Return values for other modes. Functions for use in external tools.

README.md

@@ -13,7 +13,37 @@ To install the par command-line application:
 go get -u github.com/akalin/gopar/cmd/par
 ```
 
-## License
+or run
+
+```
+go build cmd/par/main.go
+```
+
+after a checkout of this repository.
+
+### Usage
+
+Create, verify and repair parity files. Run `par --help` for an overview of all options.
+
+### libgopar
+
+Use gopar in your own Go code. Feed a string array with the commandline arguments to Gopar():
+
+```
+import "github.com/akalin/gopar/libgopar"
+my_args := []strings
+libgopar.Gopar(my_args)
+```
+
+Alternatively, compile a C library:
+
+```
+go build -buildmode=c-shared -o libgopar.so ./libgopar/C.go
+```
+
+This library exposes the `gopar()` function.
+
+### License
 
 Use of this source code is governed by a BSD-style license that can be
 found in the LICENSE file.

cmd/par/C.go

@@ -0,0 +1,33 @@
+package main
+
+import (
+	"C"
+	"unsafe"
+	"fmt"
+
+	"github.com/akalin/gopar/libgopar"
+)
+
+//export gopar
+func gopar(argc_ C.int, argv_ **C.char) int {
+	retval := 7
+	defer func() {
+		if r := recover(); r != nil {
+			// libgopar only panics with strings currently
+			fmt.Println("libgopar panicked! ", r)
+		}
+	}()
+
+	length := int(argc_)
+	cStrings := (*[1 << 28]*C.char)(unsafe.Pointer(argv_))[:length:length]
+
+	args_ := make([]string, length+1)
+	args_[0] = "libgopar"
+	for i, cString := range cStrings {
+		args_[i+1] = C.GoString(cString)
+	}
+	retval = libgopar.Par(args_,true)
+	return retval
+}
+
+func main(){}