;+
;FUNCTION: mav_pfdpu_part_decompress_data2
;PURPOSE:
; Decompresses ESA science packets (SWEA/SWIA/STATIC). If the packet is already
; uncompressed, it is simply returned unchanged.
;
;USAGE:
; decompressed_pkt = mav_pfdpu_part_decompress_data2(compressed_pkt)
;
;INPUTS:
; compressed_pkt: ESA science packet that is possibly compressed.
;
;KEYWORDS:
;
; $LastChangedBy: jimm $
; $LastChangedDate: 2015-03-22 14:24:35 -0700 (Sun, 22 Mar 2015) $
; $LastChangedRevision: 17163 $
; $URL: svn+ssh://thmsvn@ambrosia.ssl.berkeley.edu/repos/spdsoft/tags/spedas_5_0/projects/maven/swea/mav_pfdpu_part_decompress_data2.pro $
;
;CREATED BY: David L. Mitchell 04-25-13
;FILE: mav_pfdpu_part_decompress_data2.pro
;-
compile_opt idl2
function mav_pfdpu_getbit,bfr,bitinx
inx = bitinx / 8
bit = bitinx mod 8
bmask = [128b,64b,32b,16b,8b,4b,2b,1b]
bitinx++
return, (bfr[Inx] and bmask[bit]) ne 0
end
function mav_pfdpu_GetBits,bfr,bitinx, leng
if leng gt (n_elements(bfr)*8 - bitinx) then begin
return,0
endif
r=0
for i=0,leng-1 do begin
r = r*2 + mav_pfdpu_GetBit(bfr,bitinx)
endfor
return, r
end
function mav_pfdpu_NextA,bfr,bitinx
if(mav_pfdpu_GetBits(bfr,bitinx,1) eq 0) then return,0 ; // 0
if(mav_pfdpu_GetBits(bfr,bitinx,1) eq 0) then return,1 ; // 10
n = mav_pfdpu_GetBits(bfr,bitinx,2)
if( n lt 3 ) then return, n+2 ; // 1100-1110
n = mav_pfdpu_GetBits(bfr,bitinx,8)
return, n ; // 1111xxxxxxxx
end
function mav_pfdpu_NextB,bfr,bitinx
n = mav_pfdpu_GetBits(bfr,bitinx,3)
case n of
0: return, (0)
1: return, (1)
2: return,( 2 + mav_pfdpu_GetBits(bfr,bitinx,1))
3: return,( 4 + mav_pfdpu_GetBits(bfr,bitinx,2))
4: begin
m = mav_pfdpu_GetBits(bfr,bitinx,2);
if( m eq 0 ) then return,( 8 )
if( m eq 1 ) then begin
p = mav_pfdpu_GetBits(bfr,bitinx,2)
if( p lt 3) then return,( 9 + p)
return,( mav_pfdpu_GetBits(bfr,bitinx, 8 ))
endif
if( m eq 2 ) then begin
p = mav_pfdpu_GetBits(bfr,bitinx,2)
if( p gt 0) then return,( -12 + p)
return,( - mav_pfdpu_GetBits(bfr,bitinx, 8 ))
endif
if( m eq 3 ) then return,( -8 )
end;
5: return,( -7 + mav_pfdpu_GetBits(bfr,bitinx,2))
6: return,( -3 + mav_pfdpu_GetBits(bfr,bitinx,1))
7: return,( -1 )
endcase
end
function mav_pfdpu_NextC,bfr,bitinx
n = mav_pfdpu_GetBits(bfr,bitinx,4)
switch (n) of
0:
1:
2:
3: return,(n);
4: return,( 4 + mav_pfdpu_GetBits(bfr,bitinx,1) )
5: return,( 6 + mav_pfdpu_GetBits(bfr,bitinx,1) )
6: return,( 8 + mav_pfdpu_GetBits(bfr,bitinx,1) )
7: if( mav_pfdpu_GetBits(bfr,bitinx,1) eq 0) then return,( 10 ) $
else return,( 11 + mav_pfdpu_GetBits(bfr,bitinx,1) )
8: begin
m = mav_pfdpu_GetBits(bfr, bitinx, 2)
if( m eq 0 ) then return,( 13 )
if( m eq 1 ) then begin
p = mav_pfdpu_GetBits(bfr, bitinx, 1)
if( p eq 0) then return,( 14 )
return,( mav_pfdpu_GetBits(bfr,bitinx,8) )
endif
if( m eq 2 ) then begin
p = mav_pfdpu_GetBits(bfr,bitinx,1)
if( p eq 1) then return,( -14 )
return,( -mav_pfdpu_GetBits(bfr,bitinx,8) )
endif
if( m eq 3 ) then return,( -13 )
end
9: if( mav_pfdpu_GetBits(bfr,bitinx,1) eq 1) then return,( -10 ) $
else return,( -12 + mav_pfdpu_GetBits(bfr,bitinx,1) )
10: return,( -9 + mav_pfdpu_GetBits(bfr,bitinx,1) )
