mvs.c

给出了 zip 压缩算法的完整实现过程。

/*
  Copyright (c) 1990-2005 Info-ZIP.  All rights reserved.

  See the accompanying file LICENSE, version 2004-May-22 or later
  (the contents of which are also included in zip.h) for terms of use.
  If, for some reason, both of these files are missing, the Info-ZIP license
  also may be found at:  ftp://ftp.info-zip.org/pub/infozip/license.html
*/
/*
 * MVS specific things
 */
#include "zip.h"
#include "mvs.h"
#include <errno.h>

static int gen_node( DIR *dirp, RECORD *recptr )
{
   char *ptr, *name, ttr[TTRLEN];
   int skip, count = 2;
   unsigned int info_byte, alias, ttrn;
   struct dirent *new;

   ptr = recptr->rest;
   while (count < recptr->count) {
      if (!memcmp( ptr, endmark, NAMELEN ))
         return 1;
      name = ptr;                    /* member name */
      ptr += NAMELEN;
      memcpy( ttr, ptr, TTRLEN );    /* ttr name    */
      ptr += TTRLEN;
      info_byte = (unsigned int) (*ptr);   /* info byte */
      if ( !(info_byte & ALIAS_MASK) ) {   /* no alias  */
         new = malloc( sizeof(struct dirent) );
         if (dirp->D_list == NULL)
            dirp->D_list = dirp->D_curpos = new;
         else
            dirp->D_curpos = (dirp->D_curpos->d_next = new);
         new->d_next = NULL;
         memcpy( new->d_name, name, NAMELEN );
         new->d_name[NAMELEN] = '\0';
         if ((name = strchr( new->d_name, ' ' )) != NULL)
            *name = '\0';      /* skip trailing blanks */
      }
      skip = (info_byte & SKIP_MASK) * 2 + 1;
      ptr += skip;
      count += (TTRLEN + NAMELEN + skip);
   }
   return 0;
}

DIR *opendir(const char *dirname)
{
   int bytes, list_end = 0;
   DIR *dirp;
   FILE *fp;
   RECORD rec;

   fp = fopen( dirname, "rb" );
   if (fp != NULL) {
      dirp = malloc( sizeof(DIR) );
      if (dirp != NULL) {
         dirp->D_list = dirp->D_curpos = NULL;
         strcpy( dirp->D_path, dirname );
         do {
            bytes = fread( &rec, 1, sizeof(rec), fp );
            if (bytes == sizeof(rec))
               list_end = gen_node( dirp, &rec );
         } while (!feof(fp) && !list_end);
         fclose( fp );
         dirp->D_curpos = dirp->D_list;
         return dirp;
      }
      fclose( fp );
   }
   return NULL;
}

struct dirent *readdir(DIR *dirp)
{
   struct dirent *cur;

   cur = dirp->D_curpos;
   dirp->D_curpos = dirp->D_curpos->d_next;
   return cur;
}

void rewinddir(DIR *dirp)
{
   dirp->D_curpos = dirp->D_list;
}

int closedir(DIR *dirp)
{
   struct dirent *node;

   while (dirp->D_list != NULL) {
      node = dirp->D_list;
      dirp->D_list = dirp->D_list->d_next;
      free( node );
   }
   free( dirp );
   return 0;
}

local char *readd(d)
DIR *d;                 /* directory stream to read from */
/* Return a pointer to the next name in the directory stream d, or NULL if
   no more entries or an error occurs. */
{
  struct dirent *e;

  e = readdir(d);
  return e == NULL ? (char *) NULL : e->d_name;
}

int procname(n, caseflag)
char *n;                /* name to process */
int caseflag;           /* true to force case-sensitive match */
/* Process a name or sh expression to operate on (or exclude).  Return
   an error code in the ZE_ class. */
{
  char *a;              /* path and name for recursion */
  DIR *d;               /* directory stream from opendir() */
  char *e;              /* pointer to name from readd() */
  int m;                /* matched flag */
  char *p;              /* path for recursion */
  struct stat s;        /* result of stat() */
  struct zlist far *z;  /* steps through zfiles list */
  int exists;           /* 1 if file exists */

  if (strcmp(n, "-") == 0)   /* if compressing stdin */
    return newname(n, 0, caseflag);
  else if (!(exists = (LSSTAT(n, &s) == 0)))
  {
#ifdef MVS
    /* special case for MVS.  stat does not work on non-HFS files so if
     * stat fails with ENOENT, try to open the file for reading anyway.
     * If the user has no OMVS segment, stat gets an initialization error,
     * even on external files.
     */
    if (errno == ENOENT || errno == EMVSINITIAL) {
      FILE *f = fopen(n, "r");
      if (f) {
        /* stat got ENOENT but fopen worked, external file */
        fclose(f);
        exists = 1;
        memset(&s, '\0', sizeof(s));   /* stat data is unreliable for externals */
        s.st_mode = S_IFREG;           /* fudge it */
      }
    }
#endif /* MVS */
  }
  if (! exists) {
    /* Not a file or directory--search for shell expression in zip file */
    p = ex2in(n, 0, (int *)NULL);       /* shouldn't affect matching chars */
    m = 1;
    for (z = zfiles; z != NULL; z = z->nxt) {
      if (MATCH(p, z->iname, caseflag))
      {
        z->mark = pcount ? filter(z->zname, caseflag) : 1;
        if (verbose)
            fprintf(mesg, "zip diagnostic: %scluding %s\n",
               z->mark ? "in" : "ex", z->name);
        m = 0;
      }
    }
    free((zvoid *)p);
    return m ? ZE_MISS : ZE_OK;
  }

  /* Live name--use if file, recurse if directory */
  if (!S_ISDIR(s.st_mode))
  {
    /* add or remove name of file */
    if ((m = newname(n, 0, caseflag)) != ZE_OK)
      return m;
  } else {
    /* Add trailing / to the directory name */
    if ((p = malloc(strlen(n)+2)) == NULL)
      return ZE_MEM;
    if (strcmp(n, ".") == 0) {
      *p = '\0';  /* avoid "./" prefix and do not create zip entry */
    } else {
      strcpy(p, n);
      a = p + strlen(p);
      if (a[-1] != '/')
        strcpy(a, "/");
      if (dirnames && (m = newname(p, 1, caseflag)) != ZE_OK) {
        free((zvoid *)p);
        return m;
      }
    }
    /* recurse into directory */
    if (recurse && (d = opendir(n)) != NULL)
    {
      while ((e = readd(d)) != NULL) {
        if (strcmp(e, ".") && strcmp(e, ".."))
        {
          if ((a = malloc(strlen(p) + strlen(e) + 1)) == NULL)
          {
            closedir(d);
            free((zvoid *)p);
            return ZE_MEM;
          }
          strcat(strcpy(a, p), e);
          if ((m = procname(a, caseflag)) != ZE_OK)   /* recurse on name */
          {
            if (m == ZE_MISS)
              zipwarn("name not matched: ", a);
            else
              ziperr(m, a);
          }
          free((zvoid *)a);
        }
      }
      closedir(d);
    }
    free((zvoid *)p);
  } /* (s.st_mode & S_IFDIR) == 0) */
  return ZE_OK;
}