xref: /lighttpd1.4/src/buffer.c (revision bade1c03)
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 __attribute_noinline__
14 buffer* buffer_init(void) {
15 	buffer * const b = calloc(1, sizeof(*b));
16 	force_assert(b);
17 	return b;
18 }
19 
20 buffer *buffer_init_buffer(const buffer *src) {
21 	buffer * const b = buffer_init();
22 	buffer_copy_string_len(b, BUF_PTR_LEN(src));
23 	return b;
24 }
25 
26 void buffer_free(buffer *b) {
27 	if (NULL == b) return;
28 
29 	free(b->ptr);
30 	free(b);
31 }
32 
33 void buffer_free_ptr(buffer *b) {
34 	free(b->ptr);
35 	b->ptr = NULL;
36 	b->used = 0;
37 	b->size = 0;
38 }
39 
40 void buffer_move(buffer * restrict b, buffer * restrict src) {
41 	buffer tmp;
42 	buffer_clear(b);
43 	tmp = *src; *src = *b; *b = tmp;
44 }
45 
46 /* make sure buffer is at least "size" big + 1 for '\0'. keep old data */
47 __attribute_cold__
48 __attribute_noinline__
49 __attribute_nonnull__()
50 __attribute_returns_nonnull__
51 static char* buffer_realloc(buffer * const restrict b, const size_t len) {
52     #define BUFFER_PIECE_SIZE 64uL  /*(must be power-of-2)*/
53     size_t sz = (len + 1 + BUFFER_PIECE_SIZE-1) & ~(BUFFER_PIECE_SIZE-1);
54     force_assert(sz > len);
55     if ((sz & (sz-1)) && sz < INT_MAX) {/* not power-2; huge val not expected */
56         /*(optimizer should recognize this and use ffs or clz or equivalent)*/
57         const size_t psz = sz;
58         for (sz = 256; sz < psz; sz <<= 1) ;
59     }
60     sz |= 1; /*(extra +1 for '\0' when needed buffer size is exact power-2)*/
61 
62     b->size = sz;
63     b->ptr = realloc(b->ptr, sz);
64 
65     force_assert(NULL != b->ptr);
66     return b->ptr;
67 }
68 
69 __attribute_cold__
70 __attribute_noinline__
71 __attribute_nonnull__()
72 __attribute_returns_nonnull__
73 static char* buffer_alloc_replace(buffer * const restrict b, const size_t size) {
74     /*(discard old data so realloc() does not copy)*/
75     if (NULL != b->ptr) {
76         free(b->ptr);
77         b->ptr = NULL;
78     }
79     /*(note: if size larger than one lshift, use size instead of power-2)*/
80     const size_t bsize2x = (b->size & ~1uL) << 1;
81     return buffer_realloc(b, bsize2x > size ? bsize2x-1 : size);
82 }
83 
84 char* buffer_string_prepare_copy(buffer * const b, const size_t size) {
85     b->used = 0;
86   #ifdef __COVERITY__ /*(b->ptr is not NULL if b->size is not 0)*/
87     force_assert(size >= b->size || b->ptr);
88   #endif
89     return (size < b->size)
90       ? b->ptr
91       : buffer_alloc_replace(b, size);
92 }
93 
94 __attribute_cold__
95 __attribute_noinline__
96 __attribute_nonnull__()
97 __attribute_returns_nonnull__
98 static char* buffer_string_prepare_append_resize(buffer * const restrict b, const size_t size) {
99     if (b->used < 2) {  /* buffer_is_blank(b) */
100         char * const s = buffer_string_prepare_copy(b, size);
101         *s = '\0'; /*(for case (1 == b->used))*/
102         return s;
103     }
104 
105     /* not empty, b->used already includes a terminating 0 */
106     /*(note: if size larger than one lshift, use size instead of power-2)*/
107     const size_t bsize2x = (b->size & ~1uL) << 1;
108     const size_t req_size = (bsize2x - b->used > size)
109       ? bsize2x-1
110       : b->used + size;
111 
112     /* check for overflow: unsigned overflow is defined to wrap around */
113     force_assert(req_size >= b->used);
114 
115     return buffer_realloc(b, req_size) + b->used - 1;
116 }
117 
118 char* buffer_string_prepare_append(buffer * const b, const size_t size) {
119     const uint32_t len = b->used ? b->used-1 : 0;
