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boinc/lib/parse.C

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// Berkeley Open Infrastructure for Network Computing
// http://boinc.berkeley.edu
// Copyright (C) 2005 University of California
//
// This is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation;
// either version 2.1 of the License, or (at your option) any later version.
//
// This software is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
// See the GNU Lesser General Public License for more details.
//
// To view the GNU Lesser General Public License visit
// http://www.gnu.org/copyleft/lesser.html
// or write to the Free Software Foundation, Inc.,
// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
// A very crude interface for parsing XML files;
// assumes all elements are either single-line or
// have start and end tags on separate lines.
// This is meant to be used ONLY for parsing XML files produced
// by the BOINC scheduling server or client.
// Could replace this with a more general parser.
#if defined(_WIN32) && !defined(__STDWX_H__) && !defined(_BOINC_WIN_) && !defined(_AFX_STDAFX_H_)
#include "boinc_win.h"
#endif
#ifndef _WIN32
#include "config.h"
#include <cstring>
#include <cstdlib>
#include <string>
#include <math.h>
#if HAVE_IEEEFP_H
#include <ieeefp.h>
#endif
#endif
#include "error_numbers.h"
#include "util.h"
#include "parse.h"
#ifdef _USING_FCGI_
#include "fcgi_stdio.h"
#endif
using std::string;
// Parse a boolean; tag is of form "foobar"
// Accept either <foobar/> or <foobar>1</foobar>
//
bool parse_bool(const char* buf, const char* tag, bool& result) {
char single_tag[256], start_tag[256];
int x;
sprintf(single_tag, "<%s/>", tag);
if (match_tag(buf, single_tag)) {
result = true;
return true;
}
sprintf(start_tag, "<%s>", tag);
if (parse_int(buf, start_tag, x)) {
result = (x != 0);
return true;
}
return false;
}
// parse a string of the form ...<tag attrs>string</tag>...;
// returns the "string" part.
// Does XML unescaping (replace &lt; with <)
// "string" may not include '<'
// Strips white space from ends.
// Use "<tag", not "<tag>", if there might be attributes
//
bool parse_str(const char* buf, const char* tag, char* dest, int destlen) {
string str;
const char* p;
char tempbuf[1024];
int len;
// sanity check on NULL and empty cases.
if (!buf || !tag || !strlen(tag))
return false;
p = strstr(buf, tag);
if (!p) return false;
p = strchr(p, '>');
p++;
const char* q = strchr(p, '<');
if (!q) return false;
len = (int)(q-p);
if (len >= destlen) len = destlen-1;
memcpy(tempbuf, p, len);
tempbuf[len] = 0;
strip_whitespace(tempbuf);
xml_unescape(tempbuf, dest);
return true;
}
bool parse_str(const char* buf, const char* tag, string& dest) {
char tempbuf[1024];
if (!parse_str(buf, tag, tempbuf, 1024)) return false;
dest = tempbuf;
return true;
}
// parse a string of the form 'xxx name="value" xxx';
// returns value in dest
//
void parse_attr(const char* buf, const char* name, char* dest, int len) {
const char* p;
const char *q;
strcpy(dest, "");
p = strstr(buf, name);
if (!p) return;
p = strchr(p, '"');
if (!p) return;
q = strchr(p+1, '"');
if (!q) return;
if (len > q-p) len = (int)(q-p);
strlcpy(dest, p+1, len);
}
void copy_stream(FILE* in, FILE* out) {
char buf[1024];
int n, m;
while (1) {
n = (int)fread(buf, 1, 1024, in);
m = (int)fwrite(buf, 1, n, out);
if (n < 1024) break;
}
}
// append to a malloc'd string
//
int strcatdup(char*& p, char* buf) {
p = (char*)realloc(p, strlen(p) + strlen(buf)+1);
if (!p) {
return ERR_MALLOC;
}
strcat(p, buf);
return 0;
}
// copy from a file to a malloc'd string until the end tag is reached
//
int dup_element_contents(FILE* in, const char* end_tag, char** pp) {
char buf[256];
int retval;
char* p = strdup("");
while (fgets(buf, 256, in)) {
if (strstr(buf, end_tag)) {
*pp = p;
return 0;
}
retval = strcatdup(p, buf);
if (retval) return retval;
}
return ERR_XML_PARSE;
}
