sfeed/xml.c

#include <ctype.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "xml.h"

static const struct {
	char *entity;
	size_t len;
	int c;
} entities[] = {
	{ .entity = "&lt;",   .len = 4, .c = '<'  },
	{ .entity = "&gt;",   .len = 4, .c = '>'  },
	{ .entity = "&apos;", .len = 6, .c = '\'' },
	{ .entity = "&amp;",  .len = 5, .c = '&'  },
	{ .entity = "&quot;", .len = 6, .c = '"'  }
};

static int
xmlparser_string_getnext(XMLParser *x)
{
	if (!*(x->str))
		return EOF;
	return (int)*(x->str++);
}

static int /* like getc(), but do some smart buffering */
xmlparser_fd_getnext(XMLParser *x)
{
	ssize_t r;

	/* previous read error was set */
	if(x->readerrno)
		return EOF;

	if(x->readoffset >= x->readlastbytes) {
		x->readoffset = 0;
again:
		r = read(x->fd, x->readbuf, sizeof(x->readbuf));
		if(r == -1) {
			if(errno == EINTR)
				goto again;
			x->readerrno = errno;
			x->readlastbytes = 0;
			return EOF;
		} else if(!r) {
			return EOF;
		}
		x->readlastbytes = r;
	}
	return (int)x->readbuf[x->readoffset++];
}

static int
xmlparser_getnext(XMLParser *x)
{
	return x->getnext(x);
}

static __inline__ void
xmlparser_parseattrs(XMLParser *x)
{
	size_t namelen = 0, valuelen;
	int c, endsep, endname = 0;

	while((c = xmlparser_getnext(x)) != EOF) {
		if(isspace(c)) { /* TODO: simplify endname ? */
			if(namelen)
				endname = 1;
			continue;
		}
		if(c == '?')
			; /* ignore */
		else if(c == '=') {
			x->name[namelen] = '\0';
		} else if(namelen && ((endname && isalpha(c)) || (c == '>' || c == '/'))) {
			/* attribute without value */
			x->name[namelen] = '\0';
			if(x->xmlattrstart)
				x->xmlattrstart(x, x->tag, x->taglen, x->name, namelen);
			if(x->xmlattr)
				x->xmlattr(x, x->tag, x->taglen, x->name, namelen, "", 0);
			if(x->xmlattrend)
				x->xmlattrend(x, x->tag, x->taglen, x->name, namelen);
			endname = 0;
			x->name[0] = c;
			namelen = 1;
		} else if(namelen && (c == '\'' || c == '"')) {
			/* attribute with value */
			endsep = c; /* c is end separator */
			if(x->xmlattrstart)
				x->xmlattrstart(x, x->tag, x->taglen, x->name, namelen);
			for(valuelen = 0; (c = xmlparser_getnext(x)) != EOF;) {
				if(c == '&') { /* entities */
					x->data[valuelen] = '\0';
					/* call data function with data before entity if there is data */
					if(valuelen && x->xmlattr)
						x->xmlattr(x, x->tag, x->taglen, x->name, namelen, x->data, valuelen);
					x->data[0] = c;
					valuelen = 1;
					while((c = xmlparser_getnext(x)) != EOF) {
						if(c == endsep)
							break;
						if(valuelen < sizeof(x->data) - 1)
							x->data[valuelen++] = c;
						else {
							/* TODO: entity too long? this should be very strange. */
							x->data[valuelen] = '\0';
							if(x->xmlattr)
								x->xmlattr(x, x->tag, x->taglen, x->name, namelen, x->data, valuelen);
							valuelen = 0;
							break;
						}
						if(c == ';') {
							x->data[valuelen] = '\0';
							if(x->xmlattrentity)
								x->xmlattrentity(x, x->tag, x->taglen, x->name, namelen, x->data, valuelen);
							valuelen = 0;
							break;
						}
					}
				} else if(c != endsep) {
					if(valuelen < sizeof(x->data) - 1) {
						x->data[valuelen++] = c;
					} else {
						x->data[valuelen] = '\0';
						if(x->xmlattr)
							x->xmlattr(x, x->tag, x->taglen, x->name, namelen, x->data, valuelen);
						x->data[0] = c;
						valuelen = 1;
					}
				}
				if(c == endsep) {
					x->data[valuelen] = '\0';
					if(x->xmlattr)
						x->xmlattr(x, x->tag, x->taglen, x->name, namelen, x->data, valuelen);
					if(x->xmlattrend)
						x->xmlattrend(x, x->tag, x->taglen, x->name, namelen);
					break;
				}
			}
			namelen = 0;
			endname = 0;
		} else if(namelen < sizeof(x->name) - 1) {
			x->name[namelen++] = c;
		}
		if(c == '>') {
			break;
		} else if(c == '/') {
			x->isshorttag = 1;
			namelen = 0;
			x->name[0] = '\0';
		}
	}
}

static __inline__ void
xmlparser_parsecomment(XMLParser *x)
{
	static const char *end = "-->";
	size_t datalen = 0, i = 0;
	char tmp[4];
	int c;

