The code set out below is not intended to be compiled, but is only intended as
a very simplistic pointer to how to load and call the dll. You will have to
look in the files referenced below for actual, working code.

There are two entry points that use the structure shown below:

BOOL WINAPI ZpSetOptions(ZPOPT) and
ZPOPT WINAPI ZpGetOptions(void)

typedef struct {
LPSTR Date;             /* Date to include after */
LPSTR szRootDir;        /* Directory to use as base for zipping */
LPSTR szTempDir;        /* Temporary directory used during zipping */
BOOL fTemp;             /* Use temporary directory '-b' during zipping */
BOOL fSuffix;           /* include suffixes (not implemented in WiZ) */
BOOL fEncrypt;          /* encrypt files */
BOOL fSystem;           /* include system and hidden files */
BOOL fVolume;           /* Include volume label */
BOOL fExtra;            /* Exclude extra attributes */
BOOL fNoDirEntries;     /* Do not add directory entries */
BOOL fExcludeDate;      /* Exclude files earlier than specified date */
BOOL fIncludeDate;      /* Include only files earlier than specified date */
BOOL fVerbose;          /* Mention oddities in zip file structure */
BOOL fQuiet;            /* Quiet operation */
BOOL fCRLF_LF;          /* Translate CR/LF to LF */
BOOL fLF_CRLF;          /* Translate LF to CR/LF */
BOOL fJunkDir;          /* Junk directory names */
BOOL fGrow;             /* Allow appending to a zip file */
BOOL fForce;            /* Make entries using DOS names (k for Katz) */
BOOL fMove;             /* Delete files added or updated in zip file */
BOOL fDeleteEntries;    /* Delete files from zip file */
BOOL fUpdate;           /* Update zip file--overwrite only if newer */
BOOL fFreshen;          /* Freshen zip file--overwrite only */
BOOL fJunkSFX;          /* Junk SFX prefix */
BOOL fLatestTime;       /* Set zip file time to time of latest file in it */
BOOL fComment;          /* Put comment in zip file */
BOOL fOffsets;          /* Update archive offsets for SFX files */
BOOL fPrivilege;        /* Use privileges (WIN32 only) */
BOOL fEncryption;       /* TRUE if encryption supported, else FALSE.
                           this is a read-only flag */
int  fRecurse;          /* Recurse into subdirectories. 1 => -r, 2 => -R */
int  fRepair;           /* Repair archive. 1 => -F, 2 => -FF */
char fLevel;            /* Compression level (0 - 9) */
} ZPOPT, _far *LPZPOPT;

BOOL WINAPI ZpSetOptions(ZPOPT);

This call will simply set the options in the zip dll until such time as
another call to this function is made. This must be made before the initial
call to make or update an archive.

ZPOPT WINAPI ZpGetOptions(void);

The call will return the above structure from the dll, with the fEncryption
flag set to the appropriate value based on whether encryption is supported
in this dll or not. It is currently used in WiZ only to determine if
encryption is actually supported.

The main entry point is ZpArchive(ZCL) where the structure shown below
is passed to the DLL when it is called.

typedef struct {
int  argc;              = Count of files to zip
LPSTR lpszZipFN;        = Archive file name
char **FNV;             = file names to zip up. Think of this an argv
} ZCL, _far *LPZCL;


For examples of how the actual calls to the dll were set up in WiZ, look in
the file makezip.c in the WiZ source directory.

For examples of how the actual loading and unloading of the dll's themselves
was done, look in wizmain.c in the WiZ source directory. Note that WiZ looks
specifically for a particular version number of the dll, and also expects to
find the company name to be Info-ZIP. This is to protect from getting different
versions of the dll loaded, with resulting unknown behavior.

There is a very simplistic example of how to load and call into the dll in
example.c and example.h. Note that this example does not implement any
command line switches at all, and is merely intended as a guide for those
brave enough to enter a new world.

There are four additional (at the moment) entry points:

ZpInit, defined as

int WINAPI ZpInit(ZIPUSERFUNCTIONS far * lpZipUserFunc);

where ZIPUSERFUNCTIONS is defined as below.

ZpVersion, defined as

ZpVer * ZpVersion(void);

where ZpVer is defined as:

typedef struct _ZpVer {
    ulg structlen;          /* length of the struct being passed */
    ulg flag;               /* bit 0: is_beta   bit 1: uses_zlib */
    char *betalevel;        /* e.g., "g BETA" or "" */
    char *date;             /* e.g., "4 Sep 95" (beta) or "4 September 1995" */
    char *zlib_version;     /* e.g., "0.95" or NULL */
    _zip_version_type zip;
    _zip_version_type os2dll;
    _zip_version_type windll;
} ZpVer;

See api.c for exactly what ZpVersion does, but the short version of
what it does is return the unzip and dll versions in the ZpVer structure.
The structure typedef's are in api.h

The typedef's for the function pointers in the structure ZIPUSERFUNCTIONS
are shown immediately below.

typedef int (WINAPI DLLPRNT) (LPSTR, unsigned long);
typedef int (WINAPI DLLPASSWORD) (LPSTR, int, LPCSTR, LPCSTR);
typedef int (WINAPI DLLSERVICE) (LPCSTR, unsigned long);
typedef int (WINAPI DLLCOMMENT) (LPSTR);

typedef struct {
DLLPRNT *print;          = pointer to application's print function.
DLLCOMMENT *comment;     = pointer to application's function for processing
                           comments.
DLLPASSWORD *password;   = pointer to application's function for processing
                           passwords.
DLLSERVICE *ServiceApplication; = Optional callback function for processing
                                  messages, relaying information.
} ZIPUSERFUNCTIONS, far * LPZIPUSERFUNCTIONS;

Last revised January 5, 1999.

Mike White