From 82c6f5e3d1ac5a92abc602a8890dc874cdc99329 Mon Sep 17 00:00:00 2001
From: Russ Cox <rsc@golang.org>
Date: Tue, 26 Oct 2010 08:36:07 -0700
Subject: [PATCH] gc, runtime: copy([]byte, string)

R=ken2
CC=golang-dev
https://golang.org/cl/2741041
---
 src/cmd/gc/builtin.c.boot |  1 +
 src/cmd/gc/runtime.go     |  1 +
 src/cmd/gc/typecheck.c    |  7 ++++++-
 src/cmd/gc/walk.c         |  5 ++++-
 src/pkg/runtime/slice.c   | 18 ++++++++++++++++++
 5 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/src/cmd/gc/builtin.c.boot b/src/cmd/gc/builtin.c.boot
index 12f870d7812..bb1a5f5fa62 100644
--- a/src/cmd/gc/builtin.c.boot
+++ b/src/cmd/gc/builtin.c.boot
@@ -33,6 +33,7 @@ char *runtimeimport =
 	"func \"\".stringiter (? string, ? int) int\n"
 	"func \"\".stringiter2 (? string, ? int) (retk int, retv int)\n"
 	"func \"\".slicecopy (to any, fr any, wid uint32) int\n"
+	"func \"\".slicestringcopy (to any, fr any) int\n"
 	"func \"\".convI2E (elem any) any\n"
 	"func \"\".convI2I (typ *uint8, elem any) any\n"
 	"func \"\".convT2E (typ *uint8, elem any) any\n"
diff --git a/src/cmd/gc/runtime.go b/src/cmd/gc/runtime.go
index 36ed7e96fff..2279384473f 100644
--- a/src/cmd/gc/runtime.go
+++ b/src/cmd/gc/runtime.go
@@ -48,6 +48,7 @@ func stringtosliceint(string) []int
 func stringiter(string, int) int
 func stringiter2(string, int) (retk int, retv int)
 func slicecopy(to any, fr any, wid uint32) int
+func slicestringcopy(to any, fr any) int
 
 // interface conversions
 func convI2E(elem any) (ret any)
diff --git a/src/cmd/gc/typecheck.c b/src/cmd/gc/typecheck.c
index 43cf4a7c367..614833740a0 100644
--- a/src/cmd/gc/typecheck.c
+++ b/src/cmd/gc/typecheck.c
@@ -926,13 +926,18 @@ reswitch:
 			goto error;
 		defaultlit(&n->left, T);
 		defaultlit(&n->right, T);
+		
+		// copy([]byte, string)
+		if(isslice(n->left->type) && n->left->type->type == types[TUINT8] && n->right->type->etype == TSTRING)
+			goto ret;
+
 		if(!isslice(n->left->type) || !isslice(n->right->type)) {
 			if(!isslice(n->left->type) && !isslice(n->right->type))
 				yyerror("arguments to copy must be slices; have %lT, %lT", n->left->type, n->right->type);
 			else if(!isslice(n->left->type))
 				yyerror("first argument to copy should be slice; have %lT", n->left->type);
 			else
-				yyerror("second argument to copy should be slice; have %lT", n->right->type);
+				yyerror("second argument to copy should be slice or string; have %lT", n->right->type);
 			goto error;
 		}
 		if(!eqtype(n->left->type->type, n->right->type->type)) {
diff --git a/src/cmd/gc/walk.c b/src/cmd/gc/walk.c
index 4588ac1c18f..bf20102c7da 100644
--- a/src/cmd/gc/walk.c
+++ b/src/cmd/gc/walk.c
@@ -1261,7 +1261,10 @@ walkexpr(Node **np, NodeList **init)
 		goto ret;
 
 	case OCOPY:
-		fn = syslook("slicecopy", 1);
+		if(n->right->type->etype == TSTRING)
+			fn = syslook("slicestringcopy", 1);
+		else
+			fn = syslook("slicecopy", 1);
 		argtype(fn, n->left->type);
 		argtype(fn, n->right->type);
 		n = mkcall1(fn, n->type, init,
diff --git a/src/pkg/runtime/slice.c b/src/pkg/runtime/slice.c
index 67e44e93c09..d0ba4ede3f8 100644
--- a/src/pkg/runtime/slice.c
+++ b/src/pkg/runtime/slice.c
@@ -217,6 +217,24 @@ out:
 	}
 }
 
+void
+·slicestringcopy(Slice to, String fm, int32 ret)
+{
+	if(fm.len == 0 || to.len == 0) {
+		ret = 0;
+		goto out;
+	}
+	
+	ret = fm.len;
+	if(to.len < ret)
+		ret = to.len;
+	
+	memmove(to.array, fm.str, ret);
+
+out:
+	FLUSH(&ret);
+}
+
 void
 ·printslice(Slice a)
 {