// copy from a file to static buffer
//
int copy_element_contents(FILE* in, const char* end_tag, char* p, int len) {
char buf[256];
int n;
strcpy(p, "");
while (fgets(buf, 256, in)) {
if (strstr(buf, end_tag)) {
return 0;
}
n = (int)strlen(buf);
if (n >= len-1) return ERR_XML_PARSE;
strcat(p, buf);
len -= n;
}
return ERR_XML_PARSE;
}
int copy_element_contents(FILE* in, const char* end_tag, string& str) {
char buf[256];
str = "";
while (fgets(buf, 256, in)) {
if (strstr(buf, end_tag)) {
return 0;
}
str += buf;
}
return ERR_XML_PARSE;
}
void file_to_str(FILE* in, string& str) {
char buf[256];
str = "";
while (fgets(buf, 256, in)) {
str += buf;
}
}
// read a file into a malloc'd string
//
int read_file_malloc(const char* pathname, char*& str) {
char buf[256];
FILE* f;
int retval;
f = fopen(pathname, "r");
if (!f) return ERR_FOPEN;
str = strdup("");
while (fgets(buf, 256, f)) {
retval = strcatdup(str, buf);
if (retval) return retval;
}
fclose(f);
return 0;
}
// replace XML element contents (element must be present)
//
void replace_element_contents(
char* buf, const char* start, const char* end, const char* replacement
) {
char temp[4096], *p, *q;
p = strstr(buf, start);
p += strlen(start);
q = strstr(p, end);
strlcpy(temp, q, sizeof(temp));
strcpy(p, replacement);
strcat(p, temp);
}
// if the string contains a substring of the form X...Y,
// remove the first such.
bool remove_element(char* buf, const char* start, const char* end) {
char* p, *q;
p = strstr(buf, start);
if (!p) return false;
q = strstr(p+strlen(start), end);
if (!q) return false;
strcpy(p, q+strlen(end));
return true;
}
// replace a substring. Do at most one instance.
//
bool str_replace(char* str, const char* substr, const char* replacement) {
char temp[4096], *p;
p = strstr(str, substr);
if (!p) return false;
int n = (int)strlen(substr);
strcpy(temp, p+n);
strcpy(p, replacement);
strcat(p, temp);
return true;
}
// if the given XML has an element of the form
// <venue name="venue_name">
// ...
// </venue>
// then return the contents of that element.
// Otherwise strip out all <venue> elements
//
void extract_venue(const char* in, const char* venue_name, char* out) {
const char* p, *q;
char* wp;
char buf[256];
sprintf(buf, "<venue name=\"%s\">", venue_name);
p = strstr(in, buf);
if (p) {
// prefs contain the specified venue
//
p += strlen(buf);
strcpy(out, p);
wp = strstr(out, "</venue");
if (wp) *wp = 0;
} else {
// prefs don't contain the specified venue
//
q = in;
strcpy(out, "");
while (1) {
p = strstr(q, "<venue");
if (!p) {
strcat(out, q);
break;
}
strncat(out, q, p-q);
q = strstr(p, "</venue>");
if (!q) break;
q += strlen("</venue>");
}
}
}
// copy a line from the given string.
// kinda like fgets() when you're reading from a string
//
char* sgets(char* buf, int len, char*& in) {
char* p;
p = strstr(in, "\n");
if (!p) return NULL;
*p = 0;
strlcpy(buf, in, len);
*p = '\n';
in = p+1;
return buf;
}
// NOTE: these used to take std::string instead of char* args.
// But this performed poorly.
//
// NOTE: output buffer should be 6X size of input
//
void xml_escape(const char* in, char* out) {
char buf[256], *p;
p = out;
for (; *in; in++) {
int x = (int) *in;
x &= 0xff; // just in case
if (x == '<') {
strcpy(p, "&lt;");
p += 4;
} else if (x == '&') {
strcpy(p, "&amp;");
p += 5;
} else if (x>127) {
sprintf(buf, "&#%d;", x);
strcpy(p, buf);
p += strlen(buf);
} else if (x<32) {
switch(x) {
case 9:
case 10:
case 13:
sprintf(buf, "&#%d;", x);
strcpy(p, buf);
p += strlen(buf);
break;
}
} else {
*p++ = x;
}
}
*p = 0;
}
// output buffer need not be larger than input
//
void xml_unescape(const char* in, char* out) {
char* p = out;
while (*in) {
if (!strncmp(in, "&lt;", 4)) {
*p++ = '<';
in += 4;
} else if (!strncmp(in, "&amp;", 5)) {
*p++ = '&';
in += 5;
} else if (!strncmp(in, "&#", 2)) {
in += 2;
char c = atoi(in);
*p++ = c;
in = strchr(in, ';');
if (in) in++;
} else {
*p++ = *in++;
}
}
*p = 0;
}
// we got an unrecognized line.
