ICU-410 add API facades for string unescaping

X-SVN-Rev: 1707

icu4c/source/common/unicode/unistr.h

@@ -71,6 +71,25 @@ U_COMMON_API ostream &operator<<(ostream& stream, const UnicodeString& s);
 #   define UNICODE_STRING(cs, length) UnicodeString(cs, length, "")
 #endif
 
+/**
+ * Unescape an entire string.
+ * ### TBD
+ */
+U_COMMON_API UnicodeString
+u_unescape(const UnicodeString &s);
+
+/**
+ * Unescape one escape sequence in a string and return the code point.
+ * <code>s[offset]</code> must be the beginning of an escape sequence.
+ * <code>offset</code> is advanced to the first character after the
+ * escape sequence.
+ * If an error occurs, then U+ffff is returned and the offset is not
+ * advanced.
+ * ### TBD
+ */
+U_COMMON_API UChar32
+u_unescape(const UnicodeString &s, int32_t &offset);
+
 /**
  * UnicodeString is a concrete implementation of the abstract class Replaceable.
  * It is a string class that stores Unicode characters directly and provides

icu4c/source/common/unicode/ustring.h

@@ -232,4 +232,13 @@ U_CAPI char* U_EXPORT2 u_austrcpy(char *s1,
 #   define U_STRING_INIT(var, cs, length) u_charsToUChars(cs, var, length+1)
 #endif
 
+/**
+ * Unescape a string of invariant characters and write
+ * the resulting Unicode characters to the destination.
+ * ### TBD
+ */
+U_CAPI int32_t U_EXPORT2
+u_unescapeChars(const char *s,
+                UChar *dest, int32_t destSize);
+
 #endif

icu4c/source/common/unistr.cpp

@@ -85,6 +85,21 @@ us_arrayCopy(const UChar *src, int32_t srcStart,
 
 UConverter* UnicodeString::fgDefaultConverter  = 0;
 
+//========================================
+// Unescaping
+//========================================
+U_COMMON_API UnicodeString
+u_unescape(const UnicodeString &s) {
+  /* ### TBD */
+  return s;
+}
+
+U_COMMON_API UChar32
+u_unescape(const UnicodeString &s, int32_t &offset) {
+  /* ### TBD */
+  return 0xffff;
+}
+
 //========================================
 // Constructors
 //========================================

icu4c/source/common/ustring.c

@@ -326,3 +326,10 @@ releaseDefaultConverter(UConverter *converter)
     ucnv_close(converter);
   }
 }
+
+U_CAPI int32_t U_EXPORT2
+u_unescapeChars(const char *s,
+                UChar *dest, int32_t destSize) {
+  /* ### TBD */
+  return 0;
+}