c[1] && c[1] <= 0xbf)
767               || (   0xed == c[0]
768                   && 0x80 <= c[1] && c[1] <= 0x9f)   )
769             &&       0x80 <= c[2] && c[2] <= 0xbf ) { c+=3; continue; }
770 
771         if ( (   (   0xf0 == c[0]
772                   && 0x90 <= c[1] && c[1] <= 0xbf)
773               || (   0xf1 <= c[0] && c[0] <= 0xf3
774                   && 0x80 <= c[1] && c[1] <= 0xbf)
775               || (   0xf4 == c[0]
776                   && 0x80 <= c[1] && c[1] <= 0x8f)   )
777             &&       0x80 <= c[2] && c[2] <= 0xbf
778             &&       0x80 <= c[3] && c[3] <= 0xbf ) { c+=4; continue; }
779 
780         return 0; /* invalid */
781     }
782     return 1; /* valid */
783 }
784 
785 /* - special case: empty string returns empty string
786  * - on windows or cygwin: replace \ with /
787  * - strip leading spaces
788  * - prepends "/" if not present already
789  * - resolve "/../", "//" and "/./" the usual way:
790  *   the first one removes a preceding component, the other two
791  *   get compressed to "/".
792  * - "/." and "/.." at the end are similar, but always leave a trailing
793  *   "/"
794  *
795  * /blah/..         gets  /
796  * /blah/../foo     gets  /foo
797  * /abc/./xyz       gets  /abc/xyz
798  * /abc//xyz        gets  /abc/xyz
799  */
800 
801 void buffer_path_simplify(buffer *b)
802 {
803     char *out = b->ptr;
804     char * const end = b->ptr + b->used - 1;
805 
806     if (__builtin_expect( (buffer_is_blank(b)), 0)) {
807         buffer_blank(b);
808         return;
809     }
810 
811   #if defined(__WIN32) || defined(__CYGWIN__)
812     /* cygwin is treating \ and / the same, so we have to that too */
813     for (char *p = b->ptr; *p; p++) {
814         if (*p == '\\') *p = '/';
815     }
816   #endif
817 
818     *end = '/'; /*(end of path modified to avoid need to check '\0')*/
819 
820     char *walk = out;
821     if (__builtin_expect( (*walk == '/'), 1)) {
822         /* scan to detect (potential) need for path simplification
823          * (repeated '/' or "/.") */
824         do {
825             if (*++walk == '.' || *walk == '/')
826                 break;
827             do { ++walk; } while (*walk != '/');
828         } while (walk != end);
829         if (__builtin_expect( (walk == end), 1)) {
830             /* common case: no repeated '/' or "/." */
831             *end = '\0'; /* overwrite extra '/' added to end of path */
832             return;
833         }
834         out = walk-1;
835     }
836     else {
837         if (walk[0] == '.' && walk[1] == '/')
838             *out = *++walk;
839         else if (walk[0] == '.' && walk[1] == '.' && walk[2] == '/')
840             *out = *(walk += 2);
841         else {
842             while (*++walk != '/') ;
843             out = walk;
844         }
845         ++walk;
846     }
847 
848     while (walk <= end) {
849         /* previous char is '/' at this point (or start of string w/o '/') */
850         if (__builtin_expect( (walk[0] == '/'), 0)) {
851             /* skip repeated '/' (e.g. "///" -> "/") */
852             if (++walk < end)
853                 continue;
854             else {
855                 ++out;
856                 break;
857             }
858         }
859         else if (__builtin_expect( (walk[0] == '.'), 0)) {
860             /* handle "./" and "../" */
861             if (walk[1] == '.' && walk[2] == '/') {
862                 /* handle "../" */
863                 while (out > b->ptr && *--out != '/') ;
864                 *out = '/'; /*(in case path had not started with '/')*/