// If it has two <'s (e.g. <foo>xx</foo>) return 0.
// If it's of the form <foo> then scan for </foo> and return 0.
// Otherwise return ERR_XML_PARSE
//
int skip_unrecognized(char* buf, FILE* in) {
char* p, *q, buf2[256];
std::string close_tag;
p = strchr(buf, '<');
if (!p) {
return ERR_XML_PARSE;
}
if (strchr(p+1, '<')) {
return 0;
}
q = strchr(p+1, '>');
if (!q) {
return ERR_XML_PARSE;
}
*q = 0;
close_tag = string("</") + string(p+1) + string(">");
while (fgets(buf2, 256, in)) {
if (strstr(buf2, close_tag.c_str())) {
return 0;
}
}
return ERR_XML_PARSE;
}
XML_PARSER::XML_PARSER(MIOFILE* _f) {
f = _f;
}
// read until find non-whitespace char.
// Return the char in the reference param
// Return true iff reached EOF
//
bool XML_PARSER::scan_nonws(int& first_char) {
int c;
while (1) {
c = f->_getc();
if (c == EOF) return true;
if (isspace(c)) continue;
first_char = c;
return false;
}
}
// we just read a <; read until we find a >,
// and copy intervening text (except spaces) to buf.
// Return true iff reached EOF
// TODO: parse attributes too
//
bool XML_PARSER::scan_tag(char* buf, int len) {
int c;
while (1) {
c = f->_getc();
if (c == EOF) return true;
if (isspace(c)) continue;
if (c == '>') {
*buf = 0;
return false;
}
if (--len > 0) {
*buf++ = c;
}
}
}
// read and copy text to buf; stop when find a <;
// ungetc() that so we read it again
// Return true iff reached EOF
//
bool XML_PARSER::copy_until_tag(char* buf, int len) {
int c;
while (1) {
c = f->_getc();
if (c == EOF) return true;
if (c == '<') {
f->_ungetc(c);
*buf = 0;
return false;
}
if (--len > 0) {
*buf++ = c;
}
}
}
// Scan something, either tag or text.
// Strip whitespace at start and end.
// Return true iff reached EOF
//
bool XML_PARSER::get(char* buf, int len, bool& is_tag) {
bool eof;
int c;
eof = scan_nonws(c);
if (eof) return true;
if (c == '<') {
eof = scan_tag(buf, len);
if (eof) return true;
is_tag = true;
} else {
buf[0] = c;
eof = copy_until_tag(buf+1, len-1);
if (eof) return true;
is_tag = false;
}
strip_whitespace(buf);
return false;
}
// We just parsed "parsed_tag".
// If it matches "start_tag", and is followed by a string
// and by the matching close tag, return the string in "buf",
// and return true.
//
bool XML_PARSER::parse_str(
char* parsed_tag, const char* start_tag, char* buf, int len
) {
bool is_tag, eof;
char end_tag[256], tag[256], tmp[64000];
// handle the archaic form <tag/>, which means empty string
//
strcpy(tag, start_tag);
strcat(tag, "/");
if (!strcmp(parsed_tag, tag)) {
strcpy(buf, "");
return true;
}
// check for start tag
//
if (strcmp(parsed_tag, start_tag)) return false;
end_tag[0] = '/';
strcpy(end_tag+1, start_tag);
// get text after start tag
//
eof = get(tmp, 64000, is_tag);
if (eof) return false;
// if it's the end tag, return empty string
//
if (is_tag) {
if (strcmp(tmp, end_tag)) {
return false;
} else {
strcpy(buf, "");
return true;
}
}
eof = get(tag, sizeof(tag), is_tag);
if (eof) return false;
if (!is_tag) return false;
if (strcmp(tag, end_tag)) return false;
strlcpy(buf, tmp, len);
return true;
}
bool XML_PARSER::parse_string(
char* parsed_tag, const char* start_tag, string& str
) {
char buf[8192];
bool flag = parse_str(parsed_tag, start_tag, buf, sizeof(buf));
if (!flag) return false;
str = buf;
return true;
}
// Same, for integers
//
bool XML_PARSER::parse_int(char* parsed_tag, const char* start_tag, int& i) {
char buf[256], *end;
bool is_tag, eof;
char end_tag[256], tag[256];
if (strcmp(parsed_tag, start_tag)) return false;
eof = get(buf, sizeof(buf), is_tag);
