tesseract/unittest/util/utf8/unicodetext.cc

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/**
* Copyright 2010 Google 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.
*/
#include "util/utf8/unicodetext.h"
#include <string.h> // for memcpy, NULL, memcmp, etc
#include <algorithm> // for max
//#include "base/logging.h" // for operator<<, CHECK, etc
//#include "base/stringprintf.h" // for StringPrintf, StringAppendF
//#include "strings/stringpiece.h" // for StringPiece, etc
#include "third_party/utf/utf.h" // for isvalidcharntorune, etc
#include "util/utf8/unilib.h" // for IsInterchangeValid, etc
#include "util/utf8/unilib_utf8_utils.h" // for OneCharLen
static int CodepointDistance(const char* start, const char* end) {
int n = 0;
// Increment n on every non-trail-byte.
for (const char* p = start; p < end; ++p) {
n += (*reinterpret_cast<const signed char*>(p) >= -0x40);
}
return n;
}
static int CodepointCount(const char* utf8, int len) {
return CodepointDistance(utf8, utf8 + len);
}
UnicodeText::const_iterator::difference_type
distance(const UnicodeText::const_iterator& first,
const UnicodeText::const_iterator& last) {
return CodepointDistance(first.it_, last.it_);
}
// ---------- Utility ----------
static int ConvertToInterchangeValid(char* start, int len) {
// This routine is called only when we've discovered that a UTF-8 buffer
// that was passed to CopyUTF8, TakeOwnershipOfUTF8, or PointToUTF8
// was not interchange valid. This indicates a bug in the caller, and
// a LOG(WARNING) is done in that case.
// This is similar to CoerceToInterchangeValid, but it replaces each
// structurally valid byte with a space, and each non-interchange
// character with a space, even when that character requires more
// than one byte in UTF8. E.g., "\xEF\xB7\x90" (U+FDD0) is
// structurally valid UTF8, but U+FDD0 is not an interchange-valid
// code point. The result should contain one space, not three.
//
// Since the conversion never needs to write more data than it
// reads, it is safe to change the buffer in place. It returns the
// number of bytes written.
char* const in = start;
char* out = start;
char* const end = start + len;
while (start < end) {
int good = UniLib::SpanInterchangeValid(start, end - start);
if (good > 0) {
if (out != start) {
memmove(out, start, good);
}
out += good;
start += good;
if (start == end) {
break;
}
}
// Is the current string invalid UTF8 or just non-interchange UTF8?
char32 rune;
int n;
if (isvalidcharntorune(start, end - start, &rune, &n)) {
// structurally valid UTF8, but not interchange valid
start += n; // Skip over the whole character.
} else { // bad UTF8
start += 1; // Skip over just one byte
}
*out++ = ' ';
}
return out - in;
}
// *************** Data representation **********
// Note: the copy constructor is undefined.
// After reserve(), resize(), or clear(), we're an owner, not an alias.
void UnicodeText::Repr::reserve(int new_capacity) {
// If there's already enough capacity, and we're an owner, do nothing.
if (capacity_ >= new_capacity && ours_) return;
// Otherwise, allocate a new buffer.
capacity_ = std::max(new_capacity, (3 * capacity_) / 2 + 20);
char* new_data = new char[capacity_];
// If there is an old buffer, copy it into the new buffer.
if (data_) {
memcpy(new_data, data_, size_);
if (ours_) delete[] data_; // If we owned the old buffer, free it.
}
data_ = new_data;
ours_ = true; // We own the new buffer.
// size_ is unchanged.
}
void UnicodeText::Repr::resize(int new_size) {
if (new_size == 0) {
clear();
} else {
if (!ours_ || new_size > capacity_) reserve(new_size);
// Clear the memory in the expanded part.
if (size_ < new_size) memset(data_ + size_, 0, new_size - size_);
size_ = new_size;
ours_ = true;
}
}
// This implementation of clear() deallocates the buffer if we're an owner.
