#include <stdio.h>  
#include <malloc.h>  
#include <string.h>  
 
typedef struct path_element_t{  
  char *element;  
  struct path_element_t *prev;  
  struct path_element_t *next;  
} path_element;  
 
int rel2abspath(char *,char *,char **);  
 
int main(int argc,char **argv){  
 
  char *buf=NULL;  
 
  if(argc==3){  
 
    rel2abspath(argv[1],argv[2],&buf);  
    printf("RESULT: %s\n",buf);  
    if(buf) free(buf);  
 
  }else{  
 
    printf("Usage: %s [abs_path] [rel_path]\n",argv[0]);  
    printf("\nExample: %s 'http://unstable.elemental.com/mozilla/build/latest/mozilla/caps/dox/nsBasePrincipal_8cpp.html#a0' '.././../////./../'\n",argv[0]);  
    return 1;  
 
  }  
 
  return 0;  
 
}  
 
int rel2abspath(char *abs_path,char *rel_path,char **buf){  
 
  char *path_n=NULL;  
  char *abs_path_n=NULL;  
  char *first_sep=NULL;  
  char *abs_second_sep=NULL;  
  char *rel_second_sep=NULL;  
  char *last_offset=NULL;  
  char *temp_path=NULL;  
  char *abs_doc=NULL;  
  char *rel_doc=NULL;  
  char chr;  
  int len=0;  
  int count=0;  
  path_element *head=NULL,*cur=NULL,*prev=NULL,*temp=NULL;  
 
  //char *abs_path="http://sdfdsf/sdff/sd";  
  //char *rel_path="../xxxx";  
 
  //printf("%s\n",abs_path);  
  //printf("%s\n",rel_path);  
 
  if((first_sep=(char *)strchr((const char *)abs_path,(int)':'))){  
 
    if(first_sep[1]=='/'&&first_sep[2]=='/'){  
 
      first_sep+=3;  
 
      if((first_sep=(char *)strchr((const char *)first_sep,(int)'/'))){  
 
        ++first_sep;  
 
      }else{  
 
        //printf("Error.Not found/.\n");  
        return 1;  
 
      }  
 
    }else{  
 
      //printf("Error.Not found //.\n");  
      return 2;  
 
    }  
 
  }else{  
 
    //printf("Error.Not found :.\n");  
    return 3;  
 
  }  
 
  if((abs_second_sep=(char *)strrchr((const char *)first_sep,(int)'/'))){  
 
    ++abs_second_sep;  
    abs_doc=abs_second_sep;  
 
    //printf("%s\n",abs_second_sep);  
 
    if(rel_path[0]!='/'){  
      len=abs_second_sep-first_sep;  
    }else{  
      len=0;  
    }  
 
    if((rel_second_sep=(char *)strrchr((const char *)rel_path,(int)'/'))){  
      len+=strlen(rel_path);  
    }  
 
    path_n=(char *)malloc(sizeof(char)*len+1);  
 
    if(rel_path[0]!='/'){  
      memcpy(path_n,first_sep,abs_second_sep-first_sep);  
 
      if(rel_second_sep){  
        rel_doc=rel_second_sep+1;  
        memcpy(path_n+(abs_second_sep-first_sep),rel_path,rel_second_sep-rel_path);  
      }else{  
        rel_doc=rel_path;  
      }  
    }else{  
      if(rel_second_sep){  
        rel_doc=rel_second_sep+1;  
        memcpy(path_n,rel_path,rel_second_sep-rel_path);  
      }else{  
        rel_doc=rel_path;  
      }  
    }  
 
    path_n[len]='\0';  
 
    //printf("%s\n",path_n);  
 
  }else{  
 
    abs_doc=first_sep;  
    len=0;  
 
    if((rel_second_sep=(char *)strrchr((const char *)rel_path,(int)'/'))){  
      len+=strlen(rel_path);  
    }  
 
    path_n=(char *)malloc(sizeof(char)*len+1);  
 
    if(rel_second_sep){  
      rel_doc=rel_second_sep+1;  
      memcpy(path_n,rel_path,rel_second_sep-rel_path);  
    }else{  
      rel_doc=rel_path;  
    }  
 
    path_n[len]='\0';  
 
  }  
 
  last_offset=path_n;  
 
  while('\0'!=(chr=*(path_n+count))){  
 
    switch(chr){  
 
      case '/':  
 
        cur=(path_element *)malloc(sizeof(path_element));  
        memset(cur,0x0,sizeof(path_element));  
        cur->next=NULL;  
        if(head==NULL){  
          head=cur;  
        }else{  
          prev->next=cur;  
        }  
        cur->prev=prev;  
        prev=cur;  
 
        len=sizeof(char)*((path_n+count)-last_offset);  
        cur->element=(char *)malloc(sizeof(char)*len+1);  
        memcpy(cur->element,last_offset,len);  
        cur->element[len]='\0';  
        //printf("%s\n",cur->element);  
         
        last_offset=path_n+count+1;  
 
        break;  
 
      default:  
 
    }  
 
    ++count;  
 
