a.cpp

UNIFY算法

 /*   92-12-22   @ftp.uu.net:/usenet/comp.sources.misc/volume25/unidiff/part01.Z   */   
    
  /*   
  **   unify.c   -   change   a   diff   to/from   a   context   diff   from/to   a   unified   diff.   
  **   
  **   Version   1.1   
  **   
  **   Author:     Wayne   Davison   <[e-mail]>   
  **   
  **   Feel   free   to   use   this   code   in   any   way   you   desire.   
  */   
    
  #include   <stdio.h>   
    
  extern   char   *malloc();   
    
  #define   FIND_NEXT 0   
  #define   PARSE_UNIDIFF 1   
  #define   UNI_LINES 2   
  #define   PARSE_CDIFF 3   
  #define   PARSE_OLD 4   
  #define   CHECK_OLD 5   
  #define   OLD_LINES 6   
  #define   PARSE_NEW 7   
  #define   NEW_LINES 8   
    
  #define   strnEQ(s1,s2,n)   (!strncmp(s1,s2,n))   
  #define   strnNE(s1,s2,n)   strncmp(s1,s2,n)   
    
  #define   AtoL(cp,n)   {n   =   atol(cp);   while   (*cp   <=   '9'   &&   *cp   >=   '0')   cp++;   }   
    
  char   buf[2048];   
    
  struct   liner   {   
          struct   liner   *link;   
          char   type;   
          int   num;   
          char   str[1];   
  }   root,   *head   =   &root,   *hold   =   &root,   *line;   
    
  long   o_first   =   0,   o_last   =   -1;   
  long   n_first   =   0,   n_last   =   0;   
    
  long   o_start,   o_end,   o_line;   
  long   n_start,   n_end,   n_line;   
    
  long   line_num   =   0;   
  int   input_type   =   0;   
  int   output_type   =   0;   
  int   echo_comments   =   0;   
  int   strip_comments   =   0;   
  int   patch_format   =   0;   
  int   use_equals   =   0;   
    
  int   state   =   FIND_NEXT;   
  int   found_index   =   0;   
  char   name[256]   =   {   '\0'   };   
    
  void   ensure_name(),   add_line(),   generate_output();   
    
  int   
  main(argc,   argv)   
  int   argc;   
  char   *argv[];   
  {   
          char   type;   
          char   ndiff; /*   Equals   '*'   when   we   have   a   new-style   context   diff   */   
          int   odiff   =   0;   
          char   star_dash_plus   =   '   ';   
          FILE   *fp_in   =   stdin;   
    
          while   (--argc)   {   
  if   (**++argv   ==   '-')   {   
          while   (*++*argv)   {   
  switch   (**argv)   {   
  case   '=': /*   use   '='   not   '   '   in   unified   diffs   */   
          use_equals   =   1;   
          break;   
  case   'c': /*   force   context   diff   output   */   
          output_type   =   2;   
          break;   
  case   'e': /*   echo   comments   to   stderr   */   
          echo_comments   =   1;   
          break;   
  case   'o': /*   old-style   diff,   no   matter   what   */   
          odiff   =   1;   
          break;   
  case   'p': /*   generate   patch   format   */   
  case   'P':   
          patch_format   =   1;   
          break;   
  case   's': /*   strip   comment   lines   */   
          strip_comments   =   1;   
          break;   
  case   'U': /*   force   patch-unified   output   */   
          patch_format   =   1;   
  case   'u': /*   force   unified   output   */   
          output_type   =   1;   
          break;   
  default:   
          fprintf(stderr,   "Unknown   option:   '%c'\n",   **argv);   
          exit(1);   
  }   
          }   
  }   else   {   
          if   (fp_in   !=   stdin)   {   
  fprintf(stderr,   "Only   one   filename   allowed.\n",   *argv);   
  exit(1);   
          }   
          if   ((fp_in   =   fopen(*argv,   "r"))   ==   NULL)   {   
  fprintf(stderr,   "Unable   to   open   '%s'.\n",   *argv);   
  exit(1);   
          }   
  }   
          }   
    
