/* Parse HyperText Document Address HTParse.c
** ================================
*/
#include "HTUtils.h"
#include "HTParse.h"
#include "tcp.h"
#define HEX_ESCAPE '%'
struct struct_parts {
char * access;
char * host;
char * absolute;
char * relative;
/* char * search; no - treated as part of path */
char * anchor;
};
/* Strip white space off a string
** ------------------------------
**
** On exit,
** Return value points to first non-white character, or to 0 if none.
** All trailing white space is OVERWRITTEN with zero.
*/
#ifdef __STDC__
char * HTStrip(char * s)
#else
char * HTStrip(s)
char *s;
#endif
{
#define SPACE(c) ((c==' ')||(c=='\t')||(c=='\n'))
char * p=s;
for(p=s;*p;p++); /* Find end of string */
for(p--;p>=s;p--) {
if(SPACE(*p)) *p=0; /* Zap trailing blanks */
else break;
}
while(SPACE(*s))s++; /* Strip leading blanks */
return s;
}
/* Scan a filename for its consituents
** -----------------------------------
**
** On entry,
** name points to a document name which may be incomplete.
** On exit,
** absolute or relative may be nonzero (but not both).
** host, anchor and access may be nonzero if they were specified.
** Any which are nonzero point to zero terminated strings.
*/
#ifdef __STDC__
PRIVATE void scan(char * name, struct struct_parts *parts)
#else
PRIVATE void scan(name, parts)
char * name;
struct struct_parts *parts;
#endif
{
char * after_access;
char * p;
int length = strlen(name);
parts->access = 0;
parts->host = 0;
parts->absolute = 0;
parts->relative = 0;
parts->anchor = 0;
after_access = name;
for(p=name; *p; p++) {
if (*p==':') {
*p = 0;
parts->access = name; /* Access name has been specified */
after_access = p+1;
}
if (*p=='/') break;
if (*p=='#') break;
}
for(p=name+length-1; p>=name; p--) {
if (*p =='#') {
parts->anchor=p+1;
*p=0; /* terminate the rest */
}
}
p = after_access;
if (*p=='/'){
if (p[1]=='/') {
parts->host = p+2; /* host has been specified */
*p=0; /* Terminate access */
p=strchr(parts->host,'/'); /* look for end of host name if any */
if(p) {
*p=0; /* Terminate host */
parts->absolute = p+1; /* Root has been found */
}
} else {
parts->absolute = p+1; /* Root found but no host */
}
} else {
parts->relative = (*after_access) ? after_access : 0; /* zero for "" */
}
/* Access specified but no host: the anchor was not really one
e.g. news:j462#36487@foo.bar -- JFG 10/7/92, from bug report */
if (parts->access && ! parts->host && parts->anchor) {
*(parts->anchor - 1) = '#'; /* Restore the '#' in the address */
parts->anchor = 0;
}
#ifdef NOT_DEFINED /* search is just treated as part of path */
{
char *p = relative ? relative : absolute;
if (p) {
char * q = strchr(p, '?'); /* Any search string? */
if (q) {
*q = 0; /* If so, chop that off. */
parts->search = q+1;