// That's not strictly necessary; we could just set size_ to 0.
void UnicodeText::Repr::clear() {
if (ours_) delete[] data_;
data_ = nullptr;
size_ = capacity_ = 0;
ours_ = true;
}
void UnicodeText::Repr::Copy(const char* data, int size) {
resize(size);
memcpy(data_, data, size);
}
void UnicodeText::Repr::TakeOwnershipOf(char* data, int size, int capacity) {
if (data == data_) return; // We already own this memory. (Weird case.)
if (ours_ && data_) delete[] data_; // If we owned the old buffer, free it.
data_ = data;
size_ = size;
capacity_ = capacity;
ours_ = true;
}
void UnicodeText::Repr::PointTo(const char* data, int size) {
if (ours_ && data_) delete[] data_; // If we owned the old buffer, free it.
data_ = const_cast<char*>(data);
size_ = size;
capacity_ = size;
ours_ = false;
}
void UnicodeText::Repr::append(const char* bytes, int byte_length) {
reserve(size_ + byte_length);
memcpy(data_ + size_, bytes, byte_length);
size_ += byte_length;
}
string UnicodeText::Repr::DebugString() const {
return tensorflow::strings::Printf("{Repr %p data=%p size=%d capacity=%d %s}",
this,
data_, size_, capacity_,
ours_ ? "Owned" : "Alias");
}
// *************** UnicodeText ******************
// ----- Constructors -----
// Default constructor
UnicodeText::UnicodeText() {
}
// Copy constructor
UnicodeText::UnicodeText(const UnicodeText& src) {
Copy(src);
}
// Substring constructor
UnicodeText::UnicodeText(const UnicodeText::const_iterator& first,
const UnicodeText::const_iterator& last) {
CHECK(first <= last) << " Incompatible iterators";
repr_.append(first.it_, last.it_ - first.it_);
}
string UnicodeText::UTF8Substring(const const_iterator& first,
const const_iterator& last) {
CHECK(first <= last) << " Incompatible iterators";
return string(first.it_, last.it_ - first.it_);
}
// ----- Copy -----
UnicodeText& UnicodeText::operator=(const UnicodeText& src) {
if (this != &src) {
Copy(src);
}
return *this;
}
UnicodeText& UnicodeText::Copy(const UnicodeText& src) {
repr_.Copy(src.repr_.data_, src.repr_.size_);
return *this;
}
UnicodeText& UnicodeText::CopyUTF8(const char* buffer, int byte_length) {
repr_.Copy(buffer, byte_length);
if (!UniLib:: IsInterchangeValid(buffer, byte_length)) {
LOG(WARNING) << "UTF-8 buffer is not interchange-valid.";
repr_.size_ = ConvertToInterchangeValid(repr_.data_, byte_length);
}
return *this;
}
UnicodeText& UnicodeText::UnsafeCopyUTF8(const char* buffer,
int byte_length) {
repr_.Copy(buffer, byte_length);
return *this;
}
// ----- TakeOwnershipOf -----
UnicodeText& UnicodeText::TakeOwnershipOfUTF8(char* buffer,
int byte_length,
int byte_capacity) {
repr_.TakeOwnershipOf(buffer, byte_length, byte_capacity);
if (!UniLib:: IsInterchangeValid(buffer, byte_length)) {
LOG(WARNING) << "UTF-8 buffer is not interchange-valid.";
repr_.size_ = ConvertToInterchangeValid(repr_.data_, byte_length);
}
return *this;
}
UnicodeText& UnicodeText::UnsafeTakeOwnershipOfUTF8(char* buffer,
int byte_length,
int byte_capacity) {
repr_.TakeOwnershipOf(buffer, byte_length, byte_capacity);
return *this;
}
// ----- PointTo -----
UnicodeText& UnicodeText::PointToUTF8(const char* buffer, int byte_length) {
if (UniLib:: IsInterchangeValid(buffer, byte_length)) {
repr_.PointTo(buffer, byte_length);
} else {
LOG(WARNING) << "UTF-8 buffer is not interchange-valid.";
repr_.Copy(buffer, byte_length);
repr_.size_ = ConvertToInterchangeValid(repr_.data_, byte_length);
}
return *this;
}
UnicodeText& UnicodeText::UnsafePointToUTF8(const char* buffer,
int byte_length) {
