#include "unicode.h"
#include "unicode-data.h"

#include <algorithm>
#include <cassert>
#include <cstddef>
#include <cstdint>
#include <map>
#include <regex>
#include <stdexcept>
#include <string>
#include <unordered_map>
#include <utility>
#include <vector>

size_t unicode_len_utf8(char src) {
 const size_t lookup[] = { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 3, 4 };
 uint8_t highbits = static_cast<uint8_t>(src) >> 4;
 return lookup[highbits];
}

static std::string unicode_cpts_to_utf8(const std::vector<uint32_t> & cps) {
 std::string result;
 for (size_t i = 0; i < cps.size(); ++i) {
 result.append(unicode_cpt_to_utf8(cps[i]));
 }
 return result;
}

uint32_t unicode_cpt_from_utf8(const std::string & utf8, size_t & offset) {
 assert(offset < utf8.size());
 if (!(utf8[offset + 0] & 0x80)) {
 auto result = utf8[offset + 0];
 offset += 1;
 return result;
 }
 if (!(utf8[offset + 0] & 0x40)) {
 throw std::invalid_argument("invalid character");
 }
 if (!(utf8[offset + 0] & 0x20)) {
 if (offset + 1 >= utf8.size() || ! ((utf8[offset + 1] & 0xc0) == 0x80)) {
 throw std::invalid_argument("invalid character");
 }
 auto result = ((utf8[offset + 0] & 0x1f) << 6) | (utf8[offset + 1] & 0x3f);
 offset += 2;
 return result;
 }
 if (!(utf8[offset + 0] & 0x10)) {
 if (offset + 2 >= utf8.size() || ! ((utf8[offset + 1] & 0xc0) == 0x80) || ! ((utf8[offset + 2] & 0xc0) == 0x80)) {
 throw std::invalid_argument("invalid character");
 }
 auto result = ((utf8[offset + 0] & 0x0f) << 12) | ((utf8[offset + 1] & 0x3f) << 6) | (utf8[offset + 2] & 0x3f);
 offset += 3;
 return result;
 }
 if (!(utf8[offset + 0] & 0x08)) {
 if (offset + 3 >= utf8.size() || ! ((utf8[offset + 1] & 0xc0) == 0x80) || ! ((utf8[offset + 2] & 0xc0) == 0x80) || !((utf8[offset + 3] & 0xc0) == 0x80)) {
 throw std::invalid_argument("invalid character");
 }
 auto result = ((utf8[offset + 0] & 0x07) << 18) | ((utf8[offset + 1] & 0x3f) << 12) | ((utf8[offset + 2] & 0x3f) << 6) | (utf8[offset + 3] & 0x3f);
 offset += 4;
 return result;
 }
 throw std::invalid_argument("failed to convert utf8 to codepoint");
}

//static std::vector<uint16_t> unicode_cpt_to_utf16(uint32_t cpt) {
// std::vector<uint16_t> result;
// if (/* 0x0000 <= cpt && */ cpt <= 0xffff) {
// result.emplace_back(cpt);
// return result;
// }
// if (0x10000 <= cpt && cpt <= 0x10ffff) {
// result.emplace_back(0xd800 | ((cpt - 0x10000) >> 10));
// result.emplace_back(0xdc00 | ((cpt - 0x10000) & 0x03ff));
// return result;
// }
// throw std::invalid_argument("failed to convert codepoint to utf16");
//}

//static std::vector<uint16_t> unicode_cpts_to_utf16(const std::vector<uint32_t> & cps) {
// std::vector<uint16_t> result;
// for (size_t i = 0; i < cps.size(); ++i) {
// auto temp = unicode_cpt_to_utf16(cps[i]);
// result.insert(result.end(), temp.begin(), temp.end());
// }
// return result;
//}

//static uint32_t unicode_cpt_from_utf16(const std::vector<uint16_t> & utf16, size_t & offset) {
// assert(offset < utf16.size());
// if (((utf16[0] >> 10) << 10) != 0xd800) {
// auto result = utf16[offset + 0];
// offset += 1;
// return result;
// }
//
// if (offset + 1 >= utf16.size() || !((utf16[1] & 0xdc00) == 0xdc00)) {
// throw std::invalid_argument("invalid character");
// }
//
// auto result = 0x10000 + (((utf16[0] & 0x03ff) << 10) | (utf16[1] & 0x03ff));
// offset += 2;
// return result;
//}

//static std::vector<uint32_t> unicode_cpts_from_utf16(const std::vector<uint16_t> & utf16) {
// std::vector<uint32_t> result;
// size_t offset = 0;
// while (offset < utf16.size()) {
// result.push_back(unicode_cpt_from_utf16(utf16, offset));
// }
// return result;
//}

static std::vector<unicode_cpt_flags> unicode_cpt_flags_array() {
 std::vector<unicode_cpt_flags> cpt_flags(MAX_CODEPOINTS, unicode_cpt_flags::UNDEFINED);

 assert (unicode_ranges_flags.begin()[0].first == 0);
 assert (unicode_ranges_flags.begin()[unicode_ranges_flags.size()-1].first == MAX_CODEPOINTS);
 for (size_t i = 1; i < unicode_ranges_flags.size(); ++i) {
 const auto range_ini = unicode_ranges_flags.begin()[i-1]; // codepoint_ini, flags
 const auto range_end = unicode_ranges_flags.begin()[i]; // codepoint_end, flags
 for (uint32_t cpt = range_ini.first; cpt < range_end.first; ++cpt) {
 cpt_flags[cpt] = range_ini.second;
 }
 }

 for (auto cpt : unicode_set_whitespace) {
 cpt_flags[cpt].is_whitespace = true;
 }

 for (auto p : unicode_map_lowercase) {
 cpt_flags[p.second].is_lowercase = true;
 }

 for (auto p : unicode_map_uppercase) {
 cpt_flags[p.second].is_uppercase = true;
 }

 for (auto &range : unicode_ranges_nfd) { // start, last, nfd
 cpt_flags[range.nfd].is_nfd = true;
 }

 return cpt_flags;
}

static std::unordered_map<uint8_t, std::string> unicode_byte_to_utf8_map() {
 std::unordered_map<uint8_t, std::string> map;
 for (int ch = 0x21; ch <= 0x7E; ++ch) { // u'!' to u'~'
 assert(0 <= ch && ch < 256);
 map[ch] = unicode_cpt_to_utf8(ch);
 }
 for (int ch = 0xA1; ch <= 0xAC; ++ch) { // u'¡' to u'¬'
 assert(0 <= ch && ch < 256);
 map[ch] = unicode_cpt_to_utf8(ch);
 }
 for (int ch = 0xAE; ch <= 0xFF; ++ch) { // u'®' to u'ÿ'
 assert(0 <= ch && ch < 256);
 map[ch] = unicode_cpt_to_utf8(ch);
 }
 auto n = 0;
 for (int ch = 0; ch < 256; ++ch) {
 if (map.find(ch) == map.end()) {
 map[ch] = unicode_cpt_to_utf8(256 + n);
 ++n;
 }
 }
 return map;
}