}
}
}
#endif
} /*scan */
/* Parse a Name relative to another name
** -------------------------------------
**
** This returns those parts of a name which are given (and requested)
** substituting bits from the related name where necessary.
**
** On entry,
** aName A filename given
** relatedName A name relative to which aName is to be parsed
** wanted A mask for the bits which are wanted.
**
** On exit,
** returns A pointer to a malloc'd string which MUST BE FREED
*/
#ifdef __STDC__
char * HTParse(const char * aName, const char * relatedName, int wanted)
#else
char * HTParse(aName, relatedName, wanted)
char * aName;
char * relatedName;
int wanted;
#endif
{
char * result = 0;
char * return_value = 0;
int len;
char * name = 0;
char * rel = 0;
char * p;
struct struct_parts given, related;
/* Make working copies of input strings to cut up:
*/
len = strlen(aName)+strlen(relatedName)+10;
result=(char *)malloc(len); /* Lots of space: more than enough */
if (result == NULL) outofmem(__FILE__, "HTParse");
StrAllocCopy(name, aName);
StrAllocCopy(rel, relatedName);
scan(name, &given);
scan(rel, &related);
result[0]=0; /* Clear string */
if (wanted & PARSE_ACCESS)
if (given.access|| related.access) {
strcat(result, given.access ? given.access : related.access);
if(wanted & PARSE_PUNCTUATION) strcat(result, ":");
}
if (given.access && related.access) /* If different, inherit nothing. */
if (strcmp(given.access, related.access)!=0) {
related.host=0;
related.absolute=0;
related.relative=0;
related.anchor=0;
}
if (wanted & PARSE_HOST)
if(given.host || related.host) {
if(wanted & PARSE_PUNCTUATION) strcat(result, "//");
strcat(result, given.host ? given.host : related.host);
}
if (given.host && related.host) /* If different hosts, inherit no path. */
if (strcmp(given.host, related.host)!=0) {
related.absolute=0;
related.relative=0;
related.anchor=0;
}
if (wanted & PARSE_PATH) {
if(given.absolute) { /* All is given */
if(wanted & PARSE_PUNCTUATION) strcat(result, "/");
strcat(result, given.absolute);
} else if(related.absolute) { /* Adopt path not name */
strcat(result, "/");
strcat(result, related.absolute);
if (given.relative) {
p = strchr(result, '?'); /* Search part? */
if (!p) p=result+strlen(result)-1;
for (; *p!='/'; p--); /* last / */
p[1]=0; /* Remove filename */
strcat(result, given.relative); /* Add given one */
HTSimplify (result);
}
} else if(given.relative) {
strcat(result, given.relative); /* what we've got */
} else if(related.relative) {
strcat(result, related.relative);
} else { /* No inheritance */
strcat(result, "/");
}
}
if (wanted & PARSE_ANCHOR)
if(given.anchor || related.anchor) {
if(wanted & PARSE_PUNCTUATION) strcat(result, "#");
strcat(result, given.anchor ? given.anchor : related.anchor);
}
free(rel);
free(name);
StrAllocCopy(return_value, result);
free(result);
return return_value; /* exactly the right length */
}
/* Simplify a filename
// -------------------
//
// A unix-style file is allowed to contain the seqeunce xxx/../ which may be
// replaced by "" , and the seqeunce "/./" which may be replaced by "/".
// Simplification helps us recognize duplicate filenames.
//
// Thus, /etc/junk/../fred becomes /etc/fred
// /etc/junk/./fred becomes /etc/junk/fred
*/
#ifdef __STDC__
void HTSimplify(char * filename)
#else
void HTSimplify(filename)
char * filename;
#endif
{
char * p;
char * q;
if (filename[0] && filename[1]) /* Bug fix 12 Mar 93 TBL */
for(p=filename+2; *p; p++) {
if (*p=='/') {
if ((p[1]=='.') && (p[2]=='.') && (p[3]=='/' || !p[3] )) {
for (q=p-1; (q>filename) && (*q!='/'); q--); /* prev slash */
if (*q=='/') {
strcpy(q, p+3); /* Remove /xxx/.. */
if (!*filename) strcpy(filename, "/");
