renamed String.h to FollyString.h

folly/FollyString.h

@@ -0,0 +1,397 @@
+/*
+ * Copyright 2012 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef FOLLY_BASE_STRING_H_
+#define FOLLY_BASE_STRING_H_
+
+#include <string>
+#include <boost/type_traits.hpp>
+
+#ifdef __GNUC__
+# include <ext/hash_set>
+# include <ext/hash_map>
+#endif
+
+#include "folly/Conv.h"
+#include "folly/FBString.h"
+#include "folly/FBVector.h"
+#include "folly/Range.h"
+#include "folly/ScopeGuard.h"
+
+// Compatibility function, to make sure toStdString(s) can be called
+// to convert a std::string or fbstring variable s into type std::string
+// with very little overhead if s was already std::string
+namespace folly {
+
+inline
+std::string toStdString(const folly::fbstring& s) {
+  return std::string(s.data(), s.size());
+}
+
+inline
+const std::string& toStdString(const std::string& s) {
+  return s;
+}
+
+// If called with a temporary, the compiler will select this overload instead
+// of the above, so we don't return a (lvalue) reference to a temporary.
+inline
+std::string&& toStdString(std::string&& s) {
+  return std::move(s);
+}
+
+/**
+ * C-Escape a string, making it suitable for representation as a C string
+ * literal.  Appends the result to the output string.
+ *
+ * Backslashes all occurrences of backslash and double-quote:
+ *   "  ->  \"
+ *   \  ->  \\
+ *
+ * Replaces all non-printable ASCII characters with backslash-octal
+ * representation:
+ *   <ASCII 254> -> \376
+ *
+ * Note that we use backslash-octal instead of backslash-hex because the octal
+ * representation is guaranteed to consume no more than 3 characters; "\3760"
+ * represents two characters, one with value 254, and one with value 48 ('0'),
+ * whereas "\xfe0" represents only one character (with value 4064, which leads
+ * to implementation-defined behavior).
+ */
+template <class String>
+void cEscape(StringPiece str, String& out);
+
+/**
+ * Similar to cEscape above, but returns the escaped string.
+ */
+template <class String>
+String cEscape(StringPiece str) {
+  String out;
+  cEscape(str, out);
+  return out;
+}
+
+/**
+ * C-Unescape a string; the opposite of cEscape above.  Appends the result
+ * to the output string.
+ *
+ * Recognizes the standard C escape sequences:
+ *
+ * \' \" \? \\ \a \b \f \n \r \t \v
+ * \[0-7]+
+ * \x[0-9a-fA-F]+
+ *
+ * In strict mode (default), throws std::invalid_argument if it encounters
+ * an unrecognized escape sequence.  In non-strict mode, it leaves
+ * the escape sequence unchanged.
+ */
+template <class String>
+void cUnescape(StringPiece str, String& out, bool strict = true);
+
+/**
+ * Similar to cUnescape above, but returns the escaped string.
+ */
+template <class String>
+String cUnescape(StringPiece str, bool strict = true) {
+  String out;
+  cUnescape(str, out, strict);
+  return out;
+}
+
+/**
+ * stringPrintf is much like printf but deposits its result into a
+ * string. Two signatures are supported: the first simply returns the
+ * resulting string, and the second appends the produced characters to
+ * the specified string and returns a reference to it.
+ */
+std::string stringPrintf(const char* format, ...)
+  __attribute__ ((format (printf, 1, 2)));
+
+/** Similar to stringPrintf, with different signiture.
+  */
+void stringPrintf(std::string* out, const char* fmt, ...)
+  __attribute__ ((format (printf, 2, 3)));
+
+std::string& stringAppendf(std::string* output, const char* format, ...)
+  __attribute__ ((format (printf, 2, 3)));
+
+/**
+ * Backslashify a string, that is, replace non-printable characters
+ * with C-style (but NOT C compliant) "\xHH" encoding.  If hex_style
+ * is false, then shorthand notations like "\0" will be used instead
+ * of "\x00" for the most common backslash cases.
+ *
+ * There are two forms, one returning the input string, and one
+ * creating output in the specified output string.
+ *
+ * This is mainly intended for printing to a terminal, so it is not
+ * particularly optimized.
+ *
+ * Do *not* use this in situations where you expect to be able to feed
+ * the string to a C or C++ compiler, as there are nuances with how C
+ * parses such strings that lead to failures.  This is for display
+ * purposed only.  If you want a string you can embed for use in C or
+ * C++, use cEscape instead.  This function is for display purposes
+ * only.
