upstream/emscripten/node_modules/entities/lib/esm/decode.js

import htmlDecodeTree from "./generated/decode-data-html.js";
import xmlDecodeTree from "./generated/decode-data-xml.js";
import decodeCodePoint, { replaceCodePoint, fromCodePoint, } from "./decode_codepoint.js";
// Re-export for use by eg. htmlparser2
export { htmlDecodeTree, xmlDecodeTree, decodeCodePoint };
export { replaceCodePoint, fromCodePoint } from "./decode_codepoint.js";
var CharCodes;
(function (CharCodes) {
    CharCodes[CharCodes["NUM"] = 35] = "NUM";
    CharCodes[CharCodes["SEMI"] = 59] = "SEMI";
    CharCodes[CharCodes["EQUALS"] = 61] = "EQUALS";
    CharCodes[CharCodes["ZERO"] = 48] = "ZERO";
    CharCodes[CharCodes["NINE"] = 57] = "NINE";
    CharCodes[CharCodes["LOWER_A"] = 97] = "LOWER_A";
    CharCodes[CharCodes["LOWER_F"] = 102] = "LOWER_F";
    CharCodes[CharCodes["LOWER_X"] = 120] = "LOWER_X";
    CharCodes[CharCodes["LOWER_Z"] = 122] = "LOWER_Z";
    CharCodes[CharCodes["UPPER_A"] = 65] = "UPPER_A";
    CharCodes[CharCodes["UPPER_F"] = 70] = "UPPER_F";
    CharCodes[CharCodes["UPPER_Z"] = 90] = "UPPER_Z";
})(CharCodes || (CharCodes = {}));
/** Bit that needs to be set to convert an upper case ASCII character to lower case */
const TO_LOWER_BIT = 0b100000;
export var BinTrieFlags;
(function (BinTrieFlags) {
    BinTrieFlags[BinTrieFlags["VALUE_LENGTH"] = 49152] = "VALUE_LENGTH";
    BinTrieFlags[BinTrieFlags["BRANCH_LENGTH"] = 16256] = "BRANCH_LENGTH";
    BinTrieFlags[BinTrieFlags["JUMP_TABLE"] = 127] = "JUMP_TABLE";
})(BinTrieFlags || (BinTrieFlags = {}));
function isNumber(code) {
    return code >= CharCodes.ZERO && code <= CharCodes.NINE;
}
function isHexadecimalCharacter(code) {
    return ((code >= CharCodes.UPPER_A && code <= CharCodes.UPPER_F) ||
        (code >= CharCodes.LOWER_A && code <= CharCodes.LOWER_F));
}
function isAsciiAlphaNumeric(code) {
    return ((code >= CharCodes.UPPER_A && code <= CharCodes.UPPER_Z) ||
        (code >= CharCodes.LOWER_A && code <= CharCodes.LOWER_Z) ||
        isNumber(code));
}
/**
 * Checks if the given character is a valid end character for an entity in an attribute.
 *
 * Attribute values that aren't terminated properly aren't parsed, and shouldn't lead to a parser error.
 * See the example in https://html.spec.whatwg.org/multipage/parsing.html#named-character-reference-state
 */
function isEntityInAttributeInvalidEnd(code) {
    return code === CharCodes.EQUALS || isAsciiAlphaNumeric(code);
}
var EntityDecoderState;
(function (EntityDecoderState) {
    EntityDecoderState[EntityDecoderState["EntityStart"] = 0] = "EntityStart";
    EntityDecoderState[EntityDecoderState["NumericStart"] = 1] = "NumericStart";
    EntityDecoderState[EntityDecoderState["NumericDecimal"] = 2] = "NumericDecimal";
    EntityDecoderState[EntityDecoderState["NumericHex"] = 3] = "NumericHex";
    EntityDecoderState[EntityDecoderState["NamedEntity"] = 4] = "NamedEntity";
})(EntityDecoderState || (EntityDecoderState = {}));
export var DecodingMode;
(function (DecodingMode) {
    /** Entities in text nodes that can end with any character. */
    DecodingMode[DecodingMode["Legacy"] = 0] = "Legacy";
    /** Only allow entities terminated with a semicolon. */
    DecodingMode[DecodingMode["Strict"] = 1] = "Strict";
    /** Entities in attributes have limitations on ending characters. */
    DecodingMode[DecodingMode["Attribute"] = 2] = "Attribute";
})(DecodingMode || (DecodingMode = {}));
/**
 * Token decoder with support of writing partial entities.
