1 /*
2 * Copyright (C) 2022 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #ifndef INCLUDE_PERFETTO_PUBLIC_STREAM_WRITER_H_
18 #define INCLUDE_PERFETTO_PUBLIC_STREAM_WRITER_H_
19
20 #include <assert.h>
21 #include <string.h>
22
23 #include "perfetto/public/abi/stream_writer_abi.h"
24 #include "perfetto/public/compiler.h"
25
26 // Returns the number of bytes available for writing in the current chunk.
PerfettoStreamWriterAvailableBytes(const struct PerfettoStreamWriter * w)27 static inline size_t PerfettoStreamWriterAvailableBytes(
28 const struct PerfettoStreamWriter* w) {
29 return PERFETTO_STATIC_CAST(size_t, w->end - w->write_ptr);
30 }
31
32 // Writes `size` bytes from `src` to the writer.
33 //
34 // WARNING: PerfettoStreamWriterAvailableBytes(`w`) must be >= `size`.
PerfettoStreamWriterAppendBytesUnsafe(struct PerfettoStreamWriter * w,const uint8_t * src,size_t size)35 static inline void PerfettoStreamWriterAppendBytesUnsafe(
36 struct PerfettoStreamWriter* w,
37 const uint8_t* src,
38 size_t size) {
39 assert(size <= PerfettoStreamWriterAvailableBytes(w));
40 memcpy(w->write_ptr, src, size);
41 w->write_ptr += size;
42 }
43
44 // Writes `size` bytes from `src` to the writer.
PerfettoStreamWriterAppendBytes(struct PerfettoStreamWriter * w,const uint8_t * src,size_t size)45 static inline void PerfettoStreamWriterAppendBytes(
46 struct PerfettoStreamWriter* w,
47 const uint8_t* src,
48 size_t size) {
49 if (PERFETTO_LIKELY(size <= PerfettoStreamWriterAvailableBytes(w))) {
50 PerfettoStreamWriterAppendBytesUnsafe(w, src, size);
51 } else {
52 PerfettoStreamWriterAppendBytesSlowpath(w, src, size);
53 }
54 }
55
56 // Writes the single byte `value` to the writer.
PerfettoStreamWriterAppendByte(struct PerfettoStreamWriter * w,uint8_t value)57 static inline void PerfettoStreamWriterAppendByte(
58 struct PerfettoStreamWriter* w,
59 uint8_t value) {
60 if (PERFETTO_UNLIKELY(PerfettoStreamWriterAvailableBytes(w) < 1)) {
61 PerfettoStreamWriterNewChunk(w);
62 }
63 *w->write_ptr++ = value;
64 }
65
66 // Returns a pointer to an area of the chunk long `size` for writing. The
67 // returned area is considered already written by the writer (it will not be
68 // used again).
69 //
70 // WARNING: PerfettoStreamWriterAvailableBytes(`w`) must be >= `size`.
PerfettoStreamWriterReserveBytesUnsafe(struct PerfettoStreamWriter * w,size_t size)71 static inline uint8_t* PerfettoStreamWriterReserveBytesUnsafe(
72 struct PerfettoStreamWriter* w,
73 size_t size) {
74 uint8_t* ret = w->write_ptr;
75 assert(size <= PerfettoStreamWriterAvailableBytes(w));
76 w->write_ptr += size;
77 return ret;
78 }
79
80 // Returns a pointer to an area of the chunk long `size` for writing. The
81 // returned area is considered already written by the writer (it will not be
82 // used again).
83 //
84 // WARNING: `size` should be smaller than the chunk size returned by the
85 // `delegate`.
PerfettoStreamWriterReserveBytes(struct PerfettoStreamWriter * w,size_t size)86 static inline uint8_t* PerfettoStreamWriterReserveBytes(
87 struct PerfettoStreamWriter* w,
88 size_t size) {
89 if (PERFETTO_LIKELY(size <= PerfettoStreamWriterAvailableBytes(w))) {
90 return PerfettoStreamWriterReserveBytesUnsafe(w, size);
91 }
92 PerfettoStreamWriterReserveBytesSlowpath(w, size);
93 return w->write_ptr - size;
94 }
95
96 // Returns the number of bytes written to the stream writer from the start.
PerfettoStreamWriterGetWrittenSize(const struct PerfettoStreamWriter * w)97 static inline size_t PerfettoStreamWriterGetWrittenSize(
98 const struct PerfettoStreamWriter* w) {
99 return w->written_previously +
100 PERFETTO_STATIC_CAST(size_t, w->write_ptr - w->begin);
101 }
102
103 #endif // INCLUDE_PERFETTO_PUBLIC_STREAM_WRITER_H_
104