+ */
+template <class String1, class String2>
+void backslashify(const String1& input, String2& output, bool hex_style=false);
+
+template <class String>
+String backslashify(const String& input, bool hex_style=false) {
+  String output;
+  backslashify(input, output, hex_style);
+  return output;
+}
+
+/**
+ * Take a string and "humanify" it -- that is, make it look better.
+ * Since "better" is subjective, caveat emptor.  The basic approach is
+ * to count the number of unprintable characters.  If there are none,
+ * then the output is the input.  If there are relatively few, or if
+ * there is a long "enough" prefix of printable characters, use
+ * backslashify.  If it is mostly binary, then simply hex encode.
+ *
+ * This is an attempt to make a computer smart, and so likely is wrong
+ * most of the time.
+ */
+template <class String1, class String2>
+void humanify(const String1& input, String2& output);
+
+template <class String>
+String humanify(const String& input) {
+  String output;
+  humanify(input, output);
+  return output;
+}
+
+/**
+ * Same functionality as Python's binascii.hexlify.  Returns true
+ * on successful conversion.
+ *
+ * If append_output is true, append data to the output rather than
+ * replace it.
+ */
+template<class InputString, class OutputString>
+bool hexlify(const InputString& input, OutputString& output,
+             bool append=false);
+
+/**
+ * Same functionality as Python's binascii.unhexlify.  Returns true
+ * on successful conversion.
+ */
+template<class InputString, class OutputString>
+bool unhexlify(const InputString& input, OutputString& output);
+
+/*
+ * A pretty-printer for numbers that appends suffixes of units of the
+ * given type.  It prints 4 sig-figs of value with the most
+ * appropriate unit.
+ *
+ * If `addSpace' is true, we put a space between the units suffix and
+ * the value.
+ *
+ * Current types are:
+ *   PRETTY_TIME         - s, ms, us, ns, etc.
+ *   PRETTY_BYTES_METRIC - kB, MB, GB, etc (goes up by 10^3 = 1000 each time)
+ *   PRETTY_BYTES        - kB, MB, GB, etc (goes up by 2^10 = 1024 each time)
+ *   PRETTY_BYTES_IEC    - KiB, MiB, GiB, etc
+ *   PRETTY_UNITS_METRIC - k, M, G, etc (goes up by 10^3 = 1000 each time)
+ *   PRETTY_UNITS_BINARY - k, M, G, etc (goes up by 2^10 = 1024 each time)
+ *   PRETTY_UNITS_BINARY_IEC - Ki, Mi, Gi, etc
+ *
+ * @author Mark Rabkin <[email protected]>
+ */
+enum PrettyType {
+  PRETTY_TIME,
+
+  PRETTY_BYTES_METRIC,
+  PRETTY_BYTES_BINARY,
+  PRETTY_BYTES = PRETTY_BYTES_BINARY,
+  PRETTY_BYTES_BINARY_IEC,
+  PRETTY_BYTES_IEC = PRETTY_BYTES_BINARY_IEC,
+
+  PRETTY_UNITS_METRIC,
+  PRETTY_UNITS_BINARY,
+  PRETTY_UNITS_BINARY_IEC,
+
+  PRETTY_NUM_TYPES
+};
+
+std::string prettyPrint(double val, PrettyType, bool addSpace = true);
+
+/**
+ * Write a hex dump of size bytes starting at ptr to out.
+ *
+ * The hex dump is formatted as follows:
+ *
+ * for the string "abcdefghijklmnopqrstuvwxyz\x02"
+00000000  61 62 63 64 65 66 67 68  69 6a 6b 6c 6d 6e 6f 70  |abcdefghijklmnop|
+00000010  71 72 73 74 75 76 77 78  79 7a 02                 |qrstuvwxyz.     |
+ *
+ * that is, we write 16 bytes per line, both as hex bytes and as printable
+ * characters.  Non-printable characters are replaced with '.'
+ * Lines are written to out one by one (one StringPiece at a time) without
+ * delimiters.
+ */
+template <class OutIt>
+void hexDump(const void* ptr, size_t size, OutIt out);
+
+/**
+ * Return the hex dump of size bytes starting at ptr as a string.
+ */
+std::string hexDump(const void* ptr, size_t size);
+
+/**
+ * Return a fbstring containing the description of the given errno value.
