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Create .ZIP files in VFP with NO ActiveX, and No $
Compression
Create .ZIP files in VFP with NO ActiveX, and No $
by
wgcs
Posted
(Edited
)
#IF .f.
I have long tried to create real .ZIP files from within VFP without using any ActiveX ocx, and had finally given up, when I stumbled upon a method written in PHP, which I have now converted to VFP.
This uses the same "compress" function from the standard zlib.dll that is used in faq184-2070, but creates proper .ZIP header/individual file headers so that pkunzip (and any other zip program) can decompress the file.
You will need the standard zlib.dll that can be downloaded here: http://www.zlib.net/zlib121-dll.zip
See this page for more about ZLIB: http://www.gzip.org/zlib/
I haven't yet converted this code to uncompress .zip files... I expect that will be more difficult.
#ENDIF
*!*
I have long tried to create real .ZIP files from within VFP without using any ActiveX ocx, and had finally given up, when I stumbled upon a method written in PHP, which I have now converted to VFP.
This uses the same "compress" function from the standard zlib.dll that is used in faq184-2070, but creates proper .ZIP header/individual file headers so that pkunzip (and any other zip program) can decompress the file.
You will need the standard zlib.dll that can be downloaded here: http://www.zlib.net/zlib121-dll.zip
See this page for more about ZLIB: http://www.gzip.org/zlib/
I haven't yet converted this code to uncompress .zip files... I expect that will be more difficult.
#ENDIF
*!*
Code:
*!* Zip file creation class
*!* makes zip files on the fly...
*!*
*!* use the functions add_dir() and add_file() to build the zip file
*!* Requirements:
*!* zlib.dll be available in the current directory or on the search path
*!* NO ActiveX needed!!
*!*
*!* see example code below
*!*
*!* v1.0 2-5-01 initial version with:
*!* - class appearance
*!* - add_file() and file() methods
*!* - gzcompress() output hacking
*!* by Denis O.Philippov, webmaster@atlant.ru, http://www.atlant.ru
*!*
*!* v1.1 9-20-01
*!* - added comments to example
*!* - by Eric Mueller http://www.themepark.com
*!*
*!* v2.0 9-19-04
*!* - Converted to VFP from PHP code found at http://www.webestilo.com/php/cod.phtml?id=6
*!* - by William GC Steinford
*!*
*!*
** // official ZIP file format: http://www.pkware.com/appnote.txt
*!* (No longer seems active)
DO UnitTest
PROCEDURE UnitTest
* Test ZipFile class:
*!* $zipfile = new zipfile()
xx= CREATEOBJECT('zipFile')
*!* // add the subdirectory ... important!
xx.Add_Dir('dir1/')
IF NOT xx.Add_File('This is a test file', 'dir1/file1.txt')
?"Error Adding File"
RETURN .f.
ENDIF
IF NOT xx.Add_File('This is a test file', 'dir1/file2.txt')
?"Error Adding File"
RETURN .f.
ENDIF
*!* // add the binary data stored in the string 'filedata'
xx.Add_Dir('dir2/')
IF NOT xx.Add_File('This is a test file', 'dir2/file1.txt')
?"Error Adding File"
RETURN .f.
ENDIF
IF NOT xx.Add_File('This is a test file', 'dir2/file2.txt')
?"Error Adding File"
RETURN .f.
ENDIF
STRTOFILE(xx.file(),'c:\temp\test.zip')
DEFINE CLASS zipFile AS Session
datasec = '' && array to store compressed data
ctrl_dir = '' && central directory
ctrl_dir_cnt = 0 && central directory item count
* This "constant" doesn't belong here
* eof_ctrl_dir = chr(0x50)+chr(0x4b)+chr(0x05)+chr(0x06)+chr(0x00)+chr(0x00)+chr(0x00)+chr(0x00) && end of Central directory record
old_offset = 0
function add_dir( tcDir )
&& adds "directory" to archive - do this before putting any files in directory!
&& tcDir - name of directory... like this: "path/"
&& ...then you can add files using add_file with names like "path/file.txt"
LOCAL lcDir, fr, crc, c_len, unc_len, new_offset
* tcDir = str_replace("", "/", tcDir)
lcDir = STRTRAN(tcDir,"\", "/")
fr = chr(0x50)+chr(0x4b)+chr(0x03)+chr(0x04)
fr = fr + chr(0x0a)+chr(0x00) && ver needed to extract
fr = fr + chr(0x00)+chr(0x00) && gen purpose bit flag
fr = fr + chr(0x00)+chr(0x00) && compression method
fr = fr + chr(0x00)+chr(0x00)+chr(0x00)+chr(0x00) && last mod time and date
fr = fr + THIS.phpPACK("V",0) && crc32
fr = fr + THIS.phpPACK("V",0) &&compressed filesize
fr = fr + THIS.phpPACK("V",0) &&uncompressed filesize
fr = fr + THIS.phpPACK("v", len(lcDir) ) &&length of pathname
fr = fr + THIS.phpPACK("v", 0 ) &&extra field length
fr = fr + lcDir
&& end of "local file header" segment
&& no "file data" segment for path
&& "data descriptor" segment (optional but necessary if archive is not served as file)
* wgcs: I assume that the undefined variables crc,c_len,unc_len will be 0 in these statements!!
