C to PB Conversion

[Florent Heyworth]

Hi Bakulesh

ASCIIZ are zero terminated strings, use them wherever you would
use char * or char[]. The STRING type used in PB corresponds
to the BSTR in C (SysAlloc* family).

The difference in return types is only apparent - PB supports
casting but in a different manner than C. Casting in PB is done
by assigning a return type to another as in (using the
getservbyname example):

LOCAL dwReturn AS DWORD
LOCAL ptServent AS servent PTR 'pointer to servent structure

dwReturn = getservbyname( "HTTP", "TCP" )
'cast the return value
ptServent = dwReturn

'alternatively (quicker and more succint) you could do:
ptservent = getservbyname( "HTTP", "TCP" )

... access the structure

The pointer notation is <DATATYPE> PTR. To get the address of
a variable use VARPTR(<DATATYPE> ) instead &<DATATYPE> as in C.

PowerBASIC is very flexible and offers UNION, UDTs and a host
of other features.

Hopefully this will be enough to get you started.

Cheers

Florent

------------------

[Bakulesh Thakker]

I am new PB programmer wanting to use PB as programming vehicle for my personal software. I am a 'C'-aware programmer so I can understand some of the things Lance is writing. But the reason why I reached this thread is because I searched for help on C to PB translation.

I have number of questions:

First I know that C expects parameter values passed "By Value". So it makes sense to prescribe variables in argument list with "*" to be translated as BYREF and other values BYVAL. But from what little C I know char * values are pointers heaxdecimal zero terminated character strings and a pointer to such values is passed BYVAL. So they should translate as ASCIIZ. But Lance says that even char types should be coded as ASCIIZ. Is this correct?

Secondly I wanted to know was this: Many API functions are translated as returning value DWORD whereas .H files show the type returned as <something> {FAR} *.

For example, consider following from WINSOCK.H (copied from CodeWarrior Lite):

struct servent FAR * PASCAL FAR getservbyname(const char FAR * name,
const char FAR * proto);

whereas in .inc file same function is shown as:

DECLARE FUNCTION getservbyname LIB "WINSOCK" (szName AS ASCIIZ, Proto AS ASCIIZ) AS DWORD

How am I going to access the components of struct servent knowing a DWORD value which is supposed to be a pointer to "struct servent" value? Do I use union?

Third thing I wanted to know is: is there some nice way to translate casting notation used in some C programme. Like for example (LONG)dwX.

I hope my query is considered appropriate here.

Thanks and regards,

-Bakulesh

[Lance Edmonds]

You may want to consider offering payment for this kind of task George, you are more likely to get some offers of assistance.

In case you want to try it yourself, I'll give you a couple of hints: most of the declarations are expecting the parameters BYVAL, and those prefixed with an "*" are expecting a BYREF parameter. UINT32 is a LONG in PB, and UINT16 is an INT. CHAR is usually ASCIIZ, and ** means a pointer to a pointer (indirection).

Lance
PowerBASIC Support

[George Bleck]

Thanks for the information John, but this is for Netscape's proprietary registry NSREG.DAT through LIBREG32.DLL

[John Spikowski]

There is a set of registry functions available on the PB FTP site.

[George Bleck]

Though this is a monumental task for someone, would anyone be able and willing to convert the below listed C code into something I can use with PB/DLL6. C is greek to me and the learning curve too great for the time I need the code in. Any help by a willing soul would be GREATLY appreciated!

/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 *
 * The contents of this file are subject to the Netscape Public License
 * Version 1.0 (the "License"); you may not use this file except in
 * compliance with the License.  You may obtain a copy of the License at
 * http://www.mozilla.org/NPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Mozilla Communicator client code, 
 * released March 31, 1998. 
 *
 * The Initial Developer of the Original Code is Netscape Communications 
 * Corporation.  Portions created by Netscape are 
 * Copyright (C) 1998 Netscape Communications Corporation.  All Rights
 * Reserved.
 *
 * Contributors:
 *     Daniel Veditz <[email protected]>
 */
/* NSReg.h
 */
#ifndef _NSREG_H_
#define _NSREG_H_

#include "xp_core.h"

typedef void (*nr_RegPackCallbackFunc) (void *userData, int32 bytes, int32 totalBytes);

typedef int32   REGERR;
typedef int32   RKEY;
typedef uint32  REGENUM;
typedef void *  HREG;

typedef struct _reginfo
{
   uint16  size;        /* must be initialized to sizeof(REGINFO) */
   uint16  entryType;
   uint32  entryLength;
} REGINFO;

