Category : BASIC Source Code
Archive   : QBFAQR01.ZIP
Filename : ZIPHEAD.BAS

'Date: 12-30-91 (20:04)
'From: HOWARD MENCHER
'Subj: READ ZIP HEADER
'--------------------------------------------------------------------------
CLS
DEFINT A-Z
DIM filenames$(255)
foundnames = 0
DIM signature AS STRING * 4: DIM junk AS STRING * 1
DIM tmpname AS STRING * 1
headsig$ = "04034B50"

TYPE ziphdr
signatr AS STRING * 4 'should be const 0x04034b50
version AS INTEGER
bitflag AS INTEGER
stortype AS INTEGER
time AS INTEGER
date AS INTEGER
crc AS LONG
ziplen AS LONG
fullsize AS LONG
fnamelen AS INTEGER
extra AS INTEGER
END TYPE

DIM ziphead AS ziphdr

INPUT "Name of .ZIP file to display ( to end):", zname$
IF zname$ = "" THEN END

getzipdir: '
' open in serial mode, read in 4 char at a time & look
' for signatures

OPEN "B", 1, zname$
WHILE NOT EOF(1)
sigpos& = SEEK(1)
GET #1, , signature$
b1 = ASC(LEFT$(signature$, 1))
b2 = ASC(MID$(signature$, 2, 1))
b3 = ASC(MID$(signature$, 3, 1))
b4 = ASC(RIGHT$(signature$, 1))

tst4$ = HEX$(b4)
IF LEN(tst4$) < 2 THEN tst4$ = "0" + tst4$

tst3$ = HEX$(b3)
IF LEN(tst3$) < 2 THEN tst3$ = "0" + tst3$

tst2$ = HEX$(b2)
IF LEN(tst2$) < 2 THEN tst2$ = "0" + tst2$

tst1$ = HEX$(b1)
IF LEN(tst1$) < 2 THEN tst1$ = "0" + tst1$

result$ = tst4$ + tst3$ + tst2$ + tst1$

IF result$ = headsig$ THEN GOSUB readhdr

WEND

CLOSE : foundnames = foundnames - 1
FOR t = 0 TO foundnames
PRINT filenames$(t)
NEXT t
END


readhdr: ' try to make sense of the zip header
SEEK #1, sigpos&
GET #1, sigpos&, ziphead
x = ziphead.fnamelen
FOR t = 1 TO x
GET #1, , tmpname$
filenames$(foundnames) = filenames$(foundnames) + tmpname$
NEXT t
foundnames = foundnames + 1

x = ziphead.extra
FOR t = 1 TO x
GET #1, , junk$
NEXT t
totloffset& = sigpos& + 30 + ziphead.fnamelen + ziphead.extra +
SEEK #1, totloffset&
RETURN