ICU-7404 add set functions to StringPiece.

X-SVN-Rev: 27642

icu4c/source/common/stringpiece.cpp

@@ -1,4 +1,4 @@
-// Copyright (C) 2009, International Business Machines
+// Copyright (C) 2009-2010, International Business Machines
 // Corporation and others. All Rights Reserved.
 //
 // Copyright 2004 and onwards Google Inc.
@@ -9,6 +9,7 @@
 #include "unicode/utypes.h"
 #include "unicode/stringpiece.h"
 #include "cstring.h"
+#include "cmemory.h"
 
 U_NAMESPACE_BEGIN
 
@@ -40,6 +41,29 @@ StringPiece::StringPiece(const StringPiece& x, int32_t pos, int32_t len) {
   length_ = len;
 }
 
+void StringPiece::set(const char* str) {
+  ptr_ = str;
+  if (str != NULL)
+    length_ = static_cast<int32_t>(uprv_strlen(str));
+  else
+    length_ = 0;
+}
+
+U_EXPORT UBool U_EXPORT2
+operator==(const StringPiece& x, const StringPiece& y) {
+  int32_t len = x.size();
+  if (len != y.size()) {
+    return false;
+  }
+  const char* p = x.data();
+  const char* p2 = y.data();
+  // Test last byte in case strings share large common prefix
+  if ((len > 0) && (p[len-1] != p2[len-1])) return false;
+  // At this point we can, but don't have to, ignore the last byte.
+  return uprv_memcmp(p, p2, len-1) == 0;
+}
+
+
 /* Microsft Visual Studios <= 8.0 complains about redefinition of this
  * static const class variable. However, the C++ standard states that this 
  * definition is correct. Perhaps there is a bug in the Microsoft compiler. 

icu4c/source/common/unicode/stringpiece.h

@@ -134,6 +134,21 @@ class U_COMMON_API StringPiece : public UMemory {
    */
   void clear() { ptr_ = NULL; length_ = 0; }
 
+  /**
+   * Reset the stringpiece to refer to new data.
+   * @param data pointer the new string data.  Need not be nul terminated.
+   * @param len the length of the new data
+   * @internal
+   */
+  void set(const char* data, int32_t len) { ptr_ = data; length_ = len; }
+
+  /**
+   * Reset the stringpiece to refer to new data.
+   * @param str a pointer to a NUL-terminated string. 
+   * @internal
+   */
+  void set(const char* str);
+
   /**
    * Removes the first n string units.
    * @param n prefix length, must be non-negative and <=length()
@@ -183,6 +198,27 @@ class U_COMMON_API StringPiece : public UMemory {
   }
 };
 
+/**
+ * Global operator == for StringPiece
+ * @param x The first StringPiece to compare.
+ * @param y The second StringPiece to compare.
+ * @return TRUE if the string data is equal
+ * @internal
+ */
+U_EXPORT UBool U_EXPORT2 
+operator==(const StringPiece& x, const StringPiece& y);
+
+/**
+ * Global operator != for StringPiece
+ * @param x The first StringPiece to compare.
+ * @param y The second StringPiece to compare.
+ * @return TRUE if the string data is not equal
+ * @internal
+ */
+inline UBool operator!=(const StringPiece& x, const StringPiece& y) {
+  return !(x == y);
+}
+
 U_NAMESPACE_END
 
 #endif  // __STRINGPIECE_H__