fr = fr + THIS.phpPACK("V", 0 ) && crc ) &&crc32
fr = fr + THIS.phpPACK("V", 0 ) && c_len ) &&compressed filesize
fr = fr + THIS.phpPACK("V", 0 ) && unc_len) &&uncompressed filesize
&& add this entry to array
this.datasec = this.datasec + fr
new_offset = len(this.datasec)
&& ext. file attributes mirrors MS-DOS directory attr byte, detailed
&& at http:&&support.microsoft.com/support/kb/articles/Q125/0/19.asp
&& now add to central record
cdrec = chr(0x50)+chr(0x4b)+chr(0x01)+chr(0x02)
cdrec = cdrec + chr(0x00)+chr(0x00) && version made by
cdrec = cdrec + chr(0x0a)+chr(0x00) && version needed to extract
cdrec = cdrec + chr(0x00)+chr(0x00) && gen purpose bit flag
cdrec = cdrec + chr(0x00)+chr(0x00) && compression method
cdrec = cdrec + chr(0x00)+chr(0x00)+chr(0x00)+chr(0x00) && last mod time & date
cdrec = cdrec + THIS.phpPACK("V",0) && crc32
cdrec = cdrec + THIS.phpPACK("V",0) &&compressed filesize
cdrec = cdrec + THIS.phpPACK("V",0) &&uncompressed filesize
cdrec = cdrec + THIS.phpPACK("v", len(lcDir) ) &&length of filename
cdrec = cdrec + THIS.phpPACK("v", 0 ) &&extra field length
cdrec = cdrec + THIS.phpPACK("v", 0 ) &&file comment length
cdrec = cdrec + THIS.phpPACK("v", 0 ) &&disk number start
cdrec = cdrec + THIS.phpPACK("v", 0 ) &&internal file attributes
ext = chr(0x00)+chr(0x00)+chr(0x10)+chr(0x00) && wgcs:This seems redundant!
ext = chr(0xff)+chr(0xff)+chr(0xff)+chr(0xff)
cdrec = cdrec + THIS.phpPACK("V", 16 ) &&external file attributes - 'directory' bit set
cdrec = cdrec + THIS.phpPACK("V", this.old_offset ) &&relative offset of local header
this.old_offset = new_offset
cdrec = cdrec + lcDir
&& optional extra field, file comment goes here
&& save to array
this.ctrl_dir = this.ctrl_dir + cdrec
THIS.ctrl_dir_cnt = THIS.ctrl_dir_cnt + 1
ENDFUNC
function add_file(tcData, tcFile)
&& adds "file" to archive
&& tcData - file contents
&& tcFile - name of file in archive. Add path if you want
LOCAL lcFile, fr, unc_len, crc, zData, c_len
lcFile = STRTRAN(tcFile,"\", "/")
&&tcFile = str_replace("", "", tcFile)
fr = chr(0x50)+chr(0x4b)+chr(0x03)+chr(0x04)
fr = fr + chr(0x14)+chr(0x00) && ver needed to extract
fr = fr + chr(0x00)+chr(0x00) && gen purpose bit flag
fr = fr + chr(0x08)+chr(0x00) && compression method
fr = fr + chr(0x00)+chr(0x00)+chr(0x00)+chr(0x00) && last mod time and date
unc_len = len(tcData)
crc = VAL(SYS(2007,tcData,0,1)) && crc32(tcData) .. wgcs:returns crc32 as a string
zdata = THIS.gzCompress(tcData)
IF EMPTY(zData)
RETURN .F.
ENDIF
* wgcs: do we have to compensate for the bug, too?