#define REGERR_OK           (0)
#define REGERR_FAIL         (1)
#define REGERR_NOMORE       (2)
#define REGERR_NOFIND       (3)
#define REGERR_BADREAD      (4)
#define REGERR_BADLOCN      (5)
#define REGERR_PARAM        (6)
#define REGERR_BADMAGIC     (7)
#define REGERR_BADCHECK     (8)
#define REGERR_NOFILE       (9)
#define REGERR_MEMORY       (10)
#define REGERR_BUFTOOSMALL  (11)
#define REGERR_NAMETOOLONG  (12)
#define REGERR_REGVERSION   (13)
#define REGERR_DELETED      (14)
#define REGERR_BADTYPE      (15)
#define REGERR_NOPATH       (16)
#define REGERR_BADNAME      (17)
#define REGERR_READONLY     (18)
#define REGERR_BADUTF8      (19)


/* Total path length */
#define MAXREGPATHLEN   (2048)
/* Name on the path (including null terminator) */
#define MAXREGNAMELEN   (512)
/* Value of an entry */
#define MAXREGVALUELEN  (0x7FFF)

/* Standard keys */
#define ROOTKEY_USERS                   (0x01)
#define ROOTKEY_COMMON                  (0x02)
#define ROOTKEY_CURRENT_USER            (0x03)
#define ROOTKEY_PRIVATE                 (0x04)

/* enumeration styles */
#define REGENUM_NORMAL                  (0x00)
#define REGENUM_CHILDREN                REGENUM_NORMAL
#define REGENUM_DESCEND                 (0x01)
#define REGENUM_DEPTH_FIRST             (0x02)

/* entry data types */
#define REGTYPE_ENTRY                 (0x0010)
#define REGTYPE_ENTRY_STRING_UTF      (REGTYPE_ENTRY + 1)
#define REGTYPE_ENTRY_INT32_ARRAY     (REGTYPE_ENTRY + 2)
#define REGTYPE_ENTRY_BYTES           (REGTYPE_ENTRY + 3)
#define REGTYPE_ENTRY_FILE            (REGTYPE_ENTRY + 4)

#define REG_DELETE_LIST_KEY  "Netscape/Communicator/SoftwareUpdate/Delete List"
#define REG_REPLACE_LIST_KEY "Netscape/Communicator/SoftwareUpdate/Replace List"
#define REG_UNINSTALL_DIR    "Netscape/Communicator/SoftwareUpdate/Uninstall/"

#define UNINSTALL_NAV_STR "_"


#define UNIX_GLOBAL_FLAG     "MOZILLA_SHARED_REGISTRY"

/* Platform-dependent declspec for library interface */
#if defined(XP_PC)
  #if defined(WIN32)

    #if defined (STANDALONE_REGISTRY)
       #define VR_INTERFACE(type)     __declspec(dllexport) type __cdecl
    #else
       #define VR_INTERFACE(type)     __declspec(dllexport) type __stdcall
    #endif

  #elif defined(XP_OS2)
  #define VR_INTERFACE(type)     type _Optlink
  #else
  #define VR_INTERFACE(type)     type _far _pascal _export
  #endif
#elif defined XP_MAC
  #define VR_INTERFACE(__x)  __declspec(export) __x
#elif defined(MOZ_STRIP_NOT_EXPORTED)
  #define VR_INTERFACE(type) __attribute__ ((dllexport)) type
#else
  #define VR_INTERFACE(type)     type
#endif

XP_BEGIN_PROTOS



/* ---------------------------------------------------------------------
 * Registry API -- General
 * ---------------------------------------------------------------------
 */

/* ---------------------------------------------------------------------
 * NR_RegOpen - Open a netscape XP registry
 *
 * Parameters:
 *    filename   - registry file to open. NULL or ""  opens the standard
 *                 local registry.
 *    hReg       - OUT: handle to opened registry
 *
 * Output:
 * ---------------------------------------------------------------------
 */
VR_INTERFACE(REGERR) NR_RegOpen(
         char *filename,   /* reg. file to open (NULL == standard registry) */
         HREG *hReg        /* OUT: handle to opened registry */
       );


