os2zip.c

给出了 zip 压缩算法的完整实现过程。

   malloc() works, for some, both work. We'll have to live with that. */

/* The use of malloc() is not very convenient, because it requires
   backtracking (i.e. free()) at error returns. We do that for system
   calls that may fail, but not for malloc() calls, because they are VERY
   unlikely to fail. If ever, we just leave some memory allocated
   over the usually short lifetime of a zip process ... */

#ifdef __GNUC__
#define alloc(x) alloca(x)
#define unalloc(x)
#else
#define alloc(x) malloc(x)
#define unalloc(x) free(x)
#endif

void GetEAs(char *path, char **bufptr, size_t *size,
                        char **cbufptr, size_t *csize)
{
  FILESTATUS4 fs;
  PDENA2 pDENA, pFound;
  EAOP2 eaop;
  PGEA2 pGEA;
  PGEA2LIST pGEAlist;
  PFEA2LIST pFEAlist;
  PEFHEADER pEAblock;
  ULONG ulAttributes, ulMemoryBlock;
  ULONG nLength;
  ULONG nBlock;
  char szName[CCHMAXPATH];

  *size = *csize = 0;

  strcpy(szName, path);
  nLength = strlen(szName);
  if (szName[nLength - 1] == '/')
    szName[nLength - 1] = 0;

  if (DosQueryPathInfo(szName, FIL_QUERYEASIZE, (PBYTE) &fs, sizeof(fs)))
    return;
  nBlock = max(fs.cbList, 65535);
  if ((pDENA = alloc((size_t) nBlock)) == NULL)
    return;

  ulAttributes = -1;

  if (DosEnumAttribute(ENUMEA_REFTYPE_PATH, szName, 1, pDENA, nBlock,
                       &ulAttributes, ENUMEA_LEVEL_NO_VALUE)
    || ulAttributes == 0
    || (pGEAlist = alloc((size_t) nBlock)) == NULL)
  {
    unalloc(pDENA);
    return;
  }

  pGEA = pGEAlist -> list;
  memset(pGEAlist, 0, nBlock);
  pFound = pDENA;

  while (ulAttributes--)
  {
    if (!(strcmp(pFound -> szName, ".LONGNAME") == 0 && use_longname_ea))
    {
      pGEA -> cbName = pFound -> cbName;
      strcpy(pGEA -> szName, pFound -> szName);

      nLength = sizeof(GEA2) + strlen(pGEA -> szName);
      nLength = ((nLength - 1) / sizeof(ULONG) + 1) * sizeof(ULONG);

      pGEA -> oNextEntryOffset = ulAttributes ? nLength : 0;
      pGEA   = (PGEA2)  ((PCH) pGEA + nLength);
    }

    pFound = (PDENA2) ((PCH) pFound + pFound -> oNextEntryOffset);
  }

  if (pGEA == pGEAlist -> list) /* no attributes to save */
  {
    unalloc(pDENA);
    unalloc(pGEAlist);
    return;
  }

  pGEAlist -> cbList = (PCH) pGEA - (PCH) pGEAlist;

  pFEAlist = (PVOID) pDENA;  /* reuse buffer */
  pFEAlist -> cbList = nBlock;

  eaop.fpGEA2List = pGEAlist;
  eaop.fpFEA2List = pFEAlist;
  eaop.oError = 0;

  if (DosQueryPathInfo(szName, FIL_QUERYEASFROMLIST,
                       (PBYTE) &eaop, sizeof(eaop)))
  {
    unalloc(pDENA);
    unalloc(pGEAlist);
    return;
  }

  /* The maximum compressed size is (in case of STORE type) the
     uncompressed size plus the size of the compression type field
     plus the size of the CRC field + 2*5 deflate overhead bytes
     for uncompressable data.
     (5 bytes per 32Kb block, max compressed size = 2 blocks) */

  ulAttributes = pFEAlist -> cbList;
  ulMemoryBlock = ulAttributes +
                  sizeof(USHORT) + sizeof(ULONG) + EB_DEFLAT_EXTRA;
  pEAblock = (PEFHEADER) malloc(sizeof(EFHEADER) + ulMemoryBlock);

  if (pEAblock == NULL)
  {
    unalloc(pDENA);
    unalloc(pGEAlist);
    return;
  }