*zdata = substr( substr(zdata, 0, len(zdata) - 4), 2) && fix crc bug
zdata = substr( substr(zdata, 1, len(zdata) - 4), 3) && fix crc bug
c_len = len(zdata)
fr = fr + THIS.phpPACK("V",crc) && crc32
fr = fr + THIS.phpPACK("V", c_len) && compressed filesize
fr = fr + THIS.phpPACK("V", unc_len) && uncompressed filesize
fr = fr + THIS.phpPACK("v", len(lcFile) ) && length of filename
fr = fr + THIS.phpPACK("v", 0 ) && extra field length
fr = fr + lcFile
&& end of "local file header" segment
&& "file data" segment
fr = fr + zdata
&& "data descriptor" segment (optional but necessary if archive is not served as file)
fr = fr + THIS.phpPACK("V",crc) && crc32
fr = fr + THIS.phpPACK("V",c_len) && compressed filesize
fr = fr + THIS.phpPACK("V",unc_len) && uncompressed filesize
&& add this entry to array
this.datasec = this.datasec + fr
new_offset = len(this.datasec)
&& now add to central directory record
cdrec = chr(0x50)+chr(0x4b)+chr(0x01)+chr(0x02)
cdrec = cdrec + chr(0x00)+chr(0x00) && version made by
cdrec = cdrec + chr(0x14)+chr(0x00) && version needed to extract
cdrec = cdrec + chr(0x00)+chr(0x00) && gen purpose bit flag
cdrec = cdrec + CHR(0x08)+chr(0x00) && compression method
cdrec = cdrec + chr(0x00)+chr(0x00)+chr(0x00)+chr(0x00) && last mod time & date
cdrec = cdrec + THIS.phpPACK("V",crc) && crc32
cdrec = cdrec + THIS.phpPACK("V", c_len) && compressed filesize
cdrec = cdrec + THIS.phpPACK("V", unc_len) && uncompressed filesize
cdrec = cdrec + THIS.phpPACK("v", len(lcFile) ) && length of filename
cdrec = cdrec + THIS.phpPACK("v", 0 ) && extra field length
cdrec = cdrec + THIS.phpPACK("v", 0 ) && file comment length
cdrec = cdrec + THIS.phpPACK("v", 0 ) && disk number start
cdrec = cdrec + THIS.phpPACK("v", 0 ) && internal file attributes
cdrec = cdrec + THIS.phpPACK("V", 32 ) && external file attributes - 'archive' bit set
cdrec = cdrec + THIS.phpPACK("V", this.old_offset ) &&relative offset of local header
&& echo "old offset is ".this->old_offset.", new offset is new_offset<br>"
this.old_offset = new_offset
cdrec = cdrec + lcFile
&& optional extra field, file comment goes here
&& save to central directory
this.ctrl_dir = this.ctrl_dir + cdrec
THIS.ctrl_dir_cnt = THIS.ctrl_dir_cnt + 1
ENDFUNC
FUNCTION file
&& dump out file
*!* LOCAL lcData, lcCtrlDir
*!* lcData = implode("", this.datasec ) && condenses/implodes the array into a string
*!* lcCtrldir = implode("", this.ctrl_dir )
return THIS.DataSec + THIS.Ctrl_Dir + ; && this.eof_ctrl_dir
chr(0x50)+chr(0x4b)+chr(0x05)+chr(0x06)+chr(0x00)+chr(0x00)+chr(0x00)+chr(0x00) ; && end of Central directory record
+ THIS.phpPACK("v", this.ctrl_dir_cnt) ; && total # of entries "on this disk"
+ THIS.phpPACK("v", this.ctrl_dir_cnt) ; && total # of entries overall
+ THIS.phpPACK("V", len(this.ctrl_dir)) ; && size of central dir
+ THIS.phpPACK("V", len(THIS.dataSec)) ; && offset to start of central dir
+ chr(0x00)+chr(0x00) && .zip file comment length
ENDFUNC
* * *
* dword is compatible with LONG
FUNCTION phpPACK( tcFmt, tnVal )
#DEFINE m0 256
#DEFINE m1 65536
#DEFINE m2 16777216
DO CASE
CASE tcFmt='V' && unsigned long (32 bit) little-endian
LOCAL b0, b1, b2, b3
b3 = Int(tnVal/m2)
b2 = Int((tnVal - b3*m2)/m1)
b1 = Int((tnVal - b3*m2 - b2*m1)/m0)
b0 = Mod(tnVal, m0)
RETURN Chr(b0)+Chr(b1)+Chr(b2)+Chr(b3)
CASE tcFmt='v' && unsigned short (16 bit) little-endian
RETURN Chr(MOD(m.tnVal,256)) + CHR(INT(m.tnVal/256))
ENDCASE
RETURN ''
ENDFUNC
FUNCTION gzCompress( InFile )
DECLARE INTEGER compress IN zlib.dll AS zlibCompress ;
STRING @ dest, INTEGER @ destLen, ;
STRING src, INTEGER srcLen
* Compresses the source buffer into the destination buffer.
* sourceLen is the byte length of the source buffer. Upon entry,
* destLen is the total size of the destination buffer, which must
* be at least 0.1% larger than sourceLen plus 12 bytes. Upon exit,
* destLen is the actual size of the compressed buffer.
LOCAL lnSize, lcBuff, lnFinalSize
lnSize = len(InFile)
*123,456,789,012,345 15 chars is enough for 100 Terabytes.
*100,000,000,000,000
lnFinalSize = MAX( 100, len(InFile)*1.2 )
lcBuff = space(lnFinalSize)
Res = zlibCompress( @lcBuff, @lnFinalSize, InFile, lnSize )
If Res=0 && Success
** RETURN PadL( alltrim(str(lnSize)), 15, '0' ) + Left( lcBuff, lnFinalSize )
RETURN Left( lcBuff, lnFinalSize )
endif
RETURN '' && error!!
ENDFUNC
ENDDEFINE
*!*
Please Note: 1 is Bad, 10 is Good :-)
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