straccum.hh

/* Masstree
 * Eddie Kohler, Yandong Mao, Robert Morris
 * Copyright (c) 2012-2013 President and Fellows of Harvard College
 * Copyright (c) 2012-2013 Massachusetts Institute of Technology
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, subject to the conditions
 * listed in the Masstree LICENSE file. These conditions include: you must
 * preserve this copyright notice, and you cannot mention the copyright
 * holders in advertising related to the Software without their permission.
 * The Software is provided WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED. This
 * notice is a summary of the Masstree LICENSE file; the license in that file
 * is legally binding.
 */
#ifndef LCDF_STRACCUM_HH
#define LCDF_STRACCUM_HH
#include <string.h>
#include <assert.h>
#include <stdarg.h>
#include "string.hh"
#if __GNUC__ > 4
# define LCDF_SNPRINTF_ATTR __attribute__((__format__(__printf__, 3, 4)))
#else
# define LCDF_SNPRINTF_ATTR /* nothing */
#endif
namespace lcdf {

/** @file <lcdf/straccum.hh>
    @brief Click's StringAccum class, used to construct Strings efficiently from pieces.
*/

class StringAccum { public:

    typedef const char *const_iterator;
    typedef char *iterator;

    typedef int (StringAccum::*unspecified_bool_type)() const;

    inline StringAccum();
    explicit inline StringAccum(int capacity);
    explicit inline StringAccum(const char* cstr);
    inline StringAccum(const char* s, int len);
    template <typename T>
    inline StringAccum(const String_base<T>& str);
    inline StringAccum(const StringAccum& x);
#if HAVE_CXX_RVALUE_REFERENCES
    inline StringAccum(StringAccum&& x);
    inline StringAccum(String&& x);
#endif
    inline ~StringAccum();
    static inline StringAccum make_transfer(String& x);

    inline StringAccum& operator=(const StringAccum& x);
#if HAVE_CXX_RVALUE_REFERENCES
    inline StringAccum& operator=(StringAccum&& x);
#endif

    inline const char* data() const;
    inline char* data();
    inline const unsigned char* udata() const;
    inline unsigned char* udata();
    inline int length() const;
    inline int capacity() const;

    const char* c_str();

    inline operator unspecified_bool_type() const;
    inline bool empty() const;
    inline bool operator!() const;

    inline const_iterator begin() const;
    inline iterator begin();
    inline const_iterator end() const;
    inline iterator end();

    inline char operator[](int i) const;
    inline char& operator[](int i);
    inline char front() const;
    inline char& front();
    inline char back() const;
    inline char& back();

    inline bool out_of_memory() const;
    void assign_out_of_memory();

    inline void clear();
    inline char* reserve(int n);
    inline void set_length(int len);
    int resize(int len);
    inline void adjust_length(int delta);
    inline void set_end(char* end);
    inline void set_end(unsigned char* end);
    inline char* extend(int nadjust, int nreserve = 0);

    inline void pop_back(int n = 1);

    inline void append(char c);
    inline void append(unsigned char c);
    inline bool append_utf8(int ch);
    inline void append(const char* cstr);
    inline void append(const char* s, int len);
    inline void append(const unsigned char* s, int len);
    inline void append(const char* first, const char* last);
    inline void append(const unsigned char* first, const unsigned char* last);
    void append_fill(int c, int len);

    template <typename T>
    void append_encoded(T& state, const unsigned char* first,
                        const unsigned char* last);
    template <typename T>
    inline void append_encoded(T& state, const char* first, const char* last);
    template <typename T>
    void append_encoded(T& state);
    template <typename T>
    inline void append_encoded(const unsigned char* first, const unsigned char* last);
    template <typename T>
    inline void append_encoded(const char* first, const char* last);

    // word joining
    template <typename I>
    inline void append_join(const String& joiner, I first, I last);
    template <typename T>
    inline void append_join(const String& joiner, const T& x);
    void append_break_lines(const String& text, int linelen, const String& leftmargin = String());

    StringAccum& snprintf(int n, const char* format, ...) LCDF_SNPRINTF_ATTR;
    StringAccum& vsnprintf(int n, const char* format, va_list val);

    String take_string();

    void swap(StringAccum& x);

