1 files changed, 99 insertions, 0 deletions
diff --git a/vanilla/node_modules/css-tree/lib/utils/string.js b/vanilla/node_modules/css-tree/lib/utils/string.js
new file mode 100644
index 0000000..928a85b
--- /dev/null
+++ b/vanilla/node_modules/css-tree/lib/utils/string.js
@@ -0,0 +1,99 @@
+import {
+    isHexDigit,
+    isWhiteSpace,
+    isValidEscape,
+    consumeEscaped,
+    decodeEscaped
+} from '../tokenizer/index.js';
+
+const REVERSE_SOLIDUS = 0x005c; // U+005C REVERSE SOLIDUS (\)
+const QUOTATION_MARK = 0x0022;  // "
+const APOSTROPHE = 0x0027;      // '
+
+export function decode(str) {
+    const len = str.length;
+    const firstChar = str.charCodeAt(0);
+    const start = firstChar === QUOTATION_MARK || firstChar === APOSTROPHE ? 1 : 0;
+    const end = start === 1 && len > 1 && str.charCodeAt(len - 1) === firstChar ? len - 2 : len - 1;
+    let decoded = '';
+
+    for (let i = start; i <= end; i++) {
+        let code = str.charCodeAt(i);
+
+        if (code === REVERSE_SOLIDUS) {
+            // special case at the ending
+            if (i === end) {
+                // if the next input code point is EOF, do nothing
+                // otherwise include last quote as escaped
+                if (i !== len - 1) {
+                    decoded = str.substr(i + 1);
+                }
+                break;
+            }
+
+            code = str.charCodeAt(++i);
+
+            // consume escaped
+            if (isValidEscape(REVERSE_SOLIDUS, code)) {
+                const escapeStart = i - 1;
+                const escapeEnd = consumeEscaped(str, escapeStart);
+
+                i = escapeEnd - 1;
+                decoded += decodeEscaped(str.substring(escapeStart + 1, escapeEnd));
+            } else {
+                // \r\n
+                if (code === 0x000d && str.charCodeAt(i + 1) === 0x000a) {
+                    i++;
+                }
+            }
+        } else {
+            decoded += str[i];
+        }
+    }
+
+    return decoded;
+}
+
+// https://drafts.csswg.org/cssom/#serialize-a-string
+// § 2.1. Common Serializing Idioms
+export function encode(str, apostrophe) {
+    const quote = apostrophe ? '\'' : '"';
+    const quoteCode = apostrophe ? APOSTROPHE : QUOTATION_MARK;
+    let encoded = '';
+    let wsBeforeHexIsNeeded = false;
+
+    for (let i = 0; i < str.length; i++) {
+        const code = str.charCodeAt(i);
+
+        // If the character is NULL (U+0000), then the REPLACEMENT CHARACTER (U+FFFD).
+        if (code === 0x0000) {
+            encoded += '\uFFFD';
+            continue;
+        }
+
+        // If the character is in the range [\1-\1f] (U+0001 to U+001F) or is U+007F,
+        // the character escaped as code point.
+        // Note: Do not compare with 0x0001 since 0x0000 is precessed before
+        if (code <= 0x001f || code === 0x007F) {
+            encoded += '\\' + code.toString(16);
+            wsBeforeHexIsNeeded = true;
+            continue;
+        }
+
+        // If the character is '"' (U+0022) or "\" (U+005C), the escaped character.
+        if (code === quoteCode || code === REVERSE_SOLIDUS) {
+            encoded += '\\' + str.charAt(i);
+            wsBeforeHexIsNeeded = false;
+        } else {
+            if (wsBeforeHexIsNeeded && (isHexDigit(code) || isWhiteSpace(code))) {
+                encoded += ' ';
+            }
+
+            // Otherwise, the character itself.
+            encoded += str.charAt(i);
+            wsBeforeHexIsNeeded = false;
+        }
+    }
+
+    return quote + encoded + quote;
+}