xref: /lighttpd1.4/src/buffer.c (revision e174e7df)
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 buffer *buffer_init_string(const char *str) {
27 	buffer * const b = buffer_init();
28 	buffer_copy_string(b, str);
29 	return b;
30 }
31 
32 void buffer_free(buffer *b) {
33 	if (NULL == b) return;
34 
35 	free(b->ptr);
36 	free(b);
37 }
38 
39 void buffer_free_ptr(buffer *b) {
40 	free(b->ptr);
41 	b->ptr = NULL;
42 	b->used = 0;
43 	b->size = 0;
44 }
45 
46 void buffer_move(buffer * restrict b, buffer * restrict src) {
47 	buffer tmp;
48 	buffer_clear(b);
49 	tmp = *src; *src = *b; *b = tmp;
50 }
51 
52 /* make sure buffer is at least "size" big + 1 for '\0'. keep old data */
53 __attribute_cold__
54 __attribute_noinline__
55 __attribute_nonnull__()
56 __attribute_returns_nonnull__
57 static char* buffer_realloc(buffer * const restrict b, const size_t len) {
58     #define BUFFER_PIECE_SIZE 64uL  /*(must be power-of-2)*/
59     size_t sz = (len + 1 + BUFFER_PIECE_SIZE-1) & ~(BUFFER_PIECE_SIZE-1);
60     force_assert(sz > len);
61     if ((sz & (sz-1)) && sz < INT_MAX) {/* not power-2; huge val not expected */
62         /*(optimizer should recognize this and use ffs or clz or equivalent)*/
63         const size_t psz = sz;
64         for (sz = 256; sz < psz; sz <<= 1) ;
65     }
66     sz |= 1; /*(extra +1 for '\0' when needed buffer size is exact power-2)*/
67 
68     b->size = sz;
69     b->ptr = realloc(b->ptr, sz);
70 
71     force_assert(NULL != b->ptr);
72     return b->ptr;
73 }
74 
75 __attribute_cold__
76 __attribute_noinline__
77 __attribute_nonnull__()
78 __attribute_returns_nonnull__
79 static char* buffer_alloc_replace(buffer * const restrict b, const size_t size) {
80     /*(discard old data so realloc() does not copy)*/
81     if (NULL != b->ptr) {
82         free(b->ptr);
83         b->ptr = NULL;
84     }
85     /*(note: if size larger than one lshift, use size instead of power-2)*/
86     const size_t bsize2x = (b->size & ~1uL) << 1;
87     return buffer_realloc(b, bsize2x > size ? bsize2x-1 : size);
88 }
89 
90 char* buffer_string_prepare_copy(buffer * const b, const size_t size) {
91     b->used = 0;
92   #ifdef __COVERITY__ /*(b->ptr is not NULL if b->size is not 0)*/
93     force_assert(size >= b->size || b->ptr);
94   #endif
95     return (size < b->size)
96       ? b->ptr
97       : buffer_alloc_replace(b, size);
98 }
99 
100 __attribute_cold__
101 __attribute_noinline__
102 __attribute_nonnull__()
103 __attribute_returns_nonnull__
104 static char* buffer_string_prepare_append_resize(buffer * const restrict b, const size_t size) {
105     if (b->used < 2) {  /* buffer_is_blank(b) */
106         char * const s = buffer_string_prepare_copy(b, size);
107         *s = '\0'; /*(for case (1 == b->used))*/
108         return s;
109     }
110 
111     /* not empty, b->used already includes a terminating 0 */
112     /*(note: if size larger than one lshift, use size instead of power-2)*/
113     const size_t bsize2x = (b->size & ~1uL) << 1;
114     const size_t req_size = (bsize2x - b->used > size)
115       ? bsize2x-1
116       : b->used + size;
117 
118     /* check for overflow: unsigned overflow is defined to wrap around */
119     force_assert(req_size >= b->used);
120 
121     return buffer_realloc(b, req_size) + b->used - 1;
122 }
123 
124 char* buffer_string_prepare_append(buffer * const b, const size_t size) {
125     const uint32_t len = b->used ? b->used-1 : 0;
126     return (b->size - len >= size + 1)
127       ? b->ptr + len
128       : buffer_string_prepare_append_resize(b, size);
129 }
130 
131 /*(prefer smaller code than inlining buffer_extend in many places in buffer.c)*/
132 __attribute_noinline__
133 char*
134 buffer_extend (buffer * const b, const size_t x)
135 {
136     /* extend buffer to append x (reallocate by power-2 (or larger), if needed)
137      * (combine buffer_string_prepare_append() and buffer_commit())
138      * (future: might make buffer.h static inline func for HTTP/1.1 performance)
139      * pre-sets '\0' byte and b->used (unlike buffer_string_prepare_append())*/
140   #if 0
141     char * const s = buffer_string_prepare_append(b, x);
