ARM Club 1/ARM_CLUB_CD.iso/contents/apps/program/a/adhes/gstobject/squash/Example/Example

RISC OS BBC BASIC V Source | 1994-09-16 | 4.2 KB | 92 lines

 -- Example program to use messages object from BASIC
 -- By George Taylor, [e-mail]
$;" at line ";
 "Adhesive"
 "BasicC"
 "UsefulBits"
 "Squash"
 -- This assembles Adhesive stuff and sets up an exit handler
 -- to deregister with Adhesive when your program exits.
 -- Because of the way BASIC works this exit handler is not called
 -- if you generate an error with error number 0.
_AdhesivePreInit
 -- Register with Adhesive with the name "test Squash object".
 -- The name is not important, it is only used for informational
 -- purposes by Adhesive.
_AdhesiveInit("test Squash object")
 -- Request the basicC object from Adhesive.
_AdhesiveRequest(
_AssembleRequests_basicC)
 -- Request the message object from Adhesive.
 -- Note we do not need to know that the message object
 -- requires the string+ object, Adhesive takes care of that
 -- for us.
_AdhesiveRequest(
_AssembleRequests_squash)
 -- We need to change HIMEM to give the C system some private workspace
 -- after our program.
 -- Do not make this smaller than 16K otherwise an error will occur.
 -- If you wish to allocate more space to the C system without the
 -- C system increasing your wimpslot then make the 16K larger.
 -- With 16K there is about 2K available for malloc() and C stack,
 -- the wimpslot is increased if possible when this runs out.
 -- NOTE:  HIMEM must not be changed inside a procedure.
-1024*16
 -- Initialise C system. Make this call once and only once during the
 -- execution of a program.
 -- NOTE:  DO NOT change HIMEM after intialising with the C system or
 --        your program will crash.
_BasicCInit
 -- Create C_printf%,C_malloc%,C_free% variables.
_UsefulBitsInit
 -- END OF INTIALISATION
 -- When doing C calls which require a pointer to a buffer
 -- for a 32bit result we shall pass a pointer into this buffer.
 -- Don't try and put more than 256 bytes in this buffer!
Q CPtrBuffer% =
_Zmalloc(256)
 -- The calls squash_GetSize and squash_Load will work for any
 -- file type. If the file is actually a squash file then this
 -- is transparent to us. To verify this we test the files 'test1'
 -- (a text file) and 'test2' (a squashed text file).
 -- Find out size and filetype of file. We need the size so we
 -- can allocate a buffer to load the file into. You would typically
 -- check the filetype is correct for the files purpose (e.g. you
 -- would check that a sprite resources file has the correct Sprite
 -- file type).
 -- NB. Squash is very effective on sprite files both in terms of
 -- speed and compressed size.
_squash_GetSize("test1",size%,filetype%)
 '"File 'test1', size=";size%;", filetype="~filetype%
 -- Allocate buffer for uncompressed file.
buffer%=
_Zmalloc(size%)
 -- Load file.
_squash_Load("test1",buffer%)
 -- Do something with the file. We shall output the first line as
 -- a string.
 $(buffer%)
 -- Free off the buffer space now we have finished with the loaded file.
_Free(buffer%)
 -- We now repeat the same operations with the file "test2".
_squash_GetSize("test2",size%,filetype%)
 '"File 'test2', size=";size%;", filetype="~filetype%
buffer%=
_Zmalloc(size%)
_squash_Load("test2",buffer%)
 $(buffer%)
_Free(buffer%)
 -- The procedures/functions below are used to provide an
 -- even simpler interface to the squash code.
_squash_GetSize(filename$,
 size%,
 filetype%)
 basicC_CCall,squash_GetSize%,size%,filename$,CPtrBuffer%
filetype%=!CPtrBuffer%
 size%=-1
_Error("failed to read squash file '"+filename$+"'")
_squash_Load(filename$, buf%)
 basicC_CCall,squash_Load%,ok%,filename$,buf%
 ok%=0
_Error("failed to load squash file '"+filename$+"'")