Merge pull request #2780 from flaviut/cleanup-crc

Use SHA1 instead of CRC
2015-06-09 15:10:21 +02:00 · 2015-06-09 15:10:21 +02:00 · 25a1987517
commit 25a1987517
parent 60bc1fd7ba badc3a0929
9 changed files with 249 additions and 190 deletions
--- a/compiler/ast.nim
+++ b/compiler/ast.nim
@ -10,7 +10,7 @@
 # abstract syntax tree + symbol table

 import
-  msgs, hashes, nversion, options, strutils, crc, ropes, idents, lists,
+  msgs, hashes, nversion, options, strutils, secure_hash, ropes, idents, lists,
  intsets, idgen

 type
--- a/compiler/cgen.nim
+++ b/compiler/cgen.nim
@ -10,12 +10,11 @@
 ## This module implements the C code generator.

 import
-  ast, astalgo, hashes, trees, platform, magicsys, extccomp,
-  options, intsets,
-  nversion, nimsets, msgs, crc, bitsets, idents, lists, types, ccgutils, os,
-  ropes, math, passes, rodread, wordrecg, treetab, cgmeth, condsyms,
-  rodutils, renderer, idgen, cgendata, ccgmerge, semfold, aliases, lowerings,
-  semparallel
+  ast, astalgo, hashes, trees, platform, magicsys, extccomp, options, intsets,
+  nversion, nimsets, msgs, secure_hash, bitsets, idents, lists, types,
+  ccgutils, os, ropes, math, passes, rodread, wordrecg, treetab, cgmeth,
+  condsyms, rodutils, renderer, idgen, cgendata, ccgmerge, semfold, aliases,
+  lowerings, semparallel