static std::unordered_map<std::string, uint8_t> unicode_utf8_to_byte_map() {
 std::unordered_map<std::string, uint8_t> map;
 for (int ch = 0x21; ch <= 0x7E; ++ch) { // u'!' to u'~'
 assert(0 <= ch && ch < 256);
 map[unicode_cpt_to_utf8(ch)] = ch;
 }
 for (int ch = 0xA1; ch <= 0xAC; ++ch) { // u'¡' to u'¬'
 assert(0 <= ch && ch < 256);
 map[unicode_cpt_to_utf8(ch)] = ch;
 }
 for (int ch = 0xAE; ch <= 0xFF; ++ch) { // u'®' to u'ÿ'
 assert(0 <= ch && ch < 256);
 map[unicode_cpt_to_utf8(ch)] = ch;
 }
 auto n = 0;
 for (int ch = 0; ch < 256; ++ch) {
 if (map.find(unicode_cpt_to_utf8(ch)) == map.end()) {
 map[unicode_cpt_to_utf8(256 + n)] = ch;
 ++n;
 }
 }
 return map;
}

static std::vector<std::string> unicode_byte_encoding_process(const std::vector<std::string> & bpe_words) {
 std::vector<std::string> bpe_encoded_words;
 for (const auto & word : bpe_words) {
 std::string text_utf;
 auto utf_word = unicode_cpts_from_utf8(word);
 for (size_t i = 0; i < utf_word.size(); ++i) {
 text_utf += unicode_cpt_to_utf8(utf_word[i]);
 }

 std::string encoded_token;
 for (char & c : text_utf) {
 encoded_token += unicode_byte_to_utf8(c);
 }
 bpe_encoded_words.emplace_back(encoded_token);
 }
 return bpe_encoded_words;
}

// GPT2 system regex: 's|'t|'re|'ve|'m|'ll|'d| ?\p{L}+| ?\p{N}+| ?[^\s\p{L}\p{N}]+|\s+(?!\S)|\s+
static std::vector<size_t> unicode_regex_split_custom_gpt2(const std::string & text, const std::vector<size_t> & offsets) {
 std::vector<size_t> bpe_offsets; // store the offset of each word
 bpe_offsets.reserve(offsets.size()); // Reserve memory for the approximate size

 const auto cpts = unicode_cpts_from_utf8(text);

 size_t start = 0;
 for (auto offset : offsets) {
 const size_t offset_ini = start;
 const size_t offset_end = start + offset;
 assert(offset_end <= cpts.size());
 start = offset_end;

 static const uint32_t OUT_OF_RANGE = 0xFFFFFFFF;
 auto _get_cpt = [&] (const size_t pos) -> uint32_t {
 return (offset_ini <= pos && pos < offset_end) ? cpts[pos] : OUT_OF_RANGE;
 };

 auto _get_flags = [&] (const size_t pos) -> unicode_cpt_flags {
 return (offset_ini <= pos && pos < offset_end) ? unicode_cpt_flags_from_cpt(cpts[pos]) : unicode_cpt_flags{};
 };

 size_t _prev_end = offset_ini;
 auto _add_token = [&] (const size_t end) -> size_t {
 assert(_prev_end <= end && end <= offset_end);
 size_t len = end - _prev_end;
 if (len > 0) {
 bpe_offsets.push_back(len);
 }
 _prev_end = end;
 //if (len > 0) {
 // std::string s = "";
 // for(size_t p = end-len; p < end; p++)
 // s += unicode_cpt_to_utf8(cpts[p]);
 // printf(">>> '%s'\n", s.c_str());
 //}
 return len;
 };

 for (size_t pos = offset_ini; pos < offset_end; /*pos++*/ ) {
 const uint32_t cpt = _get_cpt(pos);
 const auto flags = _get_flags(pos);

 // regex: 's|'t|'re|'ve|'m|'ll|'d
 if (cpt == '\'' && pos+1 < offset_end) {
 uint32_t cpt_next = _get_cpt(pos+1);
 if (cpt_next == 's' || cpt_next == 't' || cpt_next == 'm' || cpt_next == 'd') {
 pos += _add_token(pos+2);
 continue;
 }
 if (pos+2 < offset_end) {
 uint32_t cpt_next_next = _get_cpt(pos+2);
 if ((cpt_next == 'r' && cpt_next_next == 'e') ||
 (cpt_next == 'v' && cpt_next_next == 'e') ||
 (cpt_next == 'l' && cpt_next_next == 'l')) {
 pos += _add_token(pos+3);
 continue;
 }
 }
 }

 auto flags2 = (cpt == ' ' ? _get_flags(pos+1) : flags);
 // regex: <space>?\p{L}+
 if (flags2.is_letter) {
 pos += (cpt == ' ');
 while (flags2.is_letter) {
 flags2 = _get_flags(++pos);
 }
 _add_token(pos);
 continue;
 }
 // regex: <space>?\p{N}+
 if (flags2.is_number) {
 pos += (cpt == ' ');
 while (flags2.is_number) {
 flags2 = _get_flags(++pos);
 }
 _add_token(pos);
 continue;
 }
 // regex: <space>?[^\s\p{L}\p{N}]+
 if (!(flags2.is_whitespace | flags2.is_letter | flags2.is_number) && flags2.as_uint()) {
 pos += (cpt == ' ');
 while (!(flags2.is_whitespace | flags2.is_letter | flags2.is_number) && flags2.as_uint()) {
 flags2 = _get_flags(++pos);
 }
 _add_token(pos);
 continue;
 }

 size_t num_whitespaces = 0;
 while (_get_flags(pos+num_whitespaces).is_whitespace) {
 num_whitespaces++;
 }

 // regex: \s+(?!\S)
 if (num_whitespaces > 1 && _get_cpt(pos+num_whitespaces) != OUT_OF_RANGE) {
 pos += num_whitespaces - 1;
 _add_token(pos);
 continue;
 }

 // regex: \s+
 if (num_whitespaces > 0) {
 pos += num_whitespaces;
 _add_token(pos);
 continue;
 }

