212 lines
8.6 KiB
C++
212 lines
8.6 KiB
C++
// This file is part of the uSTL library, an STL implementation.
|
|
//
|
|
// Copyright (c) 2005 by Mike Sharov <msharov@users.sourceforge.net>
|
|
// This file is free software, distributed under the MIT License.
|
|
//
|
|
// This file contains stream iterators that read and write UTF-8 encoded
|
|
// characters. The encoding is defined as follows:
|
|
//
|
|
// U-00000000 - U-0000007F: 0xxxxxxx
|
|
// U-00000080 - U-000007FF: 110xxxxx 10xxxxxx
|
|
// U-00000800 - U-0000FFFF: 1110xxxx 10xxxxxx 10xxxxxx
|
|
// U-00010000 - U-001FFFFF: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
|
|
// U-00200000 - U-03FFFFFF: 111110xx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
|
|
// U-04000000 - U-7FFFFFFF: 1111110x 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
|
|
// U-80000000 - U-FFFFFFFF: 11111110 100000xx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
|
|
|
|
#pragma once
|
|
#include "uiterator.h"
|
|
|
|
namespace ustl {
|
|
|
|
//----------------------------------------------------------------------
|
|
|
|
typedef uint8_t utf8subchar_t; ///< Type for the encoding subcharacters.
|
|
|
|
//----------------------------------------------------------------------
|
|
|
|
inline size_t Utf8Bytes (wchar_t v) __attribute__((const));
|
|
inline size_t Utf8Bytes (const wchar_t* first, const wchar_t* last) __attribute__((pure));
|
|
inline size_t Utf8SequenceBytes (wchar_t c) __attribute__((const));
|
|
|
|
//----------------------------------------------------------------------
|
|
|
|
/// Returns the number of bytes required to UTF-8 encode \p v.
|
|
inline size_t Utf8Bytes (wchar_t v)
|
|
{
|
|
if ((uint32_t) v < 128)
|
|
return (1);
|
|
size_t n;
|
|
#if __i386__ || __x86_64__
|
|
uint32_t r = 0;
|
|
asm ("bsr\t%2, %%eax\n\t"
|
|
"add\t$4, %0\n\t"
|
|
"div\t%3":"=a"(n),"+d"(r):"r"(v),"c"(5));
|
|
#else
|
|
static const uint32_t c_Bounds[7] = { 0x0000007F, 0x000007FF, 0x0000FFFF, 0x001FFFFF, 0x03FFFFFF, 0x7FFFFFFF, 0xFFFFFFFF };
|
|
for (n = 0; c_Bounds[n++] < uint32_t(v););
|
|
#endif
|
|
return (n);
|
|
}
|
|
|
|
/// Measures the size of a wchar_t array in UTF-8 encoding.
|
|
inline size_t Utf8Bytes (const wchar_t* first, const wchar_t* last)
|
|
{
|
|
size_t bc = 0;
|
|
for (; first < last; ++first)
|
|
bc += Utf8Bytes(*first);
|
|
return (bc);
|
|
}
|
|
|
|
/// Returns the number of bytes in a UTF-8 sequence that starts with \p c.
|
|
inline size_t Utf8SequenceBytes (wchar_t c) // a wchar_t to keep c in a full register
|
|
{
|
|
// Count the leading bits. Header bits are 1 * nBytes followed by a 0.
|
|
// 0 - single byte character. Take 7 bits (0xFF >> 1)
|
|
// 1 - error, in the middle of the character. Take 6 bits (0xFF >> 2)
|
|
// so you will keep reading invalid entries until you hit the next character.
|
|
// >2 - multibyte character. Take remaining bits, and get the next bytes.
|
|
// All errors are ignored, since the user can not correct them.
|
|
//
|
|
wchar_t mask = 0x80;
|
|
size_t nBytes = 0;
|
|
for (; c & mask; ++nBytes)
|
|
mask >>= 1;
|
|
return (nBytes ? nBytes : 1); // A sequence is always at least 1 byte.
|
|
}
|
|
|
|
//----------------------------------------------------------------------
|
|
|
|
/// \class utf8in_iterator utf8.h ustl.h
|
|
/// \ingroup IteratorAdaptors
|
|
///
|
|
/// \brief An iterator adaptor to character containers for reading UTF-8 encoded text.
|
|
///
|
|
/// For example, you can copy from ustl::string to ustl::vector<wchar_t> with
|
|
/// copy (utf8in (str.begin()), utf8in (str.end()), back_inserter(wvect));
|
|
/// There is no error handling; if the reading frame slips you'll get extra
|
|
/// characters, one for every misaligned byte. Although it is possible to skip
|
|
/// to the start of the next character, that would result in omitting the
|
|
/// misformatted character and the one after it, making it very difficult to
|
|
/// detect by the user. It is better to write some strange characters and let
|
|
/// the user know his file is corrupted. Another problem is overflow on bad
|
|
/// encodings (like a 0xFF on the end of a string). This is checked through
|
|
/// the end-of-string nul character, which will always be there as long as
|
|
/// you are using the string class.
|
|
///
|
|
template <typename Iterator, typename WChar = wchar_t>
|
|
class utf8in_iterator {
|
|
public:
|
|
typedef typename iterator_traits<Iterator>::value_type value_type;
|
|
typedef typename iterator_traits<Iterator>::difference_type difference_type;
|
|
typedef typename iterator_traits<Iterator>::pointer pointer;
|
|
typedef typename iterator_traits<Iterator>::reference reference;
|
|
public:
|
|
explicit utf8in_iterator (const Iterator& is) : m_i (is), m_v (0) { Read(); }
|
|
utf8in_iterator (const utf8in_iterator& i) : m_i (i.m_i), m_v (i.m_v) {}
|
|
inline const utf8in_iterator& operator= (const utf8in_iterator& i) { m_i = i.m_i; m_v = i.m_v; return (*this); }
|
|
inline Iterator base (void) const { return (m_i - (Utf8Bytes(m_v) - 1)); }
|
|
/// Reads and returns the next value.
