much more efficient rod file generation

compiler/rodutils.nim

@@ -7,8 +7,8 @@
 #    distribution, for details about the copyright.
 #
 
-## Utilities for the compiler. Aim is to reduce the coupling between 
-## the compiler and the evolving stdlib.
+## Serialization utilities for the compiler.
+import strutils
 
 proc c_sprintf(buf, frmt: cstring) {.importc: "sprintf", nodecl, varargs.}
 
@@ -25,3 +25,97 @@ proc ToStrMaxPrecision*(f: BiggestFloat): string =
     c_sprintf(buf, "%#.16e", f) 
     result = $buf
 
+proc encodeStr*(s: string, result: var string) =
+  for i in countup(0, len(s) - 1): 
+    case s[i]
+    of 'a'..'z', 'A'..'Z', '0'..'9', '_': add(result, s[i])
+    else: add(result, '\\' & toHex(ord(s[i]), 2))
+
+proc hexChar(c: char, xi: var int) = 
+  case c
+  of '0'..'9': xi = (xi shl 4) or (ord(c) - ord('0'))
+  of 'a'..'f': xi = (xi shl 4) or (ord(c) - ord('a') + 10)
+  of 'A'..'F': xi = (xi shl 4) or (ord(c) - ord('A') + 10)
+  else: nil
+
+proc decodeStr*(s: cstring, pos: var int): string =
+  var i = pos
+  result = ""
+  while true: 
+    case s[i]
+    of '\\': 
+      inc(i, 3)
+      var xi = 0
+      hexChar(s[i-2], xi)
+      hexChar(s[i-1], xi)
+      add(result, chr(xi))
+    of 'a'..'z', 'A'..'Z', '0'..'9', '_': 
+      add(result, s[i])
+      inc(i)
+    else: break 
+  pos = i
+
+const
+  chars = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
+
+template encodeIntImpl(self: expr) =
+  var d: char
+  var v = x
+  var rem = v mod 190
+  if rem < 0: 
+    add(result, '-')
+    v = - (v div 190)
+    rem = - rem
+  else: 
+    v = v div 190
+  var idx = int(rem)
+  if idx < 62: d = chars[idx]
+  else: d = chr(idx - 62 + 128)
+  if v != 0: self(v, result)
+  add(result, d)
+
+proc encodeVBiggestInt*(x: BiggestInt, result: var string) =
+  ## encode a biggest int as a variable length base 190 int.
+  encodeIntImpl(encodeVBiggestInt)
+  
+proc encodeVInt*(x: int, result: var string) = 
+  ## encode an int as a variable length base 190 int.
+  encodeIntImpl(encodeVInt)
+
+template decodeIntImpl() =
+  var i = pos
+  var sign = - 1
+  assert(s[i] in {'a'..'z', 'A'..'Z', '0'..'9', '-', '\x80'..'\xFF'})
+  if s[i] == '-': 
+    inc(i)
+    sign = 1
+  result = 0
+  while true: 
+    case s[i]
+    of '0'..'9': result = result * 190 - (ord(s[i]) - ord('0'))
+    of 'a'..'z': result = result * 190 - (ord(s[i]) - ord('a') + 10)
+    of 'A'..'Z': result = result * 190 - (ord(s[i]) - ord('A') + 36)
+    of '\x80'..'\xFF': result = result * 190 - (ord(s[i]) - 128 + 62)
+    else: break
+    inc(i)
+  result = result * sign
+  pos = i
+
+proc decodeVInt*(s: cstring, pos: var int): int = 
+  decodeIntImpl()
+
+proc decodeVBiggestInt*(s: cstring, pos: var int): biggestInt =
+  decodeIntImpl()
+
+iterator decodeVIntArray*(s: cstring): int =
+  var i = 0
+  while s[i] != '\0':
+    yield decodeVInt(s, i)
+    if s[i] == ' ': inc i
+
+iterator decodeStrArray*(s: cstring): string =
+  var i = 0
+  while s[i] != '\0':
+    yield decodeStr(s, i)
+    if s[i] == ' ': inc i
+