	if(x->xmlcommentstart)
		x->xmlcommentstart(x);
	while((c = xmlparser_getnext(x)) != EOF) {
		if(c == end[i]) {
			if(end[++i] == '\0') { /* end */
				x->data[datalen] = '\0';
				if(x->xmlcomment)
					x->xmlcomment(x, x->data, datalen);
				if(x->xmlcommentend)
					x->xmlcommentend(x);
				return;
			}
		} else if(i) {
			if(x->xmlcomment) {
				x->data[datalen] = '\0';
				if(datalen)
					x->xmlcomment(x, x->data, datalen);
				memcpy(tmp, end, i);
				tmp[i] = '\0';
				x->xmlcomment(x, tmp, i);
			}
			i = 0;
			x->data[0] = c;
			datalen = 1;
		} else if(datalen < sizeof(x->data) - 1) {
			x->data[datalen++] = c;
		} else {
			x->data[datalen] = '\0';
			if(x->xmlcomment)
				x->xmlcomment(x, x->data, datalen);
			x->data[0] = c;
			datalen = 1;
		}
	}
}

static __inline__ void
xmlparser_parsecdata(XMLParser *x)
{
	static const char *end = "]]>";
	size_t datalen = 0, i = 0;
	char tmp[4];
	int c;

	if(x->xmlcdatastart)
		x->xmlcdatastart(x);
	while((c = xmlparser_getnext(x)) != EOF) {
		if(c == end[i]) {
			if(end[++i] == '\0') { /* end */
				x->data[datalen] = '\0';
				if(x->xmlcdata)
					x->xmlcdata(x, x->data, datalen);
				if(x->xmlcdataend)
					x->xmlcdataend(x);
				return;
			}
		} else if(i) {
			x->data[datalen] = '\0';
			if(x->xmlcdata) {
				if(datalen)
					x->xmlcdata(x, x->data, datalen);
				memcpy(tmp, end, i);
				tmp[i] = '\0';
				x->xmlcdata(x, tmp, i);
			}
			i = 0;
			x->data[0] = c;
			datalen = 1;
		} else if(datalen < sizeof(x->data) - 1) {
			x->data[datalen++] = c;
		} else {
			x->data[datalen] = '\0';
			if(x->xmlcdata)
				x->xmlcdata(x, x->data, datalen);
			x->data[0] = c;
			datalen = 1;
		}
	}
}

int
xml_codepointtoutf8(uint32_t cp, uint32_t *utf)
{
	if(cp >= 0x10000) {
		/* 4 bytes */
		*utf = 0xf0808080 | ((cp & 0xfc0000) << 6) |
		       ((cp & 0x3f000) << 4) | ((cp & 0xfc0) << 2) |
		       (cp & 0x3f);
		return 4;
	} else if(cp >= 0x00800) {
		/* 3 bytes */
		*utf = 0xe08080 |
		       ((cp & 0x3f000) << 4) | ((cp & 0xfc0) << 2) |
		       (cp & 0x3f);
		return 3;
	} else if(cp >= 0x80) {
		/* 2 bytes */
		*utf = 0xc080 |
		       ((cp & 0xfc0) << 2) | (cp & 0x3f);
		return 2;
	}
	*utf = cp & 0xff;
	return *utf ? 1 : 0; /* 1 byte */
}

ssize_t
xml_namedentitytostr(const char *e, char *buf, size_t bufsiz)
{
	size_t i;

	/* buffer is too small */
	if(bufsiz < 2)
		return -1;

	/* doesn't start with &: can't match */
	if(*e != '&')
		return 0;

	for(i = 0; sizeof(entities) / sizeof(*entities); i++) {
		/* NOTE: compares max 6 chars */
		if(!strncasecmp(e, entities[i].entity, 6)) {
			buf[0] = entities[i].c;
			buf[1] = '\0';
			return 1;
		}
	}
	return 0;
}

ssize_t
xml_numericentitytostr(const char *e, char *buf, size_t bufsiz)
{
	uint32_t l = 0, cp = 0;
	size_t b, len;
	char *end;

	/* buffer is too small */
	if(bufsiz < 5)
		return -1;

	/* not a numeric entity */
	if(!(e[0] == '&' && e[1] == '#'))
		return 0;

	/* e[1] == '#', numeric / hexadecimal entity */
	e += 2; /* skip "&#" */
	errno = 0;
	/* hex (16) or decimal (10) */
	if(*e == 'x')
		l = strtoul(e + 1, &end, 16);
	else
		l = strtoul(e, &end, 10);
	/* invalid value or not a well-formed entity */
	if(errno != 0 || (*end != '\0' && *end != ';'))
		return 0;
	if(!(len = xml_codepointtoutf8(l, &cp)))
		return 0;
	/* make string */
	for(b = 0; b < len; b++)
		buf[b] = (cp >> (8 * (len - 1 - b))) & 0xff;
	buf[len] = '\0';
	return (ssize_t)len;
}

