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/*
** This file contains code use for resolving relative URLs
*/
#include <stdlib.h>
#include "url.h"
#if INTERFACE
/*
** A parsed URI is held in an instance of the following structure.
** Each component is recorded in memory obtained from malloc().
**
** The examples are from the URI
**
** http://192.168.1.1:8080/cgi-bin/printenv?name=xyzzy&addr=none#frag
*/
typedef struct Url Url;
struct Url {
char *zScheme; /* Ex: "http" */
char *zAuthority; /* Ex: "192.168.1.1:8080" */
char *zPath; /* Ex: "cgi-bin/printenv" */
char *zQuery; /* Ex: "name=xyzzy&addr=none" */
char *zFragment; /* Ex: "frag" */
};
#endif
/*
** Return the length of the next component of the URL in z[] given
** that the component starts at z[0]. The initial sequence of the
** component must be zInit[]. The component is terminated by any
** character in zTerm[]. The length returned is 0 if the component
** doesn't exist. The length includes the zInit[] string, but not
** the termination character.
**
** Component zInit zTerm
** ---------- ------- -------
** scheme "" ":/?#"
** authority "//" "/?#"
** path "/" "?#"
** query "?" "#"
** fragment "#" ""
*/
static int ComponentLength(const char *z, const char *zInit, const char *zTerm){
int i, n;
for(n=0; zInit[n]; n++){
if( zInit[n]!=z[n] ) return 0;
}
while( z[n] ){
for(i=0; zTerm[i]; i++){
if( z[n]==zTerm[i] ) return n;
}
n++;
}
return n;
}
/*
** Duplicate a string of length n.
*/
static char *StrNDup(const char *z, int n){
char *zResult;
if( n<=0 ){
n = strlen(z);
}
zResult = malloc( n + 1 );
if( zResult ){
memcpy(zResult, z, n);
zResult[n] = 0;
}
return zResult;
}
/*
** Parse a text URI into an Url structure.
*/
Url *ParseUrl(const char *zUri){
Url *p;
int n;
p = malloc( sizeof(*p) );
if( p==0 ) return 0;
memset(p, 0, sizeof(*p));
if( zUri==0 || zUri[0]==0 ) return p;
while( isspace(zUri[0]) ){ zUri++; }
n = ComponentLength(zUri, "", ":/?# ");
if( n>0 && zUri[n]==':' ){
p->zScheme = StrNDup(zUri, n);
zUri += n+1;
}
n = ComponentLength(zUri, "//", "/?# ");
if( n>0 ){
p->zAuthority = StrNDup(&zUri[2], n-2);
zUri += n;
}
n = ComponentLength(zUri, "", "?# ");
if( n>0 ){
p->zPath = StrNDup(zUri, n);
zUri += n;
}
n = ComponentLength(zUri, "?", "# ");
if( n>0 ){
p->zQuery = StrNDup(&zUri[1], n-1);
zUri += n;
}
n = ComponentLength(zUri, "#", " ");
if( n>0 ){
p->zFragment = StrNDup(&zUri[1], n-1);
}
return p;
}
/*
** Delete an Url structure.
*/
void FreeUrl(Url *p){
if( p==0 ) return;
if( p->zScheme ) free(p->zScheme);
if( p->zAuthority ) free(p->zAuthority);
if( p->zPath ) free(p->zPath);
if( p->zQuery ) free(p->zQuery);
if( p->zFragment ) free(p->zFragment);
free(p);
