ch2-6: 提炼 qsort 例子

examples/ch2-06-qsort/v2-qsort/main.go

@@ -6,14 +6,22 @@ package main
 /*
 #include <stdlib.h>
 
-static int compare(const void* a, const void* b) {
+typedef int (*qsort_cmp_func_t)(const void* a, const void* b);
+
+// disable static
+int qsort_compare_callback(const void* a, const void* b) {
 	const int* pa = (int*)a;
 	const int* pb = (int*)b;
 	return *pa - *pb;
 }
 
-static void qsort_proxy(int* values, size_t len, size_t elemsize) {
+static int compare(const void* a, const void* b) {
-	qsort(values, len, sizeof(values[0]), compare);
+	const int* pa = (int*)a;
+	const int* pb = (int*)b;
+	return *pa - *pb;
+}
+static qsort_cmp_func_t get_compare_ptr() {
+	return compare;
 }
 */
 import "C"
@@ -21,14 +29,24 @@ import "C"
 import "unsafe"
 import "fmt"
 
+func qsort(base unsafe.Pointer, num, size C.size_t, cmp C.qsort_cmp_func_t) {
+	C.qsort(base, num, size, C.qsort_cmp_func_t(cmp))
+}
+
 func main() {
 	values := []int32{42, 9, 101, 95, 27, 25}
 
-	C.qsort_proxy(
+	qsort(unsafe.Pointer(&values[0]),
-		(*C.int)(unsafe.Pointer(&values[0])),
+		C.size_t(len(values)), C.size_t(unsafe.Sizeof(values[0])),
-		C.size_t(len(values)),
+		C.get_compare_ptr(), // static callback must use proxy get
-		C.size_t(unsafe.Sizeof(values[0])),
 	)
+	fmt.Println(values)
 
+	values = []int32{42, 9, 101, 95, 27, 25}
+
+	qsort(unsafe.Pointer(&values[0]),
+		C.size_t(len(values)), C.size_t(unsafe.Sizeof(values[0])),
+		C.qsort_cmp_func_t(unsafe.Pointer(C.qsort_compare_callback)),
+	)
 	fmt.Println(values)
 }

examples/ch2-06-qsort/v3-qsort/main.go

@@ -9,14 +9,6 @@ package main
 typedef int (*qsort_cmp_func_t)(const void* a, const void* b);
 
 extern int go_qsort_compare(void* a, void* b);
-
-static int compare(const void* a, const void* b) {
-	return go_qsort_compare((void*)(a), (void*)(b));
-}
-
-static qsort_cmp_func_t get_compare_ptr() {
-	return compare;
-}
 */
 import "C"
 import (
@@ -24,20 +16,24 @@ import (
 	"unsafe"
 )
 
-func main() {
-	values := []int32{42, 9, 101, 95, 27, 25}
-
-	C.qsort(unsafe.Pointer(&values[0]),
-		C.size_t(len(values)), C.size_t(unsafe.Sizeof(values[0])),
-		C.get_compare_ptr(),
-	)
-
-	fmt.Println(values)
-}
-
 //export go_qsort_compare
 func go_qsort_compare(a, b unsafe.Pointer) C.int {
 	pa := (*C.int)(a)
 	pb := (*C.int)(b)
 	return C.int(*pa - *pb)
 }
+
+func qsort(base unsafe.Pointer, num, size C.size_t, cmp C.qsort_cmp_func_t) {
+	C.qsort(base, num, size, C.qsort_cmp_func_t(cmp))
+}
+
+func main() {
+	values := []int32{42, 9, 101, 95, 27, 25}
+
+	qsort(unsafe.Pointer(&values[0]),
+		C.size_t(len(values)), C.size_t(unsafe.Sizeof(values[0])),
+		C.qsort_cmp_func_t(unsafe.Pointer(C.go_qsort_compare)),
+	)
+
+	fmt.Println(values)
+}

examples/ch2-06-qsort/v4-qsort/main.go

@@ -3,6 +3,10 @@
 
 package main
 
+import (
+	"fmt"
+)
+
 /*
 #include <stdlib.h>
 
@@ -11,25 +15,40 @@ extern int go_qsort_compare(void* a, void* b);
 */
 import "C"
 import (
-	"fmt"
+	"sync"
 	"unsafe"
 )
 
-func main() {
+var go_qsort_compare_info struct {
-	values := []int32{42, 9, 101, 95, 27, 25}
+	fn func(a, b unsafe.Pointer) int
-
+	sync.Mutex
-	C.qsort(unsafe.Pointer(&values[0]),
-		C.size_t(len(values)), C.size_t(unsafe.Sizeof(values[0])),
-		(C.qsort_cmp_func_t)(unsafe.Pointer(C.go_qsort_compare)),
-	)
-
-	fmt.Println(values)
 }
 
