Move string utility file (#4164)

Moves the string file to string.h. This is required since other required utilities will soon need to be added to regexp.h.

1 files changed, 271 insertions, 0 deletions

diff --git a/src/util/string.h b/src/util/string.h
new file mode 100644
index 000000000..032105812
--- /dev/null
+++ b/src/util/string.h
@@ -0,0 +1,271 @@
+/*********************                                                        */
+/*! \file string.h
+ ** \verbatim
+ ** Top contributors (to current version):
+ **   Andrew Reynolds, Tim King, Tianyi Liang
+ ** This file is part of the CVC4 project.
+ ** Copyright (c) 2009-2019 by the authors listed in the file AUTHORS
+ ** in the top-level source directory) and their institutional affiliations.
+ ** All rights reserved.  See the file COPYING in the top-level source
+ ** directory for licensing information.\endverbatim
+ **
+ ** \brief The string data type.
+ **/
+
+#include "cvc4_public.h"
+
+#ifndef CVC4__UTIL__STRING_H
+#define CVC4__UTIL__STRING_H
+
+#include <cstddef>
+#include <functional>
+#include <ostream>
+#include <string>
+#include <vector>
+#include "util/rational.h"
+
+namespace CVC4 {
+
+/** The CVC4 string class
+ *
+ * This data structure is the domain of values for the string type. It can also
+ * be used as a generic utility for representing strings.
+ */
+class CVC4_PUBLIC String {
+ public:
+  /**
+   * This is the cardinality of the alphabet that is representable by this
+   * class. Notice that this must be greater than or equal to the cardinality
+   * of the alphabet that the string theory reasons about.
+   *
+   * This must be strictly less than std::numeric_limits<unsigned>::max().
+   *
+   * As per the SMT-LIB standard for strings, we support the first 3 planes of
+   * Unicode characters, where 196608 = 3*16^4.
+   */
+  static inline unsigned num_codes() { return 196608; }
+  /** constructors for String
+   *
+   * Internally, a CVC4::String is represented by a vector of unsigned
+   * integers (d_str) representing the code points of the characters.
+   *
+   * To build a string from a C++ string, we may process escape sequences
+   * according to the SMT-LIB standard. In particular, if useEscSequences is
+   * true, we convert unicode escape sequences:
+   *  \u d_3 d_2 d_1 d_0
+   *  \u{d_0}
+   *  \u{d_1 d_0}
+   *  \u{d_2 d_1 d_0}
+   *  \u{d_3 d_2 d_1 d_0}
+   *  \u{d_4 d_3 d_2 d_1 d_0}
+   * where d_0 ... d_4 are hexidecimal digits, to the appropriate character.
+   *
+   * If useEscSequences is false, then the characters of the constructed
+   * CVC4::String correspond one-to-one with the input string.
+   */
+  String() = default;
+  explicit String(const std::string& s, bool useEscSequences = false)
+      : d_str(toInternal(s, useEscSequences))
+  {
+  }
+  explicit String(const char* s, bool useEscSequences = false)
+      : d_str(toInternal(std::string(s), useEscSequences))
+  {
+  }
+  explicit String(const std::vector<unsigned>& s);
+
+  String& operator=(const String& y) {
+    if (this != &y) {
+      d_str = y.d_str;
+    }
+    return *this;
+  }
+
+  String concat(const String& other) const;
+
+  bool operator==(const String& y) const { return cmp(y) == 0; }
+  bool operator!=(const String& y) const { return cmp(y) != 0; }
+  bool operator<(const String& y) const { return cmp(y) < 0; }
+  bool operator>(const String& y) const { return cmp(y) > 0; }
+  bool operator<=(const String& y) const { return cmp(y) <= 0; }
+  bool operator>=(const String& y) const { return cmp(y) >= 0; }
+
+  /**
+   * Returns true if this string is equal to y for their first n characters.
+   * If n is larger than the length of this string or y, this method returns
+   * true if and only if this string is equal to y.
+   */
+  bool strncmp(const String& y, std::size_t n) const;
+  /**
+   * Returns true if this string is equal to y for their last n characters.
+   * Similar to strncmp, if n is larger than the length of this string or y,
+   * this method returns true if and only if this string is equal to y.
+   */
+  bool rstrncmp(const String& y, std::size_t n) const;
+
+  /* toString
+   * Converts this string to a std::string.
+   *
+   * The unprintable characters are converted to unicode escape sequences as
+   * described above.
+   *
+   * If useEscSequences is false, the string's printable characters are
+   * printed as characters. Notice that for all std::string s having only
+   * printable characters, we have that
+   *    CVC4::String( s ).toString() = s.
+   */
+  std::string toString(bool useEscSequences = false) const;
+  /** is this the empty string? */
+  bool empty() const { return d_str.empty(); }
+  /** is this the empty string? */
+  bool isEmptyString() const { return empty(); }
+  /** is less than or equal to string y */
+  bool isLeq(const String& y) const;
+  /** Return the length of the string */
+  std::size_t size() const { return d_str.size(); }
+
+  bool isRepeated() const;
+  bool tailcmp(const String& y, int& c) const;
+
+  /**
