Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 343 insertions, 0 deletions

diff --git a/intl/icu/source/common/unicode/stringpiece.h b/intl/icu/source/common/unicode/stringpiece.h
new file mode 100644
index 0000000000..df7f36089d
--- /dev/null
+++ b/intl/icu/source/common/unicode/stringpiece.h
@@ -0,0 +1,343 @@
+// © 2016 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
+// Copyright (C) 2009-2013, International Business Machines
+// Corporation and others. All Rights Reserved.
+//
+// Copyright 2001 and onwards Google Inc.
+// Author: Sanjay Ghemawat
+
+// This code is a contribution of Google code, and the style used here is
+// a compromise between the original Google code and the ICU coding guidelines.
+// For example, data types are ICU-ified (size_t,int->int32_t),
+// and API comments doxygen-ified, but function names and behavior are
+// as in the original, if possible.
+// Assertion-style error handling, not available in ICU, was changed to
+// parameter "pinning" similar to UnicodeString.
+//
+// In addition, this is only a partial port of the original Google code,
+// limited to what was needed so far. The (nearly) complete original code
+// is in the ICU svn repository at icuhtml/trunk/design/strings/contrib
+// (see ICU ticket 6765, r25517).
+
+#ifndef __STRINGPIECE_H__
+#define __STRINGPIECE_H__
+
+/**
+ * \file 
+ * \brief C++ API: StringPiece: Read-only byte string wrapper class.
+ */
+
+#include "unicode/utypes.h"
+
+#if U_SHOW_CPLUSPLUS_API
+
+#include <cstddef>
+#include <type_traits>
+
+#include "unicode/uobject.h"
+#include "unicode/std_string.h"
+
+// Arghh!  I wish C++ literals were "string".
+
+U_NAMESPACE_BEGIN
+
+/**
+ * A string-like object that points to a sized piece of memory.
+ *
+ * We provide non-explicit singleton constructors so users can pass
+ * in a "const char*" or a "string" wherever a "StringPiece" is
+ * expected.
+ *
+ * Functions or methods may use StringPiece parameters to accept either a
+ * "const char*" or a "string" value that will be implicitly converted to a
+ * StringPiece.
+ *
+ * Systematic usage of StringPiece is encouraged as it will reduce unnecessary
+ * conversions from "const char*" to "string" and back again.
+ *
+ * @stable ICU 4.2
+ */
+class U_COMMON_API StringPiece : public UMemory {
+ private:
+  const char*   ptr_;
+  int32_t       length_;
+
+ public:
+  /**
+   * Default constructor, creates an empty StringPiece.
+   * @stable ICU 4.2
+   */
+  StringPiece() : ptr_(nullptr), length_(0) { }
+
+  /**
+   * Constructs from a NUL-terminated const char * pointer.
+   * @param str a NUL-terminated const char * pointer
+   * @stable ICU 4.2
+   */
+  StringPiece(const char* str);
+#if defined(__cpp_char8_t) || defined(U_IN_DOXYGEN)
+  /**
+   * Constructs from a NUL-terminated const char8_t * pointer.
+   * @param str a NUL-terminated const char8_t * pointer
+   * @stable ICU 67
+   */
+  StringPiece(const char8_t* str) : StringPiece(reinterpret_cast<const char*>(str)) {}
+#endif
+  /**
+   * Constructs an empty StringPiece.
+   * Needed for type disambiguation from multiple other overloads.
+   * @param p nullptr
+   * @stable ICU 67
+   */
+  StringPiece(std::nullptr_t p) : ptr_(p), length_(0) {}
+
+  /**
+   * Constructs from a std::string.
+   * @stable ICU 4.2
+   */
+  StringPiece(const std::string& str)
+    : ptr_(str.data()), length_(static_cast<int32_t>(str.size())) { }
+#if defined(__cpp_lib_char8_t) || defined(U_IN_DOXYGEN)
+  /**
+   * Constructs from a std::u8string.
+   * @stable ICU 67
+   */
+  StringPiece(const std::u8string& str)
+    : ptr_(reinterpret_cast<const char*>(str.data())),
+      length_(static_cast<int32_t>(str.size())) { }
+#endif
+
+  /**
+   * Constructs from some other implementation of a string piece class, from any
+   * C++ record type that has these two methods:
+   *
+   * \code{.cpp}
+   *
+   *   struct OtherStringPieceClass {
+   *     const char* data();  // or const char8_t*
+   *     size_t size();
+   *   };
+   *
+   * \endcode
+   *
+   * The other string piece class will typically be std::string_view from C++17
+   * or absl::string_view from Abseil.
+   *
+   * Starting with C++20, data() may also return a const char8_t* pointer,
+   * as from std::u8string_view.
+   *
+   * @param str the other string piece
+   * @stable ICU 65
+   */
+  template <typename T,
+            typename = typename std::enable_if<
+                (std::is_same<decltype(T().data()), const char*>::value
+#if defined(__cpp_char8_t)
+                    || std::is_same<decltype(T().data()), const char8_t*>::value
+#endif
+                ) &&
+                std::is_same<decltype(T().size()), size_t>::value>::type>
+  StringPiece(T str)
+      : ptr_(reinterpret_cast<const char*>(str.data())),
+        length_(static_cast<int32_t>(str.size())) {}
+
+  /**
+   * Constructs from a const char * pointer and a specified length.
+   * @param offset a const char * pointer (need not be terminated)
+   * @param len the length of the string; must be non-negative
+   * @stable ICU 4.2
+   */
+  StringPiece(const char* offset, int32_t len) : ptr_(offset), length_(len) { }
+#if defined(__cpp_char8_t) || defined(U_IN_DOXYGEN)
+  /**
+   * Constructs from a const char8_t * pointer and a specified length.
