/*
|| ----------------------------------------------------------------------------
||
|| HETGET.C     (c) Copyright Leland Lucius, 2000-2006
||              Released under terms of the Q Public License.
||
|| Extract files from an HET file
||
|| ----------------------------------------------------------------------------
*/

#include "hstdinc.h"

#include "hercules.h"
#include "hetlib.h"
#include "sllib.h"
#include "herc_getopt.h"

/*
|| Local volatile data
*/
#define O_NL        0x80
#define O_ASCII     0x40
#define O_STRIP     0x20
#define O_UNBLOCK   0x10
struct
{
    char *ifile;
    char *ofile;
    int fileno;
    int lrecl;
    int blksize;
    unsigned char flags;
    unsigned char recfm;
}
opts = 
{
    NULL,
    NULL,
    0,
    0,
    0,
    0,
    0,
};

/*
|| Local constant data
*/
static const char help[] =
    "%s - Extract files from an HET file\n\n"
    "Usage: %s [options] hetfile outfile fileno [recfm lrecl blksize]\n\n"
    "Options:\n"
    "  -a  convert to ASCII (implies -u)\n"
    "  -h  display usage summary\n"
    "  -n  file is an NL (or BLP like) tape\n"
    "  -u  unblock (removes BDWs and RDWs if RECFM=V)\n"
    "  -s  strip trailing blanks (requires -a)\n";

/*
|| Valid record formats
*/
#define O_UNDEFINED 0x80
#define O_FIXED     0x40
#define O_VARIABLE  0x20
#define O_BLOCKED   0x08
#define O_SPANNED   0x04

static const struct
{
    char *recfm;
    int fmt;
}
valfm[] =
{
    { "U",      O_UNDEFINED | 0         | 0         },
    { "UA",     O_UNDEFINED | 0         | 0         },
    { "UM",     O_UNDEFINED | 0         | 0         },
    { "F",      O_FIXED     | 0         | 0         },
    { "FA",     O_FIXED     | 0         | 0         },
    { "FM",     O_FIXED     | 0         | 0         },
    { "FB",     O_FIXED     | O_BLOCKED | 0         },
    { "FBA",    O_FIXED     | O_BLOCKED | 0         },
    { "FBM",    O_FIXED     | O_BLOCKED | 0         },
    { "FS",     O_FIXED     | O_BLOCKED | 0         },
    { "FSA",    O_FIXED     | O_BLOCKED | 0         },
    { "FSM",    O_FIXED     | O_BLOCKED | 0         },
    { "FBS",    O_FIXED     | O_BLOCKED | 0         },
    { "FBSA",   O_FIXED     | O_BLOCKED | 0         },
    { "FBSM",   O_FIXED     | O_BLOCKED | 0         },
    { "V",      O_VARIABLE  | 0         | 0         },
    { "VA",     O_VARIABLE  | 0         | 0         },
    { "VM",     O_VARIABLE  | 0         | 0         },
    { "VB",     O_VARIABLE  | O_BLOCKED | 0         },
    { "VBA",    O_VARIABLE  | O_BLOCKED | 0         },
    { "VBM",    O_VARIABLE  | O_BLOCKED | 0         },
    { "VS",     O_VARIABLE  | 0         | O_SPANNED },
    { "VSA",    O_VARIABLE  | 0         | O_SPANNED },
    { "VSM",    O_VARIABLE  | 0         | O_SPANNED },
    { "VBS",    O_VARIABLE  | O_BLOCKED | O_SPANNED },
    { "VBSA",   O_VARIABLE  | O_BLOCKED | O_SPANNED },
    { "VBSM",   O_VARIABLE  | O_BLOCKED | O_SPANNED },
};
#define VALFMCNT ( sizeof( valfm ) / sizeof( valfm[ 0 ] ) )

/*
|| Block and record management
*/
unsigned char *blkptr = NULL;
int blkidx = 0;
int blklen = 0;
unsigned char *recptr = NULL;
int recidx = 0;
int reclen = 0;

#ifdef EXTERNALGUI
/*
|| Previously reported file position
*/
static OFF_T prevpos = 0;
/*
|| Report progress every this many bytes
*/
#define PROGRESS_MASK (~0x3FFFF /* 256K */)
#endif /*EXTERNALGUI*/

/*
|| Merge DCB information from HDR2 label
*/
void
merge( SLLABEL *lab )
{
    SLFMT fmt;
    int i;

    /*
    || Make the label more managable
    */
    sl_fmtlab( &fmt, lab );

