/*
 * Copyright 2006 The Android Open Source Project
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef SkUtils_DEFINED
#define SkUtils_DEFINED

#include "SkTypes.h"
#include "SkMath.h"
#include "SkOpts.h"
#include "SkTypeface.h"

/** Similar to memset(), but it assigns a 16, 32, or 64-bit value into the buffer.
    @param buffer   The memory to have value copied into it
    @param value    The value to be copied into buffer
    @param count    The number of times value should be copied into the buffer.
*/
static inline void sk_memset16(uint16_t buffer[], uint16_t value, int count) {
    SkOpts::memset16(buffer, value, count);
}
static inline void sk_memset32(uint32_t buffer[], uint32_t value, int count) {
    SkOpts::memset32(buffer, value, count);
}
static inline void sk_memset64(uint64_t buffer[], uint64_t value, int count) {
    SkOpts::memset64(buffer, value, count);
}
///////////////////////////////////////////////////////////////////////////////

#define kMaxBytesInUTF8Sequence     4

#ifdef SK_DEBUG
    int SkUTF8_LeadByteToCount(unsigned c);
#else
    #define SkUTF8_LeadByteToCount(c)   ((((0xE5 << 24) >> ((unsigned)c >> 4 << 1)) & 3) + 1)
#endif

inline int SkUTF8_CountUTF8Bytes(const char utf8[]) {
    SkASSERT(utf8);
    return SkUTF8_LeadByteToCount(*(const uint8_t*)utf8);
}

int         SkUTF8_CountUnichars(const char utf8[]);

/** These functions are safe: invalid sequences will return -1; */
int SkUTF8_CountUnichars(const void* utf8, size_t byteLength);
int SkUTF16_CountUnichars(const void* utf16, size_t byteLength);
int SkUTF32_CountUnichars(const void* utf32, size_t byteLength);
int SkUTFN_CountUnichars(SkTypeface::Encoding encoding, const void* utfN, size_t byteLength);

/** This function is safe: invalid UTF8 sequences will return -1
 *  When -1 is returned, ptr is unchanged.
 *  Precondition: *ptr < end;
 */
SkUnichar SkUTF8_NextUnicharWithError(const char** ptr, const char* end);

/** this version replaces invalid utf-8 sequences with code point U+FFFD. */
inline SkUnichar SkUTF8_NextUnichar(const char** ptr, const char* end) {
    SkUnichar val = SkUTF8_NextUnicharWithError(ptr, end);
    if (val < 0) {
        *ptr = end;
        return 0xFFFD;  // REPLACEMENT CHARACTER
    }
    return val;
}

SkUnichar   SkUTF8_ToUnichar(const char utf8[]);
SkUnichar   SkUTF8_NextUnichar(const char**);
SkUnichar   SkUTF8_PrevUnichar(const char**);

/** Return the number of bytes need to convert a unichar
    into a utf8 sequence. Will be 1..kMaxBytesInUTF8Sequence,
    or 0 if uni is illegal.
*/
size_t      SkUTF8_FromUnichar(SkUnichar uni, char utf8[] = nullptr);

///////////////////////////////////////////////////////////////////////////////

#define SkUTF16_IsHighSurrogate(c)  (((c) & 0xFC00) == 0xD800)
#define SkUTF16_IsLowSurrogate(c)   (((c) & 0xFC00) == 0xDC00)

int SkUTF16_CountUnichars(const uint16_t utf16[]);
// returns the current unichar and then moves past it (*p++)
SkUnichar SkUTF16_NextUnichar(const uint16_t**);
SkUnichar SkUTF16_NextUnichar(const uint16_t** srcPtr, const uint16_t* end);

// this guy backs up to the previus unichar value, and returns it (*--p)
SkUnichar SkUTF16_PrevUnichar(const uint16_t**);
size_t SkUTF16_FromUnichar(SkUnichar uni, uint16_t utf16[] = nullptr);

size_t SkUTF16_ToUTF8(const uint16_t utf16[], int numberOf16BitValues,
                      char utf8[] = nullptr);

inline bool SkUnichar_IsVariationSelector(SkUnichar uni) {
/*  The 'true' ranges are:
 *      0x180B  <= uni <=  0x180D
 *      0xFE00  <= uni <=  0xFE0F
 *      0xE0100 <= uni <= 0xE01EF
 */
    if (uni < 0x180B || uni > 0xE01EF) {
        return false;
    }
    if ((uni > 0x180D && uni < 0xFE00) || (uni > 0xFE0F && uni < 0xE0100)) {
        return false;
    }
    return true;
}

namespace SkHexadecimalDigits {
    extern const char gUpper[16];  // 0-9A-F
    extern const char gLower[16];  // 0-9a-f
}

#endif