[SVGDom/experimental] Initial SVGLength support

experimental/svg/model/SkSVGAttributeParser.cpp

+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkParse.h"
+#include "SkSVGAttributeParser.h"
+#include "SkSVGTypes.h"
+
+namespace {
+
+// TODO: these should be shared with SkParse.cpp
+
+inline bool is_between(char c, char min, char max) {
+    SkASSERT(min <= max);
+    return (unsigned)(c - min) <= (unsigned)(max - min);
+}
+
+inline bool is_eos(char c) {
+    return !c;
+}
+
+inline bool is_ws(char c) {
+    return is_between(c, 1, 32);
+}
+
+inline bool is_sep(char c) {
+    return is_ws(c) || c == ',' || c == ';';
+}
+
+} // anonymous ns
+
+SkSVGAttributeParser::SkSVGAttributeParser(const char attributeString[])
+    : fChr(attributeString) {}
+
+template <typename F>
+inline bool SkSVGAttributeParser::advanceWhile(F f) {
+    auto initial = fChr;
+    while (f(*fChr)) {
+        fChr++;
+    }
+    return fChr != initial;
+}
+
+inline bool SkSVGAttributeParser::parseEOSAtom() {
+    return is_eos(*fChr);
+}
+
+inline bool SkSVGAttributeParser::parseSepAtom() {
+    return this->advanceWhile(is_sep);
+}
+
+inline bool SkSVGAttributeParser::parseWSAtom() {
+    return this->advanceWhile(is_ws);
+}
+

[robertphillips, 2016/08/02 22:25:56]

consumeExpectedToken ?

[f(malita), 2016/08/03 16:50:51]

Done (parseExpectedStringToken for consistency with the other private methods,
also renamed to parseFooToken).

+inline bool SkSVGAttributeParser::parseStringAtom(const char* expected) {
+    const char* c = fChr;
+
+    while (*c && *expected && *c == *expected) {
+        c++;
+        expected++;
+    }
+
+    if (*expected) {
+        return false;
+    }
+
+    fChr = c;
+    return true;
+}
+
+bool SkSVGAttributeParser::parseScalarAtom(SkScalar* res) {
+    if (const char* next = SkParse::FindScalar(fChr, res)) {
+        fChr = next;
+        return true;
+    }
+    return false;
+}
+
+bool SkSVGAttributeParser::parseHexAtom(uint32_t* res) {
+     if (const char* next = SkParse::FindHex(fChr, res)) {
+         fChr = next;
+         return true;
+     }
+     return false;
+}
+
+bool SkSVGAttributeParser::parseLengthUnitAtom(SkSVGLength::Unit* unit) {
+    static const struct {
+        const char*       fUnitName;
+        SkSVGLength::Unit fUnit;
+    } gUnitInfo[] = {
+        { "%" , SkSVGLength::Unit::kPercentage },
+        { "em", SkSVGLength::Unit::kEMS        },
+        { "ex", SkSVGLength::Unit::kEXS        },
+        { "px", SkSVGLength::Unit::kPX         },
+        { "cm", SkSVGLength::Unit::kCM         },
+        { "mm", SkSVGLength::Unit::kMM         },
+        { "in", SkSVGLength::Unit::kIN         },
+        { "pt", SkSVGLength::Unit::kPT         },
+        { "pc", SkSVGLength::Unit::kPC         },
+    };
+
+    for (size_t i = 0; i < SK_ARRAY_COUNT(gUnitInfo); ++i) {
+        if (this->parseStringAtom(gUnitInfo[i].fUnitName)) {
+            *unit = gUnitInfo[i].fUnit;
+            return true;
+        }
+    }
+    return false;
+}
+
+bool SkSVGAttributeParser::parseNamedColorAtom(SkColor* c) {
+    if (const char* next = SkParse::FindNamedColor(fChr, strlen(fChr), c)) {
+        fChr = next;
+        return true;
+    }
+    return false;
+}
+
+bool SkSVGAttributeParser::parseHexColorAtom(SkColor* c) {
+    uint32_t v;
+    const char* initial = fChr;
+
+    if (!this->parseStringAtom("#") || !this->parseHexAtom(&v)) {
+        return false;
+    }
+
+    switch (fChr - initial) {
+    case 7:
+        // matched #xxxxxxx
+        break;
+    case 4:
+        // matched '#xxx;
+        v = ((v << 12) & 0x00f00000) |
+            ((v <<  8) & 0x000ff000) |
+            ((v <<  4) & 0x00000ff0) |
+            ((v <<  0) & 0x0000000f);
+        break;
+    default:
+        return false;
+    }
+
+    *c = v | 0xff000000;
+    return true;
+}
+
+// https://www.w3.org/TR/SVG/types.html#DataTypeColor
+bool SkSVGAttributeParser::parseColor(SkSVGColor* color) {
+    SkColor c;
+
+    // TODO: rgb(...)
+    if (this->parseHexColorAtom(&c) || this->parseNamedColorAtom(&c)) {
+        *color = SkSVGColor(c);
+        return true;
+    }
+
+    return false;
+}
+
+// https://www.w3.org/TR/SVG/types.html#DataTypeNumber
+bool SkSVGAttributeParser::parseNumber(SkSVGNumber* number) {
+    // consume WS
+    this->parseWSAtom();
+
+    SkScalar s;
+    if (this->parseScalarAtom(&s)) {
+        *number = SkSVGNumber(s);
+        // consume trailing separators
+        this->parseSepAtom();
+        return true;
+    }
+
+    return false;
+}
+
+// https://www.w3.org/TR/SVG/types.html#DataTypeLength
+bool SkSVGAttributeParser::parseLength(SkSVGLength* length) {
+    SkScalar s;
+    SkSVGLength::Unit u = SkSVGLength::Unit::kNumber;
+
+    if (this->parseScalarAtom(&s) &&
+        (this->parseLengthUnitAtom(&u) || this->parseSepAtom() || this->parseEOSAtom())) {
+        *length = SkSVGLength(s, u);
+        // consume trailing separators
+        this->parseSepAtom();
+        return true;
+    }
+
+    return false;
+}