/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "utf.h"
#include "base/logging.h"
#include "mirror/array.h"
#include "mirror/object-inl.h"
#include "utf-inl.h"
namespace art {
// This is used only from debugger and test code.
size_t CountModifiedUtf8Chars(const char* utf8) {
return CountModifiedUtf8Chars(utf8, strlen(utf8));
}
/*
* This does not validate UTF8 rules (nor did older code). But it gets the right answer
* for valid UTF-8 and that's fine because it's used only to size a buffer for later
* conversion.
*
* Modified UTF-8 consists of a series of bytes up to 21 bit Unicode code points as follows:
* U+0001 - U+007F 0xxxxxxx
* U+0080 - U+07FF 110xxxxx 10xxxxxx
* U+0800 - U+FFFF 1110xxxx 10xxxxxx 10xxxxxx
* U+10000 - U+1FFFFF 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
*
* U+0000 is encoded using the 2nd form to avoid nulls inside strings (this differs from
* standard UTF-8).
* The four byte encoding converts to two utf16 characters.
*/
size_t CountModifiedUtf8Chars(const char* utf8, size_t byte_count) {
DCHECK_LE(byte_count, strlen(utf8));
size_t len = 0;
const char* end = utf8 + byte_count;
for (; utf8 < end; ++utf8) {
int ic = *utf8;
len++;
if (LIKELY((ic & 0x80) == 0)) {
// One-byte encoding.
continue;
}
// Two- or three-byte encoding.
utf8++;
if ((ic & 0x20) == 0) {
// Two-byte encoding.
continue;
}
utf8++;
if ((ic & 0x10) == 0) {
// Three-byte encoding.
continue;
}
// Four-byte encoding: needs to be converted into a surrogate
// pair.
utf8++;
len++;
}
return len;
}
// This is used only from debugger and test code.
void ConvertModifiedUtf8ToUtf16(uint16_t* utf16_data_out, const char* utf8_data_in) {
while (*utf8_data_in != '\0') {
const uint32_t ch = GetUtf16FromUtf8(&utf8_data_in);
const uint16_t leading = GetLeadingUtf16Char(ch);
const uint16_t trailing = GetTrailingUtf16Char(ch);
*utf16_data_out++ = leading;
if (trailing != 0) {
*utf16_data_out++ = trailing;
}
}
}
void ConvertModifiedUtf8ToUtf16(uint16_t* utf16_data_out, size_t out_chars,
const char* utf8_data_in, size_t in_bytes) {
const char *in_start = utf8_data_in;
const char *in_end = utf8_data_in + in_bytes;
uint16_t *out_p = utf16_data_out;
if (LIKELY(out_chars == in_bytes)) {
// Common case where all characters are ASCII.
for (const char *p = in_start; p < in_end;) {
// Safe even if char is signed because ASCII characters always have
// the high bit cleared.
*out_p++ = dchecked_integral_cast<uint16_t>(*p++);
}
return;
}
// String contains non-ASCII characters.
for (const char *p = in_start; p < in_end;) {
const uint32_t ch = GetUtf16FromUtf8(&p);
const uint16_t leading = GetLeadingUtf16Char(ch);
const uint16_t trailing = GetTrailingUtf16Char(ch);
*out_p++ = leading;
if (trailing != 0) {
*out_p++ = trailing;
}
}
}
void ConvertUtf16ToModifiedUtf8(char* utf8_out, size_t byte_count,
const uint16_t* utf16_in, size_t char_count) {
if (LIKELY(byte_count == char_count)) {
// Common case where all characters are ASCII.
const uint16_t *utf16_end = utf16_in + char_count;
for (const uint16_t *p = utf16_in; p < utf16_end;) {
*utf8_out++ = dchecked_integral_cast<char>(*p++);
}
return;
}
// String contains non-ASCII characters.
while (char_count--) {
const uint16_t ch = *utf16_in++;
if (ch > 0 && ch <= 0x7f) {
*utf8_out++ = ch;
} else {
// Char_count == 0 here implies we've encountered an unpaired
// surrogate and we have no choice but to encode it as 3-byte UTF
// sequence. Note that unpaired surrogates can occur as a part of
// "normal" operation.
