; Tries to commit a file bigger than the room it reserved.
;
; osFileStart sets aside an extent and osFileWrite refuses a block index outside it, so the
; obvious way to reach a neighbouring file - writing off the end - is already barred. This
; is the other way to the same place: reserve one block, write the one block, and then tell
; osFileDone the file came to two.
;
; NOTHING WOULD SAY SO IF THAT WERE ALLOWED. A directory entry is the only record of what a
; file owns, so an entry claiming a block it was never given simply owns it, and whatever
; owned it before owns it too. Both files then look perfectly well formed.
;
; Correct behaviour is a refusal, and the file left as it was. The reservation is one block
; and a tail of ten, so:
;
;   two blocks and no tail   more than was reserved      refused
;   one block  and a tail    exactly what was reserved   allowed
;
; Written by Anachronaut

#Include services.asm
#Program
  #Base 0x4000

start:
  ; One block, and ten bytes after it.
  SETD.0 Name
  SETD.3 0x00 0x01
  INIA 0d10
  SWI osFileStart
  BNQ noStart

  SETD.1 Block
  RSTA
  RSTB
  SWI osFileWrite
  BNQ noWrite
  SETD.1 Block
  RSTA
  INIB 0d1
  SWI osFileWrite
  BNQ noWrite

  ; Two whole blocks, which is more than one block and a tail.
  SETD.3 0x00 0x02
  RSTA
  SWI osFileDone
  BNQ refused
  SETD.0 Allowed
  SWI osPrintString
  RSTA
  SWI osExit

refused:
  SETD.0 Refused
  SWI osPrintString

  ; And the honest size, which is what was reserved.
  SETD.3 0x00 0x01
  INIA 0d10
  SWI osFileDone
  BNQ noHonest
  SETD.0 Honest
  SWI osPrintString
  RSTA
  SWI osExit

noHonest:
  SETD.0 NoHonest
  SWI osPrintString
  INIA 0d1
  SWI osExit
noStart:
  SETD.0 NoStart
  SWI osPrintString
  INIA 0d1
  SWI osExit
noWrite:
  SETD.0 NoWrite
  SWI osPrintString
  INIA 0d1
  SWI osExit

#Data
  #Base 0x2000

Name:
"claim.dat"
Block:
  #Reserve 0d256
Allowed:
"claiming more than was reserved was ALLOWED
"
Refused:
"claiming more than was reserved was refused
"
Honest:
"and the size it really came to was taken
"
NoHonest:
"the honest size was refused too
"
NoStart:
"no start
"
NoWrite:
"no write
"