120     return (b->size - len >= size + 1)
121       ? b->ptr + len
122       : buffer_string_prepare_append_resize(b, size);
123 }
124 
125 /*(prefer smaller code than inlining buffer_extend in many places in buffer.c)*/
126 __attribute_noinline__
127 char*
128 buffer_extend (buffer * const b, const size_t x)
129 {
130     /* extend buffer to append x (reallocate by power-2 (or larger), if needed)
131      * (combine buffer_string_prepare_append() and buffer_commit())
132      * (future: might make buffer.h static inline func for HTTP/1.1 performance)
133      * pre-sets '\0' byte and b->used (unlike buffer_string_prepare_append())*/
134   #if 0
135     char * const s = buffer_string_prepare_append(b, x);
136     b->used += x + (0 == b->used);
137   #else
138     const uint32_t len = b->used ? b->used-1 : 0;
139     char * const s = (b->size - len >= x + 1)
140       ? b->ptr + len
141       : buffer_string_prepare_append_resize(b, x);
142     b->used = len+x+1;
143   #endif
144     s[x] = '\0';
145     return s;
146 }
147 
148 void buffer_commit(buffer *b, size_t size)
149 {
150 	size_t sz = b->used;
151 	if (0 == sz) sz = 1;
152 
153 	if (size > 0) {
154 		/* check for overflow: unsigned overflow is defined to wrap around */
155 		sz += size;
156 		force_assert(sz > size);
157 	}
158 
159 	b->used = sz;
160 	b->ptr[sz - 1] = '\0';
161 }
162 
163 __attribute_cold__ /*(reduce code size due to inlining)*/
164 void buffer_copy_string(buffer * restrict b, const char * restrict s) {
165     if (__builtin_expect( (NULL == s), 0)) s = "";
166     buffer_copy_string_len(b, s, strlen(s));
167 }
168 
169 void buffer_copy_string_len(buffer * const restrict b, const char * const restrict s, const size_t len) {
170     b->used = len + 1;
171     char * const restrict d = (len < b->size)
172       ? b->ptr
173       : buffer_alloc_replace(b, len);
174     d[len] = '\0';
175     memcpy(d, s, len);
176 }
177 
178 __attribute_cold__ /*(reduce code size due to inlining)*/
179 void buffer_append_string(buffer * restrict b, const char * restrict s) {
180     if (__builtin_expect( (NULL == s), 0)) s = "";
181     buffer_append_string_len(b, s, strlen(s));
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
268 buffer_copy_string_len_lc (buffer * const restrict b, const char * const restrict s, const size_t len)
269 {
270     char * const restrict d = buffer_string_prepare_copy(b, len);
271     b->used = len+1;
272     d[len] = '\0';
273     for (size_t i = 0; i < len; ++i)
274         d[i] = (!light_isupper(s[i])) ? s[i] : s[i] | 0x20;
275 }
276 
277 void buffer_append_uint_hex_lc(buffer *b, uintmax_t value) {
278 	char *buf;
279 	unsigned int shift = 0;
280 
281 	{
282 		uintmax_t copy = value;
283 		do {
284 			copy >>= 8;
285 			shift += 8; /* counting bits */
286 		} while (0 != copy);
287 	}
288 
289 	buf = buffer_extend(b, shift >> 2); /*nibbles (4 bits)*/
290 
291 	while (shift > 0) {
292 		shift -= 4;
293 		*(buf++) = hex_chars_lc[(value >> shift) & 0x0F];
294 	}
295 }
296 
297 __attribute_nonnull__()
298 __attribute_returns_nonnull__
299 static char* utostr(char buf[LI_ITOSTRING_LENGTH], uintmax_t val) {
300 	char *cur = buf+LI_ITOSTRING_LENGTH;
301 	uintmax_t x;
302 	do {
303 		*(--cur) = (char) ('0' + (int)(val - (x = val/10) * 10));
304 	} while (0 != (val = x));           /* val % 10 */
305 	return cur;
306 }
307 
308 __attribute_nonnull__()
309 __attribute_returns_nonnull__
310 static char* itostr(char buf[LI_ITOSTRING_LENGTH], intmax_t val) {
311 	/* absolute value not defined for INTMAX_MIN, but can take absolute
312 	 * value of any negative number via twos complement cast to unsigned.