/* ---------------------------------------------------------------------
 * NR_RegClose - Close a netscape XP registry
 *
 * Parameters:
 *    hReg     - handle of open registry to be closed.
 *
 * After calling this routine the handle is no longer valid
 * ---------------------------------------------------------------------
 */
VR_INTERFACE(REGERR) NR_RegClose(
         HREG hReg         /* handle of open registry to close */
       );


/* ---------------------------------------------------------------------
 * NR_RegIsWritable - Check read/write status of open registry
 *
 * Parameters:
 *    hReg     - handle of open registry to query
 * Returns:
 *    REGERR_OK if writable, REGERR_READONLY if not, possibly
 *    other errors for an invalid hReg
 * ---------------------------------------------------------------------
 */
VR_INTERFACE(REGERR) NR_RegIsWritable(
         HREG hReg         /* handle of open registry to query */
       );

VR_INTERFACE(REGERR) NR_RegPack(
         HREG hReg,         /* handle of open registry to pack */
         void *userData,
         nr_RegPackCallbackFunc fn
       );


/* ---------------------------------------------------------------------
 * NR_RegSetUsername - Set the current username
 * 
 * If the current user profile name is not set then trying to use
 * HKEY_CURRENT_USER will result in an error.
 *
 * Parameters:
 *     name     - name of the current user
 *
 * Output:
 * ---------------------------------------------------------------------
 */
VR_INTERFACE(REGERR) NR_RegSetUsername(
         const char *name  /* name of current user */
       );

/* ---------------------------------------------------------------------
 * DO NOT USE -- Will be removed 
 * ---------------------------------------------------------------------
 */
VR_INTERFACE(REGERR) NR_RegGetUsername(
         char **name        /* on return, an alloc'ed copy of the current user name */
       );






/* ---------------------------------------------------------------------
 * Registry API -- Key Management functions
 * ---------------------------------------------------------------------
 */

/* ---------------------------------------------------------------------
 * NR_RegAddKey - Add a key node to the registry
 *
 * Can also be used to find an existing node for convenience.
 *
 * Parameters:
 *    hReg     - handle of open registry
 *    key      - registry key obtained from NR_RegGetKey(),
 *               or one of the standard top-level keys
 *    path     - relative path of key to be added.  Intermediate
 *               nodes will be added if necessary.
 *    newkey   - If not null returns RKEY of new or found node
 * ---------------------------------------------------------------------
 */
VR_INTERFACE(REGERR) NR_RegAddKey(
         HREG hReg,        /* handle of open registry */
         RKEY key,         /* root key */
         char *path,       /* relative path of subkey to add */
         RKEY *newKey      /* if not null returns newly created key */
       );


/* ---------------------------------------------------------------------
 * NR_RegAddKeyRaw - Add a key node to the registry
 *
 *      This routine is different from NR_RegAddKey() in that it takes 
 *      a keyname rather than a path.
 *
 * Parameters:
 *    hReg     - handle of open registry
 *    key      - registry key obtained from NR_RegGetKey(),
 *               or one of the standard top-level keys
 *    keyname  - name of key to be added. No parsing of this
 *               name happens.
 *    newkey   - if not null the RKEY of the new key is returned
 * ---------------------------------------------------------------------
 */
VR_INTERFACE(REGERR) NR_RegAddKeyRaw(
         HREG hReg,        /* handle of open registry */
         RKEY key,         /* root key */
         char *keyname,    /* name of key to add */
         RKEY *newKey      /* if not null returns newly created key */
       );


/* ---------------------------------------------------------------------
 * NR_RegDeleteKey - Delete the specified key
 *
 * Note that delete simply orphans blocks and makes no attempt
 * to reclaim space in the file. Use NR_RegPack()
 *
 * Cannot be used to delete keys with child keys
 *
 * Parameters:
 *    hReg     - handle of open registry
 *    key      - starting node RKEY, typically one of the standard ones.
 *    path     - relative path of key to delete
 * ---------------------------------------------------------------------
 */
VR_INTERFACE(REGERR) NR_RegDeleteKey(
         HREG hReg,        /* handle of open registry */
         RKEY key,         /* root key */
         char *path        /* relative path of subkey to delete */
       );