+ * Takes care not to overwrite the actual system errno, so calling
+ * errnoStr(errno) is valid.
+ */
+fbstring errnoStr(int err);
+
+/**
+ * Return the demangled (prettyfied) version of a C++ type.
+ *
+ * This function tries to produce a human-readable type, but the type name will
+ * be returned unchanged in case of error or if demangling isn't supported on
+ * your system.
+ *
+ * Use for debugging -- do not rely on demangle() returning anything useful.
+ *
+ * This function may allocate memory (and therefore throw).
+ */
+fbstring demangle(const char* name);
+inline fbstring demangle(const std::type_info& type) {
+  return demangle(type.name());
+}
+
+/**
+ * Debug string for an exception: include type and what().
+ */
+inline fbstring exceptionStr(const std::exception& e) {
+  return folly::to<fbstring>(demangle(typeid(e)), ": ", e.what());
+}
+
+/*
+ * Split a string into a list of tokens by delimiter.
+ *
+ * The split interface here supports different output types, selected
+ * at compile time: StringPiece, fbstring, or std::string.  If you are
+ * using a vector to hold the output, it detects the type based on
+ * what your vector contains.  If the output vector is not empty, split
+ * will append to the end of the vector.
+ *
+ * You can also use splitTo() to write the output to an arbitrary
+ * OutputIterator (e.g. std::inserter() on a std::set<>), in which
+ * case you have to tell the function the type.  (Rationale:
+ * OutputIterators don't have a value_type, so we can't detect the
+ * type in splitTo without being told.)
+ *
+ * Examples:
+ *
+ *   std::vector<folly::StringPiece> v;
+ *   folly::split(":", "asd:bsd", v);
+ *
+ *   std::set<StringPiece> s;
+ *   folly::splitTo<StringPiece>(":", "asd:bsd:asd:csd",
+ *    std::inserter(s, s.begin()));
+ *
+ * Split also takes a flag (ignoreEmpty) that indicates whether adjacent
+ * delimiters should be treated as one single separator (ignoring empty tokens)
+ * or not (generating empty tokens).
+ */
+
+template<class Delim, class String, class OutputType>
+void split(const Delim& delimiter,
+           const String& input,
+           std::vector<OutputType>& out,
+           bool ignoreEmpty = false);
+
+template<class Delim, class String, class OutputType>
+void split(const Delim& delimiter,
+           const String& input,
+           folly::fbvector<OutputType>& out,
+           bool ignoreEmpty = false);
+
+template<class OutputValueType, class Delim, class String,
+         class OutputIterator>
+void splitTo(const Delim& delimiter,
+             const String& input,
+             OutputIterator out,
+             bool ignoreEmpty = false);
+
+/*
+ * Join list of tokens.
+ *
+ * Stores a string representation of tokens in the same order with
+ * deliminer between each element.
+ */
+
+template <class Delim, class Iterator, class String>
+void join(const Delim& delimiter,
+          Iterator begin,
+          Iterator end,
+          String& output);
+
+template <class Delim, class Container, class String>
+void join(const Delim& delimiter,
+          const Container& container,
+          String& output) {
+  join(delimiter, container.begin(), container.end(), output);
+}
+
+template <class Delim, class Container>
+std::string join(const Delim& delimiter,
+                 const Container& container) {
+  std::string output;
+  join(delimiter, container.begin(), container.end(), output);
+  return output;
+}
+
+} // namespace folly
+
+// Hash functions for string and fbstring usable with e.g. hash_map
+#ifdef __GNUC__
+namespace __gnu_cxx {
+
+template <class C>
+struct hash<folly::basic_fbstring<C> > : private hash<const C*> {
+  size_t operator()(const folly::basic_fbstring<C> & s) const {
+    return hash<const C*>::operator()(s.c_str());
+  }
+};
+
+template <class C>
+struct hash<std::basic_string<C> > : private hash<const C*> {
+  size_t operator()(const std::basic_string<C> & s) const {
+    return hash<const C*>::operator()(s.c_str());
+  }
+};
+
+} // namespace __gnu_cxx
+#endif
+
+// Hook into boost's type traits
+namespace boost {
+template <class T>
+struct has_nothrow_constructor<folly::basic_fbstring<T> > : true_type {
+  enum { value = true };
+};
+} // namespace boost
+
+#include "folly/String-inl.h"
+
+#endif