  *bufptr = (char *) pEAblock;
  *size = sizeof(EFHEADER);

  pEAblock -> nID = EF_OS2EA;
  pEAblock -> nSize = sizeof(pEAblock -> lSize);
  pEAblock -> lSize = ulAttributes; /* uncompressed size */

  nLength = memcompress((char *) (pEAblock + 1), ulMemoryBlock,
                        (char *) pFEAlist, ulAttributes);
  *size += nLength;
  pEAblock -> nSize += nLength;

  if ((pEAblock = (PEFHEADER) malloc(sizeof(EFHEADER))) == NULL)
  {
    unalloc(pDENA);
    unalloc(pGEAlist);
    return;
  }

  *cbufptr = (char *) pEAblock;
  *csize = sizeof(EFHEADER);

  pEAblock -> nID = EF_OS2EA;
  pEAblock -> nSize = sizeof(pEAblock -> lSize);
  pEAblock -> lSize = ulAttributes;

  if (noisy)
    printf(" (%ld bytes EA's)", ulAttributes);

  unalloc(pDENA);
  unalloc(pGEAlist);
}

#else /* !__32BIT__ */

typedef struct
{
  ULONG oNextEntryOffset;
  BYTE fEA;
  BYTE cbName;
  USHORT cbValue;
  CHAR szName[1];
}
FEA2, *PFEA2;

typedef struct
{
  ULONG cbList;
  FEA2 list[1];
}
FEA2LIST, *PFEA2LIST;

void GetEAs(char *path, char **bufptr, size_t *size,
                        char **cbufptr, size_t *csize)
{
  FILESTATUS2 fs;
  PDENA1 pDENA, pFound;
  EAOP eaop;
  PGEALIST pGEAlist;
  PGEA pGEA;
  PFEALIST pFEAlist;
  PFEA pFEA;
  PFEA2LIST pFEA2list;
  PFEA2 pFEA2;
  EFHEADER *pEAblock;
  ULONG ulAttributes;
  USHORT nLength, nMaxSize;
  char szName[CCHMAXPATH];

  *size = *csize = 0;

  strcpy(szName, path);
  nLength = strlen(szName);
  if (szName[nLength - 1] == '/')
    szName[nLength - 1] = 0;

  if (DosQueryPathInfo(szName, FIL_QUERYEASIZE, (PBYTE) &fs, sizeof(fs))
      || fs.cbList <= 2 * sizeof(ULONG))
    return;

  ulAttributes = -1;
  nMaxSize = (USHORT) min(fs.cbList * 2, 65520L);

  if ((pDENA = malloc((size_t) nMaxSize)) == NULL)
    return;

  if (DosEnumAttribute(ENUMEA_REFTYPE_PATH, szName, 1, pDENA, fs.cbList,
                       &ulAttributes, ENUMEA_LEVEL_NO_VALUE)
    || ulAttributes == 0
    || (pGEAlist = malloc(nMaxSize)) == NULL)
  {
    free(pDENA);
    return;
  }

  pGEA = pGEAlist -> list;
  pFound = pDENA;

  while (ulAttributes--)
  {
    nLength = strlen(pFound -> szName);

    if (!(strcmp(pFound -> szName, ".LONGNAME") == 0 && use_longname_ea))
    {
      pGEA -> cbName = pFound -> cbName;
      strcpy(pGEA -> szName, pFound -> szName);

      pGEA++;
      pGEA = (PGEA) (((PCH) pGEA) + nLength);
    }

    pFound++;
    pFound = (PDENA1) (((PCH) pFound) + nLength);
  }

  if (pGEA == pGEAlist -> list)
  {
    free(pDENA);
    free(pGEAlist);
    return;
  }

  pGEAlist -> cbList = (PCH) pGEA - (PCH) pGEAlist;

  pFEAlist = (PFEALIST) pDENA; /* reuse buffer */
  pFEAlist -> cbList = fs.cbList;
  pFEA = pFEAlist -> list;

  eaop.fpGEAList = pGEAlist;
  eaop.fpFEAList = pFEAlist;
  eaop.oError = 0;

  if (DosQueryPathInfo(szName, FIL_QUERYEASFROMLIST,
                       (PBYTE) &eaop, sizeof(eaop)))
  {
    free(pDENA);
    free(pGEAlist);
    return;
  }

