[Nim] Bfbs Nim Generator (#7534)

* Bfbs Nim Generator * Remove commented out tests * add missing line to idl.h * Commit python reflection changes * Commit python reflection changes and move tests * Remove default string addition * Move tests to python file * Fix element size check when element is table * remove whitespace changes * add element_type docs and commit further to namer and remove kkeep * Bfbs Nim Generator * Remove commented out tests * add missing line to idl.h * Commit python reflection changes * Commit python reflection changes and move tests * Remove default string addition * Move tests to python file * Fix element size check when element is table * remove whitespace changes * add element_type docs and commit further to namer and remove kkeep * remove unused variables * added tests to ci * added tests to ci * fixes * Added reflection type Field, Variable to namer * Moved reflection namer impl to bfbsnamer * Remove whitespace at end of line * Added nim to generated code * Revert whitespace removal Co-authored-by: Derek Bailey <derekbailey@google.com>
2022-10-21 21:30:04 +03:00
parent e301702964
commit 872a497464
57 changed files with 3344 additions and 34 deletions
--- a/nim/flatbuffers/src/table.nim
+++ b/nim/flatbuffers/src/table.nim
@@ -0,0 +1,149 @@
+import endian
+
+
+type
+   uoffset* = uint32 ## offset in to the buffer
+   soffset* = int32 ## offset from start of table, to a vtable
+   voffset* = uint16 ## offset from start of table to value
+
+type Offsets* = uoffset | soffset | voffset
+
+type Vtable* = object
+   Bytes*: seq[byte]
+   Pos*: uoffset
+
+
+using this: Vtable
+
+
+func GetVal*[T](b: ptr seq[byte]): T {.inline.} =
+   when T is float64:
+      result = cast[T](GetVal[uint64](b))
+   elif T is float32:
+      result = cast[T](GetVal[uint32](b))
+   elif T is string:
+      result = cast[T](b[])
+   else:
+      if b[].len < T.sizeof:
+         b[].setLen T.sizeof
+      result = cast[ptr T](unsafeAddr b[][0])[]
+
+
+template Get*[T](this; off: uoffset): T =
+   var seq = this.Bytes[off..^1]
+   GetVal[T](addr seq)
+
+template Get*[T](this; off: soffset): T =
+   var seq = this.Bytes[off..^1]
+   GetVal[T](addr seq)
+
+template Get*[T](this; off: voffset): T =
+   var seq = this.Bytes[off..^1]
+   GetVal[T](addr seq)
+
+func WriteVal*[T: not SomeFloat](b: var openArray[byte]; off: uoffset;
+      n: T) {.inline.} =
+   when sizeof(T) == 8:
+      littleEndianX(addr b[off], unsafeAddr n, T.sizeof)
+   elif sizeof(T) == 4:
+      littleEndianX(addr b[off], unsafeAddr n, T.sizeof)
+   elif sizeof(T) == 2:
+      littleEndianX(addr b[off], unsafeAddr n, T.sizeof)
+   elif sizeof(T) == 1:
+      b[off] = n.uint8
+   else:
+      discard
+      #littleEndianX(addr b[off], unsafeAddr n, T.sizeof)
+      #{.error:"shouldnt appear".}
+
+func WriteVal*[T: not SomeFloat](b: var seq[byte]; off: uoffset;
+      n: T) {.inline.} =
+   when sizeof(T) == 8:
+      littleEndianX(addr b[off], unsafeAddr n, T.sizeof)
+   elif sizeof(T) == 4:
+      littleEndianX(addr b[off], unsafeAddr n, T.sizeof)
+   elif sizeof(T) == 2:
+      littleEndianX(addr b[off], unsafeAddr n, T.sizeof)
+   elif sizeof(T) == 1:
+      b[off] = n.uint8
+   else:
+      discard
+      #littleEndianX(addr b[off], unsafeAddr n, T.sizeof)
+      #{.error:"shouldnt appear".}
+
+func WriteVal*[T: SomeFloat](b: var openArray[byte]; off: uoffset;
+      n: T) {.inline.} =
+   when T is float64:
+      WriteVal(b, off, cast[uint64](n))
+   elif T is float32:
+      WriteVal(b, off, cast[uint32](n))
+
+func WriteVal*[T: SomeFloat](b: var seq[byte]; off: uoffset; n: T) {.inline.} =
+   when T is float64:
+      WriteVal(b, off, cast[uint64](n))
+   elif T is float32:
+      WriteVal(b, off, cast[uint32](n))
+
+func Offset*(this; off: voffset): voffset =
+   let vtable = (this.Pos - this.Get[:uoffset](this.Pos)).voffset
+   let vtableEnd = this.Get[:voffset](vtable)
+   if off < vtableEnd:
+      return this.Get[:voffset](vtable + off)
+   return 0
+
+
+func Indirect*(this; off: uoffset): uoffset =
+   result = off + this.Get[:uoffset](off)
+
+func VectorLen*(this; off: uoffset): int =
+   var newoff: uoffset = off + this.Pos
+   newoff += this.Get[:uoffset](newoff)
+   return this.Get[:uoffset](newoff).int
+
+func Vector*(this; off: uoffset): uoffset =
+   let newoff: uoffset = off + this.Pos
+   var x: uoffset = newoff + this.Get[:uoffset](newoff)
+   x += (uoffset.sizeof).uoffset
+   result = x
+
+func Union*(this; off: uoffset): Vtable =
+   let newoff: uoffset = off + this.Pos
+   result.Pos = newoff + this.Get[:uoffset](newoff)
+   result.Bytes = this.Bytes
+
+func GetSlot*[T](this; slot: voffset; d: T): T =
+   let off = this.Offset(slot)
+   if off == 0:
+      return d
+   return this.Get[T](this.Pos + off)
+
+func GetOffsetSlot*[T: Offsets](this; slot: voffset; d: T): T =
+   let off = this.Offset(slot)
+   if off == 0:
+      return d
+   return off
+
+func ByteVector*(this; off: uoffset): seq[byte] =
+   let
+      newoff: uoffset = off + this.Get[:uoffset](off)
+      start = newoff + (uoffset.sizeof).uoffset
+   var newseq = this.Bytes[newoff..^1]
+   let
+      length = GetVal[uoffset](addr newseq)
+   result = this.Bytes[start..<start+length]
+
+func String*(this; off: uoffset): string =
+   var byte_seq = this.ByteVector(off)
+   result = GetVal[string](addr byte_seq)
+
+using this: var Vtable
+
+proc Mutate*[T](this; off: uoffset; n: T): bool =
+   WriteVal(this.Bytes, off, n)
+   return true
+
+func MutateSlot*[T](this; slot: voffset; n: T): bool =
+   let off: voffset = this.Offset(slot)
+   if off != 0:
+      return this.Mutate(this.Pos + off.uoffset, n)
+   return false