 // no matches
 _add_token(++pos);
 }
 }

 return bpe_offsets;
}

// LLAMA3 system regex: "(?i:'s|'t|'re|'ve|'m|'ll|'d)|[^\r\n\p{L}\p{N}]?\p{L}+|\p{N}{1,3}| ?[^\s\p{L}\p{N}]+[\r\n]*|\s*[\r\n]+|\s+(?!\S)|\s+"
static std::vector<size_t> unicode_regex_split_custom_llama3(const std::string & text, const std::vector<size_t> & offsets) {
 std::vector<size_t> bpe_offsets; // store the offset of each word
 bpe_offsets.reserve(offsets.size()); // Reserve memory for the approximate size

 const auto cpts = unicode_cpts_from_utf8(text);

 size_t start = 0;
 for (auto offset : offsets) {
 const size_t offset_ini = start;
 const size_t offset_end = start + offset;
 assert(offset_end <= cpts.size());
 start = offset_end;

 static const uint32_t OUT_OF_RANGE = 0xFFFFFFFF;
 auto _get_cpt = [&] (const size_t pos) -> uint32_t {
 return (offset_ini <= pos && pos < offset_end) ? cpts[pos] : OUT_OF_RANGE;
 };

 auto _get_flags = [&] (const size_t pos) -> unicode_cpt_flags {
 return (offset_ini <= pos && pos < offset_end) ? unicode_cpt_flags_from_cpt(cpts[pos]) : unicode_cpt_flags{};
 };

 size_t _prev_end = offset_ini;
 auto _add_token = [&] (const size_t end) -> size_t {
 assert(_prev_end <= end && end <= offset_end);
 size_t len = end - _prev_end;
 if (len > 0) {
 bpe_offsets.push_back(len);
 }
 _prev_end = end;
 //if (len > 0) {
 // std::string s = "";
 // for(size_t p = end-len; p < end; p++)
 // s += unicode_cpt_to_utf8(cpts[p]);
 // printf(">>> '%s'\n", s.c_str());
 //}
 return len;
 };

 for (size_t pos = offset_ini; pos < offset_end; /*pos++*/ ) {
 const uint32_t cpt = _get_cpt(pos);
 const auto flags = _get_flags(pos);

 // regex: (?i:'s|'t|'re|'ve|'m|'ll|'d) // case insensitive
 if (cpt == '\'' && pos+1 < offset_end) {
 uint32_t cpt_next = unicode_tolower(_get_cpt(pos+1));
 if (cpt_next == 's' || cpt_next == 't' || cpt_next == 'm' || cpt_next == 'd') {
 pos += _add_token(pos+2);
 continue;
 }
 if (pos+2 < offset_end) {
 uint32_t cpt_next_next = unicode_tolower(_get_cpt(pos+2));
 if ((cpt_next == 'r' && cpt_next_next == 'e') ||
 (cpt_next == 'v' && cpt_next_next == 'e') ||
 (cpt_next == 'l' && cpt_next_next == 'l')) {
 pos += _add_token(pos+3);
 continue;
 }
 }
 }

 // regex: [^\r\n\p{L}\p{N}]?\p{L}+
 if (!(cpt == '\r' || cpt == '\n' || flags.is_number)) {
 if (flags.is_letter || _get_flags(pos+1).is_letter) { // one or more letters
 pos++;
 while (_get_flags(pos).is_letter) {
 pos++;
 }
 _add_token(pos);
 continue;
 }
 }

 // regex: \p{N}{1,3}
 if (flags.is_number) {
 size_t ini = pos;
 while (_get_flags(pos).is_number) {
 if (++pos - ini >= 3 ) {
 _add_token(pos);
 ini = pos;
 }
 }
 _add_token(pos);
 continue;
 }

 // regex: <space>?[^\s\p{L}\p{N}]+[\r\n]*
 auto flags2 = (cpt == ' ' ? _get_flags(pos+1) : flags);
 if (!(flags2.is_whitespace | flags2.is_letter | flags2.is_number) && flags.as_uint()) {
 pos += (cpt == ' ');
 while (!(flags2.is_whitespace | flags2.is_letter | flags2.is_number) && flags2.as_uint()) {
 flags2 = _get_flags(++pos);
 }
 uint32_t cpt2 = _get_cpt(pos);
 while (cpt2 == '\r' || cpt2 == '\n') {
 cpt2 = _get_cpt(++pos);
 }
 _add_token(pos);
 continue;
 }

 size_t num_whitespaces = 0;
 size_t last_end_r_or_n = 0;
 while (_get_flags(pos+num_whitespaces).is_whitespace) {
 uint32_t cpt2 = _get_cpt(pos+num_whitespaces);
 if (cpt2 == '\r' || cpt2 == '\n') {
 last_end_r_or_n = pos + num_whitespaces + 1;
 }
 num_whitespaces++;
 }

 // regex: \s*[\r\n]+
 if (last_end_r_or_n > 0) {
 pos = last_end_r_or_n;
 _add_token(pos);
 continue;
 }

 // regex: \s+(?!\S)
 if (num_whitespaces > 1 && _get_cpt(pos+num_whitespaces) != OUT_OF_RANGE) {
 pos += num_whitespaces - 1;
 _add_token(pos);
 continue;
 }

 // regex: \s+
 if (num_whitespaces > 0) {
 pos += num_whitespaces;
 _add_token(pos);
 continue;
 }

 // no matches
 _add_token(++pos);
 }
 }

 return bpe_offsets;
}

// Qwen2 system regex: "(?i:'s|'t|'re|'ve|'m|'ll|'d)|[^\\r\\n\\p{L}\\p{N}]?\\p{L}+|\\p{N}| ?[^\\s\\p{L}\\p{N}]+[\\r\\n]*|\\s*[\\r\\n]+|\\s+(?!\\S)|\\s+"
static std::vector<size_t> unicode_regex_split_custom_qwen2(const std::string & text, const std::vector<size_t> & offsets) {
 std::vector<size_t> bpe_offsets; // store the offset of each word
 bpe_offsets.reserve(offsets.size()); // Reserve memory for the approximate size

 const auto cpts = unicode_cpts_from_utf8(text);

 size_t start = 0;
 for (auto offset : offsets) {
 const size_t offset_ini = start;
 const size_t offset_end = start + offset;
 assert(offset_end <= cpts.size());
 start = offset_end;

 static const uint32_t OUT_OF_RANGE = 0xFFFFFFFF;
 auto _get_cpt = [&] (const size_t pos) -> uint32_t {
 return (offset_ini <= pos && pos < offset_end) ? cpts[pos] : OUT_OF_RANGE;
 };

 auto _get_flags = [&] (const size_t pos) -> unicode_cpt_flags {
 return (offset_ini <= pos && pos < offset_end) ? unicode_cpt_flags_from_cpt(cpts[pos]) : unicode_cpt_flags{};
 };

 size_t _prev_end = offset_ini;
 auto _add_token = [&] (const size_t end) -> size_t {
 assert(_prev_end <= end && end <= offset_end);
 size_t len = end - _prev_end;
 if (len > 0) {
 bpe_offsets.push_back(len);
 }
 _prev_end = end;
 //if (len > 0) {
 // std::string s = "";
 // for(size_t p = end-len; p < end; p++)
 // s += unicode_cpt_to_utf8(cpts[p]);
 // printf(">>> '%s'\n", s.c_str());
 //}
 return len;
 };

 for (size_t pos = offset_ini; pos < offset_end; /*pos++*/ ) {
 const uint32_t cpt = _get_cpt(pos);
 const auto flags = _get_flags(pos);