/* ---------------------------------------------------------------------
 * NR_RegDeleteKeyRaw - Delete the specified raw key
 *
 * Note that delete simply orphans blocks and makes no attempt
 * to reclaim space in the file. Use NR_RegPack()
 *
 * Parameters:
 *    hReg     - handle of open registry
 *    key      - RKEY or parent to the raw key you wish to delete
 *    keyname  - name of child key to delete
 * ---------------------------------------------------------------------
 */
VR_INTERFACE(REGERR) NR_RegDeleteKeyRaw(
         HREG hReg,        /* handle of open registry */
         RKEY key,         /* root key */
         char *keyname     /* name subkey to delete */
       );


/* ---------------------------------------------------------------------
 * NR_RegGetKey - Get the RKEY value of a node from its path
 *
 * Parameters:
 *    hReg     - handle of open registry
 *    key      - starting node RKEY, typically one of the standard ones.
 *    path     - relative path of key to find.  (a blank path just gives you
 *               the starting key--useful for verification, VersionRegistry)
 *    result   - if successful the RKEY of the specified sub-key
 * ---------------------------------------------------------------------
 */
VR_INTERFACE(REGERR) NR_RegGetKey(
         HREG hReg,        /* handle of open registry */
         RKEY key,         /* root key */
         char *path,       /* relative path of subkey to find */
         RKEY *result      /* returns RKEY of specified sub-key */
       );


/* ---------------------------------------------------------------------
 * NR_RegGetKeyRaw - Get the RKEY value of a node from its keyname
 *
 * Parameters:
 *    hReg     - handle of open registry
 *    key      - starting node RKEY, typically one of the standard ones.
 *    keyname  - keyname of key to find.  (a blank keyname just gives you
 *               the starting key--useful for verification, VersionRegistry)
 *    result   - if successful the RKEY of the specified sub-key
 * ---------------------------------------------------------------------
 */
VR_INTERFACE(REGERR) NR_RegGetKeyRaw(
         HREG hReg,        /* handle of open registry */
         RKEY key,         /* root key */
         char *keyname,       /* name of key to get */
         RKEY *result      /* returns RKEY of specified sub-key */
       );


/* ---------------------------------------------------------------------
 * NR_RegEnumSubkeys - Enumerate the subkey names for the specified key
 *
 * Returns REGERR_NOMORE at end of enumeration.
 *
 * Parameters:
 *    hReg     - handle of open registry
 *    key      - RKEY of key to enumerate--obtain with NR_RegGetKey()
 *    eState   - enumerations state, must contain NULL to start
 *    buffer   - location to store subkey names.  Once an enumeration
 *               is started user must not modify contents since values
 *               are built using the previous contents.
 *    bufsize  - size of buffer for names
 *    style    - 0 returns direct child keys only, REGENUM_DESCEND
 *               returns entire sub-tree
 * ---------------------------------------------------------------------
 */
VR_INTERFACE(REGERR) NR_RegEnumSubkeys(
         HREG    hReg,        /* handle of open registry */
         RKEY    key,         /* containing key */
         REGENUM *state,      /* enum state, must be NULL to start */
         char    *buffer,     /* buffer for entry names */
         uint32  bufsize,     /* size of buffer */
         uint32  style        /* 0: children only; REGENUM_DESCEND: sub-tree */
       );



/* ---------------------------------------------------------------------
 * Registry API -- Entry Management functions
 * ---------------------------------------------------------------------
 */


/* ---------------------------------------------------------------------
 * NR_RegGetEntryInfo - Get some basic info about the entry data
 *
 * Parameters:
 *    hReg     - handle of open registry
 *    key      - RKEY of key that contains entry--obtain with NR_RegGetKey()
 *    name     - name of entry
 *    info     - return: Entry info object
 * ---------------------------------------------------------------------
 */
VR_INTERFACE(REGERR) NR_RegGetEntryInfo(
         HREG    hReg,     /* handle of open registry */
         RKEY    key,      /* containing key */
         char    *name,    /* entry name */
         REGINFO *info     /* returned entry info */
       );

       
/* ---------------------------------------------------------------------
 * NR_RegGetEntryString - Get the UTF string value associated with the
 *                       named entry of the specified key.
 *
 * Parameters:
 *    hReg     - handle of open registry
 *    key      - RKEY of key that contains entry--obtain with NR_RegGetKey()
 *    name     - name of entry
 *    buffer   - destination for string
 *    bufsize  - size of buffer
 * ---------------------------------------------------------------------
 */
VR_INTERFACE(REGERR) NR_RegGetEntryString(
         HREG   hReg,      /* handle of open registry */
         RKEY   key,       /* containing key */
         char   *name,     /* entry name */
         char   *buffer,   /* buffer to hold value (UTF String) */
         uint32 bufsize    /* length of buffer */
       );

