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authorAndrew Gallant (Ocelot) <Andrew.Gallant@tufts.edu>2012-05-01 01:08:03 -0400
committerAndrew Gallant (Ocelot) <Andrew.Gallant@tufts.edu>2012-05-01 01:08:03 -0400
commit83a71d464887f4b6cf9124d2f8c565e6f17f2bd3 (patch)
treeca86805900a974f684dc5531311a53e4836ec784 /nexgb/xgbgen/go_union.go
parent73154769b3eba60fe48a7c08882e8e64b1545e3f (diff)
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unions, events and errors... oh my
Diffstat (limited to 'nexgb/xgbgen/go_union.go')
-rw-r--r--nexgb/xgbgen/go_union.go134
1 files changed, 132 insertions, 2 deletions
diff --git a/nexgb/xgbgen/go_union.go b/nexgb/xgbgen/go_union.go
index 5721c49..3b7365d 100644
--- a/nexgb/xgbgen/go_union.go
+++ b/nexgb/xgbgen/go_union.go
@@ -3,13 +3,143 @@ package main
// Union types
func (u *Union) Define(c *Context) {
c.Putln("// Union definition %s", u.SrcName())
+ c.Putln("// Note that to *create* a Union, you should *never* create")
+ c.Putln("// this struct directly (unless you know what you're doing).")
+ c.Putln("// Instead use one of the following constructors for '%s':",
+ u.SrcName())
+ for _, field := range u.Fields {
+ c.Putln("// New%s%s(%s %s) %s", u.SrcName(), field.SrcName(),
+ field.SrcName(), field.SrcType(), u.SrcName())
+ }
+
+ c.Putln("type %s struct {", u.SrcName())
+ for _, field := range u.Fields {
+ field.Define(c)
+ }
+ c.Putln("}")
+ c.Putln("")
+
+ // Write functions for each field that create instances of this
+ // union using the corresponding field.
+ u.New(c)
+
+ // Write function that reads bytes and produces this union.
+ u.Read(c)
+
+ // Write function that reads bytes and produces a list of this union.
+ u.ReadList(c)
+
+ // Write function that writes bytes given this union.
+ u.Write(c)
+
+ // Write function that writes a list of this union.
+ u.WriteList(c)
+
+ // Write function that computes the size of a list of these unions.
+ u.WriteListSize(c)
}
-func (u *Union) Read(c *Context, prefix string) {
+func (u *Union) New(c *Context) {
+ for _, field := range u.Fields {
+ c.Putln("// Union constructor for %s for field %s.",
+ u.SrcName(), field.SrcName())
+ c.Putln("func New%s%s(%s %s) %s {",
+ u.SrcName(), field.SrcName(), field.SrcName(),
+ field.SrcType(), u.SrcName())
+ c.Putln("var b int")
+ c.Putln("buf := make([]byte, %s)", u.Size())
+ c.Putln("")
+ field.Write(c)
+ c.Putln("")
+ c.Putln("// Create the Union type")
+ c.Putln("v := %s{}", u.SrcName())
+ c.Putln("")
+ c.Putln("// Now copy buf into all fields")
+ c.Putln("")
+ for _, field2 := range u.Fields {
+ c.Putln("b = 0 // always read the same bytes")
+ field2.Read(c)
+ c.Putln("")
+ }
+ c.Putln("return v")
+ c.Putln("}")
+ c.Putln("")
+ }
+}
+
+func (u *Union) Read(c *Context) {
c.Putln("// Union read %s", u.SrcName())
+ c.Putln("func Read%s(buf []byte, v *%s) int {", u.SrcName(), u.SrcName())
+ c.Putln("var b int")
+ c.Putln("")
+ for _, field := range u.Fields {
+ c.Putln("b = 0 // re-read the same bytes")
+ field.Read(c)
+ c.Putln("")
+ }
+ c.Putln("return %s", u.Size())
+ c.Putln("}")
+ c.Putln("")
+}
+
+func (u *Union) ReadList(c *Context) {
+ c.Putln("// Union list read %s", u.SrcName())
+ c.Putln("func Read%sList(buf []byte, dest []%s) int {",
+ u.SrcName(), u.SrcName())
+ c.Putln("b := 0")
+ c.Putln("for i := 0; i < len(dest); i++ {")
+ c.Putln("dest[i] = %s{}", u.SrcName())
+ c.Putln("b += Read%s(buf[b:], &dest[i])", u.SrcName())
+ c.Putln("}")
+ c.Putln("return pad(b)")
+ c.Putln("}")
+ c.Putln("")
}
-func (u *Union) Write(c *Context, prefix string) {
+// This is a bit tricky since writing from a Union implies that only
+// the data inside ONE of the elements is actually written.
+// However, we only currently support unions where every field has the
+// *same* *fixed* size. Thus, we make sure to always read bytes into
+// every field which allows us to simply pick the first field and write it.
+func (u *Union) Write(c *Context) {
c.Putln("// Union write %s", u.SrcName())
+ c.Putln("// Each field in a union must contain the same data.")
+ c.Putln("// So simply pick the first field and write that to the wire.")
+ c.Putln("func (v %s) Bytes() []byte {", u.SrcName())
+ c.Putln("buf := make([]byte, %s)", u.Size().Reduce("v.", ""))
+ c.Putln("b := 0")
+ c.Putln("")
+ u.Fields[0].Write(c)
+ c.Putln("return buf")
+ c.Putln("}")
+ c.Putln("")
+}
+
+func (u *Union) WriteList(c *Context) {
+ c.Putln("// Union list write %s", u.SrcName())
+ c.Putln("func %sListBytes(buf []byte, list []%s) int {",
+ u.SrcName(), u.SrcName())
+ c.Putln("b := 0")
+ c.Putln("var unionBytes []byte")
+ c.Putln("for _, item := range list {")
+ c.Putln("unionBytes = item.Bytes()")
+ c.Putln("copy(buf[b:], len(unionBytes))")
+ c.Putln("b += pad(len(unionBytes))")
+ c.Putln("}")
+ c.Putln("return b")
+ c.Putln("}")
+ c.Putln("")
+}
+
+func (u *Union) WriteListSize(c *Context) {
+ c.Putln("// Union list size %s", u.SrcName())
+ c.Putln("func %sListSize(list []%s) int {", u.SrcName(), u.SrcName())
+ c.Putln("size := 0")
+ c.Putln("for _, item := range list {")
+ c.Putln("size += %s", u.Size().Reduce("item.", ""))
+ c.Putln("}")
+ c.Putln("return size")
+ c.Putln("}")
+ c.Putln("")
}