CFStringEncodingConverterExt.h

/*	CFStringEncodingConverterExt.h
	Copyright (c) 1998-2018, Apple Inc. and the Swift project authors
 
	Portions Copyright (c) 2014-2018, Apple Inc. and the Swift project authors
	Licensed under Apache License v2.0 with Runtime Library Exception
	See http://swift.org/LICENSE.txt for license information
	See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
*/

#if !defined(__COREFOUNDATION_CFSTRINGENCODINGCONVERETEREXT__)
#define __COREFOUNDATION_CFSTRINGENCODINGCONVERETEREXT__ 1

#include <CoreFoundation/CFStringEncodingConverter.h>

CF_EXTERN_C_BEGIN

#define MAX_DECOMPOSED_LENGTH (10)

enum {
    kCFStringEncodingConverterStandard = 0,
    kCFStringEncodingConverterCheapEightBit = 1,
    kCFStringEncodingConverterStandardEightBit = 2,
    kCFStringEncodingConverterCheapMultiByte = 3,
    kCFStringEncodingConverterPlatformSpecific = 4, // Other fields are ignored
    kCFStringEncodingConverterICU = 5 // Other fields are ignored
};

/* kCFStringEncodingConverterStandard */
typedef CFIndex (*CFStringEncodingToBytesProc)(uint32_t flags, const UniChar *characters, CFIndex numChars, uint8_t *bytes, CFIndex maxByteLen, CFIndex *usedByteLen);
typedef CFIndex (*CFStringEncodingToUnicodeProc)(uint32_t flags, const uint8_t *bytes, CFIndex numBytes, UniChar *characters, CFIndex maxCharLen, CFIndex *usedCharLen);
/* kCFStringEncodingConverterCheapEightBit */
typedef bool (*CFStringEncodingCheapEightBitToBytesProc)(uint32_t flags, UniChar character, uint8_t *byte);
typedef bool (*CFStringEncodingCheapEightBitToUnicodeProc)(uint32_t flags, uint8_t byte, UniChar *character);
/* kCFStringEncodingConverterStandardEightBit */
typedef uint16_t (*CFStringEncodingStandardEightBitToBytesProc)(uint32_t flags, const UniChar *characters, CFIndex numChars, uint8_t *byte);
typedef uint16_t (*CFStringEncodingStandardEightBitToUnicodeProc)(uint32_t flags, uint8_t byte, UniChar *characters);
/* kCFStringEncodingConverterCheapMultiByte */
typedef uint16_t (*CFStringEncodingCheapMultiByteToBytesProc)(uint32_t flags, UniChar character, uint8_t *bytes);
typedef uint16_t (*CFStringEncodingCheapMultiByteToUnicodeProc)(uint32_t flags, const uint8_t *bytes, CFIndex numBytes, UniChar *character);

typedef CFIndex (*CFStringEncodingToBytesLenProc)(uint32_t flags, const UniChar *characters, CFIndex numChars);
typedef CFIndex (*CFStringEncodingToUnicodeLenProc)(uint32_t flags, const uint8_t *bytes, CFIndex numBytes);

typedef CFIndex (*CFStringEncodingToBytesPrecomposeProc)(uint32_t flags, const UniChar *character, CFIndex numChars, uint8_t *bytes, CFIndex maxByteLen, CFIndex *usedByteLen);
typedef bool (*CFStringEncodingIsValidCombiningCharacterProc)(UniChar character);

typedef struct {
    // These conversion functions should be accessed and called as dictated by .encodingClass.
    // An encoding class of kCFStringEncodingConverterStandard corresponds to .standard; kCFStringEncodingConverterCheapEightBit corresponds to .cheapEightBit; etc.
    union {
        CFStringEncodingToBytesProc standard;
        CFStringEncodingCheapEightBitToBytesProc cheapEightBit;
        CFStringEncodingStandardEightBitToBytesProc standardEightBit;
        CFStringEncodingCheapMultiByteToBytesProc cheapMultibyte;
    } toBytes;
    union {
        CFStringEncodingToUnicodeProc standard;
        CFStringEncodingCheapEightBitToUnicodeProc cheapEightBit;
        CFStringEncodingStandardEightBitToUnicodeProc standardEightBit;
        CFStringEncodingCheapMultiByteToUnicodeProc cheapMultibyte;
    } toUnicode;

    uint16_t maxBytesPerChar;
    uint16_t maxDecomposedCharLen;
    uint8_t encodingClass;
    uint32_t :24;
    CFStringEncodingToBytesLenProc toBytesLen;
    CFStringEncodingToUnicodeLenProc toUnicodeLen;
    CFStringEncodingToBytesFallbackProc toBytesFallback;
    CFStringEncodingToUnicodeFallbackProc toUnicodeFallback;
    CFStringEncodingToBytesPrecomposeProc toBytesPrecompose;
    CFStringEncodingIsValidCombiningCharacterProc isValidCombiningChar;
} CFStringEncodingConverter;

enum {
    kCFStringEncodingGetConverterSelector = 0,
    kCFStringEncodingIsDecomposableCharacterSelector = 1,
    kCFStringEncodingDecomposeCharacterSelector = 2,
    kCFStringEncodingIsValidLatin1CombiningCharacterSelector = 3,
    kCFStringEncodingPrecomposeLatin1CharacterSelector = 4
};

#define BOOTSTRAPFUNC_NAME	CFStringEncodingBootstrap
typedef const CFStringEncodingConverter* (*CFStringEncodingBootstrapProc)(uint32_t encoding, const void *getSelector);

/* Latin precomposition */
/* This function does not precompose recursively nor to U+01E0 and U+01E1.
*/
extern bool CFStringEncodingIsValidCombiningCharacterForLatin1(UniChar character);
extern UniChar CFStringEncodingPrecomposeLatinCharacter(const UniChar *character, CFIndex numChars, CFIndex *usedChars);

/* Convenience functions for converter development */
typedef struct _CFStringEncodingUnicodeTo8BitCharMap {
    UniChar _u;
    uint8_t _c;
    uint8_t :8;
} CFStringEncodingUnicodeTo8BitCharMap;

/* Binary searches CFStringEncodingUnicodeTo8BitCharMap */
CF_INLINE bool CFStringEncodingUnicodeTo8BitEncoding(const CFStringEncodingUnicodeTo8BitCharMap *theTable, CFIndex numElem, UniChar character, uint8_t *ch) {
    const CFStringEncodingUnicodeTo8BitCharMap *p, *q, *divider;

    if ((character < theTable[0]._u) || (character > theTable[numElem-1]._u)) {
        return 0;
    }
    p = theTable;
    q = p + (numElem-1);
    while (p <= q) {
        divider = p + ((q - p) >> 1);	/* divide by 2 */
        if (character < divider->_u) { q = divider - 1; }
        else if (character > divider->_u) { p = divider + 1; }
        else { *ch = divider->_c; return 1; }
    }
    return 0;
}


CF_EXTERN_C_END

#endif /* ! __COREFOUNDATION_CFSTRINGENCODINGCONVERETEREXT__ */