Fix gif test.

src/pixie/fileformats/gif.nim

@@ -1,9 +1,32 @@
-import chroma, flatty/binny, pixie/common, pixie/images, math, bitty
+import chroma, flatty/binny, pixie/common, pixie/images, math
 
 const gifSignatures* = @["GIF87a", "GIF89a"]
 
 # See: https://en.wikipedia.org/wiki/GIF
 
+type
+  BitStream* = ref object
+    data: seq[uint8] # data
+    pos: int         # position in bits
+    len: int         # len in bits
+
+proc newBitStream*(data: string): BitStream =
+  result = BitStream()
+  result.data = cast[seq[uint8]](data)
+  result.len = result.data.len * 8
+
+proc readBit(bs: BitStream, pos: int): int =
+  let byteIndex = pos div 8
+  let bitIndex = pos mod 8
+  result = bs.data[byteIndex].int shr (bitIndex) and 1
+
+proc read*(bs: BitStream, bits: int): int =
+  ## Reads number of bits
+  for i in 0 ..< bits:
+    result = result shl 1
+    result += bs.readBit(bs.pos + bits - i - 1)
+  bs.pos += bits
+
 proc decodeGIF*(data: string): Image =
   ## Decodes GIF data into an Image.
 

tests/test_gif.nim

@@ -1,35 +1,4 @@
-import pixie/fileformats/gif, pixie/fileformats/png, print, parseutils, flatty/hexprint, flatty/binlisting
-
-# let binary = decodeBinListing """
-#   0:     47 49 46 38 39 61
-#   6:     03 00
-#   8:     05 00
-#   A:     F7
-#   B:     00
-#   C:     00
-#   D:     00 00 00
-#   10:    80 00 00
-#   85:    00 00 00
-#   30A:   FF FF FF
-#   30D:   21 F9
-#   30F:   04
-#   310:   01
-#   311:   00 00
-#   313:   10 16
-#   314:   00
-#   315:   2C
-#   316:   00 00 00 00
-#   31A:   03 00 05 00
-#   31E:   00
-#   31F:   08
-#   320:   0B
-#   321:   00 51 FC 1B 28 70 A0 C1 83 01 01
-#   32C:   00
-#   32D:   3B
-# """
-
-# echo hexPrint(binary)
-# writeFile("tests/images/gif/3x5.gif", binary)
+import pixie/fileformats/gif, pixie/fileformats/png
 
 var img = decodeGIF(readFile("tests/images/gif/3x5.gif"))
 writeFile("tests/images/gif/3x5.png", img.encodePng())