142     b->used += x + (0 == b->used);
143   #else
144     const uint32_t len = b->used ? b->used-1 : 0;
145     char * const s = (b->size - len >= x + 1)
146       ? b->ptr + len
147       : buffer_string_prepare_append_resize(b, x);
148     b->used = len+x+1;
149   #endif
150     s[x] = '\0';
151     return s;
152 }
153 
154 void buffer_commit(buffer *b, size_t size)
155 {
156 	size_t sz = b->used;
157 	if (0 == sz) sz = 1;
158 
159 	if (size > 0) {
160 		/* check for overflow: unsigned overflow is defined to wrap around */
161 		sz += size;
162 		force_assert(sz > size);
163 	}
164 
165 	b->used = sz;
166 	b->ptr[sz - 1] = '\0';
167 }
168 
169 __attribute_cold__ /*(reduce code size due to inlining)*/
170 void buffer_copy_string(buffer * restrict b, const char * restrict s) {
171     if (__builtin_expect( (NULL == s), 0)) s = "";
172     buffer_copy_string_len(b, s, strlen(s));
173 }
174 
175 void buffer_copy_string_len(buffer * const restrict b, const char * const restrict s, const size_t len) {
176     b->used = len + 1;
177     char * const restrict d = (len < b->size)
178       ? b->ptr
179       : buffer_alloc_replace(b, len);
180     d[len] = '\0';
181     memcpy(d, s, len);
182 }
183 
184 __attribute_cold__ /*(reduce code size due to inlining)*/
185 void buffer_append_string(buffer * restrict b, const char * restrict s) {
186     if (__builtin_expect( (NULL == s), 0)) s = "";
187     buffer_append_string_len(b, s, strlen(s));
188 }
189 
190 /**
191  * append a string to the end of the buffer
192  *
193  * the resulting buffer is terminated with a '\0'
194  * s is treated as a un-terminated string (a \0 is handled a normal character)
195  *
196  * @param b a buffer
197  * @param s the string
198  * @param s_len size of the string (without the terminating \0)
199  */
200 
201 void buffer_append_string_len(buffer * const restrict b, const char * const restrict s, const size_t len) {
202     memcpy(buffer_extend(b, len), s, len);
203 }
204 
205 void buffer_append_str2(buffer * const restrict b, const char * const s1, const size_t len1, const char * const s2, const size_t len2) {
206     char * const restrict s = buffer_extend(b, len1+len2);
207   #ifdef HAVE_MEMPCPY
208     mempcpy(mempcpy(s, s1, len1), s2, len2);
209   #else
210     memcpy(s,      s1, len1);
211     memcpy(s+len1, s2, len2);
212   #endif
213 }
214 
215 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) {
216     char * restrict s = buffer_extend(b, len1+len2+len3);
217   #ifdef HAVE_MEMPCPY
218     mempcpy(mempcpy(mempcpy(s, s1, len1), s2, len2), s3, len3);
219   #else
220     memcpy(s,         s1, len1);
221     memcpy((s+=len1), s2, len2);
222     memcpy((s+=len2), s3, len3);
223   #endif
224 }
225 
226 void buffer_append_iovec(buffer * const restrict b, const struct const_iovec * const iov, const size_t n) {
227     size_t len = 0;
228     for (size_t i = 0; i < n; ++i)
229         len += iov[i].iov_len;
230     char *s = buffer_extend(b, len);
231     for (size_t i = 0; i < n; ++i) {
232         if (0 == iov[i].iov_len) continue;
233       #ifdef HAVE_MEMPCPY
234         s = mempcpy(s, iov[i].iov_base, iov[i].iov_len);
235       #else
236         memcpy(s, iov[i].iov_base, iov[i].iov_len);
237         s += iov[i].iov_len;
238       #endif
239     }
240 }
241 
242 void buffer_append_path_len(buffer * restrict b, const char * restrict a, size_t alen) {
243     char * restrict s = buffer_string_prepare_append(b, alen+1);
244     const int aslash = (alen && a[0] == '/');
245     if (b->used > 1 && s[-1] == '/') {
246         if (aslash) {
247             ++a;
248             --alen;
249         }
250     }
251     else {
252         if (0 == b->used) b->used = 1;
253         if (!aslash) {
254             *s++ = '/';
255             ++b->used;
256         }
257     }
258     b->used += alen;
259     s[alen] = '\0';
260     memcpy(s, a, alen);
261 }
262 
263 void
264 buffer_copy_path_len2 (buffer * const restrict b, const char * const restrict s1, size_t len1, const char * const restrict s2, size_t len2)
265 {
266     /*(similar to buffer_copy_string_len(b, s1, len1) but combined allocation)*/