 // regex: (?i:'s|'t|'re|'ve|'m|'ll|'d) // case insensitive
 if (cpt == '\'' && pos+1 < offset_end) {
 uint32_t cpt_next = unicode_tolower(_get_cpt(pos+1));
 if (cpt_next == 's' || cpt_next == 't' || cpt_next == 'm' || cpt_next == 'd') {
 pos += _add_token(pos+2);
 continue;
 }
 if (pos+2 < offset_end) {
 uint32_t cpt_next_next = unicode_tolower(_get_cpt(pos+2));
 if ((cpt_next == 'r' && cpt_next_next == 'e') ||
 (cpt_next == 'v' && cpt_next_next == 'e') ||
 (cpt_next == 'l' && cpt_next_next == 'l')) {
 pos += _add_token(pos+3);
 continue;
 }
 }
 }

 // regex: [^\r\n\p{L}\p{N}]?\p{L}+
 if (!(cpt == '\r' || cpt == '\n' || flags.is_number)) {
 if (flags.is_letter || _get_flags(pos+1).is_letter) { // one or more letters
 pos++;
 while (_get_flags(pos).is_letter) {
 pos++;
 }
 _add_token(pos);
 continue;
 }
 }

 // regex: \p{N}
 if (flags.is_number) {
 pos++;
 _add_token(pos);
 continue;
 }

 // regex: <space>?[^\s\p{L}\p{N}]+[\r\n]*
 auto flags2 = (cpt == ' ' ? _get_flags(pos+1) : flags);
 if (!(flags2.is_whitespace | flags2.is_letter | flags2.is_number) && flags.as_uint()) {
 pos += (cpt == ' ');
 while (!(flags2.is_whitespace | flags2.is_letter | flags2.is_number) && flags2.as_uint()) {
 flags2 = _get_flags(++pos);
 }
 uint32_t cpt2 = _get_cpt(pos);
 while (cpt2 == '\r' || cpt2 == '\n') {
 cpt2 = _get_cpt(++pos);
 }
 _add_token(pos);
 continue;
 }

 size_t num_whitespaces = 0;
 size_t last_end_r_or_n = 0;
 while (_get_flags(pos+num_whitespaces).is_whitespace) {
 uint32_t cpt2 = _get_cpt(pos+num_whitespaces);
 if (cpt2 == '\r' || cpt2 == '\n') {
 last_end_r_or_n = pos + num_whitespaces + 1;
 }
 num_whitespaces++;
 }

 // regex: \s*[\r\n]+
 if (last_end_r_or_n > 0) {
 pos = last_end_r_or_n;
 _add_token(pos);
 continue;
 }

 // regex: \s+(?!\S)
 if (num_whitespaces > 1 && _get_cpt(pos+num_whitespaces) != OUT_OF_RANGE) {
 pos += num_whitespaces - 1;
 _add_token(pos);
 continue;
 }

 // regex: \s+
 if (num_whitespaces > 0) {
 pos += num_whitespaces;
 _add_token(pos);
 continue;
 }

 // no matches
 _add_token(++pos);
 }
 }

 return bpe_offsets;
}

template <typename CharT>
static std::vector<size_t> unicode_regex_split_stl(const std::basic_string<CharT> & text, const std::basic_string<CharT> & regex, const std::vector<size_t> & offsets) {
 using BidirIt = typename std::basic_string<CharT>::const_iterator;
#ifdef _MSC_VER
 // Bypass bug in MSVC: https://github.com/ggml-org/llama.cpp/issues/17830
 constexpr auto regex_flags = std::regex_constants::ECMAScript;
#else
 constexpr auto regex_flags = std::regex_constants::optimize | std::regex_constants::nosubs;
#endif
 std::basic_regex<CharT> expr(regex, regex_flags);
 std::vector<size_t> bpe_offsets; // store the offset of each word
 bpe_offsets.reserve(offsets.size()); // Reserve memory for the approximate size
 size_t start = 0;
 for (auto offset : offsets) {
 std::regex_iterator<BidirIt> it(text.begin() + start, text.begin() + start + offset, expr);
 std::regex_iterator<BidirIt> end;

 int64_t start_idx = 0;
 while (it != end) {
 std::match_results<BidirIt> match = *it;
 if (match.position() > start_idx) {
 bpe_offsets.emplace_back(match.position() - start_idx);
 }
 bpe_offsets.emplace_back(match.length());
 start_idx = match.position() + match.length();
 ++it;
 }

 if (start_idx < (int64_t) offset) {
 bpe_offsets.emplace_back(offset - start_idx);
 }
 start += offset;
 }

 return bpe_offsets;
}

// K2 system regex patterns (from tokenization_kimi.py):
// [\p{Han}]+|[^\r\n\p{L}\p{N}]?[\p{Lu}\p{Lt}\p{Lm}\p{Lo}\p{M}&&[^\p{Han}]]*[\p{Ll}\p{Lm}\p{Lo}\p{M}&&[^\p{Han}]]+(?i:'s|'t|'re|'ve|'m|'ll|'d)?|[^\r\n\p{L}\p{N}]?[\p{Lu}\p{Lt}\p{Lm}\p{Lo}\p{M}&&[^\p{Han}]]+[\p{Ll}\p{Lm}\p{Lo}\p{M}&&[^\p{Han}]]*(?i:'s|'t|'re|'ve|'m|'ll|'d)?|\p{N}{1,3}| ?[^\s\p{L}\p{N}]+[\r\n]*|\s*[\r\n]+|\s+(?!\S)|\s+
static std::vector<size_t> unicode_regex_split_custom_kimi_k2(const std::string & text, const std::vector<size_t> & offsets) {
 std::vector<size_t> bpe_offsets;
 bpe_offsets.reserve(offsets.size());

 const auto cpts = unicode_cpts_from_utf8(text);