 */
export class EntityDecoder {
    constructor(
    /** The tree used to decode entities. */
    decodeTree, 
    /**
     * The function that is called when a codepoint is decoded.
     *
     * For multi-byte named entities, this will be called multiple times,
     * with the second codepoint, and the same `consumed` value.
     *
     * @param codepoint The decoded codepoint.
     * @param consumed The number of bytes consumed by the decoder.
     */
    emitCodePoint, 
    /** An object that is used to produce errors. */
    errors) {
        this.decodeTree = decodeTree;
        this.emitCodePoint = emitCodePoint;
        this.errors = errors;
        /** The current state of the decoder. */
        this.state = EntityDecoderState.EntityStart;
        /** Characters that were consumed while parsing an entity. */
        this.consumed = 1;
        /**
         * The result of the entity.
         *
         * Either the result index of a numeric entity, or the codepoint of a
         * numeric entity.
         */
        this.result = 0;
        /** The current index in the decode tree. */
        this.treeIndex = 0;
        /** The number of characters that were consumed in excess. */
        this.excess = 1;
        /** The mode in which the decoder is operating. */
        this.decodeMode = DecodingMode.Strict;
    }
    /** Resets the instance to make it reusable. */
    startEntity(decodeMode) {
        this.decodeMode = decodeMode;
        this.state = EntityDecoderState.EntityStart;
        this.result = 0;
        this.treeIndex = 0;
        this.excess = 1;
        this.consumed = 1;
    }
    /**
     * Write an entity to the decoder. This can be called multiple times with partial entities.
     * If the entity is incomplete, the decoder will return -1.
     *
     * Mirrors the implementation of `getDecoder`, but with the ability to stop decoding if the
     * entity is incomplete, and resume when the next string is written.
     *
     * @param string The string containing the entity (or a continuation of the entity).
     * @param offset The offset at which the entity begins. Should be 0 if this is not the first call.
     * @returns The number of characters that were consumed, or -1 if the entity is incomplete.
     */
    write(str, offset) {
        switch (this.state) {
            case EntityDecoderState.EntityStart: {
                if (str.charCodeAt(offset) === CharCodes.NUM) {
                    this.state = EntityDecoderState.NumericStart;
                    this.consumed += 1;
                    return this.stateNumericStart(str, offset + 1);
                }
                this.state = EntityDecoderState.NamedEntity;
                return this.stateNamedEntity(str, offset);
            }
            case EntityDecoderState.NumericStart: {
                return this.stateNumericStart(str, offset);
            }
            case EntityDecoderState.NumericDecimal: {
                return this.stateNumericDecimal(str, offset);
            }
            case EntityDecoderState.NumericHex: {
                return this.stateNumericHex(str, offset);
            }
            case EntityDecoderState.NamedEntity: {
                return this.stateNamedEntity(str, offset);
            }
        }
    }
    /**
     * Switches between the numeric decimal and hexadecimal states.
     *
     * Equivalent to the `Numeric character reference state` in the HTML spec.
     *
     * @param str The string containing the entity (or a continuation of the entity).
     * @param offset The current offset.
     * @returns The number of characters that were consumed, or -1 if the entity is incomplete.
     */
    stateNumericStart(str, offset) {
        if (offset >= str.length) {
            return -1;
        }
        if ((str.charCodeAt(offset) | TO_LOWER_BIT) === CharCodes.LOWER_X) {
            this.state = EntityDecoderState.NumericHex;
            this.consumed += 1;
            return this.stateNumericHex(str, offset + 1);
        }
        this.state = EntityDecoderState.NumericDecimal;
        return this.stateNumericDecimal(str, offset);
    }
    addToNumericResult(str, start, end, base) {
        if (start !== end) {
            const digitCount = end - start;
            this.result =
                this.result * Math.pow(base, digitCount) +
                    parseInt(str.substr(start, digitCount), base);
            this.consumed += digitCount;
        }
    }
    /**
     * Parses a hexadecimal numeric entity.