 //export go_qsort_compare
 func go_qsort_compare(a, b unsafe.Pointer) C.int {
-	pa := (*C.int)(a)
+	return C.int(go_qsort_compare_info.fn(a, b))
-	pb := (*C.int)(b)
+}
-
+
-	return C.int(*pa - *pb)
+func qsort(base unsafe.Pointer, num, size int, cmp func(a, b unsafe.Pointer) int) {
+	go_qsort_compare_info.Lock()
+	defer go_qsort_compare_info.Unlock()
+
+	go_qsort_compare_info.fn = cmp
+
+	C.qsort(base, C.size_t(num), C.size_t(size),
+		C.qsort_cmp_func_t(C.go_qsort_compare),
+	)
+}
+
+func main() {
+	values := []int32{42, 9, 101, 95, 27, 25}
+
+	qsort(unsafe.Pointer(&values[0]), len(values), int(unsafe.Sizeof(values[0])),
+		func(a, b unsafe.Pointer) int {
+			pa, pb := (*C.int)(a), (*C.int)(b)
+			return int(*pa - *pb)
+		},
+	)
+
+	fmt.Println(values)
 }

examples/ch2-06-qsort/v5-qsort/main.go

@@ -3,48 +3,85 @@
 
 package main
 
-import (
-	"fmt"
-)
-
 /*
 #include <stdlib.h>
 
 typedef int (*qsort_cmp_func_t)(const void* a, const void* b);
+
 extern int  go_qsort_compare(void* a, void* b);
 */
 import "C"
+
 import (
+	"fmt"
+	"reflect"
 	"sync"
 	"unsafe"
 )
 
-func main() {
+var go_qsort_compare_info struct {
-	values := []int32{42, 9, 101, 95, 27, 25}
+	slice    interface{}
+	base     uintptr
+	elemsize uintptr
+	fn       func(a, b int) int
+	sync.Mutex
+}
 
-	go_qsort_compare_info.Lock()
+//export go_qsort_compare_save_base
-	defer go_qsort_compare_info.Unlock()
+func go_qsort_compare_save_base(base unsafe.Pointer) {
-
+	go_qsort_compare_info.base = uintptr(base)
-	go_qsort_compare_info.fn = func(a, b unsafe.Pointer) C.int {
-		pa := (*C.int)(a)
-		pb := (*C.int)(b)
-		return C.int(*pa - *pb)
-	}
-
-	C.qsort(unsafe.Pointer(&values[0]),
-		C.size_t(len(values)), C.size_t(unsafe.Sizeof(values[0])),
-		(C.qsort_cmp_func_t)(unsafe.Pointer(C.go_qsort_compare)),
-	)
-
-	fmt.Println(values)
 }
 
 //export go_qsort_compare
 func go_qsort_compare(a, b unsafe.Pointer) C.int {
-	return go_qsort_compare_info.fn(a, b)
+	if go_qsort_compare_info.base == 0 {
+		sv := reflect.ValueOf(go_qsort_compare_info.slice)
+		go_qsort_compare_info.base = uintptr(unsafe.Pointer(sv.Index(0).Addr().Pointer()))
+	}
+
+	var (
+		// array memory is locked
+		base     = go_qsort_compare_info.base
+		elemsize = go_qsort_compare_info.elemsize
+	)
+
+	i := int((uintptr(a) - base) / elemsize)
+	j := int((uintptr(b) - base) / elemsize)
+
+	return C.int(go_qsort_compare_info.fn(i, j))
 }
 
-var go_qsort_compare_info struct {
+func qsort(slice interface{}, fn func(a, b int) int) {
-	fn func(a, b unsafe.Pointer) C.int
+	sv := reflect.ValueOf(slice)
-	sync.RWMutex
+	if sv.Kind() != reflect.Slice {
+		panic(fmt.Sprintf("qsort called with non-slice value of type %T", slice))
+	}
+	if sv.Len() == 0 {
+		return
+	}
+
+	go_qsort_compare_info.Lock()
+	defer go_qsort_compare_info.Unlock()
+
+	// baseMem = unsafe.Pointer(sv.Index(0).Addr().Pointer())
+	// baseMem maybe moved, so must saved after call C.fn
+	go_qsort_compare_info.slice = slice
+	go_qsort_compare_info.elemsize = sv.Type().Elem().Size()
+	go_qsort_compare_info.fn = fn
+
+	C.qsort(
+		unsafe.Pointer(sv.Index(0).Addr().Pointer()),
+		C.size_t(sv.Len()), C.size_t(sv.Type().Elem().Size()),
+		C.qsort_cmp_func_t(C.go_qsort_compare),
+	)
+}
+
+func main() {
+	values := []int64{42, 9, 101, 95, 27, 25}
+
+	qsort(values, func(i, j int) int {
+		return int(values[i] - values[j])
+	})
+
+	fmt.Println(values)
 }