313 	 * negative sign is prepended after (now unsigned) value is converted
314 	 * to string */
315 	uintmax_t uval = val >= 0 ? (uintmax_t)val : ((uintmax_t)~val) + 1;
316 	char *cur = utostr(buf, uval);
317 	if (val < 0) *(--cur) = '-';
318 
319 	return cur;
320 }
321 
322 void buffer_append_int(buffer *b, intmax_t val) {
323 	char buf[LI_ITOSTRING_LENGTH];
324 	const char * const str = itostr(buf, val);
325 	buffer_append_string_len(b, str, buf+sizeof(buf) - str);
326 }
327 
328 void buffer_append_strftime(buffer * const restrict b, const char * const restrict format, const struct tm * const restrict tm) {
329     /*(localtime_r() or gmtime_r() producing tm should not have failed)*/
330     if (__builtin_expect( (NULL == tm), 0)) return;
331 
332     /*(expecting typical format strings to result in < 64 bytes needed;
333      * skipping buffer_string_space() calculation and providing fixed size)*/
334     size_t rv = strftime(buffer_string_prepare_append(b, 63), 64, format, tm);
335 
336     /* 0 (in some apis) signals the string may have been too small;
337      * but the format could also just have lead to an empty string */
338     if (__builtin_expect( (0 == rv), 0) || __builtin_expect( (rv > 63), 0)) {
339         /* unexpected; give it a second try with a larger string */
340         rv = strftime(buffer_string_prepare_append(b, 4095), 4096, format, tm);
341         if (__builtin_expect( (rv > 4095), 0))/*(input format was ridiculous)*/
342             return;
343     }
344 
345     /*buffer_commit(b, rv);*/
346     b->used += (uint32_t)rv + (0 == b->used);
347 }
348 
349 
350 size_t li_itostrn(char *buf, size_t buf_len, intmax_t val) {
351 	char p_buf[LI_ITOSTRING_LENGTH];
352 	char* const str = itostr(p_buf, val);
353 	size_t len = (size_t)(p_buf+sizeof(p_buf)-str);
354 	force_assert(len <= buf_len);
355 	memcpy(buf, str, len);
356 	return len;
357 }
358 
359 size_t li_utostrn(char *buf, size_t buf_len, uintmax_t val) {
360 	char p_buf[LI_ITOSTRING_LENGTH];
361 	char* const str = utostr(p_buf, val);
362 	size_t len = (size_t)(p_buf+sizeof(p_buf)-str);
363 	force_assert(len <= buf_len);
364 	memcpy(buf, str, len);
365 	return len;
366 }
367 
368 #define li_ntox_lc(n) ((n) <= 9 ? (n) + '0' : (n) + 'a' - 10)
369 
370 /* c (char) and n (nibble) MUST be unsigned integer types */
371 #define li_cton(c,n) \
372   (((n) = (c) - '0') <= 9 || (((n) = ((c)&0xdf) - 'A') <= 5 ? ((n) += 10) : 0))
373 
374 /* converts hex char (0-9, A-Z, a-z) to decimal.
375  * returns 0xFF on invalid input.
376  */
377 char hex2int(unsigned char hex) {
378 	unsigned char n;
379 	return li_cton(hex,n) ? (char)n : 0xFF;
380 }
381 
382 int li_hex2bin (unsigned char * const bin, const size_t binlen, const char * const hexstr, const size_t len)
383 {
384     /* validate and transform 32-byte MD5 hex string to 16-byte binary MD5,
385      * or 64-byte SHA-256 or SHA-512-256 hex string to 32-byte binary digest */
386     if (len > (binlen << 1)) return -1;
387     for (int i = 0, ilen = (int)len; i < ilen; i+=2) {
388         int hi = hexstr[i];
389         int lo = hexstr[i+1];
390         if ('0' <= hi && hi <= '9')                    hi -= '0';
391         else if ((uint32_t)(hi |= 0x20)-'a' <= 'f'-'a')hi += -'a' + 10;
392         else                                           return -1;
393         if ('0' <= lo && lo <= '9')                    lo -= '0';
394         else if ((uint32_t)(lo |= 0x20)-'a' <= 'f'-'a')lo += -'a' + 10;
395         else                                           return -1;
396         bin[(i >> 1)] = (unsigned char)((hi << 4) | lo);
397     }
398     return 0;
399 }
400 
401 
402 __attribute_noinline__
403 int buffer_eq_icase_ssn(const char * const a, const char * const b, const size_t len) {
404     for (size_t i = 0; i < len; ++i) {
405         unsigned int ca = ((unsigned char *)a)[i];
406         unsigned int cb = ((unsigned char *)b)[i];
407         if (ca != cb) {
408             ca |= 0x20;
409             cb |= 0x20;
410             if (ca != cb) return 0;
411             if (!light_islower(ca)) return 0;
412             if (!light_islower(cb)) return 0;
413         }
414     }
415     return 1;
416 }
417 
