All:
I wanted to be able to calculate SHA1 hashes from within IDL (without
resorting to SPAWN). Since I've never seen another IDL implementation I
thought I'd share what I cooked up with the group. It works with either
a file or a string as input.
IDL> print, jc_sha1('The quick brown fox jumps over the lazy dog')
2fd4e1c67a2d28fced849ee1bb76e7391b93eb12
IDL> print, jc_sha1('')
da39a3ee5e6b4b0d3255bfef95601890afd80709
IDL> print, jc_sha1('/path/to/an/empty.file')
da39a3ee5e6b4b0d3255bfef95601890afd80709
I have not tested this on Windows or Mac (or a big endian machine).
Best regards,
John
------------------------------
function jc_SHAfunction1, x, y, z
return, (x AND y) OR ((NOT x) AND z)
end
function jc_SHAfunction2, x, y, z
return, x XOR y XOR z
end
function jc_SHAfunction3, x, y, z
return, (x AND y) OR (x AND z) OR (y AND z)
end
;;;;;;;;;;;;;;;;;;;
function jc_sha1, input, STRING=STRING, FILE=FILE
COMPILE_OPT IDL2, STRICTARRSUBS
isFile = file_test(input) or KEYWORD_SET(FILE)
if KEYWORD_SET(STRING) then isFile=0
if isFile then begin
isZeroLength = file_test(input,/ZERO_LENGTH)
canRead = file_test(input,/READ)
if ~(canRead) then begin
print, "Can't read this file"
return, -1
endif
bytearr = isZeroLength ? byte('') : read_binary(input)
endif else begin
bytearr = byte(input)
endelse
mlen = bytearr[0] eq 0b ? 0ULL : 8ULL*N_ELEMENTS(bytearr)
bytearr = bytearr[0] eq 0 ? 128b : [TEMPORARY(bytearr),128b]
while (8*N_ELEMENTS(bytearr) mod 512) ne 448 do $
bytearr = [TEMPORARY(bytearr),0b]
bytearr = [TEMPORARY(bytearr),reverse(byte(mlen,0,8))]
message = ulong(bytearr)
h0 = '67452301'xul
h1 = 'EFCDAB89'xul
h2 = '98BADCFE'xul
h3 = '10325476'xul
h4 = 'C3D2E1F0'xul
w0 = ULONARR(80)
for chind=0, n_elements(message)-1, 64 do begin
M = message[chind:chind+63]
w = w0
for i=0,15 do $
w[i] = TOTAL(M[i*4:i*4+3]*[16777216ul,65536ul,256ul,1ul],$
/PRESERVE_TYPE)
temp = w
for i=16,79 do begin
temp = w[i-3] xor w[i-8] xor w[i-14] xor w[i-16]
w[i] = (temp*2ul) OR (temp/2147483648ul)
endfor
a = h0
b = h1
c = h2
d = h3
e = h4
for i=0, 19 do begin
temp = ((a*32ul) OR (a/134217728ul)) + jc_SHAfunction1(b,c,d) $
+ e + 1518500249ull + w[i]
e = d
d = c
c = (b*1073741824ul) OR (b/4ul)
b = a
a = ulong(temp)
endfor
for i=20, 39 do begin
temp = ((a*32ul) OR (a/134217728ul)) + jc_SHAfunction2(b,c,d) $
+ e + 1859775393ull + w[i]
e = d
d = c
c = (b*1073741824ul) OR (b/4ul)
b = a
a = ulong(temp)
endfor
for i=40, 59 do begin
temp = ((a*32ul) OR (a/134217728ul)) + jc_SHAfunction3(b,c,d) $
+ e + 2400959708ull + w[i]
e = d
d = c
c = (b*1073741824ul) OR (b/4)
b = a
a = ulong(temp)
endfor
for i=60, 79 do begin
temp = ((a*32ul) OR (a/134217728ul)) + jc_SHAfunction2(b,c,d) $
+ e + 3395469782ull + w[i]
e = d
d = c
c = (b*1073741824ul) OR (b/4ul)
b = a
a = ulong(temp)
endfor
h0 += a
h1 += b
h2 += c
h3 += d
h4 += e
endfor
h0 = string(h0,format='(z08)')
h1 = string(h1,format='(z08)')
h2 = string(h2,format='(z08)')
h3 = string(h3,format='(z08)')
h4 = string(h4,format='(z08)')
return, h0+h1+h2+h3+h4
end
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