1 #include "image_io/base/data_segment.h"
2
3 #include <algorithm>
4 #include <cstring>
5
6 namespace photos_editing_formats {
7 namespace image_io {
8
9 using std::default_delete;
10 using std::shared_ptr;
11
Create(const DataRange & data_range,const Byte * buffer,DataSegment::BufferDispositionPolicy buffer_policy)12 shared_ptr<DataSegment> DataSegment::Create(
13 const DataRange& data_range, const Byte* buffer,
14 DataSegment::BufferDispositionPolicy buffer_policy) {
15 return shared_ptr<DataSegment>(
16 new DataSegment(data_range, buffer, buffer_policy),
17 default_delete<DataSegment>());
18 }
19
Find(size_t start_location,Byte value) const20 size_t DataSegment::Find(size_t start_location, Byte value) const {
21 if (!Contains(start_location)) {
22 return GetEnd();
23 }
24 const Byte* location = reinterpret_cast<const Byte*>(
25 memchr((buffer_ + start_location) - GetBegin(), value,
26 GetEnd() - start_location));
27 return location ? (location - buffer_) + GetBegin() : GetEnd();
28 }
29
Find(size_t location,const char * str,size_t str_length) const30 size_t DataSegment::Find(size_t location, const char* str,
31 size_t str_length) const {
32 char char0 = *str;
33 while (Contains(location)) {
34 size_t memchr_count = GetEnd() - location;
35 const void* void0_ptr = memchr(GetBuffer(location), char0, memchr_count);
36 if (void0_ptr) {
37 const Byte* byte0_ptr = reinterpret_cast<const Byte*>(void0_ptr);
38 size_t byte0_location = (byte0_ptr - buffer_) + GetBegin();
39 if (byte0_location + str_length <= GetEnd()) {
40 const char* char0_ptr = reinterpret_cast<const char*>(void0_ptr);
41 if (strncmp(char0_ptr, str, str_length) == 0) {
42 return byte0_location;
43 }
44 }
45 }
46 ++location;
47 }
48 return GetEnd();
49 }
50
GetValidatedByte(size_t location,const DataSegment * segment1,const DataSegment * segment2)51 ValidatedByte DataSegment::GetValidatedByte(size_t location,
52 const DataSegment* segment1,
53 const DataSegment* segment2) {
54 for (const DataSegment* segment : {segment1, segment2}) {
55 if (segment && segment->Contains(location)) {
56 return segment->GetValidatedByte(location);
57 }
58 }
59 return InvalidByte();
60 }
61
Find(size_t start_location,Byte value,const DataSegment * segment1,const DataSegment * segment2)62 size_t DataSegment::Find(size_t start_location, Byte value,
63 const DataSegment* segment1,
64 const DataSegment* segment2) {
65 if (segment1 && segment2 && segment1->GetEnd() == segment2->GetBegin()) {
66 size_t value_location = segment2->GetEnd();
67 if (segment1->Contains(start_location)) {
68 value_location = segment1->Find(start_location, value);
69 if (value_location == segment1->GetEnd()) {
70 value_location = segment2->Find(segment2->GetBegin(), value);
71 }
72 } else {
73 value_location = segment2->Find(start_location, value);
74 }
75 return value_location;
76 }
77 size_t segment1_end = segment1 ? segment1->GetEnd() : 0;
78 return segment2 ? std::max(segment1_end, segment2->GetEnd()) : segment1_end;
79 }
80
81 } // namespace image_io
82 } // namespace photos_editing_formats
83