     *
     * Equivalent to the `Hexademical character reference state` in the HTML spec.
     *
     * @param str The string containing the entity (or a continuation of the entity).
     * @param offset The current offset.
     * @returns The number of characters that were consumed, or -1 if the entity is incomplete.
     */
    stateNumericHex(str, offset) {
        const startIdx = offset;
        while (offset < str.length) {
            const char = str.charCodeAt(offset);
            if (isNumber(char) || isHexadecimalCharacter(char)) {
                offset += 1;
            }
            else {
                this.addToNumericResult(str, startIdx, offset, 16);
                return this.emitNumericEntity(char, 3);
            }
        }
        this.addToNumericResult(str, startIdx, offset, 16);
        return -1;
    }
    /**
     * Parses a decimal numeric entity.
     *
     * Equivalent to the `Decimal character reference state` in the HTML spec.
     *
     * @param str The string containing the entity (or a continuation of the entity).
     * @param offset The current offset.
     * @returns The number of characters that were consumed, or -1 if the entity is incomplete.
     */
    stateNumericDecimal(str, offset) {
        const startIdx = offset;
        while (offset < str.length) {
            const char = str.charCodeAt(offset);
            if (isNumber(char)) {
                offset += 1;
            }
            else {
                this.addToNumericResult(str, startIdx, offset, 10);
                return this.emitNumericEntity(char, 2);
            }
        }
        this.addToNumericResult(str, startIdx, offset, 10);
        return -1;
    }
    /**
     * Validate and emit a numeric entity.
     *
     * Implements the logic from the `Hexademical character reference start
     * state` and `Numeric character reference end state` in the HTML spec.
     *
     * @param lastCp The last code point of the entity. Used to see if the
     *               entity was terminated with a semicolon.
     * @param expectedLength The minimum number of characters that should be
     *                       consumed. Used to validate that at least one digit
     *                       was consumed.
     * @returns The number of characters that were consumed.
     */
    emitNumericEntity(lastCp, expectedLength) {
        var _a;
        // Ensure we consumed at least one digit.
        if (this.consumed <= expectedLength) {
            (_a = this.errors) === null || _a === void 0 ? void 0 : _a.absenceOfDigitsInNumericCharacterReference(this.consumed);
            return 0;
        }
        // Figure out if this is a legit end of the entity
        if (lastCp === CharCodes.SEMI) {
            this.consumed += 1;
        }
        else if (this.decodeMode === DecodingMode.Strict) {
            return 0;
        }
        this.emitCodePoint(replaceCodePoint(this.result), this.consumed);
        if (this.errors) {
            if (lastCp !== CharCodes.SEMI) {
                this.errors.missingSemicolonAfterCharacterReference();
            }
            this.errors.validateNumericCharacterReference(this.result);
        }
        return this.consumed;
    }
    /**
     * Parses a named entity.
     *
     * Equivalent to the `Named character reference state` in the HTML spec.
     *
     * @param str The string containing the entity (or a continuation of the entity).
     * @param offset The current offset.
     * @returns The number of characters that were consumed, or -1 if the entity is incomplete.
     */
    stateNamedEntity(str, offset) {
        const { decodeTree } = this;
        let current = decodeTree[this.treeIndex];
        // The mask is the number of bytes of the value, including the current byte.
        let valueLength = (current & BinTrieFlags.VALUE_LENGTH) >> 14;
        for (; offset < str.length; offset++, this.excess++) {
            const char = str.charCodeAt(offset);
            this.treeIndex = determineBranch(decodeTree, current, this.treeIndex + Math.max(1, valueLength), char);
            if (this.treeIndex < 0) {
                return this.result === 0 ||
                    // If we are parsing an attribute
                    (this.decodeMode === DecodingMode.Attribute &&
                        // We shouldn't have consumed any characters after the entity,
                        (valueLength === 0 ||
                            // And there should be no invalid characters.