+   * @param str a const char8_t * pointer (need not be terminated)
+   * @param len the length of the string; must be non-negative
+   * @stable ICU 67
+   */
+  StringPiece(const char8_t* str, int32_t len) :
+      StringPiece(reinterpret_cast<const char*>(str), len) {}
+#endif
+
+  /**
+   * Substring of another StringPiece.
+   * @param x the other StringPiece
+   * @param pos start position in x; must be non-negative and <= x.length().
+   * @stable ICU 4.2
+   */
+  StringPiece(const StringPiece& x, int32_t pos);
+  /**
+   * Substring of another StringPiece.
+   * @param x the other StringPiece
+   * @param pos start position in x; must be non-negative and <= x.length().
+   * @param len length of the substring;
+   *            must be non-negative and will be pinned to at most x.length() - pos.
+   * @stable ICU 4.2
+   */
+  StringPiece(const StringPiece& x, int32_t pos, int32_t len);
+
+  /**
+   * Returns the string pointer. May be nullptr if it is empty.
+   *
+   * data() may return a pointer to a buffer with embedded NULs, and the
+   * returned buffer may or may not be null terminated.  Therefore it is
+   * typically a mistake to pass data() to a routine that expects a NUL
+   * terminated string.
+   * @return the string pointer
+   * @stable ICU 4.2
+   */
+  const char* data() const { return ptr_; }
+  /**
+   * Returns the string length. Same as length().
+   * @return the string length
+   * @stable ICU 4.2
+   */
+  int32_t size() const { return length_; }
+  /**
+   * Returns the string length. Same as size().
+   * @return the string length
+   * @stable ICU 4.2
+   */
+  int32_t length() const { return length_; }
+  /**
+   * Returns whether the string is empty.
+   * @return true if the string is empty
+   * @stable ICU 4.2
+   */
+  UBool empty() const { return length_ == 0; }
+
+  /**
+   * Sets to an empty string.
+   * @stable ICU 4.2
+   */
+  void clear() { ptr_ = nullptr; length_ = 0; }
+
+  /**
+   * Reset the stringpiece to refer to new data.
+   * @param xdata pointer the new string data.  Need not be nul terminated.
+   * @param len the length of the new data
+   * @stable ICU 4.8
+   */
+  void set(const char* xdata, int32_t len) { ptr_ = xdata; length_ = len; }
+
+  /**
+   * Reset the stringpiece to refer to new data.
+   * @param str a pointer to a NUL-terminated string. 
+   * @stable ICU 4.8
+   */
+  void set(const char* str);
+
+#if defined(__cpp_char8_t) || defined(U_IN_DOXYGEN)
+  /**
+   * Resets the stringpiece to refer to new data.
+   * @param xdata pointer the new string data. Need not be NUL-terminated.
+   * @param len the length of the new data
+   * @stable ICU 67
+   */
+  inline void set(const char8_t* xdata, int32_t len) {
+      set(reinterpret_cast<const char*>(xdata), len);
+  }
+
+  /**
+   * Resets the stringpiece to refer to new data.
+   * @param str a pointer to a NUL-terminated string.
+   * @stable ICU 67
+   */
+  inline void set(const char8_t* str) {
+      set(reinterpret_cast<const char*>(str));
+  }
+#endif
+
+  /**
+   * Removes the first n string units.
+   * @param n prefix length, must be non-negative and <=length()
+   * @stable ICU 4.2
+   */
+  void remove_prefix(int32_t n) {
+    if (n >= 0) {
+      if (n > length_) {
+        n = length_;
+      }
+      ptr_ += n;
+      length_ -= n;
+    }
+  }
+
+  /**
+   * Removes the last n string units.
+   * @param n suffix length, must be non-negative and <=length()
+   * @stable ICU 4.2
+   */
+  void remove_suffix(int32_t n) {
+    if (n >= 0) {
+      if (n <= length_) {
+        length_ -= n;
+      } else {
+        length_ = 0;
+      }
+    }
+  }
+
+  /**
+   * Searches the StringPiece for the given search string (needle);
+   * @param needle The string for which to search.
+   * @param offset Where to start searching within this string (haystack).
+   * @return The offset of needle in haystack, or -1 if not found.
+   * @stable ICU 67
+   */
+  int32_t find(StringPiece needle, int32_t offset);
+
+  /**
+   * Compares this StringPiece with the other StringPiece, with semantics
+   * similar to std::string::compare().
+   * @param other The string to compare to.
+   * @return below zero if this < other; above zero if this > other; 0 if this == other.
+   * @stable ICU 67
+   */
+  int32_t compare(StringPiece other);
+
+  /**
+   * Maximum integer, used as a default value for substring methods.
+   * @stable ICU 4.2
+   */
+  static const int32_t npos; // = 0x7fffffff;
+
+  /**
+   * Returns a substring of this StringPiece.
+   * @param pos start position; must be non-negative and <= length().
+   * @param len length of the substring;
+   *            must be non-negative and will be pinned to at most length() - pos.
+   * @return the substring StringPiece
+   * @stable ICU 4.2
+   */
+  StringPiece substr(int32_t pos, int32_t len = npos) const {
+    return StringPiece(*this, pos, len);
+  }
+};
+
+/**
+ * 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
+ * @stable ICU 4.8
+ */
+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
+ * @stable ICU 4.8
+ */
+inline bool operator!=(const StringPiece& x, const StringPiece& y) {
+  return !(x == y);
+}
+
+U_NAMESPACE_END
+
+#endif /* U_SHOW_CPLUSPLUS_API */
+
+#endif  // __STRINGPIECE_H__