 import strutils except `%` # collides with ropes.`%`

--- a/compiler/crc.nim
+++ b/compiler/crc.nim
@ -1,147 +0,0 @@
-#
-#
-#           The Nim Compiler
-#        (c) Copyright 2012 Andreas Rumpf
-#
-#    See the file "copying.txt", included in this
-#    distribution, for details about the copyright.
-#
-
-import 
-  strutils
-
-type 
-  TCrc32* = int32
-
-const 
-  InitCrc32* = TCrc32(- 1)
-  InitAdler32* = int32(1)
-
-proc updateCrc32*(val: int8, crc: TCrc32): TCrc32 {.inline.}
-proc updateCrc32*(val: char, crc: TCrc32): TCrc32 {.inline.}
-proc crcFromBuf*(buf: pointer, length: int): TCrc32
-proc strCrc32*(s: string): TCrc32
-proc crcFromFile*(filename: string): TCrc32
-proc updateAdler32*(adler: int32, buf: pointer, length: int): int32
-# implementation
-
-type 
-  TCRC_TabEntry = int
-
-const 
-  crc32table: array[0..255, TCRC_TabEntry] = [0, 1996959894, - 301047508, 
-    - 1727442502, 124634137, 1886057615, - 379345611, - 1637575261, 249268274, 
-    2044508324, - 522852066, - 1747789432, 162941995, 2125561021, - 407360249, 
-    - 1866523247, 498536548, 1789927666, - 205950648, - 2067906082, 450548861, 
-    1843258603, - 187386543, - 2083289657, 325883990, 1684777152, - 43845254, 
-    - 1973040660, 335633487, 1661365465, - 99664541, - 1928851979, 997073096, 
-    1281953886, - 715111964, - 1570279054, 1006888145, 1258607687, - 770865667, 
-    - 1526024853, 901097722, 1119000684, - 608450090, - 1396901568, 853044451, 
-    1172266101, - 589951537, - 1412350631, 651767980, 1373503546, - 925412992, 
-    - 1076862698, 565507253, 1454621731, - 809855591, - 1195530993, 671266974, 
-    1594198024, - 972236366, - 1324619484, 795835527, 1483230225, - 1050600021, 
-    - 1234817731, 1994146192, 31158534, - 1731059524, - 271249366, 1907459465, 
-    112637215, - 1614814043, - 390540237, 2013776290, 251722036, - 1777751922, 
-    - 519137256, 2137656763, 141376813, - 1855689577, - 429695999, 1802195444, 
-    476864866, - 2056965928, - 228458418, 1812370925, 453092731, - 2113342271, 
-    - 183516073, 1706088902, 314042704, - 1950435094, - 54949764, 1658658271, 
-    366619977, - 1932296973, - 69972891, 1303535960, 984961486, - 1547960204, 
-    - 725929758, 1256170817, 1037604311, - 1529756563, - 740887301, 1131014506, 
-    879679996, - 1385723834, - 631195440, 1141124467, 855842277, - 1442165665, 
-    - 586318647, 1342533948, 654459306, - 1106571248, - 921952122, 1466479909, 
-    544179635, - 1184443383, - 832445281, 1591671054, 702138776, - 1328506846, 
-    - 942167884, 1504918807, 783551873, - 1212326853, - 1061524307, - 306674912, 
-    - 1698712650, 62317068, 1957810842, - 355121351, - 1647151185, 81470997, 
-    1943803523, - 480048366, - 1805370492, 225274430, 2053790376, - 468791541, 
-    - 1828061283, 167816743, 2097651377, - 267414716, - 2029476910, 503444072, 
-    1762050814, - 144550051, - 2140837941, 426522225, 1852507879, - 19653770, 
-    - 1982649376, 282753626, 1742555852, - 105259153, - 1900089351, 397917763, 
-    1622183637, - 690576408, - 1580100738, 953729732, 1340076626, - 776247311, 
-    - 1497606297, 1068828381, 1219638859, - 670225446, - 1358292148, 906185462, 
-    1090812512, - 547295293, - 1469587627, 829329135, 1181335161, - 882789492, 
-    - 1134132454, 628085408, 1382605366, - 871598187, - 1156888829, 570562233, 
-    1426400815, - 977650754, - 1296233688, 733239954, 1555261956, - 1026031705, 