examples/ch2-06-qsort/v6-qsort/main.go

@@ -1,56 +0,0 @@
-// Copyright © 2018 ChaiShushan <chaishushan{AT}gmail.com>.
-// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
-
-package main
-
-import (
-	"fmt"
-)
-
-/*
-#include <stdlib.h>
-
-typedef int (*qsort_cmp_func_t)(const void* a, const void* b);
-extern int go_qsort_compare(void* a, void* b);
-*/
-import "C"
-import (
-	"sync"
-	"unsafe"
-)
-
-func main() {
-	values := []int32{42, 9, 101, 95, 27, 25}
-
-	qsort(values, func(a, b unsafe.Pointer) C.int {
-		pa := (*C.int)(a)
-		pb := (*C.int)(b)
-		return C.int(*pa - *pb)
-	})
-
-	fmt.Println(values)
-}
-
-func qsort(values []int32, fn func(a, b unsafe.Pointer) C.int) {
-	go_qsort_compare_info.Lock()
-	defer go_qsort_compare_info.Unlock()
-
-	go_qsort_compare_info.fn = fn
-
-	C.qsort(
-		unsafe.Pointer(&values[0]),
-		C.size_t(len(values)),
-		C.size_t(unsafe.Sizeof(values[0])),
-		(C.qsort_cmp_func_t)(unsafe.Pointer(C.go_qsort_compare)),
-	)
-}
-
-//export go_qsort_compare
-func go_qsort_compare(a, b unsafe.Pointer) C.int {
-	return go_qsort_compare_info.fn(a, b)
-}
-
-var go_qsort_compare_info struct {
-	fn func(a, b unsafe.Pointer) C.int
-	sync.RWMutex
-}

examples/ch2-06-qsort/v7-qsort/main.go

@@ -1,92 +0,0 @@
-// Copyright © 2018 ChaiShushan <chaishushan{AT}gmail.com>.
-// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
-
-package main
-
-/*
-#include <stdlib.h>
-
-typedef int (*qsort_cmp_func_t)(const void* a, const void* b);
-
-extern int  go_qsort_compare(void* a, void* b);
-extern void go_qsort_compare_save_base(void* base);
-
-static void
-qsort_proxy(
-	void* base, size_t num, size_t size,
-	int (*compare)(const void* a, const void* b)
-) {
-	go_qsort_compare_save_base(base);
-	qsort(base, num, size, compare);
-}
-*/
-import "C"
-
-import (
-	"fmt"
-	"reflect"
-	"sync"
-	"unsafe"
-)
-
-func main() {
-	values := []int64{42, 9, 101, 95, 27, 25}
-
-	fmt.Println(values)
-	defer fmt.Println(values)
-
-	qsort(values, func(i, j int) int {
-		return int(values[i] - values[j])
-	})
-}
-
-func qsort(slice interface{}, fn func(a, b int) int) {
-	sv := reflect.ValueOf(slice)
-	if sv.Kind() != reflect.Slice {
-		panic(fmt.Sprintf("qsort called with non-slice value of type %T", slice))
-	}
-	if sv.Len() == 0 {
-		return
-	}
-
-	go_qsort_compare_info.Lock()
-	defer go_qsort_compare_info.Unlock()
-
-	// baseMem = unsafe.Pointer(sv.Index(0).Addr().Pointer())
-	// baseMem maybe moved, so must saved after call C.fn
-	go_qsort_compare_info.elemsize = sv.Type().Elem().Size()
-	go_qsort_compare_info.fn = fn
-
-	C.qsort_proxy(
-		unsafe.Pointer(unsafe.Pointer(sv.Index(0).Addr().Pointer())),
-		C.size_t(sv.Len()),
-		C.size_t(sv.Type().Elem().Size()),
-		(C.qsort_cmp_func_t)(unsafe.Pointer(C.go_qsort_compare)),
-	)
-}
-
-//export go_qsort_compare
-func go_qsort_compare(a, b unsafe.Pointer) C.int {
-	var (
-		// array memory is locked
-		base     = go_qsort_compare_info.base
-		elemsize = go_qsort_compare_info.elemsize
-	)
-
-	i := int((uintptr(a) - base) / elemsize)
-	j := int((uintptr(b) - base) / elemsize)
-
-	return C.int(go_qsort_compare_info.fn(i, j))
-}
-
-//export go_qsort_compare_save_base
-func go_qsort_compare_save_base(base unsafe.Pointer) {
-	go_qsort_compare_info.base = uintptr(base)
-}
-
-var go_qsort_compare_info struct {
-	base     uintptr
-	elemsize uintptr
-	fn       func(a, b int) int
-	sync.RWMutex
-}