repr_.PointTo(buffer, byte_length);
return *this;
}
UnicodeText& UnicodeText::PointTo(const UnicodeText& src) {
repr_.PointTo(src.repr_.data_, src.repr_.size_);
return *this;
}
UnicodeText& UnicodeText::PointTo(const const_iterator &first,
const const_iterator &last) {
CHECK(first <= last) << " Incompatible iterators";
repr_.PointTo(first.utf8_data(), last.utf8_data() - first.utf8_data());
return *this;
}
// ----- Append -----
UnicodeText& UnicodeText::append(const UnicodeText& u) {
repr_.append(u.repr_.data_, u.repr_.size_);
return *this;
}
UnicodeText& UnicodeText::append(const const_iterator& first,
const const_iterator& last) {
CHECK(first <= last) << " Incompatible iterators";
repr_.append(first.it_, last.it_ - first.it_);
return *this;
}
UnicodeText& UnicodeText::UnsafeAppendUTF8(const char* utf8, int len) {
repr_.append(utf8, len);
return *this;
}
// ----- substring searching -----
UnicodeText::const_iterator UnicodeText::find(const UnicodeText& look,
const_iterator start_pos) const {
CHECK_GE(start_pos.utf8_data(), utf8_data());
CHECK_LE(start_pos.utf8_data(), utf8_data() + utf8_length());
return UnsafeFind(look, start_pos);
}
UnicodeText::const_iterator UnicodeText::find(const UnicodeText& look) const {
return UnsafeFind(look, begin());
}
UnicodeText::const_iterator UnicodeText::UnsafeFind(
const UnicodeText& look, const_iterator start_pos) const {
// Due to the magic of the UTF8 encoding, searching for a sequence of
// letters is equivalent to substring search.
StringPiece searching(utf8_data(), utf8_length());
StringPiece look_piece(look.utf8_data(), look.utf8_length());
LOG(FATAL) << "Not implemented";
//StringPiece::size_type found =
// searching.find(look_piece, start_pos.utf8_data() - utf8_data());
StringPiece::size_type found = StringPiece::npos;
if (found == StringPiece::npos) return end();
return const_iterator(utf8_data() + found);
}
bool UnicodeText::HasReplacementChar() const {
// Equivalent to:
// UnicodeText replacement_char;
// replacement_char.push_back(0xFFFD);
// return find(replacement_char) != end();
StringPiece searching(utf8_data(), utf8_length());
StringPiece looking_for("\xEF\xBF\xBD", 3);
LOG(FATAL) << "Not implemented";
//return searching.find(looking_for) != StringPiece::npos;
return false;
}
// ----- other methods -----
// Clear operator
void UnicodeText::clear() {
repr_.clear();
}
// Destructor
UnicodeText::~UnicodeText() {}
void UnicodeText::push_back(char32 c) {
if (UniLib::IsValidCodepoint(c)) {
char buf[UTFmax];
int len = runetochar(buf, &c);
if (UniLib::IsInterchangeValid(buf, len)) {
repr_.append(buf, len);
} else {
LOG(WARNING) << "Unicode value 0x" << std::hex << c
<< " is not valid for interchange";
repr_.append(" ", 1);
}
} else {
LOG(WARNING) << "Illegal Unicode value: 0x" << std::hex << c;
repr_.append(" ", 1);
}
}
int UnicodeText::size() const {
return CodepointCount(repr_.data_, repr_.size_);
}
bool operator==(const UnicodeText& lhs, const UnicodeText& rhs) {
if (&lhs == &rhs) return true;
if (lhs.repr_.size_ != rhs.repr_.size_) return false;
return memcmp(lhs.repr_.data_, rhs.repr_.data_, lhs.repr_.size_) == 0;
}
string UnicodeText::DebugString() const {
return tensorflow::strings::Printf("{UnicodeText %p chars=%d repr=%s}",
this,
size(),
repr_.DebugString().c_str());
}
// ******************* UnicodeText::const_iterator *********************
// The implementation of const_iterator would be nicer if it
// inherited from boost::iterator_facade
// (http://boost.org/libs/iterator/doc/iterator_facade.html).