267     memcpy(buffer_string_prepare_copy(b, len1+len2+1), s1, len1);
268     b->used = len1 + 1;                    /*('\0' byte will be written below)*/
269 
270     buffer_append_path_len(b, s2, len2);/*(choice: not inlined, special-cased)*/
271 }
272 
273 void
274 buffer_copy_string_len_lc (buffer * const restrict b, const char * const restrict s, const size_t len)
275 {
276     char * const restrict d = buffer_string_prepare_copy(b, len);
277     b->used = len+1;
278     d[len] = '\0';
279     for (size_t i = 0; i < len; ++i)
280         d[i] = (!light_isupper(s[i])) ? s[i] : s[i] | 0x20;
281 }
282 
283 void buffer_append_uint_hex_lc(buffer *b, uintmax_t value) {
284 	char *buf;
285 	unsigned int shift = 0;
286 
287 	{
288 		uintmax_t copy = value;
289 		do {
290 			copy >>= 8;
291 			shift += 8; /* counting bits */
292 		} while (0 != copy);
293 	}
294 
295 	buf = buffer_extend(b, shift >> 2); /*nibbles (4 bits)*/
296 
297 	while (shift > 0) {
298 		shift -= 4;
299 		*(buf++) = hex_chars_lc[(value >> shift) & 0x0F];
300 	}
301 }
302 
303 __attribute_nonnull__()
304 __attribute_returns_nonnull__
305 static char* utostr(char buf[LI_ITOSTRING_LENGTH], uintmax_t val) {
306 	char *cur = buf+LI_ITOSTRING_LENGTH;
307 	uintmax_t x;
308 	do {
309 		*(--cur) = (char) ('0' + (int)(val - (x = val/10) * 10));
310 	} while (0 != (val = x));           /* val % 10 */
311 	return cur;
312 }
313 
314 __attribute_nonnull__()
315 __attribute_returns_nonnull__
316 static char* itostr(char buf[LI_ITOSTRING_LENGTH], intmax_t val) {
317 	/* absolute value not defined for INTMAX_MIN, but can take absolute
318 	 * value of any negative number via twos complement cast to unsigned.
319 	 * negative sign is prepended after (now unsigned) value is converted
320 	 * to string */
321 	uintmax_t uval = val >= 0 ? (uintmax_t)val : ((uintmax_t)~val) + 1;
322 	char *cur = utostr(buf, uval);
323 	if (val < 0) *(--cur) = '-';
324 
325 	return cur;
326 }
327 
328 void buffer_append_int(buffer *b, intmax_t val) {
329 	char buf[LI_ITOSTRING_LENGTH];
330 	const char * const str = itostr(buf, val);
331 	buffer_append_string_len(b, str, buf+sizeof(buf) - str);
332 }
333 
334 void buffer_append_strftime(buffer * const restrict b, const char * const restrict format, const struct tm * const restrict tm) {
335     /*(localtime_r() or gmtime_r() producing tm should not have failed)*/
336     if (__builtin_expect( (NULL == tm), 0)) return;
337 
338     /*(expecting typical format strings to result in < 64 bytes needed;
339      * skipping buffer_string_space() calculation and providing fixed size)*/
340     size_t rv = strftime(buffer_string_prepare_append(b, 63), 64, format, tm);
341 
342     /* 0 (in some apis) signals the string may have been too small;
343      * but the format could also just have lead to an empty string */
344     if (__builtin_expect( (0 == rv), 0) || __builtin_expect( (rv > 63), 0)) {
345         /* unexpected; give it a second try with a larger string */
346         rv = strftime(buffer_string_prepare_append(b, 4095), 4096, format, tm);
347         if (__builtin_expect( (rv > 4095), 0))/*(input format was ridiculous)*/
348             return;
349     }
350 
351     /*buffer_commit(b, rv);*/
352     b->used += (uint32_t)rv + (0 == b->used);
353 }
354 
355 
356 size_t li_itostrn(char *buf, size_t buf_len, intmax_t val) {
357 	char p_buf[LI_ITOSTRING_LENGTH];
358 	char* const str = itostr(p_buf, val);
359 	size_t len = (size_t)(p_buf+sizeof(p_buf)-str);
360 	force_assert(len <= buf_len);
361 	memcpy(buf, str, len);
362 	return len;
363 }
364 
365 size_t li_utostrn(char *buf, size_t buf_len, uintmax_t val) {
366 	char p_buf[LI_ITOSTRING_LENGTH];
367 	char* const str = utostr(p_buf, val);
368 	size_t len = (size_t)(p_buf+sizeof(p_buf)-str);
369 	force_assert(len <= buf_len);
370 	memcpy(buf, str, len);
371 	return len;
372 }
373 
374 #define li_ntox_lc(n) ((n) <= 9 ? (n) + '0' : (n) + 'a' - 10)
375 
376 /* c (char) and n (nibble) MUST be unsigned integer types */
377 #define li_cton(c,n) \
378   (((n) = (c) - '0') <= 9 || (((n) = ((c)&0xdf) - 'A') <= 5 ? ((n) += 10) : 0))
379 
380 /* converts hex char (0-9, A-Z, a-z) to decimal.