+   * Return the first position y occurs in this string, or std::string::npos
+   * otherwise.
+   */
+  std::size_t find(const String& y, const std::size_t start = 0) const;
+  /**
+   * Return the first position y occurs in this string searching from the end,
+   * or std::string::npos otherwise.
+   */
+  std::size_t rfind(const String& y, const std::size_t start = 0) const;
+  /** Returns true if y is a prefix of this */
+  bool hasPrefix(const String& y) const;
+  /** Returns true if y is a suffix of this */
+  bool hasSuffix(const String& y) const;
+  /** Replace the first occurrence of s in this string with t */
+  String replace(const String& s, const String& t) const;
+  /** Return the substring of this string starting at index i */
+  String substr(std::size_t i) const;
+  /** Return the substring of this string starting at index i with size at most
+   * j */
+  String substr(std::size_t i, std::size_t j) const;
+  /** Return the prefix of this string of size at most i */
+  String prefix(std::size_t i) const { return substr(0, i); }
+  /** Return the suffix of this string of size at most i */
+  String suffix(std::size_t i) const { return substr(size() - i, i); }
+
+  /**
+   * Checks if there is any overlap between this string and another string. This
+   * corresponds to checking whether one string contains the other and whether a
+   * substring of one is a prefix of the other and vice-versa.
+   *
+   * @param y The other string
+   * @return True if there is an overlap, false otherwise
+   */
+  bool noOverlapWith(const String& y) const;
+
+  /** string overlap
+  *
+  * if overlap returns m>0,
+  * then the maximal suffix of this string that is a prefix of y is of length m.
+  *
+  * For example, if x is "abcdef", then:
+  * x.overlap("defg") = 3
+  * x.overlap("ab") = 0
+  * x.overlap("d") = 0
+  * x.overlap("bcdefdef") = 5
+  */
+  std::size_t overlap(const String& y) const;
+  /** string reverse overlap
+  *
+  * if roverlap returns m>0,
+  * then the maximal prefix of this string that is a suffix of y is of length m.
+  *
+  * For example, if x is "abcdef", then:
+  * x.roverlap("aaabc") = 3
+  * x.roverlap("def") = 0
+  * x.roverlap("d") = 0
+  * x.roverlap("defabcde") = 5
+  *
+  * Notice that x.overlap(y) = y.roverlap(x)
+  */
+  std::size_t roverlap(const String& y) const;
+
+  /**
+   * Returns true if this string corresponds in text to a number, for example
+   * this returns true for strings "7", "12", "004", "0" and false for strings
+   * "abc", "4a", "-4", "".
+   */
+  bool isNumber() const;
+  /** Returns the corresponding rational for the text of this string. */
+  Rational toNumber() const;
+  /** Get the unsigned representation (code points) of this string */
+  const std::vector<unsigned>& getVec() const { return d_str; }
+  /**
+   * Get the unsigned (code point) value of the first character in this string
+   */
+  unsigned front() const;
+  /**
+   * Get the unsigned (code point) value of the last character in this string
+   */
+  unsigned back() const;
+  /** is the unsigned a digit?
+   *
+   * This is true for code points between 48 ('0') and 57 ('9').
+   */
+  static bool isDigit(unsigned character);
+  /** is the unsigned a hexidecimal digit?
+   *
+   * This is true for code points between 48 ('0') and 57 ('9'), code points
+   * between 65 ('A') and 70 ('F) and code points between 97 ('a') and 102 ('f).
+   */
+  static bool isHexDigit(unsigned character);
+  /** is the unsigned a printable code point?
+   *
+   * This is true for Unicode 32 (' ') to 126 ('~').
+   */
+  static bool isPrintable(unsigned character);
+
+  /**
+   * Returns the maximum length of string representable by this class.
+   * Corresponds to the maximum size of d_str.
+   */
+  static size_t maxSize();
+ private:
+  /**
+   * Helper for toInternal: add character ch to vector vec, storing a string in
+   * internal format. This throws an error if ch is not a printable character,
+   * since non-printable characters must be escaped in SMT-LIB.
+   */
+  static void addCharToInternal(unsigned char ch, std::vector<unsigned>& vec);
+  /**
+   * Convert the string s to the internal format (vector of code points).
+   * The argument useEscSequences is whether to process unicode escape
+   * sequences.
+   */
+  static std::vector<unsigned> toInternal(const std::string& s,
+                                          bool useEscSequences);
+
+  /**
+   * Returns a negative number if *this < y, 0 if *this and y are equal and a
+   * positive number if *this > y.
+   */
+  int cmp(const String& y) const;
+
+  std::vector<unsigned> d_str;
+}; /* class String */
+
+namespace strings {
+
+struct CVC4_PUBLIC StringHashFunction {
+  size_t operator()(const ::CVC4::String& s) const {
+    return std::hash<std::string>()(s.toString());
+  }
+}; /* struct StringHashFunction */
+
+}  // namespace strings
+
+std::ostream& operator<<(std::ostream& os, const String& s) CVC4_PUBLIC;
+
+}  // namespace CVC4
+
+#endif /* CVC4__UTIL__STRING_H */