    /*
    || Merge the record format;
    */
    if( opts.recfm == 0 )
    {
        opts.recfm = O_UNDEFINED;
        for( i = 0 ; i < (int)VALFMCNT ; i++ )
        {
            if( strcasecmp( fmt.slds2.recfm, valfm[ i ].recfm ) == 0 )
            {
                opts.recfm = valfm[ i ].fmt;
                break;
            }
        }
    }

    /*
    || Merge in the record length
    */
    if( opts.lrecl == 0 )
    {
        opts.lrecl = atoi( fmt.slds2.lrecl );
    }

    /*
    || Merge in the block size
    */
    if( opts.blksize == 0 )
    {
        /*
        || Try the blksize field first
        */
        opts.blksize = atoi( fmt.slds2.blksize );
        if( opts.blksize == 0 )
        {
            /*
            || Still zero, so try the lblkln field
            */
            opts.blksize = atoi( fmt.slds2.lblkln );
        }
    }

    /*
    || Locate final RECFM string
    */
    for( i = 0 ; i < (int)VALFMCNT ; i++ )
    {
        if( strcasecmp( fmt.slds2.recfm, valfm[ i ].recfm ) == 0 )
        {
            break;
        }
    }

    /*
    || Print DCB attributes
    */
    printf( "DCB Attributes used:\n" );
    printf( "  RECFM=%-4.4s  LRECL=%-5.5d  BLKSIZE=%d\n",
        valfm[ i ].recfm,
        opts.lrecl,
        opts.blksize );

    return;
}

/*
|| Return block length from BDW
*/
int
bdw_length( const unsigned char *ptr  )
{
    unsigned int len;

    /*
    || Extended format BDW? 
    */
    if( ptr[ 0 ] & 0x80 )
    {
        /*
        || Length is 31 bits
        */
        len  = ptr[ 0 ] << 24;
        len += ptr[ 1 ] << 16;
        len += ptr[ 2 ] << 8;
        len += ptr[ 3 ];
        len &= 0x7fffffff;
    }
    else
    {
        /*
        || Length is 15 bits
        */
        len  = ptr[ 0 ] << 8;
        len += ptr[ 1 ];
    }

    return( len );
}

/*
|| Return record length from RDW
*/
int
rdw_length( const unsigned char *ptr )
{
    unsigned int len;

    /*
    || Get the record length
    */
    len  = ptr[ 0 ] << 8;
    len += ptr[ 1 ];

    return( len );
}

/*
|| Retrieves a block from the tape file and resets variables
*/
int
getblock( HETB *hetb )
{
    int rc;

    /*
    || Read a block from the tape
    */
    rc = het_read( hetb, blkptr );
    if( rc < 0 )
    {
        return( rc );
    }

    /*
    || Save the block length (should we use BDW for RECFM=V files???)
    */
    blklen = rc;

    return( rc );
}

/*
|| Retrieve logical records from the tape - doesn't handle SPANNED records
*/
int
getrecord( HETB *hetb )
{
    int rc;
    
    /*
    || Won't be null if we've been here before
    */
    if( recptr != NULL )
    {
        recidx += reclen;
    }

    /*
    || Need a new block first time through or we've exhausted current block
    */
    if( ( recptr == NULL ) || ( recidx >= blklen ) )
    {
        /*
        || Go get another block
        */
        rc = getblock( hetb );
        if( rc < 0 )
        {
            return( rc );
        }
    
        /*
        || For RECFM=V, bump index past BDW
        */
        recidx = 0;
        if( opts.recfm & O_VARIABLE )
        {
            recidx = 4;
        }
    }

    /*
    || Set the new record pointer
    */
    recptr = &blkptr[ recidx ];

    /*
    || Set the record length depending on record type
    */
    if( opts.recfm & O_FIXED )
    {
        reclen = opts.lrecl;
    }
    else if( opts.recfm & O_VARIABLE )
    {
        reclen = rdw_length( recptr );
    }
    else
    {
        reclen = blklen;
    }

    return( reclen );
}

/*
|| Retrieve and validate a standard label
*/
int
get_sl( HETB *hetb, SLLABEL *lab )
{
    int rc;
    
    /*
    || Read a block
    */
    rc = het_read( hetb, blkptr );
    if( rc >= 0 )
    {
        /*
        || Does is look like a standard label?
        */
        if( sl_islabel( lab, blkptr, rc ) == TRUE )
        {
            return( 0 );
        }
    }
    else
    {
        printf( "%s while reading block\n", het_error( rc ) );
    }

    return( -1 );
}

/*
|| Extract the file from the tape
*/
int
getfile( HETB *hetb, FILE *outf )
{
    SLFMT fmt;
    SLLABEL lab;
    unsigned char *ptr;
    int fileno;
    int rc;
    