381  * returns 0xFF on invalid input.
382  */
383 char hex2int(unsigned char hex) {
384 	unsigned char n;
385 	return li_cton(hex,n) ? (char)n : 0xFF;
386 }
387 
388 int li_hex2bin (unsigned char * const bin, const size_t binlen, const char * const hexstr, const size_t len)
389 {
390     /* validate and transform 32-byte MD5 hex string to 16-byte binary MD5,
391      * or 64-byte SHA-256 or SHA-512-256 hex string to 32-byte binary digest */
392     if (len > (binlen << 1)) return -1;
393     for (int i = 0, ilen = (int)len; i < ilen; i+=2) {
394         int hi = hexstr[i];
395         int lo = hexstr[i+1];
396         if ('0' <= hi && hi <= '9')                    hi -= '0';
397         else if ((uint32_t)(hi |= 0x20)-'a' <= 'f'-'a')hi += -'a' + 10;
398         else                                           return -1;
399         if ('0' <= lo && lo <= '9')                    lo -= '0';
400         else if ((uint32_t)(lo |= 0x20)-'a' <= 'f'-'a')lo += -'a' + 10;
401         else                                           return -1;
402         bin[(i >> 1)] = (unsigned char)((hi << 4) | lo);
403     }
404     return 0;
405 }
406 
407 
408 __attribute_noinline__
409 int buffer_eq_icase_ssn(const char * const a, const char * const b, const size_t len) {
410     for (size_t i = 0; i < len; ++i) {
411         unsigned int ca = ((unsigned char *)a)[i];
412         unsigned int cb = ((unsigned char *)b)[i];
413         if (ca != cb) {
414             ca |= 0x20;
415             cb |= 0x20;
416             if (ca != cb) return 0;
417             if (!light_islower(ca)) return 0;
418             if (!light_islower(cb)) return 0;
419         }
420     }
421     return 1;
422 }
423 
424 int buffer_eq_icase_ss(const char * const a, const size_t alen, const char * const b, const size_t blen) {
425     /* 1 = equal; 0 = not equal */ /* short string sizes expected (< INT_MAX) */
426     return (alen == blen) ? buffer_eq_icase_ssn(a, b, blen) : 0;
427 }
428 
429 int buffer_eq_icase_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) ? buffer_eq_icase_ssn(b->ptr, s, slen) : 0;
433 }
434 
435 int buffer_eq_slen(const buffer * const b, const char * const s, const size_t slen) {
436     /* Note: b must be initialized, i.e. 0 != b->used; uninitialized is not eq*/
437     /* 1 = equal; 0 = not equal */ /* short string sizes expected (< INT_MAX) */
438     return (b->used == slen + 1 && 0 == memcmp(b->ptr, s, slen));
439 }
440 
441 
442 /**
443  * check if two buffer contain the same data
444  */
445 
446 int buffer_is_equal(const buffer *a, const buffer *b) {
447 	/* 1 = equal; 0 = not equal */
448 	return (a->used == b->used && 0 == memcmp(a->ptr, b->ptr, a->used));
449 }
450 
451 
452 void li_tohex_lc(char * const restrict buf, size_t buf_len, const char * const restrict s, size_t s_len) {
453 	force_assert(2 * s_len > s_len);
454 	force_assert(2 * s_len < buf_len);
455 
456 	for (size_t i = 0; i < s_len; ++i) {
457 		buf[2*i]   = hex_chars_lc[(s[i] >> 4) & 0x0F];
458 		buf[2*i+1] = hex_chars_lc[s[i] & 0x0F];
459 	}
460 	buf[2*s_len] = '\0';
461 }
462 
463 void li_tohex_uc(char * const restrict buf, size_t buf_len, const char * const restrict s, size_t s_len) {
464 	force_assert(2 * s_len > s_len);
465 	force_assert(2 * s_len < buf_len);
466 
467 	for (size_t i = 0; i < s_len; ++i) {
468 		buf[2*i]   = hex_chars_uc[(s[i] >> 4) & 0x0F];
469 		buf[2*i+1] = hex_chars_uc[s[i] & 0x0F];
470 	}
471 	buf[2*s_len] = '\0';
472 }
473 
474 
475 void buffer_substr_replace (buffer * const restrict b, const size_t offset,
476                             const size_t len, const buffer * const restrict replace)
477 {
478     const size_t blen = buffer_clen(b);
479     const size_t rlen = buffer_clen(replace);
480 
481     if (rlen > len) {
482         buffer_extend(b, blen-len+rlen);
483         memmove(b->ptr+offset+rlen, b->ptr+offset+len, blen-offset-len);
484     }
485 
486     memcpy(b->ptr+offset, replace->ptr, rlen);
487 
488     if (rlen < len) {
489         memmove(b->ptr+offset+rlen, b->ptr+offset+len, blen-offset-len);
490         buffer_truncate(b, blen-len+rlen);
491     }
492 }
493 
494 
495 void buffer_append_string_encoded_hex_lc(buffer * const restrict b, const char * const restrict s, size_t len) {
496     unsigned char * const p = (unsigned char *)buffer_extend(b, len*2);
497     for (size_t i = 0; i < len; ++i) {
498         p[(i<<1)]   = hex_chars_lc[(s[i] >> 4) & 0x0F];
499         p[(i<<1)+1] = hex_chars_lc[(s[i])      & 0x0F];
500     }
501 }
502 
503 void buffer_append_string_encoded_hex_uc(buffer * const restrict b, const char * const restrict s, size_t len) {