if (eof) return false;
if (is_tag) return false;
i = strtol(buf, &end, 0);
if (end != buf+strlen(buf)) return false;
end_tag[0] = '/';
strcpy(end_tag+1, start_tag);
eof = get(tag, sizeof(tag), is_tag);
if (eof) return false;
if (!is_tag) return false;
if (strcmp(tag, end_tag)) return false;
return true;
}
// Same, for doubles
//
bool XML_PARSER::parse_double(char* parsed_tag, const char* start_tag, double& x) {
char buf[256], *end;
bool is_tag, eof;
char end_tag[256], tag[256];
if (strcmp(parsed_tag, start_tag)) return false;
eof = get(buf, sizeof(buf), is_tag);
if (eof) return false;
if (is_tag) return false;
x = strtod(buf, &end);
if (end != buf+strlen(buf)) return false;
end_tag[0] = '/';
strcpy(end_tag+1, start_tag);
eof = get(tag, sizeof(tag), is_tag);
if (eof) return false;
if (!is_tag) return false;
if (strcmp(tag, end_tag)) return false;
return true;
}
// Same, for bools
//
bool XML_PARSER::parse_bool(char* parsed_tag, const char* start_tag, bool& b) {
char buf[256], *end;
bool is_tag, eof;
char end_tag[256], tag[256];
// handle the archaic form <tag/>, which means true
//
strcpy(tag, start_tag);
strcat(tag, "/");
if (!strcmp(parsed_tag, tag)) {
b = true;
return true;
}
// otherwise look for something of the form <tag>int</tag>
//
if (strcmp(parsed_tag, start_tag)) return false;
eof = get(buf, sizeof(buf), is_tag);
if (eof) return false;
if (is_tag) return false;
b = (strtol(buf, &end, 0) != 0);
if (end != buf+strlen(buf)) return false;
end_tag[0] = '/';
strcpy(end_tag+1, start_tag);
eof = get(tag, sizeof(tag), is_tag);
if (eof) return false;
if (!is_tag) return false;
if (strcmp(tag, end_tag)) return false;
return true;
}
// parse a start tag (optionally preceded by <?xml>)
//
bool XML_PARSER::parse_start(const char* start_tag) {
char tag[256];
bool eof, is_tag;
eof = get(tag, sizeof(tag), is_tag);
if (eof || !is_tag ) {
return false;
}
if (strstr(tag, "?xml")) {
eof = get(tag, sizeof(tag), is_tag);
if (eof || !is_tag ) {
return false;
}
}
if (strcmp(tag, start_tag)) {
return false;
}
return true;
}
// copy everything up to (but not including) the given end tag.
// The copied text may include XML tags.
// strips whitespace.
//
int XML_PARSER::element_contents(const char* end_tag, char* buf, int buflen) {
int n=0;
int retval=0;
while (1) {
if (n == buflen-1) {
retval = ERR_XML_PARSE;
break;
}
int c = f->_getc();
if (c == EOF) {
retval = ERR_XML_PARSE;
break;
}
buf[n++] = c;
buf[n] = 0;
char* p = strstr(buf, end_tag);
if (p) {
*p = 0;
break;
}
}
buf[n] = 0;
strip_whitespace(buf);
return retval;
}
// sample use is shown below
#if 0
void parse(FILE* f) {
char tag[256];
bool is_tag, flag;
MIOFILE mf;
XML_PARSER xp(f);
char name[256];
int val;
double x;
mf.init_file(f);
if (!xp.parse_start("blah")) {
printf("missing start tag\n");
return;
}
while (!xp.get(tag, sizeof(tag), is_tag)) {
if (!is_tag) {
printf("unexpected text: %s\n", tag);
continue;
}
if (!strcmp(tag, "/blah")) {
printf("success\n");
return;
} else if (xp.parse_str(tag, "str", name, sizeof(name))) {
printf("got str: %s\n", name);
} else if (xp.parse_int(tag, "int", val)) {
printf("got int: %d\n", val);
} else if (xp.parse_double(tag, "double", x)) {
printf("got double: %f\n", x);
} else if (xp.parse_bool(tag, "bool", flag)) {
printf("got bool: %d\n", flag);
} else {
printf("unparsed tag: %s\n", tag);
return;
}
}
printf("unexpected EOF\n");
}
int main() {
FILE* f = fopen("foo.xml", "r");
parse(f);
}
#endif
const char *BOINC_RCSID_3f3de9eb18 = "$Id$";
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