Go API for GmSSL

go/digest.go

@@ -0,0 +1,77 @@
+/* +build cgo */
+
+package gmssl
+
+/*
+#include <openssl/evp.h>
+*/
+import "C"
+
+import (
+	"errors"
+	"fmt"
+	"runtime"
+	"unsafe"
+)
+
+func GetDigests(aliases bool) []string {
+	return []string{"sm3", "sha1", "sha256"}
+}
+
+func GetDigestLength(name string) (int, error) {
+	cname := C.CString(name)
+	defer C.free(unsafe.Pointer(cname))
+	md := C.EVP_get_digestbyname(cname)
+	if md == nil {
+		return 0, errors.New("Invalid digest name")
+	}
+	return int(C.EVP_MD_size(md)), nil
+}
+
+type DigestContext struct {
+	ctx *C.EVP_MD_CTX
+}
+
+func NewDigestContext(name string, args map[string]string) (*DigestContext, error) {
+	cname := C.CString(name)
+	defer C.free(unsafe.Pointer(cname))
+	md := C.EVP_get_digestbyname(cname)
+	if md == nil {
+		return nil, fmt.Errorf("shit")
+	}
+
+	ctx := C.EVP_MD_CTX_new()
+	if ctx == nil {
+		return nil, fmt.Errorf("shit")
+	}
+
+	ret := &DigestContext{ctx}
+	runtime.SetFinalizer(ret, func(ret *DigestContext) {
+		C.EVP_MD_CTX_free(ret.ctx)
+	})
+
+	if 1 != C.EVP_DigestInit(ctx, md) {
+		return nil, fmt.Errorf("shit")
+	}
+
+	return ret, nil
+}
+
+func (ctx *DigestContext) Update(data []byte) error {
+	if len(data) == 0 {
+		return nil
+	}
+	if 1 != C.EVP_DigestUpdate(ctx.ctx, unsafe.Pointer(&data[0]), C.size_t(len(data))) {
+		errors.New("hello")
+	}
+	return nil
+}
+
+func (ctx *DigestContext) Final() ([]byte, error) {
+	outbuf := make([]byte, 64)
+	outlen := C.uint(len(outbuf))
+	if 1 != C.EVP_DigestFinal(ctx.ctx, (*C.uchar)(unsafe.Pointer(&outbuf[0])), &outlen) {
+		return nil, errors.New("error")
+	}
+	return outbuf[:outlen], nil
+}