          while   (fgets(buf,   sizeof   buf,   fp_in))   {   
  line_num++;   
              reprocess:   
  switch   (state)   {   
  case   FIND_NEXT:   
          if   (input_type   <   2   &&   strnEQ(buf,   "@@   -",   4))   {   
  input_type   =   1;   
  if   (!output_type)   {   
          output_type   =   2;   
  }   
  ensure_name();   
  state   =   PARSE_UNIDIFF;   
  goto   reprocess;   
          }   
          if   (!(input_type   &   1)   &&   strnEQ(buf,   "********",   8))   {   
  input_type   =   2;   
  if   (!output_type)   {   
          output_type   =   1;   
  }   
  ensure_name();   
  state   =   PARSE_OLD;   
  break;   
          }   
          if   (strnEQ(buf,   "Index:   ",   7))   {   
  found_index   =   1;   
  printf("%s",   buf);   
          }   else   if   (strnEQ(buf,   "Prereq:   ",   8))   {   
  printf("%s",   buf);   
          }   else   if   (strnEQ(buf,   "***   ",   4)   
          ||   strnEQ(buf,   "---   ",   4)   
          ||   strnEQ(buf,   "+++   ",   4))   {   
  if   (!found_index)   {   
          char   *cp;   
          int   len;   
    
          for   (cp=buf+4,len=0;   *cp>'   '   &&   len<255;   cp++,len++)   {   
  ;   
          }   
          if   (!*name   ||   len   <   strlen(name))   {   
  strncpy(name,   buf+4,   len);   
  name[len]   =   '\0';   
          }   
  }   
  if   (!patch_format)   {   
          if   (output_type   ==   1   &&   (*buf   ==   '+'   
              ||   *buf   ==   '-'   &&   star_dash_plus   !=   '*')   
            ||   output_type   ==   2   &&   (*buf   ==   '*'   
              ||   *buf   ==   '-'   &&   star_dash_plus   ==   '*'))   {   
  printf("%s",   buf);   
          }   else   if   (*buf   ==   '*'   ||   *buf   ==   '+')   {   
  printf("---%s",   buf+3);   
          }   else   if   (*buf   ==   '-'   &&   star_dash_plus   ==   '*')   {   
  printf("+++%s",   buf+3);   
          }   else   {   
  printf("***%s",   buf+3);   
          }   
          star_dash_plus   =   *buf;   
  }   
          }   else   if   (patch_format   
            &&   (strnEQ(buf,   "Only   in   ",   8)   ||   strnEQ(buf,   "Common   subdir",   13)   
              ||   strnEQ(buf,   "diff   -",   6)   ||   strnEQ(buf,   "Binary   files",   12)))   {   
  if   (echo_comments)   {   
          fprintf(stderr,   "%s%s",   strip_comments   ?   ""   :   "!!!   ",   buf);   
  }   
          }   else   {   
  if   (echo_comments)   {   
          fprintf(stderr,   "%s",   buf);   
  }   
  if   (!strip_comments)   {   
          printf("%s",   buf);   
  }   
          }   
          break;   
  case   PARSE_UNIDIFF:   
  {   
          char   *cp;   
    
          if   (strnNE(buf,   "@@   -",   4))   {   
  found_index   =   0;   
  *name   =   '\0';   
  state   =   FIND_NEXT;   
  goto   reprocess;   
          }   
          cp   =   buf+4;   
          AtoL(cp,   o_start);   
          if   (*cp++   ==   ',')   {   
  AtoL(cp,   o_end);   
  cp++;   
          }   else   {   
  o_end   =   1;   
          }   
          if   (*cp++   !=   '+')   {   
  goto   bad_header;   
          }   
          AtoL(cp,   n_start);   
          if   (*cp++   ==   ',')   {   
  AtoL(cp,   n_end);   
  cp++;   
          }   else   {   
  n_end   =   1;   
          }   
          if   (*cp   !=   '@')   {   
          bad_header:   
  fprintf(stderr,   "Invalid   unified   diff   header   at   line   %ld.\n",   
  line_num);   
  exit(1);   
          }   
          o_end   =   (o_start   ?   o_start   +   o_end   -   1   :   0);