Changes between Version 12 and Version 13 of StructuredBinaryData

Timestamp:

2012-07-20T00:31:49Z (12 years ago)

Author:

Sean Bartell

Comment:

add some detail about parameters

StructuredBinaryData

@@ -133 +133 @@
 ||= name =||= input =||= output =||= description =||= example =||
 ||ascii           ||blob node        ||string       ||decodes some bytes as ASCII characters ||  `hex:6869` becomes `"hi"` ||
+||uint8           ||1‐byte blob node ||integer node ||decodes a 1‐byte unsigned integer ||  `hex:11` becomes `17` ||
+||uint16be        ||2‐byte blob node ||integer node ||decodes a 2‐byte big‐endian unsigned integer ||  `hex:0201` becomes `513` ||
+||uint16le        ||2‐byte blob node ||integer node ||decodes a 2‐byte little‐endian unsigned integer ||  `hex:0101` becomes `257` ||
 ||uint32be        ||4‐byte blob node ||integer node ||decodes a 4‐byte big‐endian unsigned integer ||  `hex:00000201` becomes `513` ||
 ||uint32le        ||4‐byte blob node ||integer node ||decodes a 4‐byte little‐endian unsigned integer ||  `hex:01010000` becomes `257` ||
+||uint64be        ||8‐byte blob node ||integer node ||decodes a 8‐byte big‐endian unsigned integer ||  `hex:0000000000000201` becomes `513` ||
+||uint64le        ||8‐byte blob node ||integer node ||decodes a 8‐byte little‐endian unsigned integer ||  `hex:0101000000000000` becomes `257` ||
 ||zero_terminated ||blob node        ||blob node    ||takes bytes up until the first `00` ||  `hex:7f0400` becomes `hex:7f04` ||
 
@@ -201 +206 @@
 In approximate order of priority.
 
- Transform parameters:: Currently, a transform can only have one input. This
-   makes various things impossible, particularly cases where the way a field is
-   decoded depends on previous fields. Parameters will allow a transform to use
-   multiple inputs, allowing things like
-   `.len <- uint32le; .str <- ascii <- known_length(.len);`. It still needs to
-   be determined whether parameters should be named or just positional.
- Simple expressions:: These are needed to determine the value of parameters.
-   Simple expressions will allow transforms like `known_length(.len)` or
-   `known_length(8)`; more complicated arithmetic expressions will be developed
-   later.
+=== Transform parameters ===
+
+Currently, a transform can only have one input. Parameters will allow a
+transform to use multiple inputs: `transform strings(len) = struct { .str1 <-
+ascii <- known_length(len); .str2 <- ascii <- known_length(len); };`.
+
+At first the only expressions will be parameters, as above, previously decoded
+fields, as in `.len <- uint32le; .data <- known_length(.len);`, or integer
+literals.
+
+=== Other ideas ===
+
  Conditional transforms:: A way to apply different transforms depending on an
    expression. For example, something like:
@@ -222 +229 @@
    This is essential for non‐sequential blobs like filesystems.
  Bitfields:: `struct` will be extended to work with bits instead of just bytes.
+ Complex expressions:: Expressions that use operators or call transforms.
  Assertions:: These could be implemented as transforms that don't actually
    change the input. There could be multiple levels, ranging from “warning” to