/* convert named- or numeric entity string to buffer string
 * returns byte-length of string. */
ssize_t
xml_entitytostr(const char *e, char *buf, size_t bufsiz)
{
	/* buffer is too small */
	if(bufsiz < 5)
		return -1;
	/* doesn't start with & */
	if(e[0] != '&')
		return 0;
	/* named entity */
	if(e[1] != '#')
		return xml_namedentitytostr(e, buf, bufsiz);
	else /* numeric entity */
		return xml_numericentitytostr(e, buf, bufsiz);
}

static void
xmlparser_parse(XMLParser *x)
{
	int c, ispi;
	size_t datalen, tagdatalen, taglen;

	while((c = xmlparser_getnext(x)) != EOF && c != '<'); /* skip until < */

	while(c != EOF) {
		if(c == '<') { /* parse tag */
			if((c = xmlparser_getnext(x)) == EOF)
				return;
			x->tag[0] = '\0';
			x->taglen = 0;
			if(c == '!') { /* cdata and comments */
				for(tagdatalen = 0; (c = xmlparser_getnext(x)) != EOF;) {
					if(tagdatalen <= strlen("[CDATA[")) /* if(d < sizeof(x->data)) */
						x->data[tagdatalen++] = c; /* TODO: prevent overflow */
					if(c == '>')
						break;
					else if(c == '-' && tagdatalen == strlen("--") &&
							(x->data[0] == '-')) { /* comment */
						xmlparser_parsecomment(x);
						break;
					} else if(c == '[') {
						if(tagdatalen == strlen("[CDATA[") &&
							x->data[1] == 'C' && x->data[2] == 'D' &&
							x->data[3] == 'A' && x->data[4] == 'T' &&
							x->data[5] == 'A' && x->data[6] == '[') { /* CDATA */
							xmlparser_parsecdata(x);
							break;
						#if 0
						} else {
							/* TODO ? */
							/* markup declaration section */
							while((c = xmlparser_getnext(x)) != EOF && c != ']');
						#endif
						}
					}
				}
			} else { /* normal tag (open, short open, close), processing instruction. */
				if(isspace(c))
					while((c = xmlparser_getnext(x)) != EOF && isspace(c));
				if(c == EOF)
					return;
				x->tag[0] = c;
				ispi = (c == '?') ? 1 : 0;
				x->isshorttag = ispi;
				taglen = 1;
				while((c = xmlparser_getnext(x)) != EOF) {
					if(c == '/') /* TODO: simplify short tag? */
						x->isshorttag = 1; /* short tag */
					else if(c == '>' || isspace(c)) {
						x->tag[taglen] = '\0';
						if(x->tag[0] == '/') { /* end tag, starts with </ */
							x->taglen = --taglen; /* len -1 because of / */
							if(taglen && x->xmltagend)
								x->xmltagend(x, &(x->tag)[1], x->taglen, 0);
						} else {
							x->taglen = taglen;
							/* start tag */
							if(x->xmltagstart)
								x->xmltagstart(x, x->tag, x->taglen);
							if(isspace(c))
								xmlparser_parseattrs(x);
							if(x->xmltagstartparsed)
								x->xmltagstartparsed(x, x->tag, x->taglen, x->isshorttag);
						}
						/* call tagend for shortform or processing instruction */
						if((x->isshorttag || ispi) && x->xmltagend)
							x->xmltagend(x, x->tag, x->taglen, 1);
						break;
					} else if(taglen < sizeof(x->tag) - 1)
						x->tag[taglen++] = c;
				}
			}
		} else {
			/* parse tag data */
			datalen = 0;
			if(x->xmldatastart)
				x->xmldatastart(x);
			while((c = xmlparser_getnext(x)) != EOF) {
				if(c == '&') {
					if(datalen) {
						x->data[datalen] = '\0';
						if(x->xmldata)
							x->xmldata(x, x->data, datalen);
					}
					x->data[0] = c;
					datalen = 1;
					while((c = xmlparser_getnext(x)) != EOF) {
						if(c == '<')
							break;
						if(datalen < sizeof(x->data) - 1)
							x->data[datalen++] = c;
						if(isspace(c))
							break;
						else if(c == ';') {
							x->data[datalen] = '\0';
							if(x->xmldataentity)
								x->xmldataentity(x, x->data, datalen);
							datalen = 0;
							break;
						}
					}
				} else if(c != '<') {
					if(datalen < sizeof(x->data) - 1) {
						x->data[datalen++] = c;
					} else {
						x->data[datalen] = '\0';
						if(x->xmldata)
							x->xmldata(x, x->data, datalen);
						x->data[0] = c;
						datalen = 1;
					}
				}
				if(c == '<') {
					x->data[datalen] = '\0';
					if(x->xmldata && datalen)
						x->xmldata(x, x->data, datalen);
					if(x->xmldataend)
						x->xmldataend(x);
					break;
				}
			}
		}
	}
}

void
xmlparser_parse_string(XMLParser *x, const char *s)
{
	x->str = s;
	x->getnext = xmlparser_string_getnext;
	xmlparser_parse(x);
}

void
xmlparser_parse_fd(XMLParser *x, int fd)
{
	x->fd = fd;
	x->getnext = xmlparser_fd_getnext;
	xmlparser_parse(x);
}