 size_t start = 0;
 for (auto offset : offsets) {
 const size_t offset_ini = start;
 const size_t offset_end = start + offset;
 assert(offset_end <= cpts.size());
 start = offset_end;

 static const uint32_t OUT_OF_RANGE = 0xFFFFFFFF;
 auto _get_cpt = [&] (const size_t pos) -> uint32_t {
 return (offset_ini <= pos && pos < offset_end) ? cpts[pos] : OUT_OF_RANGE;
 };

 auto _get_flags = [&] (const size_t pos) -> unicode_cpt_flags {
 return (offset_ini <= pos && pos < offset_end) ? unicode_cpt_flags_from_cpt(cpts[pos]) : unicode_cpt_flags{};
 };

 size_t _prev_end = offset_ini;
 auto _add_token = [&] (const size_t end) -> size_t {
 assert(_prev_end <= end && end <= offset_end);
 size_t len = end - _prev_end;
 if (len > 0) {
 bpe_offsets.push_back(len);
 }
 _prev_end = end;
 return len;
 };

 for (size_t pos = offset_ini; pos < offset_end; /*pos++*/ ) {
 const uint32_t cpt = _get_cpt(pos);
 const auto flags = _get_flags(pos);

 // Pattern 1: [\p{Han}]+ (Chinese characters)
 if (unicode_cpt_is_han(cpt)) {
 while (unicode_cpt_is_han(_get_cpt(pos))) {
 pos++;
 }
 _add_token(pos);
 continue;
 }

 // Pattern 2 & 3: Letter words excluding Han characters with optional contractions
 // [^\r\n\p{L}\p{N}]?[\p{Lu}\p{Lt}\p{Lm}\p{Lo}\p{M}&&[^\p{Han}]]*[\p{Ll}\p{Lm}\p{Lo}\p{M}&&[^\p{Han}]]+(?:'s|'t|'re|'ve|'m|'ll|'d)?
 // [^\r\n\p{L}\p{N}]?[\p{Lu}\p{Lt}\p{Lm}\p{Lo}\p{M}&&[^\p{Han}]]+[\p{Ll}\p{Lm}\p{Lo}\p{M}&&[^\p{Han}]]*(?:'s|'t|'re|'ve|'m|'ll|'d)?
 // Check if current char is a letter OR if current char could be a leading char and next char is a letter
 bool is_letter_pattern = (flags.is_letter && !unicode_cpt_is_han(cpt)) ||
 (!(cpt == '\r' || cpt == '\n' || flags.is_letter || flags.is_number) &&
 _get_flags(pos + 1).is_letter && !unicode_cpt_is_han(_get_cpt(pos + 1)));

 if (is_letter_pattern) {
 // Handle optional leading non-letter/non-number character
 bool has_leading_char = false;
 if (!(cpt == '\r' || cpt == '\n' || flags.is_letter || flags.is_number)) {
 has_leading_char = true;
 pos++;
 }

 // Match letter sequence (excluding Han characters)
 bool has_letters = false;
 while (_get_flags(pos).is_letter && !unicode_cpt_is_han(_get_cpt(pos))) {
 has_letters = true;
 pos++;
 }

 // Only proceed if we found letters (after potentially skipping leading char)
 if (has_letters || (!has_leading_char && _get_flags(pos).is_letter && !unicode_cpt_is_han(_get_cpt(pos)))) {
 if (!has_letters) pos++; // consume the first letter if we didn't already

 // Continue consuming letters
 while (_get_flags(pos).is_letter && !unicode_cpt_is_han(_get_cpt(pos))) {
 pos++;
 }

 // Check for optional contractions (?:'s|'t|'re|'ve|'m|'ll|'d)
 if (_get_cpt(pos) == '\'' && pos + 1 < offset_end) {
 uint32_t cpt_next = unicode_tolower(_get_cpt(pos + 1));
 if (cpt_next == 's' || cpt_next == 't' || cpt_next == 'm' || cpt_next == 'd') {
 pos += 2;
 } else if (pos + 2 < offset_end) {
 uint32_t cpt_next_next = unicode_tolower(_get_cpt(pos + 2));
 if ((cpt_next == 'r' && cpt_next_next == 'e') ||
 (cpt_next == 'v' && cpt_next_next == 'e') ||
 (cpt_next == 'l' && cpt_next_next == 'l')) {
 pos += 3;
 }
 }
 }

 _add_token(pos);
 continue;
 } else if (has_leading_char) {
 // We consumed a leading char but found no letters, backtrack
 pos--;
 }
 }

 // Pattern 4: \p{N}{1,3} (numbers 1-3 digits)
 if (flags.is_number) {
 size_t ini = pos;
 while (_get_flags(pos).is_number) {
 if (++pos - ini >= 3) {
 _add_token(pos);
 ini = pos;
 }
 }
 _add_token(pos);
 continue;
 }

 // Pattern 5: ?[^\s\p{L}\p{N}]+[\r\n]* (optional space + non-word chars + optional newlines)
 auto flags2 = (cpt == ' ' ? _get_flags(pos + 1) : flags);
 if (!(flags2.is_whitespace || flags2.is_letter || flags2.is_number) && flags2.as_uint()) {
 pos += (cpt == ' ');
 while (!(flags2.is_whitespace || flags2.is_letter || flags2.is_number) && flags2.as_uint()) {
 flags2 = _get_flags(++pos);
 }
 // Match optional [\r\n]*
 uint32_t cpt2 = _get_cpt(pos);
 while (cpt2 == '\r' || cpt2 == '\n') {
 cpt2 = _get_cpt(++pos);
 }
 _add_token(pos);
 continue;
 }

 // Count whitespace characters
 size_t num_whitespaces = 0;
 size_t last_end_r_or_n = 0;
 while (_get_flags(pos + num_whitespaces).is_whitespace) {
 uint32_t cpt2 = _get_cpt(pos + num_whitespaces);
 if (cpt2 == '\r' || cpt2 == '\n') {
 last_end_r_or_n = pos + num_whitespaces + 1;
 }
 num_whitespaces++;
 }

 // Pattern 6: \s*[\r\n]+ (whitespace with newlines)
 if (last_end_r_or_n > 0) {
 pos = last_end_r_or_n;
 _add_token(pos);
 continue;
 }

 // Pattern 7: \s+(?!\S) (trailing whitespace)
 if (num_whitespaces > 1 && _get_cpt(pos + num_whitespaces) != OUT_OF_RANGE) {
 pos += num_whitespaces - 1;
 _add_token(pos);
 continue;
 }

 // Pattern 8: \s+ (general whitespace)
 if (num_whitespaces > 0) {
 pos += num_whitespaces;
 _add_token(pos);
 continue;
 }