  /* now convert into new OS/2 2.0 32-bit format */

  pFEA2list = (PFEA2LIST) pGEAlist;  /* reuse buffer */
  pFEA2 = pFEA2list -> list;

  while ((PCH) pFEA - (PCH) pFEAlist < pFEAlist -> cbList)
  {
    nLength = sizeof(FEA) + pFEA -> cbName + 1 + pFEA -> cbValue;
    memcpy((PCH) pFEA2 + sizeof(pFEA2 -> oNextEntryOffset), pFEA, nLength);
    memset((PCH) pFEA2 + sizeof(pFEA2 -> oNextEntryOffset) + nLength, 0, 3);
    pFEA = (PFEA) ((PCH) pFEA + nLength);

    nLength = sizeof(FEA2) + pFEA2 -> cbName + 1 + pFEA2 -> cbValue;
    nLength = ((nLength - 1) / sizeof(ULONG) + 1) * sizeof(ULONG);
    /* rounded up to 4-byte boundary */
    pFEA2 -> oNextEntryOffset =
      ((PCH) pFEA - (PCH) pFEAlist < pFEAlist -> cbList) ? nLength : 0;
    pFEA2 = (PFEA2) ((PCH) pFEA2 + nLength);
  }

  pFEA2list -> cbList = (PCH) pFEA2 - (PCH) pFEA2list;
  ulAttributes = pFEA2list -> cbList;

  pEAblock = (PEFHEADER) pDENA; /* reuse buffer */

  *bufptr = (char *) pEAblock;
  *size = sizeof(EFHEADER);

  pEAblock -> nID = EF_OS2EA;
  pEAblock -> nSize = sizeof(pEAblock -> lSize);
  pEAblock -> lSize = ulAttributes; /* uncompressed size */

  nLength = (USHORT) memcompress((char *) (pEAblock + 1),
    nMaxSize - sizeof(EFHEADER), (char *) pFEA2list, ulAttributes);

  *size += nLength;
  pEAblock -> nSize += nLength;

  pEAblock = (PEFHEADER) pGEAlist;

  *cbufptr = (char *) pEAblock;
  *csize = sizeof(EFHEADER);

  pEAblock -> nID = EF_OS2EA;
  pEAblock -> nSize = sizeof(pEAblock -> lSize);
  pEAblock -> lSize = ulAttributes;

  if (noisy)
    printf(" (%ld bytes EA's)", ulAttributes);
}

#endif /* __32BIT__ */

void GetACL(char *path, char **bufptr, size_t *size,
                        char **cbufptr, size_t *csize)
{
  static char *buffer;
  char *cbuffer;
  long bytes, cbytes;
  PEFHEADER pACLblock;

  if (buffer == NULL) /* avoid frequent allocation (for every file) */
    if ((buffer = malloc(ACL_BUFFERSIZE)) == NULL)
      return;

  if (acl_get(NULL, path, buffer))
    return; /* this will be the most likely case */

  bytes = strlen(buffer);

  /* The maximum compressed size is (in case of STORE type) the
     uncompressed size plus the size of the compression type field
     plus the size of the CRC field + 2*5 deflate overhead bytes
     for uncompressable data.
     (5 bytes per 32Kb block, max compressed size = 2 blocks) */

  cbytes = bytes + sizeof(USHORT) + sizeof(ULONG) + EB_DEFLAT_EXTRA;
  if ((*bufptr = realloc(*bufptr, *size + sizeof(EFHEADER) + cbytes)) == NULL)
    return;

  pACLblock = (PEFHEADER) (*bufptr + *size);

  cbuffer = (char *) (pACLblock + 1);
  cbytes = memcompress(cbuffer, cbytes, buffer, bytes);

  *size += sizeof(EFHEADER) + cbytes;

  pACLblock -> nID = EF_ACL;
  pACLblock -> nSize = sizeof(pACLblock -> lSize) + cbytes;
  pACLblock -> lSize = bytes; /* uncompressed size */

  if ((*cbufptr = realloc(*cbufptr, *csize + sizeof(EFHEADER))) == NULL)
    return;

  pACLblock = (PEFHEADER) (*cbufptr + *csize);
  *csize += sizeof(EFHEADER);

  pACLblock -> nID = EF_ACL;
  pACLblock -> nSize = sizeof(pACLblock -> lSize);
  pACLblock -> lSize = bytes;

  if (noisy)
    printf(" (%ld bytes ACL)", bytes);
}

#ifdef USE_EF_UT_TIME

int GetExtraTime(struct zlist far *z, iztimes *z_utim)
{
  int eb_c_size = EB_HEADSIZE + EB_UT_LEN(1);
  int eb_l_size = eb_c_size;
  char *eb_c_ptr;
  char *eb_l_ptr;
  unsigned long ultime;