-    - 1244606671, 752459403, 1541320221, - 1687895376, - 328994266, 1969922972, 
-    40735498, - 1677130071, - 351390145, 1913087877, 83908371, - 1782625662, 
-    - 491226604, 2075208622, 213261112, - 1831694693, - 438977011, 2094854071, 
-    198958881, - 2032938284, - 237706686, 1759359992, 534414190, - 2118248755, 
-    - 155638181, 1873836001, 414664567, - 2012718362, - 15766928, 1711684554, 
-    285281116, - 1889165569, - 127750551, 1634467795, 376229701, - 1609899400, 
-    - 686959890, 1308918612, 956543938, - 1486412191, - 799009033, 1231636301, 
-    1047427035, - 1362007478, - 640263460, 1088359270, 936918000, - 1447252397, 
-    - 558129467, 1202900863, 817233897, - 1111625188, - 893730166, 1404277552, 
-    615818150, - 1160759803, - 841546093, 1423857449, 601450431, - 1285129682, 
-    - 1000256840, 1567103746, 711928724, - 1274298825, - 1022587231, 1510334235, 
-    755167117]
-
-proc updateCrc32(val: int8, crc: TCrc32): TCrc32 = 
-  result = TCrc32(crc32table[(int(crc) xor (int(val) and 0x000000FF)) and
-      0x000000FF]) xor (crc shr TCrc32(8))
-
-proc updateCrc32(val: char, crc: TCrc32): TCrc32 = 
-  result = updateCrc32(toU8(ord(val)), crc)
-
-proc strCrc32(s: string): TCrc32 = 
-  result = InitCrc32
-  for i in countup(0, len(s) - 1): result = updateCrc32(s[i], result)
-  
-proc `><`*(c: TCrc32, s: string): TCrc32 = 
-  result = c
-  for i in 0..len(s)-1: result = updateCrc32(s[i], result)  
-  
-type 
-  TByteArray = array[0..10000000, int8]
-  PByteArray = ref TByteArray
-
-proc crcFromBuf(buf: pointer, length: int): TCrc32 = 
-  var p = cast[PByteArray](buf)
-  result = InitCrc32
-  for i in countup(0, length - 1): result = updateCrc32(p[i], result)
-  
-proc crcFromFile(filename: string): TCrc32 = 
-  const 
-    bufSize = 8000 # don't use 8K for the memory allocator!
-  var 
-    bin: File
-  result = InitCrc32
-  if not open(bin, filename): 
-    return                    # not equal if file does not exist
-  var buf = alloc(bufSize)
-  var p = cast[PByteArray](buf)
-  while true: 
-    var readBytes = readBuffer(bin, buf, bufSize)
-    for i in countup(0, readBytes - 1): result = updateCrc32(p[i], result)
-    if readBytes != bufSize: break 
-  dealloc(buf)
-  close(bin)
-
-const 
-  base = int32(65521) # largest prime smaller than 65536 
-                      # NMAX = 5552; original code with unsigned 32 bit integer 
-                      # NMAX is the largest n 
-                      # such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1 
-  nmax = 3854 # code with signed 32 bit integer 
-              # NMAX is the largest n such that 
-              # 255n(n+1)/2 + (n+1)(BASE-1) <= 2^31-1 
-              # The penalty is the time loss in the extra MOD-calls. 
-
-proc updateAdler32(adler: int32, buf: pointer, length: int): int32 = 
-  var 
-    s1, s2: int32
-    L, k, b: int
-  s1 = adler and int32(0x0000FFFF)
-  s2 = (adler shr int32(16)) and int32(0x0000FFFF)
-  L = length
-  b = 0
-  while (L > 0): 
-    if L < nmax: k = L
-    else: k = nmax
-    dec(L, k)
-    while (k > 0): 
-      s1 = s1 +% int32((cast[cstring](buf))[b])
-      s2 = s2 +% s1
-      inc(b)
-      dec(k)
-    s1 = `%%`(s1, base)
-    s2 = `%%`(s2, base)
-  result = (s2 shl int32(16)) or s1
--- a/compiler/extccomp.nim
+++ b/compiler/extccomp.nim
@ -13,7 +13,7 @@
 # nim files.