418 int buffer_eq_icase_ss(const char * const a, const size_t alen, const char * const b, const size_t blen) {
419     /* 1 = equal; 0 = not equal */ /* short string sizes expected (< INT_MAX) */
420     return (alen == blen) ? buffer_eq_icase_ssn(a, b, blen) : 0;
421 }
422 
423 int buffer_eq_icase_slen(const buffer * const b, const char * const s, const size_t slen) {
424     /* Note: b must be initialized, i.e. 0 != b->used; uninitialized is not eq*/
425     /* 1 = equal; 0 = not equal */ /* short string sizes expected (< INT_MAX) */
426     return (b->used == slen + 1) ? buffer_eq_icase_ssn(b->ptr, s, slen) : 0;
427 }
428 
429 int buffer_eq_slen(const buffer * const b, const char * const s, const size_t slen) {
430     /* Note: b must be initialized, i.e. 0 != b->used; uninitialized is not eq*/
431     /* 1 = equal; 0 = not equal */ /* short string sizes expected (< INT_MAX) */
432     return (b->used == slen + 1 && 0 == memcmp(b->ptr, s, slen));
433 }
434 
435 
436 /**
437  * check if two buffer contain the same data
438  */
439 
440 int buffer_is_equal(const buffer *a, const buffer *b) {
441 	/* 1 = equal; 0 = not equal */
442 	return (a->used == b->used && 0 == memcmp(a->ptr, b->ptr, a->used));
443 }
444 
445 
446 void li_tohex_lc(char * const restrict buf, size_t buf_len, const char * const restrict s, size_t s_len) {
447 	force_assert(2 * s_len > s_len);
448 	force_assert(2 * s_len < buf_len);
449 
450 	for (size_t i = 0; i < s_len; ++i) {
451 		buf[2*i]   = hex_chars_lc[(s[i] >> 4) & 0x0F];
452 		buf[2*i+1] = hex_chars_lc[s[i] & 0x0F];
453 	}
454 	buf[2*s_len] = '\0';
455 }
456 
457 void li_tohex_uc(char * const restrict buf, size_t buf_len, const char * const restrict s, size_t s_len) {
458 	force_assert(2 * s_len > s_len);
459 	force_assert(2 * s_len < buf_len);
460 
461 	for (size_t i = 0; i < s_len; ++i) {
462 		buf[2*i]   = hex_chars_uc[(s[i] >> 4) & 0x0F];
463 		buf[2*i+1] = hex_chars_uc[s[i] & 0x0F];
464 	}
465 	buf[2*s_len] = '\0';
466 }
467 
468 
469 void buffer_substr_replace (buffer * const restrict b, const size_t offset,
470                             const size_t len, const buffer * const restrict replace)
471 {
472     const size_t blen = buffer_clen(b);
473     const size_t rlen = buffer_clen(replace);
474 
475     if (rlen > len) {
476         buffer_extend(b, blen-len+rlen);
477         memmove(b->ptr+offset+rlen, b->ptr+offset+len, blen-offset-len);
478     }
479 
480     memcpy(b->ptr+offset, replace->ptr, rlen);
481 
482     if (rlen < len) {
483         memmove(b->ptr+offset+rlen, b->ptr+offset+len, blen-offset-len);
484         buffer_truncate(b, blen-len+rlen);
485     }
486 }
487 
488 
489 void buffer_append_string_encoded_hex_lc(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_lc[(s[i] >> 4) & 0x0F];
493         p[(i<<1)+1] = hex_chars_lc[(s[i])      & 0x0F];
494     }
495 }
496 
497 void buffer_append_string_encoded_hex_uc(buffer * const restrict b, const char * const restrict s, size_t len) {
498     unsigned char * const p = (unsigned char *)buffer_extend(b, len*2);
499     for (size_t i = 0; i < len; ++i) {
500         p[(i<<1)]   = hex_chars_uc[(s[i] >> 4) & 0x0F];
501         p[(i<<1)+1] = hex_chars_uc[(s[i])      & 0x0F];
502     }
503 }
504 
505 
506 /* everything except: ! ( ) * - . 0-9 A-Z _ a-z */
507 static const char encoded_chars_rel_uri_part[] = {
508 	/*
509 	0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F
510 	*/
511 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  00 -  0F control chars */
512 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  10 -  1F */
513 	1, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 0, 0, 1,  /*  20 -  2F space " # $ % & ' + , / */
514 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1,  /*  30 -  3F : ; < = > ? */
515 	1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  40 -  4F @ */
516 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0,  /*  50 -  5F [ \ ] ^ */
517 	1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  60 -  6F ` */
518 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 1,  /*  70 -  7F { | } DEL */
519 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  80 -  8F */
520 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  90 -  9F */
