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 - -r : compress with run-length encoding - -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.

+ + + + + +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 + -r : compress with run-length encoding + -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.

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