Open -C libz Example

The example demonstrates how to use the libz library to compress a file -and decompress it. The library can compress and decompress any kind of file -(txt, doc, xls, xml, mpeg, ppt, mp3 etc).

Design and -Implementation

The following sections provide more information -about the steps that the example performs.

Capabilities

Program -capabilities are defined in openclibz.mmp: CAPABILITY -None

Implementation details of EXE

This example is a -console based application. This application can be launched from the icon -(openclibz) in installed folder and also from eshell. When we launch it through -icon it prompts the user to enter the mode to process. The strategy parameter -is used to select the compression algorithm. For compressing a file, it reads -the file and then compresses it using the API of the libz library and then -stores the compressed content in a (.gz) file. If you want to decompress, -type d. For decompressing a file, it opens the compressed (.gz) file using -libz API's and then reads the content and decompresses it . To check what -happens to the content of the string after compression then type s. Enter -the string you want and see the data in compressed format . This option -is to demonstrate compression of string using libz API's.

To run this application -through eshell:

Usage : openclibz [-d] [-f] [-h] [-r] [-1 to -9] [files...] +Open C libz Example +

The example demonstrates how to use the libz library to compress +a file and decompress it. The library can compress and decompress +any kind of file (txt, doc, xls, xml, mpeg, ppt, mp3 etc).

Download

Click on the following link to download the example: openclibz.zip

Click: browse to view the example code.

Design +and Implementation

The following sections provide more +information about the steps that the example performs.

Capabilities

Program capabilities are defined in openclibz.mmp: CAPABILITY None

Implementation +details of EXE

This example is a console based application. +This application can be launched from the icon (openclibz) in installed +folder and also from eshell. When we launch it through icon it prompts +the user to enter the mode to process. The strategy parameter is used +to select the compression algorithm. For compressing a file, it reads +the file and then compresses it using the API of the libz library +and then stores the compressed content in a (.gz) file. If you want +to decompress, type d. For decompressing a file, it opens the compressed +(.gz) file using libz API's and then reads the content and decompresses +it . To check what happens to the content of the string after compression +then type s. Enter the string you want and see the data in compressed +format . This option is to demonstrate compression of string using +libz API's.

To run this application through eshell:

Usage : openclibz [-d] [-f] [-h] [-r] [-1 to -9] [files...] -d : decompress -f : compress with Z_FILTERED -h : compress with Huffman encoding @@ -40,27 +37,27 @@ -1 to -9 : compression level files : absolute path of files

Some usage tips

Once you choose compression -process, enter the file name. You should provide absolute path of the file -you want to compress. (drive letter):\[(folder name)\]filename. - To get : on phone you have to press 1 few times. To get on phone you have -to press 1 few times. To get on emulator is bit tricky. If you are lucky -then pressing 1 will get it for you, otherwise change the mode. using "\ BUTTON" -(Just above the enter button in the keyboard) and then try pressing 1. To -press enter on phone we are supposed to press 0 four times.

Cross -platform usage

We can compress the file on any platform and uncompress -it on any other platform. For example Unix's gzip files can be compressed -using the example application and decompressed using Unix's gunzip. Compression -can be done in a single step, if the buffers are large enough; or compression -can be done by repeated calls of the compression function. In the second scenario, -application must provide more input and consume the output (providing more -output space) before each call.

APIs Used

compress, uncompress, gzopen, gzclose, gzread, gzwrite, gzerror from -libz library

fopen, fclose, fread, fwrite, mmap, munmap, fstat, unlink, printf, scanf from -libc library

Building and -Using

The Symbian -build process describes how to build this example application.

To -build the example application, go to the openclibz\group directory and build -the application. The definition for the whole application can be found in -the bld.inf file in the group subdirectory of the applications main directory.

+process, enter the file name. You should provide absolute path of +the file you want to compress. (drive letter):\[(folder +name)\]filename. To get : on phone you have to press +1 few times. To get on phone you have to press 1 few times. To get +on emulator is bit tricky. If you are lucky then pressing 1 will get +it for you, otherwise change the mode. using "\ BUTTON" (Just above +the enter button in the keyboard) and then try pressing 1. To press +enter on phone we are supposed to press 0 four times.

Cross +platform usage

We can compress the file on any platform +and uncompress it on any other platform. For example Unix's gzip +files can be compressed using the example application and decompressed +using Unix's gunzip. Compression can be done in a single step, if +the buffers are large enough; or compression can be done by repeated +calls of the compression function. In the second scenario, application +must provide more input and consume the output (providing more output +space) before each call.