 // No matches - consume single character
 _add_token(++pos);
 }
 }

 return bpe_offsets;
}

// AFMOE digit handling: splits digits with leading 1-2 based on total length modulo 3
static std::vector<size_t> unicode_regex_split_custom_afmoe(const std::string & text, const std::vector<size_t> & offsets) {
 std::vector<size_t> bpe_offsets;
 bpe_offsets.reserve(offsets.size());

 const auto cpts = unicode_cpts_from_utf8(text);

 size_t start = 0;
 for (auto offset : offsets) {
 const size_t offset_ini = start;
 const size_t offset_end = start + offset;
 assert(offset_end <= cpts.size());
 start = offset_end;

 auto _get_flags = [&] (const size_t pos) -> unicode_cpt_flags {
 return (offset_ini <= pos && pos < offset_end) ? unicode_cpt_flags_from_cpt(cpts[pos]) : unicode_cpt_flags{};
 };

 size_t _prev_end = offset_ini;
 auto _add_token = [&] (const size_t end) -> size_t {
 assert(_prev_end <= end && end <= offset_end);
 size_t len = end - _prev_end;
 if (len > 0) {
 bpe_offsets.push_back(len);
 }
 _prev_end = end;
 return len;
 };

 for (size_t pos = offset_ini; pos < offset_end; ) {
 const auto flags = _get_flags(pos);

 // Handle digit sequences with special splitting logic
 if (flags.is_number) {
 size_t digit_start = pos;
 size_t digit_count = 0;

 // Count consecutive digits
 while (_get_flags(pos).is_number && pos < offset_end) {
 digit_count++;
 pos++;
 }

 // Split based on total length modulo 3
 size_t remainder = digit_count % 3;
 size_t current = digit_start;

 // Emit leading 1-2 digits if needed
 if (remainder > 0) {
 _add_token(current + remainder);
 current += remainder;
 }

 // Emit groups of 3
 while (current < digit_start + digit_count) {
 _add_token(current + 3);
 current += 3;
 }
 continue;
 }

 // For non-digits, just move forward
 pos++;
 }

 // Add any remaining content
 if (_prev_end < offset_end) {
 _add_token(offset_end);
 }
 }

 return bpe_offsets;
}

// regex: [^\n]+|[\n]+
// splits text into runs of non-newline characters and runs of newline characters
static std::vector<size_t> unicode_regex_split_custom_newlines(const std::string & text, const std::vector<size_t> & offsets) {
 std::vector<size_t> bpe_offsets;
 bpe_offsets.reserve(offsets.size());

 const auto cpts = unicode_cpts_from_utf8(text);

 size_t start = 0;
 for (auto offset : offsets) {
 const size_t offset_ini = start;
 const size_t offset_end = start + offset;
 assert(offset_end <= cpts.size());
 start = offset_end;

 size_t pos = offset_ini;
 while (pos < offset_end) {
 const bool is_newline = (cpts[pos] == '\n');
 const size_t run_start = pos;
 while (pos < offset_end && (cpts[pos] == '\n') == is_newline) {
 pos++;
 }
 bpe_offsets.push_back(pos - run_start);
 }
 }

 return bpe_offsets;
}

static std::vector<size_t> unicode_regex_split_custom(const std::string & text, const std::string & regex_expr, const std::vector<size_t> & offsets) {
 std::vector<size_t> bpe_offsets;

 if (regex_expr == "'s|'t|'re|'ve|'m|'ll|'d| ?\\p{L}+| ?\\p{N}+| ?[^\\s\\p{L}\\p{N}]+|\\s+(?!\\S)") {
 bpe_offsets = unicode_regex_split_custom_gpt2(text, offsets);
 } else if (
 regex_expr == "(?i:'s|'t|'re|'ve|'m|'ll|'d)|[^\\r\\n\\p{L}\\p{N}]?\\p{L}+|\\p{N}{1,3}| ?[^\\s\\p{L}\\p{N}]+[\\r\\n]*|\\s*[\\r\\n]+|\\s+(?!\\S)|\\s+" ||
 regex_expr == "(?:'[sS]|'[tT]|'[rR][eE]|'[vV][eE]|'[mM]|'[lL][lL]|'[dD])|[^\\r\\n\\p{L}\\p{N}]?\\p{L}+|\\p{N}{1,3}| ?[^\\s\\p{L}\\p{N}]+[\\r\\n]*|\\s*[\\r\\n]+|\\s+(?!\\S)|\\s+") {
 bpe_offsets = unicode_regex_split_custom_llama3(text, offsets);
 } else if (
 regex_expr == "(?:'[sS]|'[tT]|'[rR][eE]|'[vV][eE]|'[mM]|'[lL][lL]|'[dD])|[^\\r\\n\\p{L}\\p{N}]?\\p{L}+|\\p{N}| ?[^\\s\\p{L}\\p{N}]+[\\r\\n]*|\\s*[\\r\\n]+|\\s+(?!\\S)|\\s+") {
 bpe_offsets = unicode_regex_split_custom_qwen2(text, offsets);
 } else if (regex_expr == "\\p{Han}+") {
 // K2's first pattern - handle all K2 patterns together
 bpe_offsets = unicode_regex_split_custom_kimi_k2(text, offsets);
 } else if (regex_expr == "\\p{AFMoE_digits}") {
 // AFMOE digit pattern - use custom implementation for proper splitting
 bpe_offsets = unicode_regex_split_custom_afmoe(text, offsets);
 } else if (regex_expr == "[^\\n]+|[\\n]+") {
 bpe_offsets = unicode_regex_split_custom_newlines(text, offsets);
 } else if (regex_expr == "\\d{1,3}(?=(?:\\d{3})*\\b)") {
 // tiny_aya digit grouping pattern from tokenizer.json:
 // {"type": "Split", "pattern": {"Regex": "\\d{1,3}(?=(?:\\d{3})*\\b)"}, "behavior": "Isolated"}
 // Splits digits into groups of 3 from the right (e.g., 1234567 -> 1, 234, 567)
 // TODO: Revisit this regex, in case there are any subtle tokenization differences with the original regex.
 bpe_offsets = unicode_regex_split_custom_afmoe(text, offsets);
 }

 return bpe_offsets;
}

//
// interface
//

std::string unicode_cpt_to_utf8(uint32_t cpt) {
 std::string result;