/* ---------------------------------------------------------------------
 * NR_RegGetEntry - Get the value data associated with the
 *                  named entry of the specified key.
 *
 * Parameters:
 *    hReg     - handle of open registry
 *    key      - RKEY of key that contains entry--obtain with NR_RegGetKey()
 *    name     - name of entry
 *    buffer   - destination for data
 *    size     - in:  size of buffer
 *               out: size of actual data (incl. \0 term. for strings)
 * ---------------------------------------------------------------------
 */
VR_INTERFACE(REGERR) NR_RegGetEntry(
         HREG   hReg,      /* handle of open registry */
         RKEY   key,       /* containing key */
         char   *name,     /* entry name */
         void   *buffer,   /* buffer to hold value */
         uint32 *size      /* in:length of buffer */
       );                  /* out: data length, >>includes<< null terminator*/


/* ---------------------------------------------------------------------
 * NR_RegSetEntryString - Store a UTF-8 string value associated with the
 *                       named entry of the specified key.  Used for
 *                       both creation and update.
 *
 * Parameters:
 *    hReg     - handle of open registry
 *    key      - RKEY of key that contains entry--obtain with NR_RegGetKey()
 *    name     - name of entry
 *    buffer   - UTF-8 String to store
 * ---------------------------------------------------------------------
 */
VR_INTERFACE(REGERR) NR_RegSetEntryString(
         HREG hReg,        /* handle of open registry */
         RKEY key,         /* containing key */
         char *name,       /* entry name */
         char *buffer      /* UTF String value */
       );


/* ---------------------------------------------------------------------
 * NR_RegSetEntry - Store value data associated with the named entry
 *                  of the specified key.  Used for both creation and update.
 *
 * Parameters:
 *    hReg     - handle of open registry
 *    key      - RKEY of key that contains entry--obtain with NR_RegGetKey()
 *    name     - name of entry
 *    type     - type of data to be stored
 *    buffer   - data to store
 *    size     - length of data to store in bytes
 * ---------------------------------------------------------------------
 */
VR_INTERFACE(REGERR) NR_RegSetEntry(
         HREG   hReg,        /* handle of open registry */
         RKEY   key,         /* containing key */
         char   *name,       /* entry name */
         uint16 type,        /* type of value data */
         void   *buffer,     /* data buffer */
         uint32 size         /* data length in bytes; incl. null term for strings */
       );


/* ---------------------------------------------------------------------
 * NR_RegDeleteEntry - Delete the named entry
 *
 * Parameters:
 *    hReg     - handle of open registry
 *    key      - RKEY of key that contains entry--obtain with NR_RegGetKey()
 *    name     - name of entry
 * ---------------------------------------------------------------------
 */
VR_INTERFACE(REGERR) NR_RegDeleteEntry(
         HREG hReg,        /* handle of open registry */
         RKEY key,         /* containing key */
         char *name        /* value name */
       );


/* ---------------------------------------------------------------------
 * NR_RegEnumEntries - Enumerate the entry names for the specified key
 *
 * Returns REGERR_NOMORE at end of enumeration.
 *
 * Parameters:
 *    hReg     - handle of open registry
 *    key      - RKEY of key that contains entry--obtain with NR_RegGetKey()
 *    eState   - enumerations state, must contain NULL to start
 *    buffer   - location to store entry names
 *    bufsize  - size of buffer for names
 * ---------------------------------------------------------------------
 */
VR_INTERFACE(REGERR) NR_RegEnumEntries(
         HREG    hReg,        /* handle of open registry */
         RKEY    key,         /* containing key */
         REGENUM *state,      /* enum state, must be NULL to start */
         char    *buffer,     /* buffer for entry names */
         uint32  bufsize,     /* size of buffer */
         REGINFO *info        /* optional; returns info about entry */
       );


VR_INTERFACE(void)      NR_ShutdownRegistry(void);
VR_INTERFACE(REGERR)    NR_StartupRegistry(void);


XP_END_PROTOS

#endif   /* _NSREG_H_ */

/* EOF: NSReg.h */