504     unsigned char * const p = (unsigned char *)buffer_extend(b, len*2);
505     for (size_t i = 0; i < len; ++i) {
506         p[(i<<1)]   = hex_chars_uc[(s[i] >> 4) & 0x0F];
507         p[(i<<1)+1] = hex_chars_uc[(s[i])      & 0x0F];
508     }
509 }
510 
511 
512 /* everything except: ! ( ) * - . 0-9 A-Z _ a-z */
513 static const char encoded_chars_rel_uri_part[] = {
514 	/*
515 	0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F
516 	*/
517 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  00 -  0F control chars */
518 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  10 -  1F */
519 	1, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 0, 0, 1,  /*  20 -  2F space " # $ % & ' + , / */
520 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1,  /*  30 -  3F : ; < = > ? */
521 	1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  40 -  4F @ */
522 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0,  /*  50 -  5F [ \ ] ^ */
523 	1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  60 -  6F ` */
524 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 1,  /*  70 -  7F { | } DEL */
525 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  80 -  8F */
526 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  90 -  9F */
527 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  A0 -  AF */
528 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  B0 -  BF */
529 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  C0 -  CF */
530 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  D0 -  DF */
531 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  E0 -  EF */
532 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  F0 -  FF */
533 };
534 
535 /* everything except: ! ( ) * - . / 0-9 A-Z _ a-z */
536 static const char encoded_chars_rel_uri[] = {
537 	/*
538 	0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F
539 	*/
540 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  00 -  0F control chars */
541 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  10 -  1F */
542 	1, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0,  /*  20 -  2F space " # $ % & ' + , */
543 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1,  /*  30 -  3F : ; < = > ? */
544 	1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  40 -  4F @ */
545 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0,  /*  50 -  5F [ \ ] ^ */
546 	1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  60 -  6F ` */
547 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 1,  /*  70 -  7F { | } DEL */
548 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  80 -  8F */
549 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  90 -  9F */
550 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  A0 -  AF */
551 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  B0 -  BF */
552 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  C0 -  CF */
553 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  D0 -  DF */
554 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  E0 -  EF */
555 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  F0 -  FF */
556 };
557 
558 static const char encoded_chars_html[] = {
559 	/*
560 	0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F
561 	*/
562 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  00 -  0F control chars */
563 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  10 -  1F */
564 	0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0,  /*  20 -  2F " & ' */
565 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0,  /*  30 -  3F < > */
566 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  40 -  4F */
567 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  50 -  5F */
568 	1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  60 -  6F ` */
569 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1,  /*  70 -  7F DEL */
570 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  80 -  8F */
571 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  90 -  9F */
572 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  A0 -  AF */
573 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  B0 -  BF */
574 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  C0 -  CF */
575 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  D0 -  DF */
576 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  E0 -  EF */
577 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  F0 -  FF */
578 };
579 
580 static const char encoded_chars_minimal_xml[] = {
581 	/*
582 	0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F
583 	*/