521 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  A0 -  AF */
522 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  B0 -  BF */
523 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  C0 -  CF */
524 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  D0 -  DF */
525 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  E0 -  EF */
526 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  F0 -  FF */
527 };
528 
529 /* everything except: ! ( ) * - . / 0-9 A-Z _ a-z */
530 static const char encoded_chars_rel_uri[] = {
531 	/*
532 	0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F
533 	*/
534 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  00 -  0F control chars */
535 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  10 -  1F */
536 	1, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0,  /*  20 -  2F space " # $ % & ' + , */
537 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1,  /*  30 -  3F : ; < = > ? */
538 	1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  40 -  4F @ */
539 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0,  /*  50 -  5F [ \ ] ^ */
540 	1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  60 -  6F ` */
541 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 1,  /*  70 -  7F { | } DEL */
542 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  80 -  8F */
543 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  90 -  9F */
544 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  A0 -  AF */
545 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  B0 -  BF */
546 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  C0 -  CF */
547 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  D0 -  DF */
548 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  E0 -  EF */
549 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  F0 -  FF */
550 };
551 
552 static const char encoded_chars_html[] = {
553 	/*
554 	0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F
555 	*/
556 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  00 -  0F control chars */
557 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  10 -  1F */
558 	0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0,  /*  20 -  2F " & ' */
559 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0,  /*  30 -  3F < > */
560 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  40 -  4F */
561 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  50 -  5F */
562 	1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  60 -  6F ` */
563 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1,  /*  70 -  7F DEL */
564 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  80 -  8F */
565 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  90 -  9F */
566 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  A0 -  AF */
567 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  B0 -  BF */
568 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  C0 -  CF */
569 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  D0 -  DF */
570 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  E0 -  EF */
571 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  F0 -  FF */
572 };
573 
574 static const char encoded_chars_minimal_xml[] = {
575 	/*
576 	0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F
577 	*/
578 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  00 -  0F control chars */
579 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  10 -  1F */
580 	0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0,  /*  20 -  2F " & ' */
581 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0,  /*  30 -  3F < > */
582 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  40 -  4F */
583 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  50 -  5F */
584 	1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  60 -  6F ` */
585 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1,  /*  70 -  7F DEL */
586 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  80 -  8F */
587 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  90 -  9F */
588 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  A0 -  AF */
