working commit

vendor/github.com/tetratelabs/wabin/wasm/counts.go

@@ -0,0 +1,86 @@
+package wasm
+
+import "fmt"
+
+// ImportFuncCount returns the possibly empty count of imported functions. This plus SectionElementCount of
+// SectionIDFunction is the size of the function index namespace.
+func (m *Module) ImportFuncCount() uint32 {
+	return m.importCount(ExternTypeFunc)
+}
+
+// ImportTableCount returns the possibly empty count of imported tables. This plus SectionElementCount of SectionIDTable
+// is the size of the table index namespace.
+func (m *Module) ImportTableCount() uint32 {
+	return m.importCount(ExternTypeTable)
+}
+
+// ImportMemoryCount returns the possibly empty count of imported memories. This plus SectionElementCount of
+// SectionIDMemory is the size of the memory index namespace.
+func (m *Module) ImportMemoryCount() uint32 {
+	return m.importCount(ExternTypeMemory) // TODO: once validation happens on decode, this is zero or one.
+}
+
+// ImportGlobalCount returns the possibly empty count of imported globals. This plus SectionElementCount of
+// SectionIDGlobal is the size of the global index namespace.
+func (m *Module) ImportGlobalCount() uint32 {
+	return m.importCount(ExternTypeGlobal)
+}
+
+// importCount returns the count of a specific type of import. This is important because it is easy to mistake the
+// length of the import section with the count of a specific kind of import.
+func (m *Module) importCount(et ExternType) (res uint32) {
+	for _, im := range m.ImportSection {
+		if im.Type == et {
+			res++
+		}
+	}
+	return
+}
+
+// SectionElementCount returns the count of elements in a given section ID
+//
+// For example...
+// * SectionIDType returns the count of FunctionType
+// * SectionIDCustom returns one if the NameSection is present
+// * SectionIDHostFunction returns the count of HostFunctionSection
+// * SectionIDExport returns the count of unique export names
+func (m *Module) SectionElementCount(sectionID SectionID) uint32 { // element as in vector elements!
+	switch sectionID {
+	case SectionIDCustom:
+		numCustomSections := uint32(len(m.CustomSections))
+		if m.NameSection != nil {
+			numCustomSections++
+		}
+		return numCustomSections
+	case SectionIDType:
+		return uint32(len(m.TypeSection))
+	case SectionIDImport:
+		return uint32(len(m.ImportSection))
+	case SectionIDFunction:
+		return uint32(len(m.FunctionSection))
+	case SectionIDTable:
+		return uint32(len(m.TableSection))
+	case SectionIDMemory:
+		if m.MemorySection != nil {
+			return 1
+		}
+		return 0
+	case SectionIDGlobal:
+		return uint32(len(m.GlobalSection))
+	case SectionIDExport:
+		return uint32(len(m.ExportSection))
+	case SectionIDStart:
+		if m.StartSection != nil {
+			return 1
+		}
+		return 0
+	case SectionIDElement:
+		return uint32(len(m.ElementSection))
+	case SectionIDCode:
+		return uint32(len(m.CodeSection))
+	case SectionIDData:
+		return uint32(len(m.DataSection))
+	default:
+		panic(fmt.Errorf("BUG: unknown section: %d", sectionID))
+	}
+}