 import
-  lists, ropes, os, strutils, osproc, platform, condsyms, options, msgs, crc
+  lists, ropes, os, strutils, osproc, platform, condsyms, options, msgs, secure_hash

 type
  TSystemCC* = enum
@ -572,26 +572,24 @@ proc getCompileCFileCmd*(cfilename: string, isExternal = false): string =
    "nim", quoteShell(getPrefixDir()),
    "lib", quoteShell(libpath)])

-proc footprint(filename: string): TCrc32 =
-  # note, '><' further modifies a crc value with a string.
-  result = crcFromFile(filename) ><
-      platform.OS[targetOS].name ><
-      platform.CPU[targetCPU].name ><
-      extccomp.CC[extccomp.cCompiler].name ><
-      getCompileCFileCmd(filename, true)
+proc footprint(filename: string): SecureHash =
+  result = secureHash(
+    $secureHashFile(filename) &
+    platform.OS[targetOS].name &
+    platform.CPU[targetCPU].name &
+    extccomp.CC[extccomp.cCompiler].name &
+    getCompileCFileCmd(filename, true))

 proc externalFileChanged(filename: string): bool =
  if gCmd notin {cmdCompileToC, cmdCompileToCpp, cmdCompileToOC, cmdCompileToLLVM}:
    return false

  var crcFile = toGeneratedFile(filename.withPackageName, "crc")
-  var currentCrc = int(footprint(filename))
+  var currentCrc = footprint(filename)
  var f: File
  if open(f, crcFile, fmRead):
-    var line = newStringOfCap(40)
-    if not f.readLine(line): line = "0"
+    let oldCrc = parseSecureHash(f.readLine())
    close(f)
-    var oldCrc = parseInt(line)
    result = oldCrc != currentCrc
  else:
    result = true
--- a/compiler/jsgen.nim
+++ b/compiler/jsgen.nim
@ -30,8 +30,8 @@ implements the required case distinction.