589 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  B0 -  BF */
590 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  C0 -  CF */
591 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  D0 -  DF */
592 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  E0 -  EF */
593 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  F0 -  FF */
594 };
595 
596 
597 
598 void buffer_append_string_encoded(buffer * const restrict b, const char * const restrict s, size_t s_len, buffer_encoding_t encoding) {
599 	unsigned char *ds, *d;
600 	size_t d_len, ndx;
601 	const char *map = NULL;
602 
603 	switch(encoding) {
604 	case ENCODING_REL_URI:
605 		map = encoded_chars_rel_uri;
606 		break;
607 	case ENCODING_REL_URI_PART:
608 		map = encoded_chars_rel_uri_part;
609 		break;
610 	case ENCODING_HTML:
611 		map = encoded_chars_html;
612 		break;
613 	case ENCODING_MINIMAL_XML:
614 		map = encoded_chars_minimal_xml;
615 		break;
616 	}
617 
618 	/* count to-be-encoded-characters */
619 	for (ds = (unsigned char *)s, d_len = 0, ndx = 0; ndx < s_len; ds++, ndx++) {
620 		if (map[*ds & 0xFF]) {
621 			switch(encoding) {
622 			case ENCODING_REL_URI:
623 			case ENCODING_REL_URI_PART:
624 				d_len += 3;
625 				break;
626 			case ENCODING_HTML:
627 			case ENCODING_MINIMAL_XML:
628 				d_len += 6;
629 				break;
630 			}
631 		} else {
632 			d_len++;
633 		}
634 	}
635 
636 	d = (unsigned char*) buffer_extend(b, d_len);
637 
638 	if (d_len == s_len) { /*(short-circuit; nothing to encoded)*/
639 		memcpy(d, s, s_len);
640 		return;
641 	}
642 
643 	for (ds = (unsigned char *)s, d_len = 0, ndx = 0; ndx < s_len; ds++, ndx++) {
644 		if (map[*ds & 0xFF]) {
645 			switch(encoding) {
646 			case ENCODING_REL_URI:
647 			case ENCODING_REL_URI_PART:
648 				d[d_len++] = '%';
649 				d[d_len++] = hex_chars_uc[((*ds) >> 4) & 0x0F];
650 				d[d_len++] = hex_chars_uc[(*ds) & 0x0F];
651 				break;
652 			case ENCODING_HTML:
653 			case ENCODING_MINIMAL_XML:
654 				d[d_len++] = '&';
655 				d[d_len++] = '#';
656 				d[d_len++] = 'x';
657 				d[d_len++] = hex_chars_uc[((*ds) >> 4) & 0x0F];
658 				d[d_len++] = hex_chars_uc[(*ds) & 0x0F];
659 				d[d_len++] = ';';
660 				break;
661 			}
662 		} else {
663 			d[d_len++] = *ds;
664 		}
665 	}
666 }
667 
668 void buffer_append_string_encoded_json(buffer * const restrict b, const char * const restrict s, const size_t len) {
669 	const unsigned char * const restrict ds = (unsigned char *)s;
670 	size_t dlen = 0;
671 
672 	/* calculate space needed for string including encodings */
673 	for (size_t i = 0; i < len; ++i) {
674 		int c = ds[i];
675 		if (c == '"' || c == '\\' || c < 0x20 || c == 0x7f) {
676 			switch (c) {
677 			  case '\b':
678 			  case '\t':
679 			  case '\n':
680 			  case '\f':
681 			  case '\r':
682 			  case '"':
683 			  case '\\':
684 				dlen += 2;
685 				break;
686 			  default:
687 				dlen += 6; /* \uCCCC */
688 				break;
689 			}
690 		}
691 		else {
692 			++dlen;
693 		}
694 	}
695 
696 	unsigned char * const d = (unsigned char *)buffer_extend(b, dlen);
697 
698 	if (__builtin_expect( (dlen == len), 1)) {/*(short-circuit; nothing to encode)*/
699 		memcpy(d, ds, len);
700 		return;
701 	}
702 
703 	dlen = 0;
704 	for (size_t i = 0; i < len; ++i) {
705 		int c = ds[i];
706 		if (c == '"' || c == '\\' || c < 0x20 || c == 0x7f) {
707 			d[dlen++] = '\\';
708 			switch (c) {
709 			  case '\b':
710 				d[dlen++] = 'b';
711 				break;
712 			  case '\t':
713 				d[dlen++] = 't';
714 				break;
715 			  case '\n':
716 				d[dlen++] = 'n';
717 				break;
718 			  case '\f':
719 				d[dlen++] = 'f';
720 				break;
721 			  case '\r':
722 				d[dlen++] = 'r';
723 				break;
724 			  case '"':
725 				d[dlen++] = '"';
726 				break;
727 			  case '\\':
728 				d[dlen++] = '\\';
729 				break;
730 			  default:
731 				d[dlen  ] = 'u';
732 				d[dlen+1] = '0';
733 				d[dlen+2] = '0';
734 				d[dlen+3] = hex_chars_lc[(c >> 4) & 0x0F];
735 				d[dlen+4] = hex_chars_lc[c & 0x0F];
736 				dlen += 5;
737 				break;
738 			}
739 		}
740 		else {
741 			d[dlen++] = c;
742 		}
743 	}
744 }
745 
746 
747 void buffer_append_string_c_escaped(buffer * const restrict b, const char * const restrict s, size_t s_len) {
