1 /*
2 * Copyright 2011 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8 #include "SkReader32.h"
9 #include "SkString.h"
10 #include "SkWriter32.h"
11
12 /*
13 * Strings are stored as: length[4-bytes] + string_data + '\0' + pad_to_mul_4
14 */
15
readString(size_t * outLen)16 const char* SkReader32::readString(size_t* outLen) {
17 size_t len = this->readU32();
18 const void* ptr = this->peek();
19
20 // skip over the string + '\0' and then pad to a multiple of 4
21 size_t alignedSize = SkAlign4(len + 1);
22 this->skip(alignedSize);
23
24 if (outLen) {
25 *outLen = len;
26 }
27 return (const char*)ptr;
28 }
29
readIntoString(SkString * copy)30 size_t SkReader32::readIntoString(SkString* copy) {
31 size_t len;
32 const char* ptr = this->readString(&len);
33 if (copy) {
34 copy->set(ptr, len);
35 }
36 return len;
37 }
38
writeString(const char str[],size_t len)39 void SkWriter32::writeString(const char str[], size_t len) {
40 if (nullptr == str) {
41 str = "";
42 len = 0;
43 }
44 if ((long)len < 0) {
45 len = strlen(str);
46 }
47
48 // [ 4 byte len ] [ str ... ] [1 - 4 \0s]
49 uint32_t* ptr = this->reservePad(sizeof(uint32_t) + len + 1);
50 *ptr = SkToU32(len);
51 char* chars = (char*)(ptr + 1);
52 memcpy(chars, str, len);
53 chars[len] = '\0';
54 }
55
WriteStringSize(const char * str,size_t len)56 size_t SkWriter32::WriteStringSize(const char* str, size_t len) {
57 if ((long)len < 0) {
58 SkASSERT(str);
59 len = strlen(str);
60 }
61 const size_t lenBytes = 4; // we use 4 bytes to record the length
62 // add 1 since we also write a terminating 0
63 return SkAlign4(lenBytes + len + 1);
64 }
65
growToAtLeast(size_t size)66 void SkWriter32::growToAtLeast(size_t size) {
67 const bool wasExternal = (fExternal != nullptr) && (fData == fExternal);
68
69 fCapacity = 4096 + SkTMax(size, fCapacity + (fCapacity / 2));
70 fInternal.realloc(fCapacity);
71 fData = fInternal.get();
72
73 if (wasExternal) {
74 // we were external, so copy in the data
75 memcpy(fData, fExternal, fUsed);
76 }
77 }
78
snapshotAsData() const79 sk_sp<SkData> SkWriter32::snapshotAsData() const {
80 return SkData::MakeWithCopy(fData, fUsed);
81 }
82