#ifdef IZ_CHECK_TZ
  if (!zp_tz_is_valid) return ZE_OK;    /* skip silently no correct tz info */
#endif

  eb_c_ptr = realloc(z->cextra, (z->cext + eb_c_size));
  if (eb_c_ptr == NULL)
    return ZE_MEM;
  z->cextra = eb_c_ptr;
  eb_c_ptr += z->cext;
  z->cext += eb_c_size;

  eb_c_ptr[0]  = 'U';
  eb_c_ptr[1]  = 'T';
  eb_c_ptr[2]  = EB_UT_LEN(1);          /* length of data part of e.f. */
  eb_c_ptr[3]  = 0;
  eb_c_ptr[4]  = EB_UT_FL_MTIME;
  ultime = (unsigned long) z_utim->mtime;
  eb_c_ptr[5]  = (char)(ultime);
  eb_c_ptr[6]  = (char)(ultime >> 8);
  eb_c_ptr[7]  = (char)(ultime >> 16);
  eb_c_ptr[8]  = (char)(ultime >> 24);

  if (z_utim->mtime != z_utim->atime || z_utim->mtime != z_utim->ctime)
  {
    eb_c_ptr[4]  = EB_UT_FL_MTIME | EB_UT_FL_ATIME | EB_UT_FL_CTIME;
    eb_l_size = EB_HEADSIZE + EB_UT_LEN(3); /* only on HPFS they can differ */
  /* so only then it makes sense to store all three time stamps */
  }

  eb_l_ptr = realloc(z->extra, (z->ext + eb_l_size));
  if (eb_l_ptr == NULL)
    return ZE_MEM;
  z->extra = eb_l_ptr;
  eb_l_ptr += z->ext;
  z->ext += eb_l_size;

  memcpy(eb_l_ptr, eb_c_ptr, eb_c_size);

  if (eb_l_size > eb_c_size)
  {
    eb_l_ptr[2]  = EB_UT_LEN(3);
    ultime = (unsigned long) z_utim->atime;
    eb_l_ptr[9]  = (char)(ultime);
    eb_l_ptr[10] = (char)(ultime >> 8);
    eb_l_ptr[11] = (char)(ultime >> 16);
    eb_l_ptr[12] = (char)(ultime >> 24);
    ultime = (unsigned long) z_utim->ctime;
    eb_l_ptr[13] = (char)(ultime);
    eb_l_ptr[14] = (char)(ultime >> 8);
    eb_l_ptr[15] = (char)(ultime >> 16);
    eb_l_ptr[16] = (char)(ultime >> 24);
  }

  return ZE_OK;
}

#endif /* USE_EF_UT_TIME */

int set_extra_field(struct zlist far *z, iztimes *z_utim)
{
  /* store EA data in local header, and size only in central headers */
  GetEAs(z->name, &z->extra, &z->ext, &z->cextra, &z->cext);

  /* store ACL data in local header, and size only in central headers */
  GetACL(z->name, &z->extra, &z->ext, &z->cextra, &z->cext);

#ifdef USE_EF_UT_TIME
  /* store extended time stamps in both headers */
  return GetExtraTime(z, z_utim);
#else /* !USE_EF_UT_TIME */
  return ZE_OK;
#endif /* ?USE_EF_UT_TIME */
}

#endif /* !UTIL */

/* Initialize the table of uppercase characters including handling of
   country dependent characters. */

void init_upper()
{
  COUNTRYCODE cc;
  unsigned nCnt, nU;

  for (nCnt = 0; nCnt < sizeof(upper); nCnt++)
    upper[nCnt] = lower[nCnt] = (unsigned char) nCnt;

  cc.country = cc.codepage = 0;
  DosMapCase(sizeof(upper), &cc, (PCHAR) upper);

  for (nCnt = 0; nCnt < 256; nCnt++)
  {
    nU = upper[nCnt];
    if (nU != nCnt && lower[nU] == (unsigned char) nU)
      lower[nU] = (unsigned char) nCnt;
  }

  for (nCnt = 'A'; nCnt <= 'Z'; nCnt++)
    lower[nCnt] = (unsigned char) (nCnt - 'A' + 'a');
}

char *StringLower(char *szArg)
{
  unsigned char *szPtr;
  for (szPtr = (unsigned char *) szArg; *szPtr; szPtr++)
    *szPtr = lower[*szPtr];
  return szArg;
}