11: return,( -7 + mav_pfdpu_GetBits(bfr,bitinx,1) )
12: return,( -5 + mav_pfdpu_GetBits(bfr,bitinx,1) )
13: return,( -3 )
14: return,( -2 )
15: return,( -1 )
endswitch
end
function mav_pfdpu_NextD, bfr, bitinx
n = mav_pfdpu_GetBits(bfr,bitinx,4)
switch (n) of
0:
1:
2:
3: return,(n)
4: return,( 4 + mav_pfdpu_GetBits(bfr,bitinx,1))
5: return,( 6 + mav_pfdpu_GetBits(bfr,bitinx,1))
6: return,( 8 + mav_pfdpu_GetBits(bfr,bitinx,1))
7: if( mav_pfdpu_GetBits(bfr,bitinx,1) eq 0) then return,(10) $
else return,( 11 + mav_pfdpu_GetBits(bfr,bitinx,1))
8: begin
m = mav_pfdpu_GetBits(bfr,bitinx,4)
if( m lt 7 ) then return,( 13+m )
if( m eq 7 ) then return,( mav_pfdpu_GetBits(bfr,bitinx,8))
if( m eq 8 ) then return,( -mav_pfdpu_GetBits(bfr,bitinx,8))
if( m gt 8 ) then return,( -28+m )
end
9: if( mav_pfdpu_GetBits(bfr,bitinx,1) eq 1) then return,(-10) else $
return,( -12 + mav_pfdpu_GetBits(bfr,bitinx,1))
10: return,( -9 + mav_pfdpu_GetBits(bfr,bitinx,1))
11: return,( -7 + mav_pfdpu_GetBits(bfr,bitinx,1))
12: return,( -5 + mav_pfdpu_GetBits(bfr,bitinx,1))
13: return,( -3 )
14: return,( -2 )
15: return,( -1 )
endswitch
end
function mav_pfdpu_DecodeA, bfr, bitinx
dst = bytarr(32)
; dprint,bitinx,dlevel=3
for i=0,32-1 do begin
dst[i] = mav_pfdpu_NextA(bfr, bitinx)
; dprint,bitinx,dst[i],format='(i4," ",z02)',dlevel=3
endfor
return, dst
end
function mav_pfdpu_DecodeB, bfr, bitinx
dst = bytarr(32)
R = mav_pfdpu_GetBits(bfr,bitinx,8)
dst[0] = R
for i=1,32-1 do begin
Del = mav_pfdpu_NextB(bfr, bitinx) ; each B value is a delta
R += Del;
dst[i] = R;
endfor
return, dst
end
function mav_pfdpu_DecodeC, bfr, bitinx
dst = bytarr(32)
R = mav_pfdpu_GetBits(bfr, bitinx, 8)
dst[0] = R
for i=1,32-1 do begin
Del = mav_pfdpu_NextC(bfr, bitinx) ; each B value is a delta
R += Del;
dst[i] = R;
endfor
return, dst
end
function mav_pfdpu_DecodeD, bfr, bitinx
dst = bytarr(32)
R = mav_pfdpu_GetBits(bfr, bitinx, 8)
dst[0] = R
for i=1,32-1 do begin
Del = mav_pfdpu_NextD(bfr, bitinx) ; each B value is a delta
R += Del;
dst[i] = R;
endfor
return, dst
end
function mav_pfdpu_part_decompress_data2, bfr
compile_opt idl2
; returns decompressed ccsds packet data for the particle instruments
cmpbyte = bfr[12]
if (cmpbyte and 128) eq 0 then return,bfr ; pkt not actually compressed return raw data.
pktbits = 8*(bfr[4]*256+bfr[5] + 7)
pktbits = pktbits - 32
decomp_bfr = bytarr(4096) ; max possible size uncompressed
for j = 0,15 do decomp_bfr[j] = bfr[j] ; First nn bytes are not compressed
DcmInx = 16 ; Start Byte
BitInx = DcmInx*8 ; Start Bit
while (BitInx lt Pktbits ) do begin ; While Bits remain
Type = mav_pfdpu_GetBits(bfr, bitinx, 2)
case (Type) of
0: b32 = mav_pfdpu_DecodeA(bfr, bitinx)
1: b32 = mav_pfdpu_DecodeB(bfr, bitinx)
2: b32 = mav_pfdpu_DecodeC(bfr, bitinx)
3: b32 = mav_pfdpu_DecodeD(bfr, bitinx)
endcase
if (DcmInx+31 gt 4095) then begin
print,"decompression error"
break
endif
decomp_bfr[DcmInx:DcmInx+31] = B32
DcmInx += 32
endwhile
decomp_size = DcmInx
decomp_bfr[4] = (decomp_size-7) / 256
decomp_bfr[5] = (decomp_size-7) mod 256
ddata = decomp_bfr[0:decomp_size-1]
return, ddata
end