// Copyright 2004 and onwards Google Inc.

//

//

#include "gutil/strings/stringpiece.h"

// IWYU pragma: no_include <pstl/glue_algorithm_defs.h>

#include "common/logging.h"

#include <string.h>

#include <algorithm>

#include <climits>

#include <string>

#include <deque>

#include <ostream>

#include "gutil/stl_util.h"

#include "gutil/strings/memutil.h"

#include "gutil/hash/legacy_hash.h"

using std::copy;

using std::max;

using std::min;

using std::reverse;

using std::sort;

using std::swap;

using std::string;

size_t std::hash<StringPiece>::operator()(StringPiece s) const {

    return HashTo32(s.data(), s.size());

}

std::ostream& operator<<(std::ostream& o, StringPiece piece) {

    o.write(piece.data(), piece.size());

    return o;

}

StringPiece::StringPiece(StringPiece x, int pos) : ptr_(x.ptr_ + pos), length_(x.length_ - pos) {

    DCHECK_LE(0, pos);

    DCHECK_LE(pos, x.length_);

}

StringPiece::StringPiece(StringPiece x, int pos, int len)

        : ptr_(x.ptr_ + pos), length_(min(len, x.length_ - pos)) {

    DCHECK_LE(0, pos);

    DCHECK_LE(pos, x.length_);

    DCHECK_GE(len, 0);

}

void StringPiece::CopyToString(string* target) const {

    STLAssignToString(target, ptr_, length_);

}

void StringPiece::AppendToString(string* target) const {

    STLAppendToString(target, ptr_, length_);

}

int StringPiece::copy(char* buf, size_type n, size_type pos) const {

    int ret = min(length_ - pos, n);

    memcpy(buf, ptr_ + pos, ret);

    return ret;

}

bool StringPiece::contains(StringPiece s) const {

    return find(s, 0) != npos;

}

int StringPiece::find(StringPiece s, size_type pos) const {

    if (length_ <= 0 || pos > static_cast<size_type>(length_)) {

        if (length_ == 0 && pos == 0 && s.length_ == 0) return 0;

        return npos;

    }

    const char* result = memmatch(ptr_ + pos, length_ - pos, s.ptr_, s.length_);

    return result ? result - ptr_ : npos;

}

int StringPiece::find(char c, size_type pos) const {

    if (length_ <= 0 || pos >= static_cast<size_type>(length_)) {

        return npos;

    }

    const char* result = static_cast<const char*>(memchr(ptr_ + pos, c, length_ - pos));

    return result != nullptr ? result - ptr_ : npos;

}

int StringPiece::rfind(StringPiece s, size_type pos) const {

    if (length_ < s.length_) return npos;

    const size_t ulen = length_;

    if (s.length_ == 0) return min(ulen, pos);

    const char* last = ptr_ + min(ulen - s.length_, pos) + s.length_;

    const char* result = std::find_end(ptr_, last, s.ptr_, s.ptr_ + s.length_);

    return result != last ? result - ptr_ : npos;

}

// Search range is [0..pos] inclusive.  If pos == npos, search everything.

int StringPiece::rfind(char c, size_type pos) const {

    // Note: memrchr() is not available on Windows.

    if (length_ <= 0) return npos;

    for (int i = min(pos, static_cast<size_type>(length_ - 1)); i >= 0; --i) {

        if (ptr_[i] == c) {

            return i;

        }

    }

    return npos;

}

// For each character in characters_wanted, sets the index corresponding

// to the ASCII code of that character to 1 in table.  This is used by

// the find_.*_of methods below to tell whether or not a character is in

// the lookup table in constant time.

// The argument `table' must be an array that is large enough to hold all

// the possible values of an unsigned char.  Thus it should be be declared

// as follows:

//   bool table[UCHAR_MAX + 1]

static inline void BuildLookupTable(StringPiece characters_wanted, bool* table) {

    const int length = characters_wanted.length();

    const char* const data = characters_wanted.data();

    for (int i = 0; i < length; ++i) {

        table[static_cast<unsigned char>(data[i])] = true;

    }

}

int StringPiece::find_first_of(StringPiece s, size_type pos) const {

    if (length_ <= 0 || s.length_ <= 0) {

        return npos;

    }

    // Avoid the cost of BuildLookupTable() for a single-character search.

    if (s.length_ == 1) return find_first_of(s.ptr_[0], pos);

    bool lookup[UCHAR_MAX + 1] = {false};

    BuildLookupTable(s, lookup);

    for (int i = pos; i < length_; ++i) {

        if (lookup[static_cast<unsigned char>(ptr_[i])]) {

            return i;

        }

    }

    return npos;

}

int StringPiece::find_first_not_of(StringPiece s, size_type pos) const {

    if (length_ <= 0) return npos;

    if (s.length_ <= 0) return 0;

    // Avoid the cost of BuildLookupTable() for a single-character search.

    if (s.length_ == 1) return find_first_not_of(s.ptr_[0], pos);

    bool lookup[UCHAR_MAX + 1] = {false};

    BuildLookupTable(s, lookup);

    for (int i = pos; i < length_; ++i) {

        if (!lookup[static_cast<unsigned char>(ptr_[i])]) {

            return i;

        }

    }

    return npos;

}

int StringPiece::find_first_not_of(char c, size_type pos) const {

    if (length_ <= 0) return npos;

    for (; pos < static_cast<size_type>(length_); ++pos) {

        if (ptr_[pos] != c) {

            return pos;

        }

    }

    return npos;

}

int StringPiece::find_last_of(StringPiece s, size_type pos) const {

    if (length_ <= 0 || s.length_ <= 0) return npos;

    // Avoid the cost of BuildLookupTable() for a single-character search.

    if (s.length_ == 1) return find_last_of(s.ptr_[0], pos);

    bool lookup[UCHAR_MAX + 1] = {false};

    BuildLookupTable(s, lookup);

    for (int i = min(pos, static_cast<size_type>(length_ - 1)); i >= 0; --i) {

        if (lookup[static_cast<unsigned char>(ptr_[i])]) {

            return i;

        }

    }

    return npos;

}

int StringPiece::find_last_not_of(StringPiece s, size_type pos) const {

    if (length_ <= 0) return npos;

    int i = min(pos, static_cast<size_type>(length_ - 1));

    if (s.length_ <= 0) return i;

    // Avoid the cost of BuildLookupTable() for a single-character search.

    if (s.length_ == 1) return find_last_not_of(s.ptr_[0], pos);

    bool lookup[UCHAR_MAX + 1] = {false};

    BuildLookupTable(s, lookup);

    for (; i >= 0; --i) {

        if (!lookup[static_cast<unsigned char>(ptr_[i])]) {

            return i;

        }

    }

    return npos;

}

int StringPiece::find_last_not_of(char c, size_type pos) const {

    if (length_ <= 0) return npos;

    for (int i = min(pos, static_cast<size_type>(length_ - 1)); i >= 0; --i) {

        if (ptr_[i] != c) {

            return i;

        }

    }

    return npos;

}

StringPiece StringPiece::substr(size_type pos, size_type n) const {

    if (pos > length_) pos = length_;

    if (n > length_ - pos) n = length_ - pos;

    return StringPiece(ptr_ + pos, n);

}

const StringPiece::size_type StringPiece::npos = size_type(-1);