#if defined(__IBMC__) && defined(__DEBUG_ALLOC__)
void DebugMalloc(void)
{
  _dump_allocated(0); /* print out debug malloc memory statistics */
}
#endif


/******************************/
/*  Function version_local()  */
/******************************/

void version_local()
{
    static ZCONST char CompiledWith[] = "Compiled with %s%s for %s%s%s%s.\n\n";
#if defined(__IBMC__) || defined(__WATCOMC__) || defined(_MSC_VER)
    char buf[80];
#endif

    printf(CompiledWith,

#ifdef __GNUC__
#  ifdef __EMX__  /* __EMX__ is defined as "1" only (sigh) */
      "emx+gcc ", __VERSION__,
#  else
      "gcc/2 ", __VERSION__,
#  endif
#elif defined(__IBMC__)
      "IBM ",
#  if (__IBMC__ < 200)
      (sprintf(buf, "C Set/2 %d.%02d", __IBMC__/100,__IBMC__%100), buf),
#  elif (__IBMC__ < 300)
      (sprintf(buf, "C Set++ %d.%02d", __IBMC__/100,__IBMC__%100), buf),
#  else
      (sprintf(buf, "Visual Age C++ %d.%02d", __IBMC__/100,__IBMC__%100), buf),
#  endif
#elif defined(__WATCOMC__)
      "Watcom C", (sprintf(buf, " (__WATCOMC__ = %d)", __WATCOMC__), buf),
#elif defined(__TURBOC__)
#  ifdef __BORLANDC__
      "Borland C++",
#    if (__BORLANDC__ < 0x0460)
        " 1.0",
#    elif (__BORLANDC__ == 0x0460)
        " 1.5",
#    else
        " 2.0",
#    endif
#  else
      "Turbo C",
#    if (__TURBOC__ >= 661)
       "++ 1.0 or later",
#    elif (__TURBOC__ == 661)
       " 3.0?",
#    elif (__TURBOC__ == 397)
       " 2.0",
#    else
       " 1.0 or 1.5?",
#    endif
#  endif
#elif defined(MSC)
      "Microsoft C ",
#  ifdef _MSC_VER
      (sprintf(buf, "%d.%02d", _MSC_VER/100, _MSC_VER%100), buf),
#  else
      "5.1 or earlier",
#  endif
#else
      "unknown compiler", "",
#endif /* __GNUC__ */

      "OS/2",

/* GRR:  does IBM C/2 identify itself as IBM rather than Microsoft? */
#if (defined(MSC) || (defined(__WATCOMC__) && !defined(__386__)))
#  if defined(M_I86HM) || defined(__HUGE__)
      " (16-bit, huge)",
#  elif defined(M_I86LM) || defined(__LARGE__)
      " (16-bit, large)",
#  elif defined(M_I86MM) || defined(__MEDIUM__)
      " (16-bit, medium)",
#  elif defined(M_I86CM) || defined(__COMPACT__)
      " (16-bit, compact)",
#  elif defined(M_I86SM) || defined(__SMALL__)
      " (16-bit, small)",
#  elif defined(M_I86TM) || defined(__TINY__)
      " (16-bit, tiny)",
#  else
      " (16-bit)",
#  endif
#else
      " 2.x/3.x (32-bit)",
#endif

#ifdef __DATE__
      " on ", __DATE__
#else
      "", ""
#endif
    );

    /* temporary debugging code for Borland compilers only */
#ifdef __TURBOC__
    printf("\t(__TURBOC__ = 0x%04x = %d)\n", __TURBOC__, __TURBOC__);
#ifdef __BORLANDC__
    printf("\t(__BORLANDC__ = 0x%04x)\n",__BORLANDC__);
#else
    printf("\tdebug(__BORLANDC__ not defined)\n");
#endif
#ifdef __TCPLUSPLUS__
    printf("\t(__TCPLUSPLUS__ = 0x%04x)\n", __TCPLUSPLUS__);
#else
    printf("\tdebug(__TCPLUSPLUS__ not defined)\n");
#endif
#ifdef __BCPLUSPLUS__
    printf("\t(__BCPLUSPLUS__ = 0x%04x)\n\n", __BCPLUSPLUS__);
#else
    printf("\tdebug(__BCPLUSPLUS__ not defined)\n\n");
#endif
#endif /* __TURBOC__ */

} /* end function version_local() */

#endif /* OS2 */