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	xml.c - sfeed - RSS and Atom parser
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	xml.c (10090B)
	---
	1 #include <errno.h>
	2 #include <stdio.h>
	3 #include <stdlib.h>
	4 #include <string.h>
	5
	6 #include "xml.h"
	7
	8 #define ISALPHA(c) ((((unsigned)c) \| 32) - 'a' < 26)
	9 #define ISSPACE(c) ((c) == ' ' \|\| ((((unsigned)c) - '\t') < 5))
	10
	11 static void
	12 xml_parseattrs(XMLParser *x)
	13 {
	14 size_t namelen = 0, valuelen;
	15 int c, endsep, endname = 0, valuestart = 0;
	16
	17 while ((c = GETNEXT()) != EOF) {
	18 if (ISSPACE(c)) {
	19 if (namelen)
	20 endname = 1;
	21 continue;
	22 } else if (c == '?')
	23 ; /* ignore */
	24 else if (c == '=') {
	25 x->name[namelen] = '\0';
	26 valuestart = 1;
	27 endname = 1;
	28 } else if (namelen && ((endname && !valuestart && ISALPH…
	29 /* attribute without value */
	30 x->name[namelen] = '\0';
	31 if (x->xmlattrstart)
	32 x->xmlattrstart(x, x->tag, x->taglen, x-…
	33 if (x->xmlattr)
	34 x->xmlattr(x, x->tag, x->taglen, x->name…
	35 if (x->xmlattrend)
	36 x->xmlattrend(x, x->tag, x->taglen, x->n…
	37 endname = 0;
	38 x->name[0] = c;
	39 namelen = 1;
	40 } else if (namelen && valuestart) {
	41 /* attribute with value */
	42 if (x->xmlattrstart)
	43 x->xmlattrstart(x, x->tag, x->taglen, x-…
	44
	45 valuelen = 0;
	46 if (c == '\'' \|\| c == '"') {
	47 endsep = c;
	48 } else {
	49 endsep = ' '; /* ISSPACE() */
	50 goto startvalue;
	51 }
	52
	53 while ((c = GETNEXT()) != EOF) {
	54 startvalue:
	55 if (c == '&') { /* entities */
	56 x->data[valuelen] = '\0';
	57 /* call data function with data …
	58 if (valuelen && x->xmlattr)
	59 x->xmlattr(x, x->tag, x-…
	60 x->data[0] = c;
	61 valuelen = 1;
	62 while ((c = GETNEXT()) != EOF) {
	63 if (c == endsep \|\| (ends…
	64 break;
	65 if (valuelen < sizeof(x-…
	66 x->data[valuelen…
	67 else {
	68 /* entity too lo…
	69 x->data[valuelen…
	70 if (x->xmlattr)
	71 x->xmlat…
	72 x->data[0] = c;
	73 valuelen = 1;
	74 break;
	75 }
	76 if (c == ';') {
	77 x->data[valuelen…
	78 if (x->xmlattren…
	79 x->xmlat…
	80 valuelen = 0;
	81 break;
	82 }
	83 }
	84 } else if (c != endsep && !(endsep == ' …
	85 if (valuelen < sizeof(x->data) -…
	86 x->data[valuelen++] = c;
	87 } else {
	88 x->data[valuelen] = '\0';
	89 if (x->xmlattr)
	90 x->xmlattr(x, x-…
	91 x->data[0] = c;
	92 valuelen = 1;
	93 }
	94 }
	95 if (c == endsep \|\| (endsep == ' ' && (c …
	96 x->data[valuelen] = '\0';
	97 if (x->xmlattr)
	98 x->xmlattr(x, x->tag, x-…
	99 if (x->xmlattrend)
	100 x->xmlattrend(x, x->tag,…
	101 break;
	102 }
	103 }
	104 namelen = endname = valuestart = 0;
	105 } else if (namelen < sizeof(x->name) - 1) {
	106 x->name[namelen++] = c;
	107 }
	108 if (c == '>') {
	109 break;
	110 } else if (c == '/') {
	111 x->isshorttag = 1;
	112 x->name[0] = '\0';
	113 namelen = 0;
	114 }
	115 }
	116 }
	117
	118 static void
	119 xml_parsecomment(XMLParser *x)
	120 {
	121 int c, i = 0;
	122
	123 while ((c = GETNEXT()) != EOF) {
	124 if (c == '-') {
	125 if (++i > 2)
	126 i = 2;
	127 continue;
	128 } else if (c == '>' && i == 2) {
	129 return;
	130 } else if (i) {
	131 i = 0;
	132 }
	133 }
	134 }
	135
	136 static void
	137 xml_parsecdata(XMLParser *x)