    /*
    || Skip to the desired file
    */
    if( opts.flags & O_NL )
    {
        /*
        || For NL tapes, just use the specified file number
        */
        fileno = opts.fileno;

        /*
        || Start skipping
        */
        while( --fileno )
        {
            /*
            || Forward space to beginning of next file
            */
            rc = het_fsf( hetb );
            if( rc < 0 )
            {
                printf( "%s while positioning to file #%d\n",
                    het_error( rc ),
                    opts.fileno );
                return( rc );
            }
        }
    }
    else
    {
        /*
        || First block should be a VOL1 record
        */
        rc = get_sl( hetb, &lab );
        if( rc < 0 || !sl_isvol( &lab, 1 ) )
        {
            printf( "Expected VOL1 label\n" );
            return( -1 );
        }

        /*
        || For SL, adjust the file # so we end up on the label before the data
        */
        fileno = ( opts.fileno * 3 ) - 2;

        /*
        || Start skipping
        */
        while( --fileno )
        {
            /*
            || Forward space to beginning of next file
            */
            rc = het_fsf( hetb );
            if( rc < 0 )
            {
                printf( "%s while positioning to file #%d\n",
                    het_error( rc ),
                    opts.fileno );
                return( rc );
            }
        }

        /*
        || Get the HDR1 label.
        */
        rc = get_sl( hetb, &lab );
        if( rc < 0 || !sl_ishdr( &lab, 1 ) )
        {
            printf( "Expected HDR1 label\n" );
            return( -1 );
        }

        /*
        || Make the label more managable
        */
        sl_fmtlab( &fmt, &lab );
        printf("File Info:\n  DSN=%-17.17s\n", fmt.slds1.dsid ); 
    
        /*
        || Get the HDR2 label.
        */
        rc = get_sl( hetb, &lab );
        if( rc < 0 || !sl_ishdr( &lab, 2 ) )
        {
            printf( "Expected HDR2 label\n" );
            return( -1 );
        }
    
        /*
        || Merge the DCB information
        */
        merge( &lab );

        /*
        || Hop over the tapemark
        */
        rc = het_fsf( hetb );
        if( rc < 0 )
        {
            printf( "%s while spacing to start of data\n",
                het_error( rc ) );
            return( rc );
        }
    }

    /*
    || Different processing when converting to ASCII
    */
    if( opts.flags & ( O_ASCII | O_UNBLOCK ) )
    {
        /*
        || Get a record
        */
        while( ( rc = getrecord( hetb ) ) >= 0 )
        {
#ifdef EXTERNALGUI
            if( extgui )
            {
                /* Report progress every nnnK */
                OFF_T curpos = FTELL( hetb->fd );
                if( ( curpos & PROGRESS_MASK ) != ( prevpos & PROGRESS_MASK ) )
                {
                    prevpos = curpos;
                    fprintf( stderr, "IPOS=%" I64_FMT "d\n", (U64)curpos );
                }
            }
#endif /*EXTERNALGUI*/
            /*
            || Get working copy of record ptr
            */
            ptr = recptr;

            /*
            || Only want data portion for RECFM=V records
            */
            if( opts.recfm & O_VARIABLE )
            {
                ptr += 4;
                rc -= 4;
            }

            /*
            || Convert record to ASCII
            */
            if( opts.flags & O_ASCII )
            {
                sl_etoa( NULL, ptr, rc );
            }

            /*
            || Strip trailing blanks
            */
            if( opts.flags & O_STRIP )
            {
                while( ptr[ rc - 1 ] == ' ' )
                {
                    rc--;
                }
            }
            
            /*
            || Write the record out
            */
            fwrite( ptr, rc, 1, outf );

            /*
            || Put out a linefeed when converting
            */
            if( opts.flags & O_ASCII )
            {
                fwrite( "\n", 1, 1, outf );
            }
        }
    }
    else
    {
        /*
        || Get a record
        */
        while( ( rc = getblock( hetb ) ) >= 0 )
        {
#ifdef EXTERNALGUI
            if( extgui )
            {
                /* Report progress every nnnK */
                OFF_T curpos = FTELL( hetb->fd );
                if( ( curpos & PROGRESS_MASK ) != ( prevpos & PROGRESS_MASK ) )
                {
                    prevpos = curpos;
                    fprintf( stderr, "IPOS=%" I64_FMT "d\n", (U64)curpos );
                }
            }
#endif /*EXTERNALGUI*/
            /*
            || Write the record out
            */
            fwrite( blkptr, blklen, 1, outf );
        }
    }

    return( rc );
}

/*
|| Prints usage information
*/
void
usage( char *name )
{
    printf( help, name, name );
}

