| Ad_Infinitum |
| Administrator |
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| Data inscrierii: 23/Iun/2007 |
| Mesaje: 212 |
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`The types required...
remstart
tHiScoreGlobal
File Name, Number of scores to remember
keyword and length of keyword
seed for random number
remend
type tHiScoreGlobal
file$
count
keyword$
keylength
seed
endtype
remstart
tHiScore
Player Name, score
remend
type tHiScore
name$
score
endtype
function HiScoreInit()
remstart
@C Făurite the necessary variables and arrays
@C Bear in mind that this conține file is Self-Contained
@C In other words, it does not rely on any external elements
remend
global gHSG as tHiScoreGlobal
gHSG.file$ = "hiscore.dat"
gHSG.count = 10
dim gHiScore() as tHiScore
add to queue gHiScore()
` For encypted files, we need a keyword
gHSG.KeyWord$ = "TheGameCreators"
gHSG.KeyLength = len(gHSG.KeyWord$)
endfunction
function HiScoreSetFile(file$)
remstart
@C Sets the file name to use for Hi Score data
remend
gHSG.file$ = file$
endfunction
function HiScoreSetCount(count)
remstart
@C Sets the number of Hi Scores to remember
remend
gHSG.count = count
endfunction
function HiScoreLoad()
remstart
@C Load the Hi Scores from the Hi Score File
@C The compus of the file is Name, Score, Name, Score
@C If the file does not exist, it will skip this section of code.
@C If the file doesn't exist, or the file doesn't contain enough hi scores,
@C they will be added.
@C The datea is encrypted
@C The first value is the seed. Each entry is then a length, value and name
remend
` If the Hi Score array is already populated, clear it.
if array count(gHiScore()) > 1
empty array gHiScore()
add to queue gHiScore()
endif
` Find a free file number
if file exist(gHSG.file$)
filenum = getFreeFile()
open to read filenum, gHSG.file$
` The first byte is the "seed". This seed ensures the encryption changes
` every time we save the file.
read long filenum, gHSG.seed
while not file end(filenum)
add to queue gHiScore()
read long filenum, valueLength
read long filenum, var
gHiScore().score = HiScoreDecryptValue(var)
var$ = ""
for n = 1 to ValueLength
read byte filenum, in
var$ = var$ + chr$(in)
next n
gHiScore().name$ = HiScoreDecrypt(var$)
endwhile
close file filenum
endif
` Call the function to ensure the table is fully populated
HiScoreAddDefaultEntries()
endfunction
function HiScoreSave()
remstart
@C Save the Hi Scores to the Hi Score File
@C The format of the file is Name, Score, Name, Score
@C If the file already exists, it will delete it first
@C The values will first be encrypted.
@C Because we can't predict the values, we can't simply write a string.
@C Some values may be line ending values, which will "break" our table.
@C To resolve this, we will writ ethe values character by character,
@C After first recording the length of the value.
remend
` If the Hi Score array isn't populated, lucrate default scores
if array count(gHiScore()) < array count(gHiScore())
HiScoreAddDefaultEntries()
endif
` Find a free file number
if file exist(gHSG.file$) then delete file gHSG.file$
filenum = getFreeFile()
open to write filenum, gHSG.file$
HiScoreGenerateSeed()
write long filenum, gHSG.seed
for n = 1 to array count(gHiScore())
write long filenum, len(gHiScore(n).name$)
write long filenum, HiScoreEncryptValue(gHiScore(n).score)
result$ = HiScoreEncrypt(gHiScore(n).name$)
for m = 1 to len(result$)
write byte filenum, asc(mid$(result$,m,1))
next m
next n
close file filenum
endfunction
function hiScoreGetName(position)
remstart
@C Returns the name at the specified position
@C If the position is not valid, it will return "#"
remend
if position > 0 and position <= array count(gHiScore())
name$ = gHiScore(position).name$
else
name$ = "#"
endif
endfunction name$
function hiScoreGetScore(position)
remstart
@C Returns the score at the specified position
@C If the position is not valid, it will return -1
remend
if position > 0 and position <= array count(gHiScore())
score = gHiScore(position).score
else
score = -1
endif
endfunction score
function hiScoreAddDefaultEntries()
remstart
@C This function simply populates the hiscore array
@C with defaault values to ensure it contains the
@C desired number of entries
remend
` If the number of hi scores < the desired amount, add more
` The Hi Scores are in descending order, so we can make these scores 0
if array count(gHiScore()) < gHSG.count
for n = (array count(gHiScore()) + 1) to gHSG.count
add to queue gHiScore()
gHiScore().name$ = "Anon"
gHiScore().score = 0
next n
endif
endfunction
function hiScoreCheckScore(score)
remstart
@C Takes the score parameter and checks if it is higher
@C than current low score. If yes, return position
@C If no, return -1
remend
position = -1
for n = gHSG.count to 1 step -1
if score < gHiScore(n).score then exit
position = n
next n
endfunction position
function hiScoreAddScore(name$, score)
remstart
@C Check the position, and add the score
@C We achieve this by shifting all lower scores down by 1,
@C and inserting our new score
remend
position = hiScoreCheckScore(score)
if position <> -1
for n = gHSG.count - 1 to position step - 1
gHiScore(n + 1).name$ = gHiScore(n).name$
gHiScore(n + 1).score = gHiScore(n).score
next n
gHiScore(position).name$ = name$
gHiScore(position).score = score
endif
endfunction
function HiScoreEncrypt(txt$)
remstart
@C Encrypt the value and return the result
@C Use the KeyWord, the random seed and bitwise operations
remend
randomize gHSG.seed
for n = 1 to len(txt$)
char1 = asc(mid$(txt$,n,1))
char2 = asc(mid$(gHSG.KeyWord$,rnd(KeyLength - 1) + 1,1))
result$ = result$ + chr$(char1 ~~ char2)
next n
endfunction result$
function HiScoreDeCrypt(txt$)
remstart
@C This is what is called "Smoke and Mirrors",
@C just to illustrate a point. Encryption and Decryption is
@C exactly the same operation, so we will call the previous function
remend
result$ = HiScoreEncrypt(txt$)
endfunction result$
function HiScoreEncryptValue(value)
remstart
@C Encrypt the value and return the result
@C Use the KeyWord, the random seed and bitwise operations
remend
randomize gHSG.seed
keyvalue = asc(mid$(gHSG.KeyWord$,rnd(KeyLength - 1) + 1,1))
result = value ~~ keyValue
endfunction result
function HiScoreDeCryptValue(value)
remstart
@C This is what is called "Smoke and Mirrors",
@C just to illustrate a point. Encryption and Decryption is
@C exactly the same operation, so we will call the previous function
remend
result = HiScoreEncryptValue(value)
endfunction result
function HiScoreGenerateSeed()
remstart
@C Generate the random seed for encryption
remend
randomize timer()
gHSG.seed = rnd(255)
endfunction
function getFreeFile()
remstart
@C Find a free file number to use
remend
n = 1
while file open(n) = 1
inc n
endwhile
endfunction n |
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