Re: [naviserver-devel] File compress larger within naviserver then standalone

[Gustaf N. <ne...@wu...>]

Dear Fox,

There is absolutely no reason why the Tcl-builtin zlib function
returns different sizes in tclsh or NaviServer. I could not
reproduce any differences in these two environments.

(i modified you script slightly, and made sure, that the
resulting compressed files is (a) binary and (b) does
not contain a newline at the end of the file).

all are the same for


=====================================
set inFile "/tmp/myImage.png"
set outFile "/tmp/myImage.png.ixz"

set myFile [open $inFile RDONLY]
fconfigure $myFile -translation binary
set content [read $myFile]
close $myFile

set binData [encoding convertto utf-8 $content]
set hexData [binary encode hex [encoding convertto utf-8 $content]]

# level 0 => 2.56 MB
# level 6 => 1.13 MB
# level not specified 1.13 MB
# level 9 => 1.11 MB

set fp [open $outFile w]
fconfigure $fp -translation binary
puts -nonewline $fp [zlib compress $hexData]
close $fp

puts [subst {
     /tmp/myImage.png:    [clock format [file mtime /tmp/myImage.png]] [file size /tmp/myImage.png]
     /tmp/myImage.png.ixz [clock format [file mtime /tmp/myImage.png.ixz]] [file size /tmp/myImage.png.ixz]
}]
=====================================

On 10.05.20 15:59, D.Fox wrote:
> Hi, I am trying to compress a image (.png) using hexadecimal and ZLIB.
> When running the below code within naviserver the created file is 
> larger then if I run standalone shell.
>
> The sample code is as follows:
> #########
> set file "/bench/myImage.png"
> set filePath "/bench/"
>
> set myFile [open $file RDONLY]
> fconfigure $ myFile -translation binary
> set content [read $myFile]
> set binData [encoding convertto utf-8 $content]
> set hexData [binary encode hex [encoding convertto utf-8 $content]]
> close $myFile
>
> set fp [open "$filePath/myCompressedHexBlobFile.ixz" w]
> puts $fp [zlib compress $hexData]
> close $fp
> #########
> Outputs:
> 846K - myImage.png
> 1.7M - myCompressedHexBlobFile.ixz - Executed within Naviserver
> 1.1M - myCompressedHexBlobFile.ixz - Executed from shell with TCLSH
> #########
> Is Navi using a different zlib compression level, why is this happening?
> If I set the compression level to nine, the created file is still at 
> 1.7mb. This is kind of a game changer, even if I source the 
> compression script the file size is still larger then if I run it via 
> terminal.
>
> Thanks
> Fox
>
>
>
>
>
>
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