  }  
 
  if((path_n+count)-last_offset>0){  
 
    cur=(path_element *)malloc(sizeof(path_element));  
    memset(cur,0x0,sizeof(path_element));  
    cur->next=NULL;  
    if(head==NULL){  
      head=cur;  
    }else{  
      prev->next=cur;  
    }  
    cur->prev=prev;  
    prev=cur;  
 
    len=sizeof(char)*((path_n+count)-last_offset);  
    cur->element=(char *)malloc(sizeof(char)*len+1);  
    memcpy(cur->element,last_offset,len);  
    cur->element[len]='\0';  
    //printf("%s\n",cur->element);  
 
  }  
 
  cur=head;  
  while(cur!=NULL){  
 
    temp=cur;  
 
    if(memcmp(cur->element,".",1)==0&&strlen(cur->element)==1){  
 
      if(cur->prev==NULL&&cur->next==NULL){// 앞 엘리먼트와 다음 엘리먼트가 null 일 경우  
        head=NULL;  
        cur=NULL;  
        free(temp);  
      }else if(cur->prev==NULL&&cur->next){// 앞 엘리먼트만 null 일 경우  
        head=cur->next;  
        head->prev=NULL;  
        cur=cur->next;  
        free(temp);  
      }else if(cur->prev&&cur->next==NULL){// 다음 엘리먼트만 null 일 경우  
        (cur->prev)->next=NULL;  
        cur=NULL;  
        free(temp);  
      }else{// 전부 null 이 아닐 경우  
        (cur->prev)->next=cur->next;  
        (cur->next)->prev=cur->prev;  
        cur=cur->next;  
        free(temp);  
      }  
 
    }else if(memcmp(cur->element,"..",2)==0&&strlen(cur->element)==2){  
 
      if(cur->prev==NULL&&cur->next==NULL){// 앞 엘리먼트와 다음 엘리먼트가 null 일 경우  
        head=NULL;  
        cur=NULL;  
        free(temp);  
      }else if(cur->prev==NULL&&cur->next){// 앞 엘리먼트만 null 일 경우  
        head=cur->next;  
        head->prev=NULL;  
        cur=cur->next;  
        free(temp);  
      }else if(cur->prev&&cur->next==NULL){// 다음 엘리먼트만 null 일 경우  
        if((cur->prev)->prev){  
          ((cur->prev)->prev)->next=NULL;  
          free(cur->prev);  
          cur=NULL;  
          free(temp);  
        }else{  
          head=NULL;  
          free(cur->prev);  
          cur=NULL;  
          free(temp);  
        }  
      }else{// 전부 null 이 아닐 경우  
        if((cur->prev)->prev){  
          ((cur->prev)->prev)->next=cur->next;  
          (cur->next)->prev=(cur->prev)->prev;  
          free(cur->prev);  
          cur=cur->next;  
          free(temp);  
        }else{  
          head=cur->next;  
          head->prev=NULL;  
          free(cur->prev);  
          cur=cur->next;  
          free(temp);  
        }  
      }  
 
    }else{  
 
      cur=cur->next;  
 
    }  
 
  }  
 
  cur=head;  
  while(cur!=NULL){  
 
    temp=cur;  
 
    if(strlen(cur->element)==0){  
 
      if(cur->prev==NULL&&cur->next==NULL){  
        head=NULL;  
        cur=NULL;  
        free(temp);  
      }else if(cur->prev&&cur->next==NULL){  
        (cur->prev)->next=NULL;  
        cur=NULL;  
        free(temp);  
      }else if(cur->prev==NULL&&cur->next){  
        head=cur->next;  
        head->prev=NULL;  
        cur=cur->next;  
        free(temp);  
      }else{  
        (cur->prev)->next=cur->next;  
        (cur->next)->prev=cur->prev;  
        cur=cur->next;  
        free(temp);  
      }  
 
    }else{  
 
      cur=cur->next;  
 
    }  
 
  }  
   
 
  cur=head;  
  len=0;  
  while(cur!=NULL){  
 
    //printf("0x%08x 0x%08x 0x%08x %s\n",cur->prev,cur,cur->next,cur->element);  
    len+=strlen(cur->element);  
    ++len;  
       
    cur=cur->next;  
 
  }  
 
  len+=first_sep-abs_path;  
 
  if(rel_doc==NULL||strlen(rel_doc)==0){  
 
    len+=strlen(abs_doc);  
 
  }else{  
 
    len+=strlen(rel_doc);  
 
  }  
 
  abs_path_n=(char *)malloc(len+1);  
  temp_path=abs_path_n;  
  memcpy(abs_path_n,abs_path,first_sep-abs_path);  
  abs_path_n+=(first_sep-abs_path);  
 
  cur=head;  
  while(cur!=NULL){  
 
    memcpy(abs_path_n,cur->element,strlen(cur->element));  
    abs_path_n+=strlen(cur->element);  
    abs_path_n[0]='/';  
    ++abs_path_n;  
 
    cur=cur->next;  
 
  }  
 
  if(rel_doc==NULL||strlen(rel_doc)==0){  
 
    memcpy(abs_path_n,abs_doc,strlen(abs_doc));  
    abs_path_n+=strlen(abs_doc);  
 
  }else{  
 
    memcpy(abs_path_n,rel_doc,strlen(rel_doc));  
    abs_path_n+=strlen(rel_doc);  
 
  }  
 
  abs_path_n[0]='\0';  
  (*buf)=temp_path;  
 
  return 0;  
 
}