vms.c

给出了 zip 压缩算法的完整实现过程。

#define DEF_DEVDIRNAM "SYS$DISK:[].zip"

char *ziptyp( char *s)
{
    int status;
    int exp_len;
    struct FAB fab;
    struct NAM_STRUCT nam;
    char result[ NAM_MAXRSS+ 1];
    char exp[ NAM_MAXRSS+ 1];
    char *p;

    fab = cc$rms_fab;                           /* Initialize FAB. */
    nam = CC_RMS_NAM;                           /* Initialize NAM[L]. */
    fab.FAB_NAM = &nam;                         /* FAB -> NAM[L] */

#ifdef NAML$C_MAXRSS

    fab.fab$l_dna =(char *) -1;         /* Using NAML for default name. */
    fab.fab$l_fna = (char *) -1;        /* Using NAML for file name. */

#endif /* def NAML$C_MAXRSS */

    FAB_OR_NAM( fab, nam).FAB_OR_NAM_FNA = s;           /* Arg file name, */
    FAB_OR_NAM( fab, nam).FAB_OR_NAM_FNS = strlen( s);  /* length. */

    FAB_OR_NAM( fab, nam).FAB_OR_NAM_DNA = DEF_DEVDIRNAM;   /* Default fspec */
    FAB_OR_NAM( fab, nam).FAB_OR_NAM_DNS = sizeof( DEF_DEVDIRNAM)- 1;

    nam.NAM_ESA = exp;                 /* Expanded name, */
    nam.NAM_ESS = NAM_MAXRSS;          /* storage size. */
    nam.NAM_RSA = result;              /* Resultant name, */
    nam.NAM_RSS = NAM_MAXRSS;          /* storage size. */

    status = sys$parse(&fab);
    if ((status & 1) == 0)
    {
        /* Invalid file name.  Return (re-allocated) original, and hope
           for a later error message.
        */
        if ((p = malloc( strlen( s)+ 1)) != NULL )
        {
            strcpy( p, s);
        }
        return p;
    }

    /* Save expanded name length from sys$parse(). */
    exp_len = nam.NAM_ESL;

    /* Leave expanded name as-is, in case of search failure. */
    nam.NAM_ESA = NULL;                 /* Expanded name, */
    nam.NAM_ESS = 0;                    /* storage size. */

    status = sys$search(&fab);
    if (status & 1)
    {   /* Zip file exists.  Use resultant (complete, exact) name. */
        if ((p = malloc( nam.NAM_RSL+ 1)) != NULL )
        {
            result[ nam.NAM_RSL] = '\0';
            strcpy( p, result);
        }
    }
    else
    {   /* New Zip file.  Use pre-search expanded name. */
        if ((p = malloc( exp_len+ 1)) != NULL )
        {
            exp[ exp_len] = '\0';
            strcpy( p, exp);
        }
    }
    return p;
} /* ziptyp() for VMS. */


/* 2004-11-23 SMS.
 *
 *       get_rms_defaults().
 *
 *    Get user-specified values from (DCL) SET RMS_DEFAULT.  FAB/RAB
 *    items of particular interest are:
 *
 *       fab$w_deq         default extension quantity (blocks) (write).
 *       rab$b_mbc         multi-block count.
 *       rab$b_mbf         multi-buffer count (used with rah and wbh).
 */

#define DIAG_FLAG (verbose >= 2)

/* Default RMS parameter values. */

#define RMS_DEQ_DEFAULT 16384   /* About 1/4 the max (65535 blocks). */
#define RMS_MBC_DEFAULT 127     /* The max, */
#define RMS_MBF_DEFAULT 2       /* Enough to enable rah and wbh. */

/* GETJPI item descriptor structure. */
typedef struct
    {
    short buf_len;
    short itm_cod;
    void *buf;
    int *ret_len;
    } jpi_item_t;

/* Durable storage */

static int rms_defaults_known = 0;

/* JPI item buffers. */
static unsigned short rms_ext;
static char rms_mbc;
static unsigned char rms_mbf;

/* Active RMS item values. */
unsigned short rms_ext_active;
char rms_mbc_active;
unsigned char rms_mbf_active;

/* GETJPI item lengths. */
static int rms_ext_len;         /* Should come back 2. */
static int rms_mbc_len;         /* Should come back 1. */
static int rms_mbf_len;         /* Should come back 1. */

/* Desperation attempts to define unknown macros.  Probably doomed.
 * If these get used, expect sys$getjpiw() to return %x00000014 =
 * %SYSTEM-F-BADPARAM, bad parameter value.
 * They keep compilers with old header files quiet, though.
 */
#ifndef JPI$_RMS_EXTEND_SIZE
#  define JPI$_RMS_EXTEND_SIZE 542
#endif /* ndef JPI$_RMS_EXTEND_SIZE */

