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#ifndef UDO_TWIGS_CHECKPOINTING
#define UDO_TWIGS_CHECKPOINTING ##
gitwgs_maxundolevels = 32
gitwgs_checkpoints[] init gitwgs_maxundolevels
gitwgs_checkpointstate = 0
gitwgs_checkpointencodemult = 10000
opcode twgs_checkpoint_encode, i, ii
ifnL, ifnR xin
iencoded = (ifnL * gitwgs_checkpointencodemult) + (ifnR / gitwgs_checkpointencodemult)
xout iencoded
endop
opcode twgs_checkpoint_decode, ii, i
iencoded xin
ifnL = int(iencoded) / gitwgs_checkpointencodemult
ifnR = frac(iencoded) * gitwgs_checkpointencodemult
xout ifnL, ifnR
endop
opcode twgs_checkpoint_clear, 0, 0
icheckpointnumber = gitwgs_checkpointstate
while (icheckpointnumber >= 0) do
ifnL, ifnR twgs_checkpoint_decode gitwgs_checkpoints[icheckpointnumber]
if (ifnL > 0 && ftexists(ifnL) == 1) then
tpvf_destroy ifnL
endif
if (ifnR > 0 && ftexists(ifnR) == 1) then
tpvf_destroy ifnR
endif
icheckpointnumber -= 1
od
gitwgs_checkpointstate = 0
endop
opcode twgs_checkpoint, 0, 0
imaxundo chnget "twgs_maxundo"
imaxundo = (imaxundo == -1) ? gitwgs_maxundolevels : imaxundo
if (imaxundo == 0 || imaxundo > gitwgs_maxundolevels) then
goto complete
endif
icheckpointnumber = gitwgs_checkpointstate
if (icheckpointnumber >= imaxundo) then
ifnL, ifnR twgs_checkpoint_decode gitwgs_checkpoints[0]
if (ifnL > 0 && ftexists(ifnL) == 1) then
tpvf_destroy ifnL
endif
if (ifnR > 0 && ftexists(ifnR) == 1) then
tpvf_destroy ifnR
endif
index = 1
itemp[] = gitwgs_checkpoints
while (index <= imaxundo) do
gitwgs_checkpoints[index - 1] = itemp[index]
index += 1
od
gitwgs_checkpointstate = icheckpointnumber ;- 1
else
gitwgs_checkpointstate = icheckpointnumber + 1
endif
ifnL = gitwgs_tpvfHandleL
ifnR = gitwgs_tpvfHandleR
ifnCheckpointL tpvf_clone ifnL
print ifnCheckpointL
if (ifnR > 0) then
ifnCheckpointR tpvf_clone ifnR
else
ifnCheckpointR = 0
endif
iencoded twgs_checkpoint_encode ifnCheckpointL, ifnCheckpointR
gitwgs_checkpoints[icheckpointnumber] = iencoded
complete:
endop
opcode twgs_undo, i, p
iapplyundo xin
icheckpointnumber = gitwgs_checkpointstate
icheckpointnumber -= 1
if (icheckpointnumber < 0) then
istatus = -1
goto complete
endif
gitwgs_checkpointstate = icheckpointnumber
ifnL, ifnR twgs_checkpoint_decode gitwgs_checkpoints[icheckpointnumber]
if (iapplyundo == 1) then ; apply or just step back and forget
if (ifnL > 0 && ftexists(ifnL) = 1) then
tpvf_destroy gitwgs_tpvfHandleL
gitwgs_tpvfHandleL = ifnL
endif
if (ifnR > 0 && ftexists(ifnR) == 1) then
tpvf_destroy gitwgs_tpvfHandleR
gitwgs_tpvfHandleR = ifnR
endif
else
if (ifnL > 0 && ftexists(ifnL) = 1) then
tpvf_destroy ifnL
endif
if (ifnL > 0 && ftexists(ifnR) = 1) then
tpvf_destroy ifnR
endif
endif
istatus = 1
complete:
xout istatus
endop
#end
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