    // see also operator<< declarations below

  private:

    enum {
        memo_space = String::MEMO_SPACE
    };

    struct rep_t {
        unsigned char* s;
        int len;
        int cap;
        rep_t()
            : s(reinterpret_cast<unsigned char*>(const_cast<char*>(String_generic::empty_data))),
              len(0), cap(0) {
        }
        explicit rep_t(uninitialized_type) {
        }
    };

    rep_t r_;

    char* grow(int ncap);
    char* hard_extend(int nadjust, int nreserve);
    void hard_append(const char* s, int len);
    void hard_append_cstr(const char* cstr);
    bool append_utf8_hard(int ch);
    void transfer_from(String& x);
};

inline StringAccum& operator<<(StringAccum& sa, char c);
inline StringAccum& operator<<(StringAccum& sa, unsigned char c);
inline StringAccum& operator<<(StringAccum& sa, const char *cstr);
template <typename T> inline StringAccum& operator<<(StringAccum& sa, const String_base<T>& str);
inline StringAccum& operator<<(StringAccum& sa, const StringAccum& x);

inline StringAccum& operator<<(StringAccum& sa, bool x);
inline StringAccum& operator<<(StringAccum& sa, short x);
inline StringAccum& operator<<(StringAccum& sa, unsigned short x);
inline StringAccum& operator<<(StringAccum& sa, int x);
inline StringAccum& operator<<(StringAccum& sa, unsigned x);
StringAccum& operator<<(StringAccum& sa, long x);
StringAccum& operator<<(StringAccum& sa, unsigned long x);
StringAccum& operator<<(StringAccum& sa, long long x);
StringAccum& operator<<(StringAccum& sa, unsigned long long x);
StringAccum& operator<<(StringAccum& sa, double x);

/** @brief Construct an empty StringAccum (with length 0). */
inline StringAccum::StringAccum() {
}

/** @brief Construct a StringAccum with room for at least @a capacity
    characters.
    @param capacity initial capacity

    If @a capacity == 0, the StringAccum is created empty. If @a capacity is
    too large (so that @a capacity bytes of memory can't be allocated), the
    StringAccum falls back to a smaller capacity (possibly zero). */
inline StringAccum::StringAccum(int capacity) {
    assert(capacity >= 0);
    grow(capacity);
}

/** @brief Construct a StringAccum containing the characters in @a cstr. */
inline StringAccum::StringAccum(const char *cstr) {
    append(cstr);
}

/** @brief Construct a StringAccum containing the characters in @a s. */
inline StringAccum::StringAccum(const char *s, int len) {
    append(s, len);
}

/** @brief Construct a StringAccum containing the characters in @a str. */
template <typename T>
inline StringAccum::StringAccum(const String_base<T> &str) {
    append(str.begin(), str.end());
}

/** @brief Construct a StringAccum containing a copy of @a x. */
inline StringAccum::StringAccum(const StringAccum &x) {
    append(x.data(), x.length());
}

#if HAVE_CXX_RVALUE_REFERENCES
/** @brief Move-construct a StringAccum from @a x. */
inline StringAccum::StringAccum(StringAccum&& x) {
    using std::swap;
    swap(r_, x.r_);
}

inline StringAccum::StringAccum(String&& x) {
    transfer_from(x);
    x._r = String::rep_type{String_generic::empty_data, 0, 0};
}
#endif

/** @brief Destroy a StringAccum, freeing its memory. */
inline StringAccum::~StringAccum() {
    if (r_.cap > 0)
        delete[] reinterpret_cast<char*>(r_.s - memo_space);
}

inline StringAccum StringAccum::make_transfer(String& x) {
    StringAccum sa;
    sa.transfer_from(x);
    x._r = String::rep_type{String_generic::empty_data, 0, 0};
    return sa;
}

/** @brief Return the contents of the StringAccum.

    The returned data() value points to length() bytes of writable memory. */
inline const char* StringAccum::data() const {
    return reinterpret_cast<const char*>(r_.s);
}

/** @overload */
inline char* StringAccum::data() {
    return reinterpret_cast<char*>(r_.s);
}

/** @brief Return the contents of the StringAccum.

    The returned data() value points to length() bytes of writable memory. */
inline const unsigned char* StringAccum::udata() const {
    return r_.s;
}

/** @overload */
inline unsigned char* StringAccum::udata() {
    return r_.s;
}

/** @brief Return the length of the StringAccum. */
inline int StringAccum::length() const {
    return r_.len;
}

/** @brief Return the StringAccum's current capacity.

    The capacity is the maximum length the StringAccum can hold without
    incurring a memory allocation. Returns -1 for out-of-memory
    StringAccums. */
inline int StringAccum::capacity() const {
    return r_.cap;
}

/** @brief Return an iterator for the first character in the StringAccum.