 if (/* 0x00 <= cpt && */ cpt <= 0x7f) {
 result.push_back(cpt);
 return result;
 }
 if (0x80 <= cpt && cpt <= 0x7ff) {
 result.push_back(0xc0 | ((cpt >> 6) & 0x1f));
 result.push_back(0x80 | (cpt & 0x3f));
 return result;
 }
 if (0x800 <= cpt && cpt <= 0xffff) {
 result.push_back(0xe0 | ((cpt >> 12) & 0x0f));
 result.push_back(0x80 | ((cpt >> 6) & 0x3f));
 result.push_back(0x80 | (cpt & 0x3f));
 return result;
 }
 if (0x10000 <= cpt && cpt <= 0x10ffff) {
 result.push_back(0xf0 | ((cpt >> 18) & 0x07));
 result.push_back(0x80 | ((cpt >> 12) & 0x3f));
 result.push_back(0x80 | ((cpt >> 6) & 0x3f));
 result.push_back(0x80 | (cpt & 0x3f));
 return result;
 }

 throw std::invalid_argument("invalid codepoint");
}

std::vector<uint32_t> unicode_cpts_normalize_nfd(const std::vector<uint32_t> & cpts) {
 auto comp = [] (const uint32_t cpt, const range_nfd & range) {
 return cpt < range.first;
 };
 std::vector<uint32_t> result(cpts.size());
 for (size_t i = 0; i < cpts.size(); ++i) {
 const uint32_t cpt = cpts[i];
 auto it = std::upper_bound(unicode_ranges_nfd.begin(), unicode_ranges_nfd.end(), cpt, comp) - 1;
 result[i] = (it->first <= cpt && cpt <= it->last) ? it->nfd : cpt;
 }
 return result;
}

std::vector<uint32_t> unicode_cpts_from_utf8(const std::string & utf8) {
 std::vector<uint32_t> result;
 result.reserve(utf8.size());
 size_t offset = 0;
 while (offset < utf8.size()) {
 try {
 result.push_back(unicode_cpt_from_utf8(utf8, offset));
 }
 catch (const std::invalid_argument & /*ex*/) {
 // Silently ignore invalid UTF-8 input to avoid leaking the exception beyond llama_tokenize
 ++offset;
 result.emplace_back(0xFFFD); // replacement character
 }
 }
 return result;
}

unicode_cpt_flags unicode_cpt_flags_from_cpt(const uint32_t cpt) {
 static const unicode_cpt_flags undef(unicode_cpt_flags::UNDEFINED);
 static const auto cpt_flags = unicode_cpt_flags_array();
 return cpt < cpt_flags.size() ? cpt_flags[cpt] : undef;
}

unicode_cpt_flags unicode_cpt_flags_from_utf8(const std::string & utf8) {
 static const unicode_cpt_flags undef(unicode_cpt_flags::UNDEFINED);
 if (utf8.empty()) {
 return undef; // undefined
 }
 size_t offset = 0;
 return unicode_cpt_flags_from_cpt(unicode_cpt_from_utf8(utf8, offset));
}

std::string unicode_byte_to_utf8(uint8_t byte) {
 static std::unordered_map<uint8_t, std::string> map = unicode_byte_to_utf8_map();
 return map.at(byte);
}

uint8_t unicode_utf8_to_byte(const std::string & utf8) {
 static std::unordered_map<std::string, uint8_t> map = unicode_utf8_to_byte_map();
 return map.at(utf8);
}

uint32_t unicode_tolower(uint32_t cpt) {
 // binary search
 auto it = std::lower_bound(unicode_map_lowercase.begin(), unicode_map_lowercase.end(), cpt,
 [](const std::pair<uint32_t, uint32_t> & pair, uint32_t value) {
 return pair.first < value;
 });
 if (it != unicode_map_lowercase.end() && it->first == cpt) {
 return it->second;
 }
 return cpt; // Return the original code point if no lowercase mapping is found
}

bool unicode_cpt_is_han(uint32_t cpt) {
 // Han character ranges (Chinese/CJK characters)
 // CJK Unified Ideographs (most common)
 if (cpt >= 0x4E00 && cpt <= 0x9FFF) return true;

 // CJK Extension A
 if (cpt >= 0x3400 && cpt <= 0x4DBF) return true;

 // CJK Extension B
 if (cpt >= 0x20000 && cpt <= 0x2A6DF) return true;

 // CJK Extension C
 if (cpt >= 0x2A700 && cpt <= 0x2B73F) return true;

 // CJK Extension D
 if (cpt >= 0x2B740 && cpt <= 0x2B81F) return true;

 // CJK Extension E
 if (cpt >= 0x2B820 && cpt <= 0x2CEAF) return true;

 // CJK Extension F
 if (cpt >= 0x2CEB0 && cpt <= 0x2EBEF) return true;

 // CJK Compatibility Ideographs
 if (cpt >= 0xF900 && cpt <= 0xFAFF) return true;

 // CJK Compatibility Ideographs Supplement
 if (cpt >= 0x2F800 && cpt <= 0x2FA1F) return true;

 return false;
}

std::vector<std::string> unicode_regex_split(const std::string & text, const std::vector<std::string> & regex_exprs, bool byte_encode) {
 // unicode categories
 static const std::map<std::string, int> k_ucat_enum = {
 { "\\p{N}", unicode_cpt_flags::NUMBER },
 { "\\p{L}", unicode_cpt_flags::LETTER },
 { "\\p{P}", unicode_cpt_flags::PUNCTUATION },
 { "\\p{M}", unicode_cpt_flags::ACCENT_MARK },
 { "\\p{S}", unicode_cpt_flags::SYMBOL },
 { "\\p{Lu}", unicode_cpt_flags::LETTER }, // Uppercase letter
 { "\\p{Ll}", unicode_cpt_flags::LETTER }, // Lowercase letter
 { "\\p{Lt}", unicode_cpt_flags::LETTER }, // Titlecase letter
 { "\\p{Lm}", unicode_cpt_flags::LETTER }, // Modifier letter
 { "\\p{Lo}", unicode_cpt_flags::LETTER }, // Other letter
 };

 static const std::map<int, int> k_ucat_cpt = {
 { unicode_cpt_flags::NUMBER, 0xD1 },
 { unicode_cpt_flags::LETTER, 0xD2 },
 { unicode_cpt_flags::PUNCTUATION, 0xD3 },
 { unicode_cpt_flags::ACCENT_MARK, 0xD4 },
 { unicode_cpt_flags::SYMBOL, 0xD5 },
 };

 static const std::map<int, std::string> k_ucat_map = {
 { unicode_cpt_flags::NUMBER, "\x30-\x39" }, // 0-9
 { unicode_cpt_flags::LETTER, "\x41-\x5A\x61-\x7A" }, // A-Za-z
 { unicode_cpt_flags::PUNCTUATION, "\x21-\x23\x25-\x2A\x2C-\x2F\x3A-\x3B\x3F-\x40\\\x5B-\\\x5D\x5F\\\x7B\\\x7D" }, // !-#%-*,-/:-;?-@\[-\]_\{\}
 { unicode_cpt_flags::ACCENT_MARK, "" }, // no sub-128 codepoints
 { unicode_cpt_flags::SYMBOL, "\\\x24\\\x2B\x3C-\x3E\x5E\x60\\\x7C" }, // $+<=>^`|
 };