/*
|| Standard main
*/
int
main( int argc, char *argv[] )
{
    HETB *hetb;
    FILE *outf;
    int rc;
    int i;

#ifdef EXTERNALGUI
    if (argc >= 1 && strncmp(argv[argc-1],"EXTERNALGUI",11) == 0)
    {
        extgui = 1;
        argc--;
        setvbuf(stderr, NULL, _IONBF, 0);
        setvbuf(stdout, NULL, _IONBF, 0);
    }
#endif /*EXTERNALGUI*/

    /* Display the program identification message */
    display_version (stderr, "Hercules HET extract files program ", FALSE);

    /*
    || Process option switches
    */
    while( TRUE )
    {
        rc = getopt( argc, argv, "abhnsu" );
        if( rc == -1 )
        {
            break;
        }

        switch( rc )
        {
            case 'a':
                opts.flags |= O_ASCII;
            break;

            case 'h':
                usage( argv[ 0 ] );
                exit( 1 );
            break;

            case 'n':
                opts.flags |= O_NL;
            break;

            case 's':
                opts.flags |= O_STRIP;
            break;

            case 'u':
                opts.flags |= O_UNBLOCK;
            break;

            default:
                usage( argv[ 0 ] );
                exit( 1 );
            break;
        }
    }

    /*
    || Calc number of non-switch arguments
    */
    argc -= optind;

    /*
    || We must have at least the first 3 parms
    */
    if( argc < 3 )
    {
        printf( "Must specify input tape, output file, and file #\n" );
        exit( 1 );
    }

    opts.ifile = argv[ optind ];
    opts.ofile = argv[ optind + 1 ];
    opts.fileno = atoi( argv[ optind + 2 ] );
    if( opts.fileno == 0 || opts.fileno > 9999 )
    {
        printf( "File number must be within 1-9999\n" );
        exit( 1 );
    }

    /*
    || If NL tape, then we require the DCB attributes
    */
    if( opts.flags & O_NL )
    {
        if( argc != 6 )
        {
            printf( "DCB attributes required for NL tapes\n" );
            exit( 1 );
        }
    }

    /*
    || If specified, get the DCB attributes
    */
    if( argc > 3 )
    {
        /*
        || Must have only three
        */
        if( argc != 6 )
        {
            usage( argv[ 0 ] );
            exit( 1 );
        }

        /*
        || Lookup the specified RECFM in our table
        */
        opts.recfm = 0;
        for( i = 0 ; i < (int)VALFMCNT ; i++ )
        {
            if( strcasecmp( argv[ optind + 3 ], valfm[ i ].recfm ) == 0 )
            {
                opts.recfm = valfm[ i ].fmt;
                break;
            }
        }

        /*
        || If we didn't find a match, show the user what the valid ones are
        */
        if( opts.recfm == 0)
        {
            /*
            || Dump out the valid RECFMs
            */
            printf( "Valid record formats are:\n" );
            for( i = 0 ; i < (int)VALFMCNT ; i++ )
            {
                printf( "  %-4.4s", valfm[ i ].recfm );
                if( ( ( i + 1 ) % 3 ) == 0 )
                {
                    printf( "\n" );
                }
            }
            exit( 1 );
        }

        /*
        || Get the record length
        */
        opts.lrecl = atoi( argv[ optind + 4 ] );

        /*
        || Get and validate the blksize
        */
        opts.blksize = atoi( argv[ optind + 5 ] );
        if( opts.blksize == 0 )
        {
            printf( "Block size can't be zero\n" );
            exit( 1 );
        }
    }

    /*
    || Open the tape file
    */
    rc = het_open( &hetb, opts.ifile, 0 );
    if( rc >= 0 )
    {
        /*
        || Get memory for the tape buffer
        */
        blkptr = malloc( HETMAX_BLOCKSIZE );
        if( blkptr != NULL )
        {
            /*
            || Open the output file
            */
            char pathname[MAX_PATH];
            hostpath(pathname, opts.ofile, sizeof(pathname));
            outf = fopen( pathname, "wb" );
            if( outf != NULL )
            {
                /*
                || Go extract the file from the tape
                */
                rc = getfile( hetb, outf );

                /*
                || Close the output file
                */
                fclose( outf );
            }
            
            /*
            || Free the buffer memory
            */
            free( blkptr );
        }
    }
    else
    {
        printf( "het_open() returned %s\n", het_error( rc ) );
    }

    /*
    || Close the tape file
    */
    het_close( &hetb );

    return 0;
}