    StringAccum iterators are simply pointers into string data, so they are
    quite efficient. @sa StringAccum::data */
inline StringAccum::const_iterator StringAccum::begin() const {
    return reinterpret_cast<char *>(r_.s);
}

/** @overload */
inline StringAccum::iterator StringAccum::begin() {
    return reinterpret_cast<char *>(r_.s);
}

/** @brief Return an iterator for the end of the StringAccum.

    The return value points one character beyond the last character in the
    StringAccum. */
inline StringAccum::const_iterator StringAccum::end() const {
    return reinterpret_cast<char *>(r_.s + r_.len);
}

/** @overload */
inline StringAccum::iterator StringAccum::end() {
    return reinterpret_cast<char *>(r_.s + r_.len);
}

/** @brief Test if the StringAccum contains characters. */
inline StringAccum::operator unspecified_bool_type() const {
    return r_.len != 0 ? &StringAccum::capacity : 0;
}

/** @brief Test if the StringAccum is empty.

    Returns true iff length() == 0. */
inline bool StringAccum::operator!() const {
    return r_.len == 0;
}

/** @brief Test if the StringAccum is empty. */
inline bool StringAccum::empty() const {
    return r_.len == 0;
}

/** @brief Test if the StringAccum is out-of-memory. */
inline bool StringAccum::out_of_memory() const {
    return unlikely(r_.cap < 0);
}

/** @brief Return the <a>i</a>th character in the string.
    @param i character index
    @pre 0 <= @a i < length() */
inline char StringAccum::operator[](int i) const {
    assert((unsigned) i < (unsigned) r_.len);
    return static_cast<char>(r_.s[i]);
}

/** @brief Return a reference to the <a>i</a>th character in the string.
    @param i character index
    @pre 0 <= @a i < length() */
inline char &StringAccum::operator[](int i) {
    assert((unsigned) i < (unsigned) r_.len);
    return reinterpret_cast<char &>(r_.s[i]);
}

/** @brief Return the first character in the string.
    @pre length() > 0 */
inline char StringAccum::front() const {
    assert(r_.len > 0);
    return static_cast<char>(r_.s[0]);
}

/** @brief Return a reference to the first character in the string.
    @pre length() > 0 */
inline char &StringAccum::front() {
    assert(r_.len > 0);
    return reinterpret_cast<char &>(r_.s[0]);
}

/** @brief Return the last character in the string.
    @pre length() > 0 */
inline char StringAccum::back() const {
    assert(r_.len > 0);
    return static_cast<char>(r_.s[r_.len - 1]);
}

/** @brief Return a reference to the last character in the string.
    @pre length() > 0 */
inline char &StringAccum::back() {
    assert(r_.len > 0);
    return reinterpret_cast<char &>(r_.s[r_.len - 1]);
}

/** @brief Clear the StringAccum's comments.

    All characters in the StringAccum are erased. Also resets the
    StringAccum's out-of-memory status. */
inline void StringAccum::clear() {
    if (r_.cap < 0)
        r_.cap = 0;
    r_.len = 0;
}

/** @brief Reserve space for at least @a n characters.
    @return a pointer to at least @a n characters, or null if allocation
    fails
    @pre @a n >= 0

    reserve() does not change the string's length(), only its capacity(). In
    a frequent usage pattern, code calls reserve(), passing an upper bound
    on the characters that could be written by a series of operations. After
    writing into the returned buffer, adjust_length() is called to account
    for the number of characters actually written.

    On failure, null is returned and errno is set to ENOMEM. */
inline char *StringAccum::reserve(int n) {
    assert(n >= 0);
    if (r_.len + n <= r_.cap)
        return reinterpret_cast<char *>(r_.s + r_.len);
    else
        return grow(r_.len + n);
}

/** @brief Set the StringAccum's length to @a len.
    @param len new length in characters
    @pre 0 <= @a len <= capacity()
    @sa adjust_length */
inline void StringAccum::set_length(int len) {
    assert(len >= 0 && r_.len <= r_.cap);
    r_.len = len;
}

inline void StringAccum::set_end(unsigned char* x) {
    assert(x >= r_.s && x <= r_.s + r_.cap);
    r_.len = x - r_.s;
}

inline void StringAccum::set_end(char* x) {
    set_end((unsigned char*) x);
}

/** @brief Adjust the StringAccum's length.
    @param delta  length adjustment
    @pre If @a delta > 0, then length() + @a delta <= capacity().
    If @a delta < 0, then length() + delta >= 0.

