1. Re: Project Programmer Wanter - PERMENUM v1.1 anyone?
CChris wrote:
>
> The following merges the final file size test with Fernando's code.
> On my WinXP pro machine, the drive size is not available (function not
> supported).
> I incluede a workaround.
> If you are running under actual DOS, this may work for you. Otherwise, oyou
> have to execute an .exw file using exwc.exe, and replace my code by Windows
> API code that fetches available space on drive. Are you stuck with DOS,
> really?
>
[snipped Eu code]
Firstly, thanks CChris for your implementation and comments!
Secondly, I want to note that I made a mistake in the specification of the limit
of the number of variations (permutations). Actually, the limit of index v in
function VariationRep is 2^53 (maximum contiguous integer in an atom). There are
many powers that are between 2^52 and 2^53 (ex.: 3^33, 21^12, 27^11, 28^11,
37^10, ...). However, in the program, because the argument "a-i" in call to
VariationRep, the actual limit would be (2^53)-1, but with the original test "if
a+1=a" the final limit is (2^53)-2. Actually, these limits will not be reached
because the current storage capacity, so they aren't used in CChris' code.
Following is a version based on CChris' code:
- I guess that a version of Ret's items a to e is implemented.
- A small optimization was made in saving the variations to the file.
- I didn't understand CChris' expression "log(length(s))*(n+1)", so I
substituted it for another one.
- I don't know if CTR-C test (check_break()) works appropriately in DOS. It
seems that in WinXP it doesn't (I can't stop after the beginning of the
generating process).
include get.e
include wildcard.e
include graphics.e
include misc.e
include machine.e
include file.e
atom mb_drive_space,buffer_lo -- # Mo available on drive, DOS buffer
atom file_size_log
constant one_meg=1048576
procedure terminate(integer i)
puts(1,"\nPlease press any key to terminate the program.\n")
if wait_key() then end if
abort(i)
end procedure
function VariationRep(atom v, integer n, sequence s)
integer ls
sequence p
if v < 1 then return {} end if
v -= 1
p = repeat(0,n)
ls = length(s)
for i = n to 1 by -1 do
p[i] = s[remainder(v,ls)+1]
v = floor(v/ls)
end for
return p
end function
integer n,fn
atom a,t
sequence s,mode,fname,pos
function OpenFile(sequence fname, sequence mode)
sequence in
integer fn
if mode[1]='w' then
fn = open(fname,"r")
if fn >= 0 then
puts(1,"That file already exists.\n")
while 1 do
in = lower(prompt_string("Overwrite and replace the file [y/n]:"))
if check_break() then terminate(1) end if
if equal(in,"n") then return -1 end if
if equal(in,"y") then exit end if
puts(1,"Please enter either y or n.\n")
end while
puts(1,'\n')
close(fn)
end if
end if
fn = open(fname,mode)
if fn < 0 then
printf(1,"Could not open output file: %s\n",{fname})
puts(1,"Maybe that data storage device does not exist or your entry was
not written in a proper file name format.\n")
end if
return fn
end function
function find_drive_space()
-- get drive for output file
sequence regs
atom buffer_hi,truename_ptr,bytes_per_cluster,num_clusters,result
integer seg16,off16_lo,off16_hi,second_char,num_bksp
regs=repeat(0,10)
buffer_lo=allocate_low(256)
buffer_hi=buffer_lo+128
seg16=floor((buffer_lo+256)/#FFFF) -- avoid segment wrap inside buffer
off16_lo=buffer_lo-65536*seg16
off16_hi=off16_lo+128
poke(buffer_lo,fname)
poke(buffer_lo+length(fname),0)
regs[REG_DS]=seg16 -- src buffer address
regs[REG_SI]=off16_lo
regs[REG_ES]=seg16 -- dst buffer address
regs[REG_DI]=off16_hi
regs[REG_AX]=#6000 -- request true name
regs=dos_interrupt(#21,regs)
if and_bits(regs[REG_FLAGS],1) then
return -1
end if
-- extract drive name
second_char=peek(buffer_hi+1)
if second_char=':' then -- local drive
poke(buffer_hi+3,0)
elsif second_char!='\\' then -- unlikely
return 0
else -- UNC for network drive
-- some versions need extra support
truename_ptr=buffer_hi+3
num_bksp=0
while 1 do
second_char=peek(truename_ptr)
if second_char=0 then
exit -- unlikely
elsif second_char='\\' then
if num_bksp then -- end of second component reached
poke(truename_ptr+1,0)
exit
else -- end of machine name reached, now scan the drive name
num_bksp=1
end if
end if
end while
end if
-- get cluster size for drive
regs[REG_CX]=44 -- <128 so we can reuse original fname buffer
regs[REG_DX]=off16_hi
regs[REG_DI]=off16_lo
regs[REG_AX]=#7303
regs=dos_interrupt(#21,regs)
if and_bits(regs[REG_FLAGS],1) or not and_bits(regs[REG_AX],#FF) then
return 0 -- error, or unsupported call
end if
bytes_per_cluster=peek4u(buffer_lo+4)*peek4u(buffer_lo+8)
result=floor(bytes_per_cluster/one_meg)
bytes_per_cluster=remainder(bytes_per_cluster,one_meg)
-- get available cluster count for drive
-- In rare cases, this may not be reliable, but reliable
-- answers are only guaranteed for local drives using the alternate mechanism.
