1 // Copyright 2014 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5
6 #include "src/unicode-inl.h"
7 #include "src/unicode-decoder.h"
8 #include <stdio.h>
9 #include <stdlib.h>
10
11 namespace unibrow {
12
Reset(uint16_t * buffer,size_t buffer_length,const uint8_t * stream,size_t stream_length)13 void Utf8DecoderBase::Reset(uint16_t* buffer, size_t buffer_length,
14 const uint8_t* stream, size_t stream_length) {
15 // Assume everything will fit in the buffer and stream won't be needed.
16 last_byte_of_buffer_unused_ = false;
17 unbuffered_start_ = NULL;
18 unbuffered_length_ = 0;
19 bool writing_to_buffer = true;
20 // Loop until stream is read, writing to buffer as long as buffer has space.
21 size_t utf16_length = 0;
22 while (stream_length != 0) {
23 size_t cursor = 0;
24 uint32_t character = Utf8::ValueOf(stream, stream_length, &cursor);
25 DCHECK(cursor > 0 && cursor <= stream_length);
26 stream += cursor;
27 stream_length -= cursor;
28 bool is_two_characters = character > Utf16::kMaxNonSurrogateCharCode;
29 utf16_length += is_two_characters ? 2 : 1;
30 // Don't need to write to the buffer, but still need utf16_length.
31 if (!writing_to_buffer) continue;
32 // Write out the characters to the buffer.
33 // Must check for equality with buffer_length as we've already updated it.
34 if (utf16_length <= buffer_length) {
35 if (is_two_characters) {
36 *buffer++ = Utf16::LeadSurrogate(character);
37 *buffer++ = Utf16::TrailSurrogate(character);
38 } else {
39 *buffer++ = character;
40 }
41 if (utf16_length == buffer_length) {
42 // Just wrote last character of buffer
43 writing_to_buffer = false;
44 unbuffered_start_ = stream;
45 unbuffered_length_ = stream_length;
46 }
47 continue;
48 }
49 // Have gone over buffer.
50 // Last char of buffer is unused, set cursor back.
51 DCHECK(is_two_characters);
52 writing_to_buffer = false;
53 last_byte_of_buffer_unused_ = true;
54 unbuffered_start_ = stream - cursor;
55 unbuffered_length_ = stream_length + cursor;
56 }
57 utf16_length_ = utf16_length;
58 }
59
60
WriteUtf16Slow(const uint8_t * stream,size_t stream_length,uint16_t * data,size_t data_length)61 void Utf8DecoderBase::WriteUtf16Slow(const uint8_t* stream,
62 size_t stream_length, uint16_t* data,
63 size_t data_length) {
64 while (data_length != 0) {
65 size_t cursor = 0;
66 uint32_t character = Utf8::ValueOf(stream, stream_length, &cursor);
67 // There's a total lack of bounds checking for stream
68 // as it was already done in Reset.
69 stream += cursor;
70 DCHECK(stream_length >= cursor);
71 stream_length -= cursor;
72 if (character > unibrow::Utf16::kMaxNonSurrogateCharCode) {
73 *data++ = Utf16::LeadSurrogate(character);
74 *data++ = Utf16::TrailSurrogate(character);
75 DCHECK(data_length > 1);
76 data_length -= 2;
77 } else {
78 *data++ = character;
79 data_length -= 1;
80 }
81 }
82 }
83
84 } // namespace unibrow
85