584 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  00 -  0F control chars */
585 	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /*  10 -  1F */
586 	0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0,  /*  20 -  2F " & ' */
587 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0,  /*  30 -  3F < > */
588 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  40 -  4F */
589 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  50 -  5F */
590 	1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  60 -  6F ` */
591 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1,  /*  70 -  7F DEL */
592 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  80 -  8F */
593 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  90 -  9F */
594 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  A0 -  AF */
595 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  B0 -  BF */
596 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  C0 -  CF */
597 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  D0 -  DF */
598 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  E0 -  EF */
599 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /*  F0 -  FF */
600 };
601 
602 
603 
604 void buffer_append_string_encoded(buffer * const restrict b, const char * const restrict s, size_t s_len, buffer_encoding_t encoding) {
605 	unsigned char *ds, *d;
606 	size_t d_len, ndx;
607 	const char *map = NULL;
608 
609 	switch(encoding) {
610 	case ENCODING_REL_URI:
611 		map = encoded_chars_rel_uri;
612 		break;
613 	case ENCODING_REL_URI_PART:
614 		map = encoded_chars_rel_uri_part;
615 		break;
616 	case ENCODING_HTML:
617 		map = encoded_chars_html;
618 		break;
619 	case ENCODING_MINIMAL_XML:
620 		map = encoded_chars_minimal_xml;
621 		break;
622 	}
623 
624 	/* count to-be-encoded-characters */
625 	for (ds = (unsigned char *)s, d_len = 0, ndx = 0; ndx < s_len; ds++, ndx++) {
626 		if (map[*ds & 0xFF]) {
627 			switch(encoding) {
628 			case ENCODING_REL_URI:
629 			case ENCODING_REL_URI_PART:
630 				d_len += 3;
631 				break;
632 			case ENCODING_HTML:
633 			case ENCODING_MINIMAL_XML:
634 				d_len += 6;
635 				break;
636 			}
637 		} else {
638 			d_len++;
639 		}
640 	}
641 
642 	d = (unsigned char*) buffer_extend(b, d_len);
643 
644 	if (d_len == s_len) { /*(short-circuit; nothing to encoded)*/
645 		memcpy(d, s, s_len);
646 		return;
647 	}
648 
649 	for (ds = (unsigned char *)s, d_len = 0, ndx = 0; ndx < s_len; ds++, ndx++) {
650 		if (map[*ds & 0xFF]) {
651 			switch(encoding) {
652 			case ENCODING_REL_URI:
653 			case ENCODING_REL_URI_PART:
654 				d[d_len++] = '%';
655 				d[d_len++] = hex_chars_uc[((*ds) >> 4) & 0x0F];
656 				d[d_len++] = hex_chars_uc[(*ds) & 0x0F];
657 				break;
658 			case ENCODING_HTML:
659 			case ENCODING_MINIMAL_XML:
660 				d[d_len++] = '&';
661 				d[d_len++] = '#';
662 				d[d_len++] = 'x';
663 				d[d_len++] = hex_chars_uc[((*ds) >> 4) & 0x0F];
664 				d[d_len++] = hex_chars_uc[(*ds) & 0x0F];
665 				d[d_len++] = ';';
666 				break;
667 			}
668 		} else {
669 			d[d_len++] = *ds;
670 		}
671 	}
672 }
673 
674 void buffer_append_string_encoded_json(buffer * const restrict b, const char * const restrict s, const size_t len) {
675 	const unsigned char * const restrict ds = (unsigned char *)s;
676 	size_t dlen = 0;
677 
678 	/* calculate space needed for string including encodings */
679 	for (size_t i = 0; i < len; ++i) {
680 		int c = ds[i];
681 		if (c == '"' || c == '\\' || c < 0x20 || c == 0x7f) {
682 			switch (c) {
683 			  case '\b':
684 			  case '\t':
685 			  case '\n':
686 			  case '\f':
687 			  case '\r':
688 			  case '"':
689 			  case '\\':
690 				dlen += 2;
691 				break;
692 			  default:
693 				dlen += 6; /* \uCCCC */
694 				break;
695 			}
696 		}
697 		else {
698 			++dlen;
699 		}
700 	}
701 
702 	unsigned char * const d = (unsigned char *)buffer_extend(b, dlen);
703 
704 	if (__builtin_expect( (dlen == len), 1)) {/*(short-circuit; nothing to encode)*/
705 		memcpy(d, ds, len);
706 		return;
707 	}
708 
709 	dlen = 0;
710 	for (size_t i = 0; i < len; ++i) {
711 		int c = ds[i];
712 		if (c == '"' || c == '\\' || c < 0x20 || c == 0x7f) {
713 			d[dlen++] = '\\';
714 			switch (c) {
715 			  case '\b':
716 				d[dlen++] = 'b';
717 				break;
718 			  case '\t':
719 				d[dlen++] = 't';
720 				break;
721 			  case '\n':
722 				d[dlen++] = 'n';
723 				break;
724 			  case '\f':
725 				d[dlen++] = 'f';
726 				break;
727 			  case '\r':
728 				d[dlen++] = 'r';
729 				break;
730 			  case '"':
731 				d[dlen++] = '"';
732 				break;
733 			  case '\\':
734 				d[dlen++] = '\\';
735 				break;
736 			  default:
737 				d[dlen  ] = 'u';
738 				d[dlen+1] = '0';
739 				d[dlen+2] = '0';
740 				d[dlen+3] = hex_chars_lc[(c >> 4) & 0x0F];
741 				d[dlen+4] = hex_chars_lc[c & 0x0F];
742 				dlen += 5;
743 				break;
744 			}
745 		}
746 		else {
747 			d[dlen++] = c;
748 		}
749 	}
750 }
751 
752 
753 void buffer_append_string_c_escaped(buffer * const restrict b, const char * const restrict s, size_t s_len) {
754 	unsigned char *ds, *d;
755 	size_t d_len, ndx;
756 
757 	/* count to-be-encoded-characters */
758 	for (ds = (unsigned char *)s, d_len = 0, ndx = 0; ndx < s_len; ds++, ndx++) {
759 		if ((*ds < 0x20) /* control character */
760 				|| (*ds >= 0x7f)) { /* DEL + non-ASCII characters */
761 			switch (*ds) {
762 			case '\t':
763 			case '\r':
764 			case '\n':
765 				d_len += 2;
766 				break;
767 			default:
768 				d_len += 4; /* \xCC */
769 				break;
770 			}
771 		} else {
772 			d_len++;
773 		}
774 	}
775 
776 	d = (unsigned char*) buffer_extend(b, d_len);
777 
778 	if (d_len == s_len) { /*(short-circuit; nothing to encoded)*/
779 		memcpy(d, s, s_len);
780 		return;
781 	}
782 
783 	for (ds = (unsigned char *)s, d_len = 0, ndx = 0; ndx < s_len; ds++, ndx++) {
784 		if ((*ds < 0x20) /* control character */
785 				|| (*ds >= 0x7f)) { /* DEL + non-ASCII characters */
786 			d[d_len++] = '\\';
787 			switch (*ds) {
788 			case '\t':
789 				d[d_len++] = 't';
790 				break;
791 			case '\r':
792 				d[d_len++] = 'r';
793 				break;
794 			case '\n':
795 				d[d_len++] = 'n';
796 				break;
797 			default:
798 				d[d_len++] = 'x';
799 				d[d_len++] = hex_chars_lc[((*ds) >> 4) & 0x0F];
800 				d[d_len++] = hex_chars_lc[(*ds) & 0x0F];
801 				break;
802 			}
803 		} else {
804 			d[d_len++] = *ds;
805 		}
806 	}
807 }
808 
809 
810 /* decodes url-special-chars inplace.
811  * replaces non-printable characters with '_'
812  * (If this is used on a portion of query string, then query string should be
813  *  split on '&', and '+' replaced with ' ' before calling this routine)
814  */
815 
816 void buffer_urldecode_path(buffer * const b) {
817     const size_t len = buffer_clen(b);
818     char *src = len ? memchr(b->ptr, '%', len) : NULL;
819     if (NULL == src) return;
820 
821     char *dst = src;
822     do {
823         /* *src == '%' */
824         unsigned char high = ((unsigned char *)src)[1];
825         unsigned char low = high ? hex2int(((unsigned char *)src)[2]) : 0xFF;
826         if (0xFF != (high = hex2int(high)) && 0xFF != low) {
827             high = (high << 4) | low;   /* map ctrls to '_' */
828             *dst = (high >= 32 && high != 127) ? high : '_';
829             src += 2;
830         } /* else ignore this '%'; leave as-is and move on */
831 
832         while ((*++dst = *++src) != '%' && *src) ;
833     } while (*src);
834     b->used = (dst - b->ptr) + 1;
835 }
836 
837 int buffer_is_valid_UTF8(const buffer *b) {
838     /* https://www.w3.org/International/questions/qa-forms-utf-8 */
839     /*assert(b->used);*//*(b->ptr must exist and be '\0'-terminated)*/
840     const unsigned char *c = (unsigned char *)b->ptr;
841     while (*c) {
842 
843         /*(note: includes ctrls)*/
844         if (                         c[0] <  0x80 ) { ++c;  continue; }
845 
846         if (         0xc2 <= c[0] && c[0] <= 0xdf
847             &&       0x80 <= c[1] && c[1] <= 0xbf ) { c+=2; continue; }
848 
849         if ( (   (   0xe0 == c[0]
850                   && 0xa0 <= c[1] && c[1] <= 0xbf)
851               || (   0xe1 <= c[0] && c[0] <= 0xef && c[0] != 0xed
852                   && 0x80 <= c[1] && c[1] <= 0xbf)
853               || (   0xed == c[0]
854                   && 0x80 <= c[1] && c[1] <= 0x9f)   )
855             &&       0x80 <= c[2] && c[2] <= 0xbf ) { c+=3; continue; }
856 
857         if ( (   (   0xf0 == c[0]
858                   && 0x90 <= c[1] && c[1] <= 0xbf)
859               || (   0xf1 <= c[0] && c[0] <= 0xf3
860                   && 0x80 <= c[1] && c[1] <= 0xbf)
861               || (   0xf4 == c[0]
862                   && 0x80 <= c[1] && c[1] <= 0x8f)   )
863             &&       0x80 <= c[2] && c[2] <= 0xbf
864             &&       0x80 <= c[3] && c[3] <= 0xbf ) { c+=4; continue; }
865 
866         return 0; /* invalid */
867     }
868     return 1; /* valid */
869 }
870 
871 /* - special case: empty string returns empty string
872  * - on windows or cygwin: replace \ with /
873  * - strip leading spaces
874  * - prepends "/" if not present already
875  * - resolve "/../", "//" and "/./" the usual way:
876  *   the first one removes a preceding component, the other two
877  *   get compressed to "/".