	138 {
	139 size_t datalen = 0, i = 0;
	140 int c;
	141
	142 while ((c = GETNEXT()) != EOF) {
	143 if (c == ']' \|\| c == '>') {
	144 if (x->xmlcdata && datalen) {
	145 x->data[datalen] = '\0';
	146 x->xmlcdata(x, x->data, datalen);
	147 datalen = 0;
	148 }
	149 }
	150
	151 if (c == ']') {
	152 if (++i > 2) {
	153 if (x->xmlcdata)
	154 for (; i > 2; i--)
	155 x->xmlcdata(x, "]", 1);
	156 i = 2;
	157 }
	158 continue;
	159 } else if (c == '>' && i == 2) {
	160 return;
	161 } else if (i) {
	162 if (x->xmlcdata)
	163 for (; i > 0; i--)
	164 x->xmlcdata(x, "]", 1);
	165 i = 0;
	166 }
	167
	168 if (datalen < sizeof(x->data) - 1) {
	169 x->data[datalen++] = c;
	170 } else {
	171 x->data[datalen] = '\0';
	172 if (x->xmlcdata)
	173 x->xmlcdata(x, x->data, datalen);
	174 x->data[0] = c;
	175 datalen = 1;
	176 }
	177 }
	178 }
	179
	180 static int
	181 codepointtoutf8(long r, char *s)
	182 {
	183 if (r == 0) {
	184 return 0; /* NUL byte */
	185 } else if (r <= 0x7F) {
	186 /* 1 byte: 0aaaaaaa */
	187 s[0] = r;
	188 return 1;
	189 } else if (r <= 0x07FF) {
	190 /* 2 bytes: 00000aaa aabbbbbb */
	191 s[0] = 0xC0 \| ((r & 0x0007C0) >> 6); /* 110aaaaa */
	192 s[1] = 0x80 \| (r & 0x00003F); /* 10bbbbbb */
	193 return 2;
	194 } else if (r <= 0xFFFF) {
	195 /* 3 bytes: aaaabbbb bbcccccc */
	196 s[0] = 0xE0 \| ((r & 0x00F000) >> 12); /* 1110aaaa */
	197 s[1] = 0x80 \| ((r & 0x000FC0) >> 6); /* 10bbbbbb */
	198 s[2] = 0x80 \| (r & 0x00003F); /* 10cccccc */
	199 return 3;
	200 } else {
	201 /* 4 bytes: 000aaabb bbbbcccc ccdddddd */
	202 s[0] = 0xF0 \| ((r & 0x1C0000) >> 18); /* 11110aaa */
	203 s[1] = 0x80 \| ((r & 0x03F000) >> 12); /* 10bbbbbb */
	204 s[2] = 0x80 \| ((r & 0x000FC0) >> 6); /* 10cccccc */
	205 s[3] = 0x80 \| (r & 0x00003F); /* 10dddddd */
	206 return 4;
	207 }
	208 }
	209
	210 static int
	211 namedentitytostr(const char e, char buf, size_t bufsiz)
	212 {
	213 static const struct {
	214 const char *entity;
	215 int c;
	216 } entities[] = {
	217 { "amp;", '&' },
	218 { "lt;", '<' },
	219 { "gt;", '>' },
	220 { "apos;", '\'' },
	221 { "quot;", '"' },
	222 };
	223 size_t i;
	224
	225 /* buffer is too small */
	226 if (bufsiz < 2)
	227 return -1;
	228
	229 for (i = 0; i < sizeof(entities) / sizeof(*entities); i++) {
	230 if (!strcmp(e, entities[i].entity)) {
	231 buf[0] = entities[i].c;
	232 buf[1] = '\0';
	233 return 1;
	234 }
	235 }
	236 return -1;
	237 }
	238
	239 static int
	240 numericentitytostr(const char e, char buf, size_t bufsiz)
	241 {
	242 long l;
	243 int len;
	244 char *end;
	245
	246 /* buffer is too small */
	247 if (bufsiz < 5)
	248 return -1;
	249
	250 errno = 0;
	251 /* hex (16) or decimal (10) */
	252 if (*e == 'x')
	253 l = strtol(++e, &end, 16);
	254 else
	255 l = strtol(e, &end, 10);
	256 /* invalid value or not a well-formed entity or invalid code poi…
	257 if (errno \|\| e == end \|\| *end != ';' \|\| l < 0 \|\| l > 0x10ffff \|\|
	258 (l >= 0xd800 && l <= 0xdfff))
	259 return -1;
	260 len = codepointtoutf8(l, buf);
	261 buf[len] = '\0';
	262
	263 return len;
	264 }
	265
	266 /* convert named- or numeric entity string to buffer string
	267 * returns byte-length of string or -1 on failure. */
	268 int