 import
-  ast, astalgo, strutils, hashes, trees, platform, magicsys, extccomp,
-  options, nversion, nimsets, msgs, crc, bitsets, idents, lists, types, os,
+  ast, astalgo, strutils, hashes, trees, platform, magicsys, extccomp, options,
+  nversion, nimsets, msgs, secure_hash, bitsets, idents, lists, types, os,
  times, ropes, math, passes, ccgutils, wordrecg, renderer, rodread, rodutils,
  intsets, cgmeth, lowerings

--- a/compiler/modules.nim
+++ b/compiler/modules.nim
@ -10,7 +10,7 @@
 ## implements the module handling

 import
-  ast, astalgo, magicsys, crc, rodread, msgs, cgendata, sigmatch, options,
+  ast, astalgo, magicsys, secure_hash, rodread, msgs, cgendata, sigmatch, options,
  idents, os, lexer, idgen, passes, syntaxes, llstream

 type
@ -19,7 +19,7 @@ type

  TModuleInMemory* = object
    compiledAt*: float
-    crc*: TCrc32
+    crc*: SecureHash
    deps*: seq[int32] ## XXX: slurped files are currently not tracked
    needsRecompile*: TNeedRecompile
    crcStatus*: TCrcStatus
@ -51,19 +51,19 @@ proc crcChanged(fileIdx: int32): bool =
  of crcNotChanged:
    result = false
  of crcCached:
-    let newCrc = crcFromFile(fileIdx.toFilename)
+    let newCrc = secureHashFile(fileIdx.toFilename)
    result = newCrc != gMemCacheData[fileIdx].crc
    gMemCacheData[fileIdx].crc = newCrc
    updateStatus()
  of crcNotTaken:
-    gMemCacheData[fileIdx].crc = crcFromFile(fileIdx.toFilename)
+    gMemCacheData[fileIdx].crc = secureHashFile(fileIdx.toFilename)
    result = true
    updateStatus()

 proc doCRC(fileIdx: int32) =
  if gMemCacheData[fileIdx].crcStatus == crcNotTaken:
    # echo "FIRST CRC: ", fileIdx.ToFilename
-    gMemCacheData[fileIdx].crc = crcFromFile(fileIdx.toFilename)
+    gMemCacheData[fileIdx].crc = secureHashFile(fileIdx.toFilename)

 proc addDep(x: PSym, dep: int32) =
  growCache gMemCacheData, dep
--- a/compiler/rodread.nim
+++ b/compiler/rodread.nim
@ -90,7 +90,7 @@

 import 
  os, options, strutils, nversion, ast, astalgo, msgs, platform, condsyms, 
-  ropes, idents, crc, idgen, types, rodutils, memfiles
+  ropes, idents, secure_hash, idgen, types, rodutils, memfiles

 type 
  TReasonForRecompile* = enum ## all the reasons that can trigger recompilation
@ -538,10 +538,11 @@ proc cmdChangeTriggersRecompilation(old, new: TCommands): bool =
  # else: trigger recompilation:
  result = true
  
