compiled-tools/relpath.c

   1
   2 #include <strings.h>
   3 #include <limits.h>
   4 #include <stdio.h>
   5
   6 #define VERSION 0.5
   7 #define MYNAME "relpath"
   8
   9 void help(FILE* fd)
  10 {
  11         fprintf(fd, "%s",
  12         "Usage: " MYNAME " [-n] <DIR-1> <DIR-2>\n"
  13         "  Print a relative path from <DIR-2> to <DIR-1>.\n"
  14         "  Useful for creating relative symlinks.\n"
  15         "Example:\n"
  16         "  This command creates <DIR-2>/symlink.txt pointing to <DIR-1>/link_target.txt:\n"
  17         "  ln -s $(" MYNAME " <DIR-1> <DIR-2>)link_target.txt <DIR-2>/symlink.txt\n"
  18         "Options:\n"
  19         "  -n  do not print newline\n"
  20         "Exit codes:\n"
  21         "  0   success\n"
  22         "  1   a directory does not exist\n"
  23         "  2   parameter error\n");
  24 }
  25
  26 int main(int argc, char *argv[]) {
  27
  28         unsigned int i = 1;
  29         unsigned int i2 = 0;
  30         unsigned int per = 0;
  31         unsigned int newline = 1;
  32         char commondir[_POSIX_PATH_MAX];
  33         char buff[_POSIX_PATH_MAX];
  34         char route[_POSIX_PATH_MAX];
  35         char realname1[_POSIX_PATH_MAX];
  36         char realname2[_POSIX_PATH_MAX];
  37
  38         while(i < argc && argv[i][0] == '-') {
  39                 if(strcmp(argv[i], "-n")==0) {
  40                         newline = 0;
  41                 }
  42                 else if(strcmp(argv[i], "--help")==0) {
  43                         help(stdout);
  44                         exit(0);
  45                 }
  46                 i++;
  47         }
  48
  49         if(i+1 < argc) {
  50                 if(realpath(argv[i], realname1)==0) exit(1);
  51                 i++;
  52                 if(realpath(argv[i], realname2)==0) exit(1);
  53         }
  54         else {
  55                 fprintf(stderr, MYNAME ": Parameter error\n");
  56                 help(stderr);
  57                 exit(2);
  58         }
  59
  60
  61         strcpy(buff, "");
  62         strcpy(commondir, "");
  63         strcpy(route, "");
  64 #ifdef DEBUG
  65         fprintf(stderr, " %s\n %s\n", realname1, realname2);
  66 #endif
  67         if(strcmp(realname1, realname2)==0) {
  68                 // directories are identical!
  69                 printf("./");
  70                 if(newline) printf("\n");
  71                 exit(0);
  72         }
  73         if(realname1[strlen(realname1)-1] != '/') strcat(realname1, "/");
  74         if(realname2[strlen(realname2)-1] != '/') strcat(realname2, "/");
  75
  76         i = 0;
  77         while(strlen(realname1)>i && strlen(realname2)>i && realname1[i] == realname2[i]) {
  78                 sprintf(buff, "%s%c", buff, realname1[i]);
  79                 if(realname1[i]=='/') {
  80                         strcat(commondir, buff);
  81                         strcpy(buff, "");
  82                         i2=i;
  83                 }
  84                 i++;
  85         }
  86
  87         //route = "../"*(1+count("/",a2)).a1
  88
  89         while(strlen(realname2)>=++i) {
  90                 if(realname2[i]=='/') per++;
  91         }
  92         strcpy(buff, "");
  93         while(per>0) {
  94                 strcat(buff, "../");
  95                 per--;
  96         }
  97         strcpy(route, buff);
  98
  99         while(strlen(realname1)>=++i2) {
 100                 sprintf(route, "%s%c", route, realname1[i2]);
 101         }
 102
 103 #ifdef DEBUG
 104         fprintf(stderr, "%s\n", commondir);
 105 #endif
 106         printf("%s", route);
 107         if(newline) printf("\n");
 108
 109         exit(0);
 110 }