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#ifndef _enc_h
#define _enc_h
#include "basics.h"
#include "range.h"
namespace re2c {
// Each encoding defines two concepts:
//
// 1) Code point -- abstract number, which represents single encoding symbol.
// E.g., Unicode defines 0x10FFFF code points, so each Unicode encoding
// must be capable of representing 0x10FFFF code points.
//
// 2) Code unit -- the smallest unit of memory, which is used in the encoded
// text. One or more code units can be needed to represent a single code
// point, depending on the encoding. For each encoding, all code points
// either are represented with equal number of code units (fixed-length
// encodings), or with variable number of code units (variable-length
// encodings).
//
// encoding | code point number | code point size | code unit number | code unit size
// ---------|-------------------|-----------------------|------------------|----------------
// ASCII | 0xFF | fixed, 1 byte | 0xFF | 1 byte
// EBCDIC | 0xFF | fixed, 1 byte | 0xFF | 1 byte
// UCS2 | 0xFFFF | fixed, 2 bytes | 0xFFFF | 2 bytes
// UTF16 | 0x10FFFF | variable, 2 - 4 bytes | 0xFFFF | 2 bytes
// UTF32 | 0x10FFFF | fixed, 4 bytes | 0x10FFFF | 4 bytes
// UTF8 | 0x10FFFF | variable, 1 - 4 bytes | 0xFF | 1 byte
// -----------------------------------------------------------------------------------------
class Enc
{
public:
// Supported encodings.
enum type_t
{ ASCII
, EBCDIC
, UCS2
, UTF16
, UTF32
, UTF8
};
// What to do with invalid code points
enum policy_t
{ POLICY_FAIL
, POLICY_SUBSTITUTE
, POLICY_IGNORE
};
private:
static const uint asc2ebc[256];
static const uint ebc2asc[256];
static const uint SURR_MIN;
static const uint SURR_MAX;
static const uint UNICODE_ERROR;
type_t type;
policy_t policy;
public:
Enc()
: type (ASCII)
, policy (POLICY_IGNORE)
{ }
bool operator != (const Enc & e) const { return type != e.type; }
inline uint nCodePoints() const;
inline uint nCodeUnits() const;
inline uint szCodePoint() const;
inline uint szCodeUnit() const;
inline bool set(type_t t);
inline void unset(type_t);
inline bool is(type_t) const;
inline void setPolicy(policy_t t);
bool encode(uint & c) const;
uint decodeUnsafe(uint c) const;
Range * encodeRange(uint l, uint h) const;
Range * fullRange() const;
};
inline uint Enc::nCodePoints() const
{
switch (type)
{
case ASCII:
case EBCDIC: return 0x100;
case UCS2: return 0x10000;
case UTF16:
case UTF32:
case UTF8: return 0x110000;
}
return ~0; // to silence gcc warning
}
inline uint Enc::nCodeUnits() const
{
switch (type)
{
case ASCII:
case EBCDIC:
case UTF8: return 0x100;
case UCS2:
case UTF16: return 0x10000;
case UTF32: return 0x110000;
}
return ~0; // to silence gcc warning
}
// returns *maximal* code point size for encoding
inline uint Enc::szCodePoint() const
{
switch (type)
{
case ASCII:
case EBCDIC: return 1;
case UCS2: return 2;
case UTF16:
case UTF32:
case UTF8: return 4;
}
return ~0; // to silence gcc warning
}
inline uint Enc::szCodeUnit() const
{
switch (type)
{
case ASCII:
case EBCDIC:
case UTF8: return 1;
case UCS2:
case UTF16: return 2;
case UTF32: return 4;
}
return ~0; // to silence gcc warning
}
inline bool Enc::set(type_t t)
{
if (type == t)
return true;
else if (type != ASCII)
return false;
else
{
type = t;
return true;
}
}
inline void Enc::unset(type_t t)
{
if (type == t)
type = ASCII;
}
inline bool Enc::is(type_t t) const
{
return type == t;
}
inline void Enc::setPolicy(policy_t t)
{
policy = t;
}
} // namespace re2c
#endif // _enc_h
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