num_clusters=peek4u(buffer_lo+12)
mb_drive_space *= num_clusters
num_clusters *= bytes_per_cluster
return result+floor(num_clusters/one_meg)
end function
fn = 1
allow_break(0)
puts(1,"PERMENUM - Permutation Enumeration Generator v1.0\n\n")
puts(1,"Generating \"forward\" or \"forward and reverse paired\", right ordered
enumeration\n" &
"of every permutation of any number of positions and any length of
items.\n\n" &
"Program may be halted at any given moment by pressing the CTR-C and then
ENTER key.\n")
while 1 do
mode = lower(prompt_string("\nEnter whether to generate either a) \"forward\"
or b) \"forward and reverse pairs\"\n" &
"of right ordered enumeration of every permutation
[e.g.: a]:\n"))
if check_break() then terminate(1) end if
if not equal(mode,"a") and not equal(mode,"b") then
while 1 do
mode = lower(prompt_string("Please enter either a or b:\n"))
if check_break() then terminate(1) end if
if equal(mode,"a") or equal(mode,"b") then exit end if
end while
end if
n = prompt_number("\nEnter the number of character places for the permutation
[e.g.: 4]:\n",{})
if check_break() then terminate(1) end if
s = prompt_string("\nEnter the character items to be permutated in the
desired forward order for\n" &
"the enumeration [e.g.: xyz]:\n")
if check_break() then terminate(1) end if
while 1 do
fname = prompt_string("\nEnter the file name for the enumeration output to
be saved as [e.g.: 4toxyz.txt\n" &
"or c:\\4toxyz.txt]:\n")
if check_break() then terminate(1) end if
fn = OpenFile(fname,"w")
if fn != -1 then exit end if
end while
-- start size testing
mb_drive_space=find_drive_space()
free_low(buffer_lo)
-- a = power(length(s),n) + 1
-- if a+1 = a then
-- puts(1,"Too many permutations to process. The limit for the total
number of forward and reverse paired," &
-- "right ordered permutations to be enumerated is 2^52 [n=2,
s=52].\n")
-- abort(1)
-- end if
if mb_drive_space=0 then
mb_drive_space=prompt_number("\nDo you know how megabytes of free space
you have on that drive? If so, please enter that number, else 0.\n",{})
if mb_drive_space=0 then
if compare(prompt_string("\nCould no determine available space on
drive.\nDo you wish to proceed, AT THE RISK OF OVERRUNNING YOUR DRIVE? (NOT
RECOMMENDED)\nIf so, type YES, any other answer exits program.\n")
,"YES") then
puts(1,"\nProgram halted by user.\n")
terminate(1)
end if
end if
end if
-- changed check using logarithms, so as to avoid overflows in power()
-- file_size_log=log(length(s))*(n+1)
-- if equal(mode,"b") then
-- file_size_log+=log(2)
-- end if
if equal(mode,"a") then
-- for mode (a) file_size = power(length(s),n) * (n+2)
file_size_log = log(length(s))* n + log(n+2)
else
-- for mode (b) file_size = power(length(s),n) * (2*n + 3)
file_size_log = log(length(s))* n + log(2*n+3)
end if
if log(one_meg)+log(mb_drive_space) > file_size_log then exit end if-- lhs is
expected to be below 53*log(2)~36.736
puts(1,sprintf("Too many permutations to process, given the available space
(%dMb) on selected drive.\n\n",mb_drive_space))
end while
a = power(length(s),n) + 1
t = floor((a-1)/100)
if t=0 then t=1 end if
pos = get_position()
if equal(mode,"a") then
for i = 1 to a-1 do
if remainder(i,t) = 0 then
position(pos[1],1)
printf(1,"%d%% done.",100*i/(a-1))
if check_break() then terminate(1) end if
end if
puts(fn,VariationRep(i,n,s)& '\n')
end for
else
for i = 1 to a-1 do
if remainder(i,t) = 0 then
position(pos[1],1)
printf(1,"%d %% done.",100*i/(a-1))
if check_break() then terminate(1) end if
end if
puts(fn,VariationRep(i,n,s)& ' ')
puts(fn,VariationRep(a-i,n,s)& '\n')
end for
end if
position(pos[1],1)
puts(1,"100% done.\n")
terminate(0)
Regards,
Fernando
