Initial data commit

Task/Bitmap-Read-a-PPM-file/Forth/bitmap-read-a-ppm-file.fth

@@ -0,0 +1,38 @@
+: read-ppm { fid -- bmp }
+  pad dup 80 fid read-line throw 0= abort" Partial line"
+  s" P6" compare abort" Only P6 supported."
+  pad dup 80 fid read-line throw 0= abort" Partial line"
+  0. 2swap >number
+  1 /string		\ skip space
+  0. 2swap >number
+  2drop drop nip    ( w h )
+  bitmap { bmp }
+  pad dup 80 fid read-line throw 0= abort" Partial line"
+  s" 255" compare abort" Only 8-bits per color channel supported"
+  0 pad !
+  bmp bdim
+  0 do
+    dup 0 do
+      pad 3 fid read-file throw
+      3 - abort" Not enough pixel data in file"
+      pad @ i j bmp b!
+    loop
+  loop drop
+  bmp ;
+
+\ testing round-trip
+4 3 bitmap value test
+red test bfill
+green 1 2 test b!
+
+s" red.ppm" w/o create-file throw
+test over write-ppm
+close-file throw
+
+s" red.ppm" r/o open-file throw
+dup read-ppm value test2
+close-file throw
+
+: bsize ( bmp -- len ) bdim * pixels bdata ;
+
+test dup bsize  test2 dup bsize  compare .    \ 0 if identical