#ifndef JPI$_RMS_DFMBC
#  define JPI$_RMS_DFMBC 535
#endif /* ndef JPI$_RMS_DFMBC */

#ifndef JPI$_RMS_DFMBFSDK
#  define JPI$_RMS_DFMBFSDK 536
#endif /* ndef JPI$_RMS_DFMBFSDK */

/* GETJPI item descriptor set. */

struct
    {
    jpi_item_t rms_ext_itm;
    jpi_item_t rms_mbc_itm;
    jpi_item_t rms_mbf_itm;
    int term;
    } jpi_itm_lst =
     { { 2, JPI$_RMS_EXTEND_SIZE, &rms_ext, &rms_ext_len },
       { 1, JPI$_RMS_DFMBC, &rms_mbc, &rms_mbc_len },
       { 1, JPI$_RMS_DFMBFSDK, &rms_mbf, &rms_mbf_len },
       0
     };

int get_rms_defaults()
{
int sts;

/* Get process RMS_DEFAULT values. */

sts = sys$getjpiw( 0, 0, 0, &jpi_itm_lst, 0, 0, 0);
if ((sts& STS$M_SEVERITY) != STS$K_SUCCESS)
    {
    /* Failed.  Don't try again. */
    rms_defaults_known = -1;
    }
else
    {
    /* Fine, but don't come back. */
    rms_defaults_known = 1;
    }

/* Limit the active values according to the RMS_DEFAULT values. */

if (rms_defaults_known > 0)
    {
    /* Set the default values. */

    rms_ext_active = RMS_DEQ_DEFAULT;
    rms_mbc_active = RMS_MBC_DEFAULT;
    rms_mbf_active = RMS_MBF_DEFAULT;

    /* Default extend quantity.  Use the user value, if set. */
    if (rms_ext > 0)
        {
        rms_ext_active = rms_ext;
        }

    /* Default multi-block count.  Use the user value, if set. */
    if (rms_mbc > 0)
        {
        rms_mbc_active = rms_mbc;
        }

    /* Default multi-buffer count.  Use the user value, if set. */
    if (rms_mbf > 0)
        {
        rms_mbf_active = rms_mbf;
        }
    }

if (DIAG_FLAG)
    {
    fprintf( stderr,
     "Get RMS defaults.  getjpi sts = %%x%08x.\n",
     sts);

    if (rms_defaults_known > 0)
        {
        fprintf( stderr,
         "               Default: deq = %6d, mbc = %3d, mbf = %3d.\n",
         rms_ext, rms_mbc, rms_mbf);
        }
    }
return sts;
}

#ifdef __DECC

/* 2004-11-23 SMS.
 *
 *       acc_cb(), access callback function for DEC C zfopen().
 *
 *    Set some RMS FAB/RAB items, with consideration of user-specified
 * values from (DCL) SET RMS_DEFAULT.  Items of particular interest are:
 *
 *       fab$w_deq         default extension quantity (blocks).
 *       rab$b_mbc         multi-block count.
 *       rab$b_mbf         multi-buffer count (used with rah and wbh).
 *
 *    See also the FOP* macros in OSDEP.H.  Currently, no notice is
 * taken of the caller-ID value, but options could be set differently
 * for read versus write access.  (I assume that specifying fab$w_deq,
 * for example, for a read-only file has no ill effects.)
 */

/* Global storage. */

int fopm_id = FOPM_ID;          /* Callback id storage, modify. */
int fopr_id = FOPR_ID;          /* Callback id storage, read. */
int fopw_id = FOPW_ID;          /* Callback id storage, write. */

/* acc_cb() */

int acc_cb( int *id_arg, struct FAB *fab, struct RAB *rab)
{
int sts;

/* Get process RMS_DEFAULT values, if not already done. */
if (rms_defaults_known == 0)
    {
    get_rms_defaults();
    }

/* If RMS_DEFAULT (and adjusted active) values are available, then set
 * the FAB/RAB parameters.  If RMS_DEFAULT values are not available,
 * suffer with the default parameters.
 */
if (rms_defaults_known > 0)
    {
    /* Set the FAB/RAB parameters accordingly. */
    fab-> fab$w_deq = rms_ext_active;
    rab-> rab$b_mbc = rms_mbc_active;
    rab-> rab$b_mbf = rms_mbf_active;

    /* Truncate at EOF on close, as we'll probably over-extend. */
    fab-> fab$v_tef = 1;