	269 xml_entitytostr(const char e, char buf, size_t bufsiz)
	270 {
	271 /* doesn't start with & */
	272 if (e[0] != '&')
	273 return -1;
	274 /* numeric entity */
	275 if (e[1] == '#')
	276 return numericentitytostr(e + 2, buf, bufsiz);
	277 else /* named entity */
	278 return namedentitytostr(e + 1, buf, bufsiz);
	279 }
	280
	281 void
	282 xml_parse(XMLParser *x)
	283 {
	284 size_t datalen, tagdatalen;
	285 int c, isend;
	286
	287 while ((c = GETNEXT()) != EOF && c != '<')
	288 ; /* skip until < */
	289
	290 while (c != EOF) {
	291 if (c == '<') { /* parse tag */
	292 if ((c = GETNEXT()) == EOF)
	293 return;
	294
	295 if (c == '!') { /* CDATA and comments */
	296 for (tagdatalen = 0; (c = GETNEXT()) != …
	297 /* NOTE: sizeof(x->data) must be…
	298 if (tagdatalen <= sizeof("[CDATA…
	299 x->data[tagdatalen++] = …
	300 if (c == '>')
	301 break;
	302 else if (c == '-' && tagdatalen …
	303 (x->data[0] == '…
	304 xml_parsecomment(x);
	305 break;
	306 } else if (c == '[') {
	307 if (tagdatalen == sizeof…
	308 !strncmp(x->data, "[…
	309 xml_parsecdata(x…
	310 break;
	311 }
	312 }
	313 }
	314 } else {
	315 /* normal tag (open, short open, close),…
	316 x->tag[0] = c;
	317 x->taglen = 1;
	318 x->isshorttag = isend = 0;
	319
	320 /* treat processing instruction as short…
	321 if (c == '?') {
	322 x->isshorttag = 1;
	323 } else if (c == '/') {
	324 if ((c = GETNEXT()) == EOF)
	325 return;
	326 x->tag[0] = c;
	327 isend = 1;
	328 }
	329
	330 while ((c = GETNEXT()) != EOF) {
	331 if (c == '/')
	332 x->isshorttag = 1; /* sh…
	333 else if (c == '>' \|\| ISSPACE(c))…
	334 x->tag[x->taglen] = '\0';
	335 if (isend) { /* end tag,…
	336 while (c != '>' …
	337 c = GETN…
	338 if (x->xmltagend)
	339 x->xmlta…
	340 x->tag[0] = '\0';
	341 x->taglen = 0;
	342 } else {
	343 /* start tag */
	344 if (x->xmltagsta…
	345 x->xmlta…
	346 if (ISSPACE(c))
	347 xml_pars…
	348 if (x->xmltagsta…
	349 x->xmlta…
	350 }
	351 /* call tagend for short…
	352 if (x->isshorttag) {
	353 if (x->xmltagend)
	354 x->xmlta…
	355 x->tag[0] = '\0';
	356 x->taglen = 0;
	357 }
	358 break;
	359 } else if (x->taglen < sizeof(x-…
	360 x->tag[x->taglen++] = c;…
	361 }
	362 }
	363 } else {
	364 /* parse tag data */
	365 datalen = 0;
	366 while ((c = GETNEXT()) != EOF) {
	367 if (c == '&') {
	368 if (datalen) {
	369 x->data[datalen] = '\0';
	370 if (x->xmldata)
	371 x->xmldata(x, x-…
	372 }
	373 x->data[0] = c;
	374 datalen = 1;
	375 while ((c = GETNEXT()) != EOF) {
	376 if (c == '<')
	377 break;
	378 if (datalen < sizeof(x->…
	379 x->data[datalen+…
	380 else {
	381 /* entity too lo…
	382 x->data[datalen]…
	383 if (x->xmldata)
	384 x->xmlda…
	385 x->data[0] = c;
	386 datalen = 1;
	387 break;
	388 }
	389 if (c == ';') {
	390 x->data[datalen]…
	391 if (x->xmldataen…
	392 x->xmlda…
	393 datalen = 0;
	394 break;
	395 }
	396 }
	397 } else if (c != '<') {
	398 if (datalen < sizeof(x->data) - …
	399 x->data[datalen++] = c;
	400 } else {
	401 x->data[datalen] = '\0';
	402 if (x->xmldata)
	403 x->xmldata(x, x-…
	404 x->data[0] = c;
	405 datalen = 1;
	406 }
	407 }
	408 if (c == '<') {
	409 x->data[datalen] = '\0';
	410 if (x->xmldata && datalen)
	411 x->xmldata(x, x->data, d…
	412 break;
	413 }
	414 }
	415 }
	416 }
	417 }