1/*
2 * Copyright 2011 The Android Open Source Project
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#ifndef SkFontMgr_android_parser_DEFINED
9#define SkFontMgr_android_parser_DEFINED
10
11#include "include/core/SkFontMgr.h"
12#include "include/core/SkString.h"
13#include "include/core/SkTypes.h"
14#include "include/private/SkTArray.h"
15#include "include/private/SkTDArray.h"
16#include "include/private/SkTHash.h"
17
18#include <climits>
19#include <limits>
20
21/** \class SkLanguage
22
23 The SkLanguage class represents a human written language, and is used by
24 text draw operations to determine which glyph to draw when drawing
25 characters with variants (ie Han-derived characters).
26*/
27class SkLanguage {
28public:
29 SkLanguage() { }
30 SkLanguage(const SkString& tag) : fTag(tag) { }
31 SkLanguage(const char* tag) : fTag(tag) { }
32 SkLanguage(const char* tag, size_t len) : fTag(tag, len) { }
33 SkLanguage(const SkLanguage& b) : fTag(b.fTag) { }
34
35 /** Gets a BCP 47 language identifier for this SkLanguage.
36 @return a BCP 47 language identifier representing this language
37 */
38 const SkString& getTag() const { return fTag; }
39
40 /** Performs BCP 47 fallback to return an SkLanguage one step more general.
41 @return an SkLanguage one step more general
42 */
43 SkLanguage getParent() const;
44
45 bool operator==(const SkLanguage& b) const {
46 return fTag == b.fTag;
47 }
48 bool operator!=(const SkLanguage& b) const {
49 return fTag != b.fTag;
50 }
51 SkLanguage& operator=(const SkLanguage& b) {
52 fTag = b.fTag;
53 return *this;
54 }
55
56private:
57 //! BCP 47 language identifier
58 SkString fTag;
59};
60
61enum FontVariants {
62 kDefault_FontVariant = 0x01,
63 kCompact_FontVariant = 0x02,
64 kElegant_FontVariant = 0x04,
65 kLast_FontVariant = kElegant_FontVariant,
66};
67typedef uint32_t FontVariant;
68
69// Must remain trivially movable (can be memmoved).
70struct FontFileInfo {
71 FontFileInfo() : fIndex(0), fWeight(0), fStyle(Style::kAuto) { }
72
73 SkString fFileName;
74 int fIndex;
75 int fWeight;
76 enum class Style { kAuto, kNormal, kItalic } fStyle;
77 SkTArray<SkFontArguments::VariationPosition::Coordinate, true> fVariationDesignPosition;
78};
79
80/**
81 * A font family provides one or more names for a collection of fonts, each of
82 * which has a different style (normal, italic) or weight (thin, light, bold,
83 * etc).
84 * Some fonts may occur in compact variants for use in the user interface.
85 * Android distinguishes "fallback" fonts to support non-ASCII character sets.
86 */
87struct FontFamily {
88 FontFamily(const SkString& basePath, bool isFallbackFont)
89 : fVariant(kDefault_FontVariant)
90 , fOrder(-1)
91 , fIsFallbackFont(isFallbackFont)
92 , fBasePath(basePath)
93 { }
94
95 SkTArray<SkString, true> fNames;
96 SkTArray<FontFileInfo, true> fFonts;
97 SkTArray<SkLanguage, true> fLanguages;
98 SkTHashMap<SkString, std::unique_ptr<FontFamily>> fallbackFamilies;
99 FontVariant fVariant;
100 int fOrder; // internal to the parser, not useful to users.
101 bool fIsFallbackFont;
102 SkString fFallbackFor;
103 const SkString fBasePath;
104};
105
106namespace SkFontMgr_Android_Parser {
107
108/** Parses system font configuration files and appends result to fontFamilies. */
109void GetSystemFontFamilies(SkTDArray<FontFamily*>& fontFamilies);
110
111/** Parses font configuration files and appends result to fontFamilies. */
112void GetCustomFontFamilies(SkTDArray<FontFamily*>& fontFamilies,
113 const SkString& basePath,
114 const char* fontsXml,
115 const char* fallbackFontsXml,
116 const char* langFallbackFontsDir = nullptr);
117
118} // SkFontMgr_Android_Parser namespace
119
120
121/** Parses a null terminated string into an integer type, checking for overflow.
122 * http://www.w3.org/TR/html-markup/datatypes.html#common.data.integer.non-negative-def
123 *
124 * If the string cannot be parsed into 'value', returns false and does not change 'value'.
125 */
126template <typename T> static bool parse_non_negative_integer(const char* s, T* value) {
127 static_assert(std::numeric_limits<T>::is_integer, "T_must_be_integer");
128
129 if (*s == '\0') {
130 return false;
131 }
132
133 const T nMax = std::numeric_limits<T>::max() / 10;
134 const T dMax = std::numeric_limits<T>::max() - (nMax * 10);
135 T n = 0;
136 for (; *s; ++s) {
137 // Check if digit
138 if (*s < '0' || '9' < *s) {
139 return false;
140 }
141 T d = *s - '0';
142 // Check for overflow
143 if (n > nMax || (n == nMax && d > dMax)) {
144 return false;
145 }
146 n = (n * 10) + d;
147 }
148 *value = n;
149 return true;
150}
151
152/** Parses a null terminated string into a signed fixed point value with bias N.
153 *
154 * Like http://www.w3.org/TR/html-markup/datatypes.html#common.data.float-def ,
155 * but may start with '.' and does not support 'e'. '-?((:digit:+(.:digit:+)?)|(.:digit:+))'
156 *
157 * Checks for overflow.
158 * Low bit rounding is not defined (is currently truncate).
159 * Bias (N) required to allow for the sign bit and 4 bits of integer.
160 *
161 * If the string cannot be parsed into 'value', returns false and does not change 'value'.
162 */
163template <int N, typename T> static bool parse_fixed(const char* s, T* value) {
164 static_assert(std::numeric_limits<T>::is_integer, "T_must_be_integer");
165 static_assert(std::numeric_limits<T>::is_signed, "T_must_be_signed");
166 static_assert(sizeof(T) * CHAR_BIT - N >= 5, "N_must_leave_four_bits_plus_sign");
167
168 bool negate = false;
169 if (*s == '-') {
170 ++s;
171 negate = true;
172 }
173 if (*s == '\0') {
174 return false;
175 }
176
177 const T nMax = (std::numeric_limits<T>::max() >> N) / 10;
178 const T dMax = (std::numeric_limits<T>::max() >> N) - (nMax * 10);
179 T n = 0;
180 T frac = 0;
181 for (; *s; ++s) {
182 // Check if digit
183 if (*s < '0' || '9' < *s) {
184 // If it wasn't a digit, check if it is a '.' followed by something.
185 if (*s != '.' || s[1] == '\0') {
186 return false;
187 }
188 // Find the end, verify digits.
189 for (++s; *s; ++s) {
190 if (*s < '0' || '9' < *s) {
191 return false;
192 }
193 }
194 // Read back toward the '.'.
195 for (--s; *s != '.'; --s) {
196 T d = *s - '0';
197 frac = (frac + (d << N)) / 10; // This requires four bits overhead.
198 }
199 break;
200 }
201 T d = *s - '0';
202 // Check for overflow
203 if (n > nMax || (n == nMax && d > dMax)) {
204 return false;
205 }
206 n = (n * 10) + d;
207 }
208 if (negate) {
209 n = -n;
210 frac = -frac;
211 }
212 *value = SkLeftShift(n, N) + frac;
213 return true;
214}
215
216#endif /* SkFontMgr_android_parser_DEFINED */
217