}
/*
** Create a string to hold the given URI. Memory to hold the string
** is obtained from malloc() and must be freed by the calling
** function.
*/
char *BuildUrl(Url *p){
int n = 1;
char *z;
if( p->zScheme ) n += strlen(p->zScheme)+1;
if( p->zAuthority ) n += strlen(p->zAuthority)+2;
if( p->zPath ) n += strlen(p->zPath)+1;
if( p->zQuery ) n += strlen(p->zQuery)+1;
if( p->zFragment ) n += strlen(p->zFragment)+1;
z = malloc( n );
if( z==0 ) return 0;
n = 0;
if( p->zScheme ){
sprintf(z, "%s:", p->zScheme);
n = strlen(z);
}
if( p->zAuthority ){
sprintf(&z[n], "//%s", p->zAuthority);
n += strlen(&z[n]);
}
if( p->zPath ){
sprintf(&z[n], "%s", p->zPath);
n += strlen(&z[n]);
}
if( p->zQuery ){
sprintf(&z[n], "?%s", p->zQuery);
n += strlen(&z[n]);
}
if( p->zFragment ){
sprintf(&z[n], "#%s", p->zFragment);
}
return z;
}
/*
** Replace the string in *pzDest with the string in zSrc
*/
static void ReplaceStr(char **pzDest, const char *zSrc){
if( *pzDest!=0 ) free(*pzDest);
if( zSrc==0 ){
*pzDest = 0;
}else{
*pzDest = StrNDup(zSrc, -1);
}
}
/*
** Remove leading and trailing spaces from the given string. Return
** a new string obtained from malloc().
*/
static char *Trim(char *z){
int i;
char *zNew;
while( isspace(*z) ) z++;
i = strlen(z);
zNew = malloc( i+1 );
if( zNew==0 ) return 0;
strcpy(zNew, z);
if( i>0 && isspace(zNew[i-1]) ){
i--;
zNew[i] = 0;
}
return zNew;
}
/*
** Resolve a sequence of URLs. Return the result in space obtained
** from malloc().
*/
char *ResolveUrl(
char *zBase, /* The base URL */
const char **azSeries /* A list of relatives. NULL terminated */
){
Url *base;
Url *term;
char *z;
base = ParseUrl(zBase);
while( azSeries[0] ){
term = ParseUrl(azSeries[0]);
azSeries++;
if( term->zScheme==0 && term->zAuthority==0 && term->zPath==0
&& term->zQuery==0 && term->zFragment ){
ReplaceStr(&base->zFragment, term->zFragment);
}else if( term->zScheme ){
Url temp;
temp = *term;
*term = *base;
*base = temp;
}else if( term->zAuthority ){
ReplaceStr(&base->zAuthority, term->zAuthority);
ReplaceStr(&base->zPath, term->zPath);
ReplaceStr(&base->zQuery, term->zQuery);
ReplaceStr(&base->zFragment, term->zFragment);
}else if( term->zPath && term->zPath[0]=='/' ){
ReplaceStr(&base->zPath, term->zPath);
ReplaceStr(&base->zQuery, term->zQuery);
ReplaceStr(&base->zFragment, term->zFragment);
}else if( term->zPath && base->zPath ){
char *zBuf;
int i, j;
zBuf = malloc( strlen(base->zPath) + strlen(term->zPath) + 2 );
if( zBuf ){
sprintf(zBuf,"%s", base->zPath);
for(i=strlen(zBuf)-1; i>=0 && zBuf[i]!='/'; i--){ zBuf[i] = 0; }
strcat(zBuf, term->zPath);
for(i=0; zBuf[i]; i++){
if( zBuf[i]=='/' && zBuf[i+1]=='.' && zBuf[i+2]=='/' ){
strcpy(&zBuf[i+1], &zBuf[i+3]);
i--;
continue;
}
if( zBuf[i]=='/' && zBuf[i+1]=='.' && zBuf[i+2]==0 ){
zBuf[i+1] = 0;
continue;
}
if( i>0 && zBuf[i]=='/' && zBuf[i+1]=='.' && zBuf[i+2]=='.'
&& (zBuf[i+3]=='/' || zBuf[i+3]==0) ){
for(j=i-1; j>=0 && zBuf[j]!='/'; j--){}
if( zBuf[i+3] ){
strcpy(&zBuf[j+1], &zBuf[i+4]);
}else{
zBuf[j+1] = 0;
}
i = j-1;
if( i<-1 ) i = -1;
continue;
}
}
free(base->zPath);
base->zPath = zBuf;
}
ReplaceStr(&base->zQuery, term->zQuery);
ReplaceStr(&base->zFragment, term->zFragment);
}
FreeUrl(term);
}
z = BuildUrl(base);
FreeUrl(base);
return z;
}
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