748 	unsigned char *ds, *d;
749 	size_t d_len, ndx;
750 
751 	/* count to-be-encoded-characters */
752 	for (ds = (unsigned char *)s, d_len = 0, ndx = 0; ndx < s_len; ds++, ndx++) {
753 		if ((*ds < 0x20) /* control character */
754 				|| (*ds >= 0x7f)) { /* DEL + non-ASCII characters */
755 			switch (*ds) {
756 			case '\t':
757 			case '\r':
758 			case '\n':
759 				d_len += 2;
760 				break;
761 			default:
762 				d_len += 4; /* \xCC */
763 				break;
764 			}
765 		} else {
766 			d_len++;
767 		}
768 	}
769 
770 	d = (unsigned char*) buffer_extend(b, d_len);
771 
772 	if (d_len == s_len) { /*(short-circuit; nothing to encoded)*/
773 		memcpy(d, s, s_len);
774 		return;
775 	}
776 
777 	for (ds = (unsigned char *)s, d_len = 0, ndx = 0; ndx < s_len; ds++, ndx++) {
778 		if ((*ds < 0x20) /* control character */
779 				|| (*ds >= 0x7f)) { /* DEL + non-ASCII characters */
780 			d[d_len++] = '\\';
781 			switch (*ds) {
782 			case '\t':
783 				d[d_len++] = 't';
784 				break;
785 			case '\r':
786 				d[d_len++] = 'r';
787 				break;
788 			case '\n':
789 				d[d_len++] = 'n';
790 				break;
791 			default:
792 				d[d_len++] = 'x';
793 				d[d_len++] = hex_chars_lc[((*ds) >> 4) & 0x0F];
794 				d[d_len++] = hex_chars_lc[(*ds) & 0x0F];
795 				break;
796 			}
797 		} else {
798 			d[d_len++] = *ds;
799 		}
800 	}
801 }
802 
803 
804 /* decodes url-special-chars inplace.
805  * replaces non-printable characters with '_'
806  * (If this is used on a portion of query string, then query string should be
807  *  split on '&', and '+' replaced with ' ' before calling this routine)
808  */
809 
810 void buffer_urldecode_path(buffer * const b) {
811     const size_t len = buffer_clen(b);
812     char *src = len ? memchr(b->ptr, '%', len) : NULL;
813     if (NULL == src) return;
814 
815     char *dst = src;
816     do {
817         /* *src == '%' */
818         unsigned char high = ((unsigned char *)src)[1];
819         unsigned char low = high ? hex2int(((unsigned char *)src)[2]) : 0xFF;
820         if (0xFF != (high = hex2int(high)) && 0xFF != low) {
821             high = (high << 4) | low;   /* map ctrls to '_' */
822             *dst = (high >= 32 && high != 127) ? high : '_';
823             src += 2;
824         } /* else ignore this '%'; leave as-is and move on */
825 
826         while ((*++dst = *++src) != '%' && *src) ;
827     } while (*src);
828     b->used = (dst - b->ptr) + 1;
829 }
830 
831 int buffer_is_valid_UTF8(const buffer *b) {
832     /* https://www.w3.org/International/questions/qa-forms-utf-8 */
833     /*assert(b->used);*//*(b->ptr must exist and be '\0'-terminated)*/
834     const unsigned char *c = (unsigned char *)b->ptr;
835     while (*c) {
836 
837         /*(note: includes ctrls)*/
838         if (                         c[0] <  0x80 ) { ++c;  continue; }
839 
840         if (         0xc2 <= c[0] && c[0] <= 0xdf
841             &&       0x80 <= c[1] && c[1] <= 0xbf ) { c+=2; continue; }
842 
843         if ( (   (   0xe0 == c[0]
844                   && 0xa0 <= c[1] && c[1] <= 0xbf)
845               || (   0xe1 <= c[0] && c[0] <= 0xef && c[0] != 0xed
846                   && 0x80 <= c[1] && c[1] <= 0xbf)
847               || (   0xed == c[0]
848                   && 0x80 <= c[1] && c[1] <= 0x9f)   )
849             &&       0x80 <= c[2] && c[2] <= 0xbf ) { c+=3; continue; }
850 
851         if ( (   (   0xf0 == c[0]
852                   && 0x90 <= c[1] && c[1] <= 0xbf)
853               || (   0xf1 <= c[0] && c[0] <= 0xf3
854                   && 0x80 <= c[1] && c[1] <= 0xbf)
855               || (   0xf4 == c[0]
856                   && 0x80 <= c[1] && c[1] <= 0x8f)   )
857             &&       0x80 <= c[2] && c[2] <= 0xbf
858             &&       0x80 <= c[3] && c[3] <= 0xbf ) { c+=4; continue; }
859 
860         return 0; /* invalid */
861     }
862     return 1; /* valid */
863 }
864 
865 /* - special case: empty string returns empty string
866  * - on windows or cygwin: replace \ with /
867  * - strip leading spaces
868  * - prepends "/" if not present already
869  * - resolve "/../", "//" and "/./" the usual way:
870  *   the first one removes a preceding component, the other two
871  *   get compressed to "/".