 // compute collapsed codepoints only if needed by at least one regex
 bool need_collapse = false;
 for (const auto & regex_expr : regex_exprs) {
 // search for unicode categories
 for (const auto & ucat : k_ucat_enum) {
 if (std::string::npos != regex_expr.find(ucat.first)) {
 need_collapse = true;
 break;
 }
 }
 }

 const auto cpts = unicode_cpts_from_utf8(text);

 // generate a "collapsed" representation of the text, where all codepoints are replaced by a single byte
 // ref: https://github.com/ggml-org/llama.cpp/pull/6920#issuecomment-2081479935
 std::string text_collapsed;
 if (need_collapse) {
 // collapse all unicode categories
 text_collapsed.resize(cpts.size());

 for (size_t i = 0; i < cpts.size(); ++i) {
 // keep single-byte codepoints as is
 if (cpts[i] < 128) {
 text_collapsed[i] = cpts[i];
 continue;
 }

 const auto flags = unicode_cpt_flags_from_cpt(cpts[i]);

 if (flags.is_whitespace) {
 //NOTE: C++ std::regex \s does not mach 0x85, Rust and Python regex does.
 //text_collapsed[i] = (char) 0x85; // <Next Line> as whitespace fallback
 text_collapsed[i] = (char) 0x0B; // <vertical tab> as whitespace fallback
 } else if (k_ucat_cpt.find(flags.category_flag()) != k_ucat_cpt.end()) {
 text_collapsed[i] = k_ucat_cpt.at(flags.category_flag());
 } else {
 text_collapsed[i] = (char) 0xD0; // fallback
 }
 }
 }

 std::vector<size_t> bpe_offsets = { cpts.size() };

 for (const auto & regex_expr : regex_exprs) {
 // first, see if we have an efficient custom regex implementation
 auto tmp = unicode_regex_split_custom(text, regex_expr, bpe_offsets);

 if (!tmp.empty()) {
 bpe_offsets = std::move(tmp);
 continue;
 }

 // fallback to general-purpose std::regex / std::wregex
 try {
 // if a unicode category is used in the regex, we use the collapsed text and replace the unicode category
 // with the corresponding collapsed representation
 bool use_collapsed = false;
 for (const auto & ucat : k_ucat_enum) {
 if (std::string::npos != regex_expr.find(ucat.first)) {
 use_collapsed = true;
 break;
 }
 }
 const auto cpts_regex = unicode_cpts_from_utf8(regex_expr);

 if (use_collapsed) {
 // sanity-check that the original regex does not contain any non-ASCII characters
 for (size_t i = 0; i < cpts_regex.size(); ++i) {
 if (cpts_regex[i] >= 128) {
 throw std::runtime_error("Regex includes both unicode categories and non-ASCII characters - not supported");
 }
 }

 // generate a collapsed representation of the regex
 std::string regex_expr_collapsed;

 // track if we are inside [], because nested [] are not allowed
 bool inside = false;
 for (size_t i = 0; i < regex_expr.size(); ++i) {
 if (regex_expr[i] == '[' && (i == 0 || regex_expr[i - 1] != '\\')) {
 regex_expr_collapsed += '[';
 inside = true;
 continue;
 }

 if (inside && regex_expr[i] == ']' && regex_expr[i - 1] != '\\') {
 regex_expr_collapsed += ']';
 inside = false;
 continue;
 }

 // Match \p{...} Unicode properties of varying lengths
 if (regex_expr[i + 0] == '\\' && i + 3 < regex_expr.size() &&
 regex_expr[i + 1] == 'p' &&
 regex_expr[i + 2] == '{') {
 // Find the closing brace
 size_t closing_brace = regex_expr.find('}', i + 3);
 if (closing_brace != std::string::npos && closing_brace <= i + 10) { // reasonable limit
 const std::string pat = regex_expr.substr(i, closing_brace - i + 1);
 if (k_ucat_enum.find(pat) != k_ucat_enum.end()) {
 if (!inside) {
 regex_expr_collapsed += '[';
 }
 regex_expr_collapsed += k_ucat_cpt.at(k_ucat_enum.at(pat));
 regex_expr_collapsed += k_ucat_map.at(k_ucat_enum.at(pat));
 if (!inside) {
 regex_expr_collapsed += ']';
 }
 i = closing_brace;
 continue;
 }
 }
 }

 regex_expr_collapsed += regex_expr[i];
 }

 //printf("text_collapsed: %s\n", text_collapsed.c_str());
 //printf("regex_expr_collapsed: %s\n", regex_expr_collapsed.c_str());
 bpe_offsets = unicode_regex_split_stl(text_collapsed, regex_expr_collapsed, bpe_offsets);
 } else {
 // no unicode category used, we can use std::wregex directly
 std::wstring wregex_expr(cpts_regex.begin(), cpts_regex.end());

 // std::wregex \s does not mach non-ASCII whitespaces, using 0x0B as fallback
 std::wstring wtext(cpts.begin(), cpts.end());
 for (size_t i = 0; i < wtext.size(); ++i) {
 if (wtext[i] > 0x7F && unicode_cpt_flags_from_cpt(wtext[i]).is_whitespace) {
 wtext[i] = 0x0B;
 }
 }

 //printf("text: %s\n", text.c_str());
 //printf("regex_expr: %s\n", regex_expr.c_str());
 bpe_offsets = unicode_regex_split_stl(wtext, wregex_expr, bpe_offsets);
 }
 } catch (std::regex_error & e) {
 fprintf(stderr, "Failed to process regex: '%s'\n", regex_expr.c_str());
 fprintf(stderr, "Regex error: %s\n", e.what());
 throw std::runtime_error("Failed to process regex");
 }
 }

 std::vector<std::string> bpe_words;
 bpe_words.reserve(bpe_offsets.size()); // reserve memory for the approximate size

 size_t start = 0;
 for (size_t & offset : bpe_offsets) {
 bpe_words.emplace_back();
 for (size_t i = start; i < start + offset; ++i) {
 bpe_words.back() += unicode_cpt_to_utf8(cpts[i]);
 }
 start += offset;
 }

 if (byte_encode) {
 return unicode_byte_encoding_process(bpe_words);
 }

 return bpe_words;
}