878  * - "/." and "/.." at the end are similar, but always leave a trailing
879  *   "/"
880  *
881  * /blah/..         gets  /
882  * /blah/../foo     gets  /foo
883  * /abc/./xyz       gets  /abc/xyz
884  * /abc//xyz        gets  /abc/xyz
885  */
886 
887 void buffer_path_simplify(buffer *b)
888 {
889     char *out = b->ptr;
890     char * const end = b->ptr + b->used - 1;
891 
892     if (__builtin_expect( (buffer_is_blank(b)), 0)) {
893         buffer_blank(b);
894         return;
895     }
896 
897   #if defined(__WIN32) || defined(__CYGWIN__)
898     /* cygwin is treating \ and / the same, so we have to that too */
899     for (char *p = b->ptr; *p; p++) {
900         if (*p == '\\') *p = '/';
901     }
902   #endif
903 
904     *end = '/'; /*(end of path modified to avoid need to check '\0')*/
905 
906     char *walk = out;
907     if (__builtin_expect( (*walk == '/'), 1)) {
908         /* scan to detect (potential) need for path simplification
909          * (repeated '/' or "/.") */
910         do {
911             if (*++walk == '.' || *walk == '/')
912                 break;
913             do { ++walk; } while (*walk != '/');
914         } while (walk != end);
915         if (__builtin_expect( (walk == end), 1)) {
916             /* common case: no repeated '/' or "/." */
917             *end = '\0'; /* overwrite extra '/' added to end of path */
918             return;
919         }
920         out = walk-1;
921     }
922     else {
923         if (walk[0] == '.' && walk[1] == '/')
924             *out = *++walk;
925         else if (walk[0] == '.' && walk[1] == '.' && walk[2] == '/')
926             *out = *(walk += 2);
927         else {
928             while (*++walk != '/') ;
929             out = walk;
930         }
931         ++walk;
932     }
933 
934     while (walk <= end) {
935         /* previous char is '/' at this point (or start of string w/o '/') */
936         if (__builtin_expect( (walk[0] == '/'), 0)) {
937             /* skip repeated '/' (e.g. "///" -> "/") */
938             if (++walk < end)
939                 continue;
940             else {
941                 ++out;
942                 break;
943             }
944         }
945         else if (__builtin_expect( (walk[0] == '.'), 0)) {
946             /* handle "./" and "../" */
947             if (walk[1] == '.' && walk[2] == '/') {
948                 /* handle "../" */
949                 while (out > b->ptr && *--out != '/') ;
950                 *out = '/'; /*(in case path had not started with '/')*/
951                 if ((walk += 3) >= end) {
952                     ++out;
953                     break;
954                 }
955                 else
956                 continue;
957             }
958             else if (walk[1] == '/') {
959                 /* handle "./" */
960                 if ((walk += 2) >= end) {
961                     ++out;
962                     break;
963                 }
964                 continue;
965             }
966             else {
967                 /* accept "." if not part of "../" or "./" */
968                 *++out = '.';
969                 ++walk;
970             }
971         }
972 
973         while ((*++out = *walk++) != '/') ;
974     }
975     *out = *end = '\0'; /* overwrite extra '/' added to end of path */
976     b->used = (out - b->ptr) + 1;
977     /*buffer_truncate(b, out - b->ptr);*/
978 }
979 
980 void buffer_to_lower(buffer * const b) {
981     unsigned char * const restrict s = (unsigned char *)b->ptr;
982     const uint_fast32_t used = b->used;
983     for (uint_fast32_t i = 0; i < used; ++i) {
984         if (light_isupper(s[i])) s[i] |= 0x20;
985     }
986 }
987 
988 
989 void buffer_to_upper(buffer * const b) {
990     unsigned char * const restrict s = (unsigned char *)b->ptr;
991     const uint_fast32_t used = b->used;
992     for (uint_fast32_t i = 0; i < used; ++i) {
993         if (light_islower(s[i])) s[i] &= 0xdf;
994     }
995 }
996