    /* If using multiple buffers, enable read-ahead and write-behind. */
    if (rms_mbf_active > 1)
        {
        rab-> rab$v_rah = 1;
        rab-> rab$v_wbh = 1;
        }

    if (DIAG_FLAG)
        {
        fprintf( mesg,
         "Open callback.  ID = %d, deq = %6d, mbc = %3d, mbf = %3d.\n",
         *id_arg, fab-> fab$w_deq, rab-> rab$b_mbc, rab-> rab$b_mbf);
        }
    }

/* Declare success. */
return 0;
}

#endif /* def __DECC */

/*
 * 2004-09-19 SMS.
 *
 *----------------------------------------------------------------------
 *
 *       decc_init()
 *
 *    On non-VAX systems, uses LIB$INITIALIZE to set a collection of C
 *    RTL features without using the DECC$* logical name method.
 *
 *----------------------------------------------------------------------
 */

#ifdef __DECC

#ifdef __CRTL_VER

#if !defined( __VAX) && (__CRTL_VER >= 70301000)

#include <unixlib.h>

/*--------------------------------------------------------------------*/

/* Global storage. */

/*    Flag to sense if decc_init() was called. */

int decc_init_done = -1;

/*--------------------------------------------------------------------*/

/* decc_init()

      Uses LIB$INITIALIZE to set a collection of C RTL features without
      requiring the user to define the corresponding logical names.
*/

/* Structure to hold a DECC$* feature name and its desired value. */

typedef struct
   {
   char *name;
   int value;
   } decc_feat_t;

/* Array of DECC$* feature names and their desired values. */

decc_feat_t decc_feat_array[] = {

   /* Preserve command-line case with SET PROCESS/PARSE_STYLE=EXTENDED */
 { "DECC$ARGV_PARSE_STYLE", 1 },

#if 0  /* Possibly useful in the future. */

   /* Preserve case for file names on ODS5 disks. */
 { "DECC$EFS_CASE_PRESERVE", 1 },

   /* Enable multiple dots (and most characters) in ODS5 file names,
      while preserving VMS-ness of ";version". */
 { "DECC$EFS_CHARSET", 1 },

#endif /* 0 */

   /* List terminator. */
 { (char *)NULL, 0 } };

/* LIB$INITIALIZE initialization function. */

static void decc_init( void)
{
int feat_index;
int feat_value;
int feat_value_max;
int feat_value_min;
int i;
int sts;

/* Set the global flag to indicate that LIB$INITIALIZE worked. */

decc_init_done = 1;

/* Loop through all items in the decc_feat_array[]. */

for (i = 0; decc_feat_array[ i].name != NULL; i++)
   {
   /* Get the feature index. */
   feat_index = decc$feature_get_index( decc_feat_array[ i].name);
   if (feat_index >= 0)
      {
      /* Valid item.  Collect its properties. */
      feat_value = decc$feature_get_value( feat_index, 1);
      feat_value_min = decc$feature_get_value( feat_index, 2);
      feat_value_max = decc$feature_get_value( feat_index, 3);

      if ((decc_feat_array[ i].value >= feat_value_min) &&
       (decc_feat_array[ i].value <= feat_value_max))
         {
         /* Valid value.  Set it if necessary. */
         if (feat_value != decc_feat_array[ i].value)
            {
            sts = decc$feature_set_value( feat_index,
             1,
             decc_feat_array[ i].value);
            }
         }
      else
         {
         /* Invalid DECC feature value. */
         printf( " INVALID DECC FEATURE VALUE, %d: %d <= %s <= %d.\n",
          feat_value,
          feat_value_min, decc_feat_array[ i].name, feat_value_max);
         }
      }
   else
      {
      /* Invalid DECC feature name. */
      printf( " UNKNOWN DECC FEATURE: %s.\n", decc_feat_array[ i].name);
      }
   }
}

/* Get "decc_init()" into a valid, loaded LIB$INITIALIZE PSECT. */

#pragma nostandard

/* Establish the LIB$INITIALIZE PSECTs, with proper alignment and
   other attributes.  Note that "nopic" is significant only on VAX.
*/
#pragma extern_model save

#pragma extern_model strict_refdef "LIB$INITIALIZ" 2, nopic, nowrt
const int spare[ 8] = { 0 };

#pragma extern_model strict_refdef "LIB$INITIALIZE" 2, nopic, nowrt
void (*const x_decc_init)() = decc_init;

#pragma extern_model restore

/* Fake reference to ensure loading the LIB$INITIALIZE PSECT. */

#pragma extern_model save

int LIB$INITIALIZE( void);

#pragma extern_model strict_refdef

int dmy_lib$initialize = (int) LIB$INITIALIZE;

#pragma extern_model restore

#pragma standard

#endif /* !defined( __VAX) && (__CRTL_VER >= 70301000) */

#endif /* def __CRTL_VER */

#endif /* def __DECC */

#endif /* VMS */