872  * - "/." and "/.." at the end are similar, but always leave a trailing
873  *   "/"
874  *
875  * /blah/..         gets  /
876  * /blah/../foo     gets  /foo
877  * /abc/./xyz       gets  /abc/xyz
878  * /abc//xyz        gets  /abc/xyz
879  */
880 
881 void buffer_path_simplify(buffer *b)
882 {
883     char *out = b->ptr;
884     char * const end = b->ptr + b->used - 1;
885 
886     if (__builtin_expect( (buffer_is_blank(b)), 0)) {
887         buffer_blank(b);
888         return;
889     }
890 
891   #if defined(__WIN32) || defined(__CYGWIN__)
892     /* cygwin is treating \ and / the same, so we have to that too */
893     for (char *p = b->ptr; *p; p++) {
894         if (*p == '\\') *p = '/';
895     }
896   #endif
897 
898     *end = '/'; /*(end of path modified to avoid need to check '\0')*/
899 
900     char *walk = out;
901     if (__builtin_expect( (*walk == '/'), 1)) {
902         /* scan to detect (potential) need for path simplification
903          * (repeated '/' or "/.") */
904         do {
905             if (*++walk == '.' || *walk == '/')
906                 break;
907             do { ++walk; } while (*walk != '/');
908         } while (walk != end);
909         if (__builtin_expect( (walk == end), 1)) {
910             /* common case: no repeated '/' or "/." */
911             *end = '\0'; /* overwrite extra '/' added to end of path */
912             return;
913         }
914         out = walk-1;
915     }
916     else {
917         if (walk[0] == '.' && walk[1] == '/')
918             *out = *++walk;
919         else if (walk[0] == '.' && walk[1] == '.' && walk[2] == '/')
920             *out = *(walk += 2);
921         else {
922             while (*++walk != '/') ;
923             out = walk;
924         }
925         ++walk;
926     }
927 
928     while (walk <= end) {
929         /* previous char is '/' at this point (or start of string w/o '/') */
930         if (__builtin_expect( (walk[0] == '/'), 0)) {
931             /* skip repeated '/' (e.g. "///" -> "/") */
932             if (++walk < end)
933                 continue;
934             else {
935                 ++out;
936                 break;
937             }
938         }
939         else if (__builtin_expect( (walk[0] == '.'), 0)) {
940             /* handle "./" and "../" */
941             if (walk[1] == '.' && walk[2] == '/') {
942                 /* handle "../" */
943                 while (out > b->ptr && *--out != '/') ;
944                 *out = '/'; /*(in case path had not started with '/')*/
945                 if ((walk += 3) >= end) {
946                     ++out;
947                     break;
948                 }
949                 else
950                 continue;
951             }
952             else if (walk[1] == '/') {
953                 /* handle "./" */
954                 if ((walk += 2) >= end) {
955                     ++out;
956                     break;
957                 }
958                 continue;
959             }
960             else {
961                 /* accept "." if not part of "../" or "./" */
962                 *++out = '.';
963                 ++walk;
964             }
965         }
966 
967         while ((*++out = *walk++) != '/') ;
968     }
969     *out = *end = '\0'; /* overwrite extra '/' added to end of path */
970     b->used = (out - b->ptr) + 1;
971     /*buffer_truncate(b, out - b->ptr);*/
972 }
973 
974 void buffer_to_lower(buffer * const b) {
975     unsigned char * const restrict s = (unsigned char *)b->ptr;
976     const uint_fast32_t used = b->used;
977     for (uint_fast32_t i = 0; i < used; ++i) {
978         if (light_isupper(s[i])) s[i] |= 0x20;
979     }
980 }
981 
982 
983 void buffer_to_upper(buffer * const b) {
984     unsigned char * const restrict s = (unsigned char *)b->ptr;
985     const uint_fast32_t used = b->used;
986     for (uint_fast32_t i = 0; i < used; ++i) {
987         if (light_islower(s[i])) s[i] &= 0xdf;
988     }
989 }
990