    The StringAccum's length after adjust_length(@a delta) equals its old
    length plus @a delta. Generally adjust_length() is used after a call to
    reserve(). @sa set_length */
inline void StringAccum::adjust_length(int delta) {
    assert(r_.len + delta >= 0 && r_.len + delta <= r_.cap);
    r_.len += delta;
}

/** @brief Reserve space and adjust length in one operation.
    @param nadjust number of characters to reserve and adjust length
    @param nreserve additional characters to reserve
    @pre @a nadjust >= 0 and @a nreserve >= 0

    This operation combines the effects of reserve(@a nadjust + @a nreserve)
    and adjust_length(@a nadjust). Returns the result of the reserve()
    call. */
inline char *StringAccum::extend(int nadjust, int nreserve) {
#if HAVE_OPTIMIZE_SIZE || __OPTIMIZE_SIZE__
    return hard_extend(nadjust, nreserve);
#else
    assert(nadjust >= 0 && nreserve >= 0);
    if (r_.len + nadjust + nreserve <= r_.cap) {
        char *x = reinterpret_cast<char *>(r_.s + r_.len);
        r_.len += nadjust;
        return x;
    } else
        return hard_extend(nadjust, nreserve);
#endif
}

/** @brief Remove characters from the end of the StringAccum.
    @param n number of characters to remove
    @pre @a n >= 0 and @a n <= length()

    Same as adjust_length(-@a n). */
inline void StringAccum::pop_back(int n) {
    assert(n >= 0 && r_.len >= n);
    r_.len -= n;
}

/** @brief Append character @a c to the StringAccum.
    @param c character to append */
inline void StringAccum::append(char c) {
    if (r_.len < r_.cap || grow(r_.len))
        r_.s[r_.len++] = c;
}

/** @overload */
inline void StringAccum::append(unsigned char c) {
    append(static_cast<char>(c));
}

/** @brief Append the first @a len characters of @a s to this StringAccum.
    @param s data to append
    @param len length of data
    @pre @a len >= 0 */
inline void StringAccum::append(const char *s, int len) {
#if HAVE_OPTIMIZE_SIZE || __OPTIMIZE_SIZE__
    hard_append(s, len);
#else
    assert(len >= 0);
    if (r_.len + len <= r_.cap) {
        memcpy(r_.s + r_.len, s, len);
        r_.len += len;
    } else
        hard_append(s, len);
#endif
}

/** @overload */
inline void StringAccum::append(const unsigned char *s, int len) {
    append(reinterpret_cast<const char *>(s), len);
}

/** @brief Append the null-terminated C string @a s to this StringAccum.
    @param s data to append */
inline void StringAccum::append(const char *cstr) {
    if (LCDF_CONSTANT_CSTR(cstr))
        append(cstr, strlen(cstr));
    else
        hard_append_cstr(cstr);
}

/** @brief Append the data from @a first to @a last to the end of this
    StringAccum.

    Does nothing if @a first >= @a last. */
inline void StringAccum::append(const char *first, const char *last) {
    if (first < last)
        append(first, last - first);
}

/** @overload */
inline void StringAccum::append(const unsigned char *first, const unsigned char *last) {
    if (first < last)
        append(first, last - first);
}

/** @brief Append Unicode character @a ch encoded in UTF-8.
    @return true if character was valid.

    Appends nothing if @a ch is not a valid Unicode character. */
inline bool StringAccum::append_utf8(int ch) {
    if (unlikely(ch <= 0))
        return false;
    else if (likely(ch <= 0x7F)) {
        append(static_cast<char>(ch));
        return true;
    } else
        return append_utf8_hard(ch);
}

template <typename T>
void StringAccum::append_encoded(T &encoder,
                                 const unsigned char *first,
                                 const unsigned char *last)
{
    unsigned char *kills = 0;
    if (first != last)
        first = encoder.start(first, last);
    while (1) {
        encoder.set_output(r_.s + r_.len, r_.s + r_.cap, first);
        if (encoder.buffer_empty())
            first = encoder.encode(first, last);
        else
            first = encoder.flush(first, last);
        if (first == last)
            break;
        r_.len = encoder.output_begin() - r_.s;
        if (!kills) {
            kills = r_.s;
            r_.s = 0;
            grow(r_.len + last - first);
            memcpy(r_.s, kills, r_.len);
        } else
            grow(r_.len + last - first);
    }
    if (kills)
        delete[] reinterpret_cast<char*>(kills - memo_space);
}

template <typename T>
inline void StringAccum::append_encoded(T &state,
                                        const char *first,
                                        const char *last) {
    append_encoded(state,
                   reinterpret_cast<const unsigned char *>(first),
                   reinterpret_cast<const unsigned char *>(last));
}