p = q-1; /* Start again with prev slash */
} else { /* xxx/.. error? */
strcpy(filename, p[3] ? p+4 : p+3); /* rm xxx/../ */
p = filename; /* Start again */
}
} else if ((p[1]=='.') && (p[2]=='/' || !p[2])) {
strcpy(p, p+2); /* Remove a slash and a dot */
}
}
}
}
/* Make Relative Name
** ------------------
**
** This function creates and returns a string which gives an expression of
** one address as related to another. Where there is no relation, an absolute
** address is retured.
**
** On entry,
** Both names must be absolute, fully qualified names of nodes
** (no anchor bits)
**
** On exit,
** The return result points to a newly allocated name which, if
** parsed by HTParse relative to relatedName, will yield aName.
** The caller is responsible for freeing the resulting name later.
**
*/
#ifdef __STDC__
char * HTRelative(const char * aName, const char *relatedName)
#else
char * HTRelative(aName, relatedName)
char * aName;
char * relatedName;
#endif
{
char * result = 0;
CONST char *p = aName;
CONST char *q = relatedName;
CONST char * after_access = 0;
CONST char * path = 0;
CONST char * last_slash = 0;
int slashes = 0;
for(;*p; p++, q++) { /* Find extent of match */
if (*p!=*q) break;
if (*p==':') after_access = p+1;
if (*p=='/') {
last_slash = p;
slashes++;
if (slashes==3) path=p;
}
}
/* q, p point to the first non-matching character or zero */
if (!after_access) { /* Different access */
StrAllocCopy(result, aName);
} else if (slashes<3){ /* Different nodes */
StrAllocCopy(result, after_access);
} else if (slashes==3){ /* Same node, different path */
StrAllocCopy(result, path);
} else { /* Some path in common */
int levels= 0;
for(; *q && (*q!='#'); q++) if (*q=='/') levels++;
result = (char *)malloc(3*levels + strlen(last_slash) + 1);
if (result == NULL) outofmem(__FILE__, "HTRelative");
result[0]=0;
for(;levels; levels--)strcat(result, "../");
strcat(result, last_slash+1);
}
if (TRACE) fprintf(stderr, "HT: `%s' expressed relative to\n `%s' is\n `%s'.",
aName, relatedName, result);
return result;
}
/* Escape undesirable characters using % HTEscape()
** -------------------------------------
**
** This function takes a pointer to a string in which
** some characters may be unacceptable unescaped.
** It returns a string which has these characters
** represented by a '%' character followed by two hex digits.
**
** Unlike HTUnEscape(), this routine returns a malloced string.
*/
PRIVATE CONST unsigned char isAcceptable[96] =
/* Bit 0 xalpha -- see HTFile.h
** Bit 1 xpalpha -- as xalpha but with plus.
** Bit 3 ... path -- as xpalphas but with /
*/
/* 0 1 2 3 4 5 6 7 8 9 A B C D E F */
{ 0,0,0,0,0,0,0,0,0,0,7,6,0,7,7,4, /* 2x !"#$%&'()*+,-./ */
7,7,7,7,7,7,7,7,7,7,0,0,0,0,0,0, /* 3x 0123456789:;<=>? */
7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, /* 4x @ABCDEFGHIJKLMNO */
7,7,7,7,7,7,7,7,7,7,7,0,0,0,0,7, /* 5X PQRSTUVWXYZ[\]^_ */
0,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, /* 6x `abcdefghijklmno */
7,7,7,7,7,7,7,7,7,7,7,0,0,0,0,0 }; /* 7X pqrstuvwxyz{\}~ DEL */
PRIVATE char *hex = "0123456789ABCDEF";
PUBLIC char * HTEscape ARGS2 (CONST char *, str,
unsigned char, mask)
{
#define ACCEPTABLE(a) ( a>=32 && a<128 && ((isAcceptable[a-32]) & mask))
CONST char * p;
char * q;
char * result;
int unacceptable = 0;
for(p=str; *p; p++)
if (!ACCEPTABLE((unsigned char)TOASCII(*p)))
unacceptable++;
result = (char *) malloc(p-str + unacceptable+ unacceptable + 1);
if (result == NULL) outofmem(__FILE__, "HTEscape");
for(q=result, p=str; *p; p++) {
unsigned char a = TOASCII(*p);
if (!ACCEPTABLE(a)) {
*q++ = HEX_ESCAPE; /* Means hex commming */
*q++ = hex[a >> 4];
*q++ = hex[a & 15];
}
else *q++ = *p;
}
*q++ = 0; /* Terminate */
return result;
}
/* Decode %xx escaped characters HTUnEscape()
** -----------------------------
**
** This function takes a pointer to a string in which some
** characters may have been encoded in %xy form, where xy is
** the acsii hex code for character 16x+y.
** The string is converted in place, as it will never grow.
*/
PRIVATE char from_hex ARGS1(char, c)
{
return c >= '0' && c <= '9' ? c - '0'
: c >= 'A' && c <= 'F'? c - 'A' + 10
: c - 'a' + 10; /* accept small letters just in case */
}
PUBLIC char * HTUnEscape ARGS1( char *, str)
{
char * p = str;
char * q = str;
while(*p) {
if (*p == HEX_ESCAPE) {
p++;
if (*p) *q = from_hex(*p++) * 16;
if (*p) *q = FROMASCII(*q + from_hex(*p++));
q++;
} else {
*q++ = *p++;
}
}
*q++ = 0;
return str;
} /* HTUnEscape */
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