if ((ch >= 0xd800 && ch <= 0xdbff) && (char_count > 0)) {
const uint16_t ch2 = *utf16_in;
// Check if the other half of the pair is within the expected
// range. If it isn't, we will have to emit both "halves" as
// separate 3 byte sequences.
if (ch2 >= 0xdc00 && ch2 <= 0xdfff) {
utf16_in++;
char_count--;
const uint32_t code_point = (ch << 10) + ch2 - 0x035fdc00;
*utf8_out++ = (code_point >> 18) | 0xf0;
*utf8_out++ = ((code_point >> 12) & 0x3f) | 0x80;
*utf8_out++ = ((code_point >> 6) & 0x3f) | 0x80;
*utf8_out++ = (code_point & 0x3f) | 0x80;
continue;
}
}
if (ch > 0x07ff) {
// Three byte encoding.
*utf8_out++ = (ch >> 12) | 0xe0;
*utf8_out++ = ((ch >> 6) & 0x3f) | 0x80;
*utf8_out++ = (ch & 0x3f) | 0x80;
} else /*(ch > 0x7f || ch == 0)*/ {
// Two byte encoding.
*utf8_out++ = (ch >> 6) | 0xc0;
*utf8_out++ = (ch & 0x3f) | 0x80;
}
}
}
}
int32_t ComputeUtf16HashFromModifiedUtf8(const char* utf8, size_t utf16_length) {
uint32_t hash = 0;
while (utf16_length != 0u) {
const uint32_t pair = GetUtf16FromUtf8(&utf8);
const uint16_t first = GetLeadingUtf16Char(pair);
hash = hash * 31 + first;
--utf16_length;
const uint16_t second = GetTrailingUtf16Char(pair);
if (second != 0) {
hash = hash * 31 + second;
DCHECK_NE(utf16_length, 0u);
--utf16_length;
}
}
return static_cast<int32_t>(hash);
}
uint32_t ComputeModifiedUtf8Hash(const char* chars) {
uint32_t hash = 0;
while (*chars != '\0') {
hash = hash * 31 + *chars++;
}
return static_cast<int32_t>(hash);
}
int CompareModifiedUtf8ToUtf16AsCodePointValues(const char* utf8, const uint16_t* utf16,
size_t utf16_length) {
for (;;) {
if (*utf8 == '\0') {
return (utf16_length == 0) ? 0 : -1;
} else if (utf16_length == 0) {
return 1;
}
const uint32_t pair = GetUtf16FromUtf8(&utf8);
// First compare the leading utf16 char.
const uint16_t lhs = GetLeadingUtf16Char(pair);
const uint16_t rhs = *utf16++;
--utf16_length;
if (lhs != rhs) {
return lhs > rhs ? 1 : -1;
}
// Then compare the trailing utf16 char. First check if there
// are any characters left to consume.
const uint16_t lhs2 = GetTrailingUtf16Char(pair);
if (lhs2 != 0) {
if (utf16_length == 0) {
return 1;
}
const uint16_t rhs2 = *utf16++;
--utf16_length;
if (lhs2 != rhs2) {
return lhs2 > rhs2 ? 1 : -1;
}
}
}
}
size_t CountUtf8Bytes(const uint16_t* chars, size_t char_count) {
size_t result = 0;
const uint16_t *end = chars + char_count;
while (chars < end) {
const uint16_t ch = *chars++;
if (LIKELY(ch != 0 && ch < 0x80)) {
result++;
continue;
}
if (ch < 0x800) {
result += 2;
continue;
}
if (ch >= 0xd800 && ch < 0xdc00) {
if (chars < end) {
const uint16_t ch2 = *chars;
// If we find a properly paired surrogate, we emit it as a 4 byte
// UTF sequence. If we find an unpaired leading or trailing surrogate,
// we emit it as a 3 byte sequence like would have done earlier.
if (ch2 >= 0xdc00 && ch2 < 0xe000) {
chars++;
result += 4;
continue;
}
}
}
result += 3;
}
return result;
}
} // namespace art