-proc processRodFile(r: PRodReader, crc: TCrc32) = 
+proc processRodFile(r: PRodReader, crc: SecureHash) = 
  var 
    w: string
-    d, inclCrc: int
+    d: int
+  var inclCrc: SecureHash
  while r.s[r.pos] != '\0': 
    var section = rdWord(r)
    if r.reason != rrNone: 
@ -549,7 +550,8 @@ proc processRodFile(r: PRodReader, crc: TCrc32) =
    case section 
    of "CRC": 
      inc(r.pos)              # skip ':'
-      if int(crc) != decodeVInt(r.s, r.pos): r.reason = rrCrcChange
+      if crc != parseSecureHash(decodeStr(r.s, r.pos)):
+        r.reason = rrCrcChange
    of "ID": 
      inc(r.pos)              # skip ':'
      r.moduleID = decodeVInt(r.s, r.pos)
@ -596,9 +598,9 @@ proc processRodFile(r: PRodReader, crc: TCrc32) =
      while r.s[r.pos] != ')': 
        w = r.files[decodeVInt(r.s, r.pos)].toFullPath
        inc(r.pos)            # skip ' '
-        inclCrc = decodeVInt(r.s, r.pos)
+        inclCrc = parseSecureHash(decodeStr(r.s, r.pos))
        if r.reason == rrNone: 
-          if not existsFile(w) or (inclCrc != int(crcFromFile(w))): 
+          if not existsFile(w) or (inclCrc != secureHashFile(w)): 
            r.reason = rrInclDeps
        if r.s[r.pos] == '\x0A': 
          inc(r.pos)
@ -649,7 +651,7 @@ proc startsWith(buf: cstring, token: string, pos = 0): bool =
  while s < token.len and buf[pos+s] == token[s]: inc s
  result = s == token.len

-proc newRodReader(modfilename: string, crc: TCrc32, 
+proc newRodReader(modfilename: string, crc: SecureHash,
                  readerIndex: int): PRodReader = 
  new(result)
  try:
@ -701,7 +703,7 @@ type
    filename*: string
    reason*: TReasonForRecompile
    rd*: PRodReader
-    crc*: TCrc32
+    crc*: SecureHash
    crcDone*: bool

  TFileModuleMap = seq[TFileModuleRec]
@ -794,13 +796,13 @@ proc loadMethods(r: PRodReader) =
    r.methods.add(rrGetSym(r, d, unknownLineInfo()))
    if r.s[r.pos] == ' ': inc(r.pos)

-proc getCRC*(fileIdx: int32): TCrc32 =
+proc getCRC*(fileIdx: int32): SecureHash =
  internalAssert fileIdx >= 0 and fileIdx < gMods.len

  if gMods[fileIdx].crcDone:
    return gMods[fileIdx].crc
  
-  result = crcFromFile(fileIdx.toFilename)
+  result = secureHashFile(fileIdx.toFilename)
  gMods[fileIdx].crc = result

 template growCache*(cache, pos) =
@ -1017,7 +1019,7 @@ proc writeType(f: File; t: PType) =
  f.write("]\n")

 proc viewFile(rodfile: string) =
-  var r = newRodReader(rodfile, 0, 0)
+  var r = newRodReader(rodfile, secureHash(""), 0)
  if r == nil:
    rawMessage(errGenerated, "cannot open file (or maybe wrong version):" &
       rodfile)
--- a/compiler/rodwrite.nim
+++ b/compiler/rodwrite.nim
@ -13,14 +13,14 @@

 import 
  intsets, os, options, strutils, nversion, ast, astalgo, msgs, platform,
-  condsyms, ropes, idents, crc, rodread, passes, importer, idgen, rodutils
+  condsyms, ropes, idents, secure_hash, rodread, passes, importer, idgen, rodutils

 # implementation

 type 
  TRodWriter = object of TPassContext
    module: PSym
-    crc: TCrc32
+    crc: SecureHash
    options: TOptions
    defines: string
    inclDeps: string
@ -38,7 +38,7 @@ type

  PRodWriter = ref TRodWriter

-proc newRodWriter(crc: TCrc32, module: PSym): PRodWriter
+proc newRodWriter(crc: SecureHash, module: PSym): PRodWriter
 proc addModDep(w: PRodWriter, dep: string)
 proc addInclDep(w: PRodWriter, dep: string)
 proc addInterfaceSym(w: PRodWriter, s: PSym)
@ -62,7 +62,7 @@ proc fileIdx(w: PRodWriter, filename: string): int =
 template filename*(w: PRodWriter): string =
  w.module.filename

