commit 6b55ba54eff4657cffe053b71e1c9cce2944a8a9
author Dan Albert <danalbert@google.com> Sun Jul 20 11:51:26 2014 -0700
committer Dan Albert <danalbert@google.com> Mon Jul 21 11:45:48 2014 -0700
tree cec574487f5fe5c039a9b2acd90ea4dbe22e8066
parent 7dd126a38ca501818b07927f310dcc0f531c0f1f

Fix mbsrtowcs(3)'s handling of len parameter.

The len parameter is a _maximum_ length. The previous code was treating
it as an exact length, causing the following typical call to fail:

    mbsrtowcs(out, &in, sizeof(out), state); // sizeof(out) > strlen(in)

Change-Id: I48e474fd54ea5f122bc168a4d74bfe08704f28cc

libc/bionic/wchar.cpp

diff --git a/libc/bionic/wchar.cpp b/libc/bionic/wchar.cpp
index ecb8b33..438ce03 100644
--- a/libc/bionic/wchar.cpp
+++ b/libc/bionic/wchar.cpp
@@ -116,11 +116,10 @@
     if (static_cast<uint8_t>((*src)[i]) < 0x80) {
       // Fast path for plain ASCII characters.
       dst[o] = (*src)[i];
-      if ((*src)[i] == '\0') {
-        *src = NULL;
-        return reset_and_return_illegal(EILSEQ, state);
-      }
       r = 1;
+      if ((*src)[i] == '\0') {
+        break;
+      }
     } else {
       r = mbrtowc(dst + o, *src + i, nmc - i, state);
       if (r == __MB_ERR_ILLEGAL_SEQUENCE) {