UnicodeText::const_iterator::const_iterator() : it_(nullptr) {}
UnicodeText::const_iterator::const_iterator(const const_iterator& other)
: it_(other.it_) {
}
UnicodeText::const_iterator&
UnicodeText::const_iterator::operator=(const const_iterator& other) {
if (&other != this)
it_ = other.it_;
return *this;
}
UnicodeText::const_iterator UnicodeText::begin() const {
return const_iterator(repr_.data_);
}
UnicodeText::const_iterator UnicodeText::end() const {
return const_iterator(repr_.data_ + repr_.size_);
}
bool operator<(const UnicodeText::const_iterator& lhs,
const UnicodeText::const_iterator& rhs) {
return lhs.it_ < rhs.it_;
}
char32 UnicodeText::const_iterator::operator*() const {
// (We could call chartorune here, but that does some
// error-checking, and we're guaranteed that our data is valid
// UTF-8. Also, we expect this routine to be called very often. So
// for speed, we do the calculation ourselves.)
// Convert from UTF-8
unsigned char byte1 = it_[0];
if (byte1 < 0x80)
return byte1;
unsigned char byte2 = it_[1];
if (byte1 < 0xE0)
return ((byte1 & 0x1F) << 6)
| (byte2 & 0x3F);
unsigned char byte3 = it_[2];
if (byte1 < 0xF0)
return ((byte1 & 0x0F) << 12)
| ((byte2 & 0x3F) << 6)
| (byte3 & 0x3F);
unsigned char byte4 = it_[3];
return ((byte1 & 0x07) << 18)
| ((byte2 & 0x3F) << 12)
| ((byte3 & 0x3F) << 6)
| (byte4 & 0x3F);
}
UnicodeText::const_iterator& UnicodeText::const_iterator::operator++() {
it_ += UniLib::OneCharLen(it_);
return *this;
}
UnicodeText::const_iterator& UnicodeText::const_iterator::operator--() {
while (UniLib::IsTrailByte(*--it_));
return *this;
}
int UnicodeText::const_iterator::get_utf8(char* utf8_output) const {
utf8_output[0] = it_[0]; if ((it_[0] & 0xff) < 0x80) return 1;
utf8_output[1] = it_[1]; if ((it_[0] & 0xff) < 0xE0) return 2;
utf8_output[2] = it_[2]; if ((it_[0] & 0xff) < 0xF0) return 3;
utf8_output[3] = it_[3];
return 4;
}
string UnicodeText::const_iterator::get_utf8_string() const {
return string(utf8_data(), utf8_length());
}
int UnicodeText::const_iterator::utf8_length() const {
if ((it_[0] & 0xff) < 0x80) {
return 1;
} else if ((it_[0] & 0xff) < 0xE0) {
return 2;
} else if ((it_[0] & 0xff) < 0xF0) {
return 3;
} else {
return 4;
}
}
UnicodeText::const_iterator UnicodeText::MakeIterator(const char* p) const {
CHECK(p != nullptr);
const char* start = utf8_data();
int len = utf8_length();
const char* end = start + len;
CHECK(p >= start);
CHECK(p <= end);
CHECK(p == end || !UniLib::IsTrailByte(*p));
return const_iterator(p);
}
string UnicodeText::const_iterator::DebugString() const {
return tensorflow::strings::Printf("{iter %p}", it_);
}
// *************************** Utilities *************************
string CodepointString(const UnicodeText& t) {
string s;
UnicodeText::const_iterator it = t.begin(), end = t.end();
while (it != end) tensorflow::strings::Appendf(&s, "%X ", *it++);
return s;
}