865                 if ((walk += 3) >= end) {
866                     ++out;
867                     break;
868                 }
869                 else
870                 continue;
871             }
872             else if (walk[1] == '/') {
873                 /* handle "./" */
874                 if ((walk += 2) >= end) {
875                     ++out;
876                     break;
877                 }
878                 continue;
879             }
880             else {
881                 /* accept "." if not part of "../" or "./" */
882                 *++out = '.';
883                 ++walk;
884             }
885         }
886 
887         while ((*++out = *walk++) != '/') ;
888     }
889     *out = *end = '\0'; /* overwrite extra '/' added to end of path */
890     b->used = (out - b->ptr) + 1;
891     /*buffer_truncate(b, out - b->ptr);*/
892 }
893 
894 void buffer_to_lower(buffer * const b) {
895     unsigned char * const restrict s = (unsigned char *)b->ptr;
896     for (uint32_t i = 0; i < b->used; ++i) {
897         if (light_isupper(s[i])) s[i] |= 0x20;
898     }
899 }
900 
901 
902 void buffer_to_upper(buffer * const b) {
903     unsigned char * const restrict s = (unsigned char *)b->ptr;
904     for (uint32_t i = 0; i < b->used; ++i) {
905         if (light_islower(s[i])) s[i] &= 0xdf;
906     }
907 }
908 
909 
910 #include <stdio.h>
911 
912 #ifdef HAVE_LIBUNWIND
913 # define UNW_LOCAL_ONLY
914 # include <libunwind.h>
915 
916 static void print_backtrace(FILE *file) {
917 	unw_cursor_t cursor;
918 	unw_context_t context;
919 	int ret;
920 	unsigned int frame = 0;
921 
922 	if (0 != (ret = unw_getcontext(&context))) goto error;
923 	if (0 != (ret = unw_init_local(&cursor, &context))) goto error;
924 
925 	fprintf(file, "Backtrace:\n");
926 
927 	while (0 < (ret = unw_step(&cursor))) {
928 		unw_word_t proc_ip = 0;
929 		unw_proc_info_t procinfo;
930 		char procname[256];
931 		unw_word_t proc_offset = 0;
932 
933 		if (0 != (ret = unw_get_reg(&cursor, UNW_REG_IP, &proc_ip))) goto error;
934 
935 		if (0 == proc_ip) {
936 			/* without an IP the other functions are useless; unw_get_proc_name would return UNW_EUNSPEC */
937 			++frame;
938 			fprintf(file, "%u: (nil)\n", frame);
939 			continue;
940 		}
941 
942 		if (0 != (ret = unw_get_proc_info(&cursor, &procinfo))) goto error;
943 
944 		if (0 != (ret = unw_get_proc_name(&cursor, procname, sizeof(procname), &proc_offset))) {
945 			switch (-ret) {
946 			case UNW_ENOMEM:
947 				memset(procname + sizeof(procname) - 4, '.', 3);
948 				procname[sizeof(procname) - 1] = '\0';
949 				break;
950 			case UNW_ENOINFO:
951 				procname[0] = '?';
952 				procname[1] = '\0';
953 				proc_offset = 0;
954 				break;
955 			default:
956 				snprintf(procname, sizeof(procname), "?? (unw_get_proc_name error %d)", -ret);
957 				break;
958 			}
959 		}
960 
961 		++frame;
962 		fprintf(file, "%u: %s (+0x%x) [%p]\n",
963 			frame,
964 			procname,
965 			(unsigned int) proc_offset,
966 			(void*)(uintptr_t)proc_ip);
967 	}
968 
969 	if (0 != ret) goto error;
970 
971 	return;
972 
973 error:
974 	fprintf(file, "Error while generating backtrace: unwind error %i\n", (int) -ret);
975 }
976 #else
977 static void print_backtrace(FILE *file) {
978 	UNUSED(file);
979 }
980 #endif
981 
982 void log_failed_assert(const char *filename, unsigned int line, const char *msg) {
983 	/* can't use buffer here; could lead to recursive assertions */
984 	fprintf(stderr, "%s.%u: %s\n", filename, line, msg);
985 	print_backtrace(stderr);
986 	fflush(stderr);
987 	abort();
988 }
989