-proc newRodWriter(crc: TCrc32, module: PSym): PRodWriter = 
+proc newRodWriter(crc: SecureHash, module: PSym): PRodWriter = 
  new(result)
  result.sstack = @[]
  result.tstack = @[]
@ -96,7 +96,7 @@ proc addInclDep(w: PRodWriter, dep: string) =
  var resolved = dep.findModule(w.module.info.toFullPath)
  encodeVInt(fileIdx(w, dep), w.inclDeps)
  add(w.inclDeps, " ")
-  encodeVInt(crcFromFile(resolved), w.inclDeps)
+  encodeStr($secureHashFile(resolved), w.inclDeps)
  add(w.inclDeps, rodNL)

 proc pushType(w: PRodWriter, t: PType) =
@ -440,7 +440,7 @@ proc writeRod(w: PRodWriter) =
  f.write(rodNL)
  
  var crc = "CRC:"
-  encodeVInt(w.crc, crc)
+  encodeStr($w.crc, crc)
  f.write(crc)
  f.write(rodNL)
  
--- a/compiler/secure_hash.nim
+++ b/compiler/secure_hash.nim
@ -0,0 +1,207 @@
+#
+#
+#           The Nim Compiler
+#        (c) Copyright 2015 Nim Contributers
+#
+#    See the file "copying.txt", included in this
+#    distribution, for details about the copyright.
+#
+
+import
+  strutils, unsigned
+
+const sha_digest_size = 20
+
+type
+  SHA1Digest = array[0 .. sha_digest_size-1, uint8]
+  SecureHash* = distinct SHA1Digest
+
+const emptySecureHash = SecureHash([
+  0u8, 0, 0, 0,
+  0, 0, 0, 0,
+  0, 0, 0, 0,
+  0, 0, 0, 0,
+  0, 0, 0, 0,
+])
+
+proc sha1(src: string) : SHA1Digest
+
+proc secureHash*(str: string): SecureHash = SecureHash(sha1(str))
+proc secureHashFile*(filename: string): SecureHash = secureHash(readFile(filename))
+proc `$`*(self: SecureHash): string =
+  result = ""
+  for v in SHA1Digest(self):
+    result.add(toHex(int(v), 2))
+
+proc parseSecureHash*(hash: string): SecureHash =
+  for i in 0.. <sha_digest_size:
+    SHA1Digest(result)[i] = uint8(parseHexInt(hash[i*2] & hash[i*2 + 1]))
+
+proc `==`*(a, b: SecureHash): bool =
+  # Not a constant-time comparison, but that's acceptable in this context
+  SHA1Digest(a) == SHA1Digest(b)
+
+
+when isMainModule:
+  let hash1 = secureHash("a93tgj0p34jagp9[agjp98ajrhp9aej]")
+  doAssert hash1 == hash1
+  doAssert parseSecureHash($hash1) == hash1
+
+
+# Copyright (c) 2011, Micael Hildenborg
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+# * Redistributions of source code must retain the above copyright
+#   notice, this list of conditions and the following disclaimer.
+# * Redistributions in binary form must reproduce the above copyright
+#   notice, this list of conditions and the following disclaimer in the
+#   documentation and/or other materials provided with the distribution.
+# * Neither the name of Micael Hildenborg nor the
+#   names of its contributors may be used to endorse or promote products
+#   derived from this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY Micael Hildenborg ''AS IS'' AND ANY
+# EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+# DISCLAIMED. IN NO EVENT SHALL Micael Hildenborg BE LIABLE FOR ANY
+# DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#
+# Ported to Nim by Erik O'Leary
+
+type
+  SHA1State = array[0 .. 5-1, uint32]
+  SHA1Buffer = array[0 .. 80-1, uint32]
+
+template clearBuffer(w: SHA1Buffer, len = 16) =
+  zeroMem(addr(w), len * sizeof(uint32))
+
+proc init(result: var SHA1State) =
+  result[0] = 0x67452301'u32
+  result[1] = 0xefcdab89'u32
+  result[2] = 0x98badcfe'u32
+  result[3] = 0x10325476'u32
+  result[4] = 0xc3d2e1f0'u32
+
+proc innerHash(state: var SHA1State, w: var SHA1Buffer) =
+  var
+    a = state[0]
+    b = state[1]
+    c = state[2]
+    d = state[3]
+    e = state[4]
+
+  var round = 0
+
+  template rot(value, bits: uint32): uint32 {.immediate.} =
+    (value shl bits) or (value shr (32 - bits))
+
+  template sha1(fun, val: uint32): stmt =
+    let t = rot(a, 5) + fun + e + val + w[round]
+    e = d
+    d = c
+    c = rot(b, 30)
+    b = a
+    a = t
+
+  template process(body: stmt): stmt =
+    w[round] = rot(w[round - 3] xor w[round - 8] xor w[round - 14] xor w[round - 16], 1)
+    body
+    inc(round)
+
+  template wrap(dest, value: expr): stmt {.immediate.} =
+    let v = dest + value
+    dest = v
+
+  while round < 16:
+    sha1((b and c) or (not b and d), 0x5a827999'u32)
+    inc(round)
+
+  while round < 20:
+    process:
+      sha1((b and c) or (not b and d), 0x5a827999'u32)
+
+  while round < 40:
+    process:
+      sha1(b xor c xor d, 0x6ed9eba1'u32)
+
+  while round < 60:
+    process:
+      sha1((b and c) or (b and d) or (c and d), 0x8f1bbcdc'u32)
+
+  while round < 80:
+    process:
+      sha1(b xor c xor d, 0xca62c1d6'u32)
+
+  wrap state[0], a
+  wrap state[1], b
+  wrap state[2], c
+  wrap state[3], d
+  wrap state[4], e
+
+template computeInternal(src: expr): stmt {.immediate.} =
+  #Initialize state
+  var state: SHA1State
+  init(state)
+
+  #Create w buffer
+  var w: SHA1Buffer
+
+  #Loop through all complete 64byte blocks.
+  let byteLen         = src.len
+  let endOfFullBlocks = byteLen - 64
+  var endCurrentBlock = 0
+  var currentBlock    = 0
+
+  while currentBlock <= endOfFullBlocks:
+    endCurrentBlock = currentBlock + 64
+
+    var i = 0
+    while currentBlock < endCurrentBlock:
+      w[i] = uint32(src[currentBlock+3]) or
+             uint32(src[currentBlock+2]) shl 8'u32 or
+             uint32(src[currentBlock+1]) shl 16'u32 or
+             uint32(src[currentBlock])   shl 24'u32
+      currentBlock += 4
+      inc(i)
+
+    innerHash(state, w)
+
+  #Handle last and not full 64 byte block if existing
+  endCurrentBlock = byteLen - currentBlock
+  clearBuffer(w)
+  var lastBlockBytes = 0
+
+  while lastBlockBytes < endCurrentBlock:
+
+    var value = uint32(src[lastBlockBytes + currentBlock]) shl
+                ((3'u32 - (lastBlockBytes and 3)) shl 3)
+
+    w[lastBlockBytes shr 2] = w[lastBlockBytes shr 2] or value
+    inc(lastBlockBytes)
+
+  w[lastBlockBytes shr 2] = w[lastBlockBytes shr 2] or (
+    0x80'u32 shl ((3'u32 - (lastBlockBytes and 3)) shl 3)
+  )
+
+  if endCurrentBlock >= 56:
+    innerHash(state, w)
+    clearBuffer(w)
+
+  w[15] = uint32(byteLen) shl 3
+  innerHash(state, w)
+
+  # Store hash in result pointer, and make sure we get in in the correct order
+  # on both endian models.
+  for i in 0 .. sha_digest_size-1:
+    result[i] = uint8((int(state[i shr 2]) shr ((3-(i and 3)) * 8)) and 255)
+
+proc sha1(src: string) : SHA1Digest =
+  ## Calculate SHA1 from input string
+  computeInternal(src)