|
|
inline WChar operator* (void) const { return (m_v); }
|
|
inline utf8in_iterator& operator++ (void) { ++m_i; Read(); return (*this); }
|
|
inline utf8in_iterator operator++ (int) { utf8in_iterator old (*this); operator++(); return (old); }
|
|
inline utf8in_iterator& operator+= (uoff_t n) { while (n--) operator++(); return (*this); }
|
|
inline utf8in_iterator operator+ (uoff_t n) { utf8in_iterator v (*this); return (v += n); }
|
|
inline bool operator== (const utf8in_iterator& i) const { return (m_i == i.m_i); }
|
|
inline bool operator< (const utf8in_iterator& i) const { return (m_i < i.m_i); }
|
|
difference_type operator- (const utf8in_iterator& i) const;
|
|
private:
|
|
void Read (void);
|
|
private:
|
|
Iterator m_i;
|
|
WChar m_v;
|
|
};
|
|
|
|
/// Steps to the next character and updates current returnable value.
|
|
template <typename Iterator, typename WChar>
|
|
void utf8in_iterator<Iterator,WChar>::Read (void)
|
|
{
|
|
const utf8subchar_t c = *m_i;
|
|
size_t nBytes = Utf8SequenceBytes (c);
|
|
m_v = c & (0xFF >> nBytes); // First byte contains bits after the header.
|
|
while (--nBytes && *++m_i) // Each subsequent byte has 6 bits.
|
|
m_v = (m_v << 6) | (*m_i & 0x3F);
|
|
}
|
|
|
|
/// Returns the distance in characters (as opposed to the distance in bytes).
|
|
template <typename Iterator, typename WChar>
|
|
typename utf8in_iterator<Iterator,WChar>::difference_type
|
|
utf8in_iterator<Iterator,WChar>::operator- (const utf8in_iterator<Iterator,WChar>& last) const
|
|
{
|
|
difference_type dist = 0;
|
|
for (Iterator first (last.m_i); first < m_i; ++dist)
|
|
first = advance (first, Utf8SequenceBytes (*first));
|
|
return (dist);
|
|
}
|
|
|
|
//----------------------------------------------------------------------
|
|
|
|
/// \class utf8out_iterator utf8.h ustl.h
|
|
/// \ingroup IteratorAdaptors
|
|
///
|
|
/// \brief An iterator adaptor to character containers for writing UTF-8 encoded text.
|
|
///
|
|
template <typename Iterator, typename WChar = wchar_t>
|
|
class utf8out_iterator {
|
|
public:
|
|
typedef typename iterator_traits<Iterator>::value_type value_type;
|
|
typedef typename iterator_traits<Iterator>::difference_type difference_type;
|
|
typedef typename iterator_traits<Iterator>::pointer pointer;
|
|
typedef typename iterator_traits<Iterator>::reference reference;
|
|
public:
|
|
explicit utf8out_iterator (const Iterator& os) : m_i (os) {}
|
|
utf8out_iterator (const utf8out_iterator& i) : m_i (i.m_i) {}
|
|
inline const Iterator& base (void) const { return (m_i); }
|
|
/// Writes \p v into the stream.
|
|
utf8out_iterator& operator= (WChar v);
|
|
inline utf8out_iterator& operator* (void) { return (*this); }
|
|
inline utf8out_iterator& operator++ (void) { return (*this); }
|
|
inline utf8out_iterator operator++ (int) { return (*this); }
|
|
inline bool operator== (const utf8out_iterator& i) const { return (m_i == i.m_i); }
|
|
inline bool operator< (const utf8out_iterator& i) const { return (m_i < i.m_i); }
|
|
private:
|
|
Iterator m_i;
|
|
};
|
|
|
|
/// Writes \p v into the stream.
|
|
template <typename Iterator, typename WChar>
|
|
utf8out_iterator<Iterator,WChar>& utf8out_iterator<Iterator,WChar>::operator= (WChar v)
|
|
{
|
|
const size_t nBytes = Utf8Bytes (v);
|
|
if (nBytes > 1) {
|
|
// Write the bits 6 bits at a time, except for the first one,
|
|
// which may be less than 6 bits.
|
|
register wchar_t shift = nBytes * 6;
|
|
*m_i++ = ((v >> (shift -= 6)) & 0x3F) | (0xFF << (8 - nBytes));
|
|
while (shift)
|
|
*m_i++ = ((v >> (shift -= 6)) & 0x3F) | 0x80;
|
|
} else // If only one byte, there is no header.
|
|
*m_i++ = v;
|
|
return (*this);
|
|
}
|
|
|
|
//----------------------------------------------------------------------
|
|
|
|
/// Returns a UTF-8 adaptor writing to \p i. Useful in conjuction with back_insert_iterator.
|
|
template <typename Iterator>
|
|
inline utf8out_iterator<Iterator> utf8out (Iterator i)
|
|
{
|
|
return (utf8out_iterator<Iterator> (i));
|
|
}
|
|
|
|
/// Returns a UTF-8 adaptor reading from \p i.
|
|
template <typename Iterator>
|
|
inline utf8in_iterator<Iterator> utf8in (Iterator i)
|
|
{
|
|
return (utf8in_iterator<Iterator> (i));
|
|
}
|
|
|
|
//----------------------------------------------------------------------
|
|
|
|
} // namespace ustl
|