template <typename T>
inline void StringAccum::append_encoded(const char *first,
                                        const char *last) {
    append_encoded<T>(reinterpret_cast<const unsigned char *>(first),
                      reinterpret_cast<const unsigned char *>(last));
}

template <typename T>
void StringAccum::append_encoded(T &encoder)
{
    while (!encoder.buffer_empty()) {
        encoder.set_output(r_.s + r_.len, r_.s + r_.cap, 0);
        if (encoder.flush_clear()) {
            r_.len = encoder.output_begin() - r_.s;
            break;
        }
        grow(r_.len + 10);
    }
}

template <typename T>
inline void StringAccum::append_encoded(const unsigned char *first,
                                        const unsigned char *last)
{
    T encoder;
    append_encoded(encoder, first, last);
    if (!encoder.buffer_empty())
        append_encoded(encoder);
}

template <typename I>
inline void StringAccum::append_join(const String &joiner, I first, I last) {
    bool later = false;
    while (first != last) {
        if (later)
            *this << joiner;
        later = true;
        *this << *first;
        ++first;
    }
}

template <typename T>
inline void StringAccum::append_join(const String &joiner, const T &x) {
    append_join(joiner, x.begin(), x.end());
}

/** @brief Assign this StringAccum to @a x. */
inline StringAccum &StringAccum::operator=(const StringAccum &x) {
    if (&x != this) {
        if (out_of_memory())
            r_.cap = 0;
        r_.len = 0;
        append(x.data(), x.length());
    }
    return *this;
}

#if HAVE_CXX_RVALUE_REFERENCES
/** @brief Move-assign this StringAccum to @a x. */
inline StringAccum &StringAccum::operator=(StringAccum &&x) {
    x.swap(*this);
    return *this;
}
#endif

/** @relates StringAccum
    @brief Append character @a c to StringAccum @a sa.
    @return @a sa
    @note Same as @a sa.append(@a c). */
inline StringAccum &operator<<(StringAccum &sa, char c) {
    sa.append(c);
    return sa;
}

/** @relates StringAccum
    @brief Append character @a c to StringAccum @a sa.
    @return @a sa
    @note Same as @a sa.append(@a c). */
inline StringAccum &operator<<(StringAccum &sa, unsigned char c) {
    sa.append(c);
    return sa;
}

/** @relates StringAccum
    @brief Append null-terminated C string @a cstr to StringAccum @a sa.
    @return @a sa
    @note Same as @a sa.append(@a cstr). */
inline StringAccum &operator<<(StringAccum &sa, const char *cstr) {
    sa.append(cstr);
    return sa;
}

/** @relates StringAccum
    @brief Append "true" or "false" to @a sa, depending on @a x.
    @return @a sa */
inline StringAccum &operator<<(StringAccum &sa, bool x) {
    sa.append(String_generic::bool_data + (-x & 6), 5 - x);
    return sa;
}

/** @relates StringAccum
    @brief Append decimal representation of @a x to @a sa.
    @return @a sa */
inline StringAccum &operator<<(StringAccum &sa, short x) {
    return sa << static_cast<long>(x);
}

/** @overload */
inline StringAccum &operator<<(StringAccum &sa, unsigned short x) {
    return sa << static_cast<unsigned long>(x);
}

/** @overload */
inline StringAccum &operator<<(StringAccum &sa, int x) {
    return sa << static_cast<long>(x);
}

/** @overload */
inline StringAccum &operator<<(StringAccum &sa, unsigned x) {
    return sa << static_cast<unsigned long>(x);
}

/** @relates StringAccum
    @brief Append the contents of @a str to @a sa.
    @return @a sa */
template <typename T>
inline StringAccum &operator<<(StringAccum &sa, const String_base<T> &str) {
    sa.append(str.data(), str.length());
    return sa;
}

inline StringAccum &operator<<(StringAccum &sa, const std::string &str) {
    sa.append(str.data(), str.length());
    return sa;
}

/** @relates StringAccum
    @brief Append the contents of @a x to @a sa.
    @return @a sa */
inline StringAccum &operator<<(StringAccum &sa, const StringAccum &x) {
    sa.append(x.begin(), x.end());
    return sa;
}

inline bool operator==(StringAccum &sa, const char *cstr) {
    return strcmp(sa.c_str(), cstr) == 0;
}

inline bool operator!=(StringAccum &sa, const char *cstr) {
    return strcmp(sa.c_str(), cstr) != 0;
}

inline void swap(StringAccum& a, StringAccum& b) {
    a.swap(b);
}

} // namespace lcdf
#undef LCDF_SNPRINTF_ATTR
#endif