                            isEntityInAttributeInvalidEnd(char)))
                    ? 0
                    : this.emitNotTerminatedNamedEntity();
            }
            current = decodeTree[this.treeIndex];
            valueLength = (current & BinTrieFlags.VALUE_LENGTH) >> 14;
            // If the branch is a value, store it and continue
            if (valueLength !== 0) {
                // If the entity is terminated by a semicolon, we are done.
                if (char === CharCodes.SEMI) {
                    return this.emitNamedEntityData(this.treeIndex, valueLength, this.consumed + this.excess);
                }
                // If we encounter a non-terminated (legacy) entity while parsing strictly, then ignore it.
                if (this.decodeMode !== DecodingMode.Strict) {
                    this.result = this.treeIndex;
                    this.consumed += this.excess;
                    this.excess = 0;
                }
            }
        }
        return -1;
    }
    /**
     * Emit a named entity that was not terminated with a semicolon.
     *
     * @returns The number of characters consumed.
     */
    emitNotTerminatedNamedEntity() {
        var _a;
        const { result, decodeTree } = this;
        const valueLength = (decodeTree[result] & BinTrieFlags.VALUE_LENGTH) >> 14;
        this.emitNamedEntityData(result, valueLength, this.consumed);
        (_a = this.errors) === null || _a === void 0 ? void 0 : _a.missingSemicolonAfterCharacterReference();
        return this.consumed;
    }
    /**
     * Emit a named entity.
     *
     * @param result The index of the entity in the decode tree.
     * @param valueLength The number of bytes in the entity.
     * @param consumed The number of characters consumed.
     *
     * @returns The number of characters consumed.
     */
    emitNamedEntityData(result, valueLength, consumed) {
        const { decodeTree } = this;
        this.emitCodePoint(valueLength === 1
            ? decodeTree[result] & ~BinTrieFlags.VALUE_LENGTH
            : decodeTree[result + 1], consumed);
        if (valueLength === 3) {
            // For multi-byte values, we need to emit the second byte.
            this.emitCodePoint(decodeTree[result + 2], consumed);
        }
        return consumed;
    }
    /**
     * Signal to the parser that the end of the input was reached.
     *
     * Remaining data will be emitted and relevant errors will be produced.
     *
     * @returns The number of characters consumed.
     */
    end() {
        var _a;
        switch (this.state) {
            case EntityDecoderState.NamedEntity: {
                // Emit a named entity if we have one.
                return this.result !== 0 &&
                    (this.decodeMode !== DecodingMode.Attribute ||
                        this.result === this.treeIndex)
                    ? this.emitNotTerminatedNamedEntity()
                    : 0;
            }
            // Otherwise, emit a numeric entity if we have one.
            case EntityDecoderState.NumericDecimal: {
                return this.emitNumericEntity(0, 2);
            }
            case EntityDecoderState.NumericHex: {
                return this.emitNumericEntity(0, 3);
            }
            case EntityDecoderState.NumericStart: {
                (_a = this.errors) === null || _a === void 0 ? void 0 : _a.absenceOfDigitsInNumericCharacterReference(this.consumed);
                return 0;
            }
            case EntityDecoderState.EntityStart: {
                // Return 0 if we have no entity.
                return 0;
            }
        }
    }
}
/**
 * Creates a function that decodes entities in a string.
 *
 * @param decodeTree The decode tree.
 * @returns A function that decodes entities in a string.
 */
function getDecoder(decodeTree) {
    let ret = "";
    const decoder = new EntityDecoder(decodeTree, (str) => (ret += fromCodePoint(str)));
    return function decodeWithTrie(str, decodeMode) {
        let lastIndex = 0;
        let offset = 0;
        while ((offset = str.indexOf("&", offset)) >= 0) {
            ret += str.slice(lastIndex, offset);
            decoder.startEntity(decodeMode);
            const len = decoder.write(str, 
            // Skip the "&"
            offset + 1);
            if (len < 0) {
                lastIndex = offset + decoder.end();
                break;
            }
            lastIndex = offset + len;
            // If `len` is 0, skip the current `&` and continue.
            offset = len === 0 ? lastIndex + 1 : lastIndex;
        }
        const result = ret + str.slice(lastIndex);
        // Make sure we don't keep a reference to the final string.
        ret = "";
        return result;
    };
}
/**
 * Determines the branch of the current node that is taken given the current
 * character. This function is used to traverse the trie.
 *
 * @param decodeTree The trie.
 * @param current The current node.
 * @param nodeIdx The index right after the current node and its value.
 * @param char The current character.
 * @returns The index of the next node, or -1 if no branch is taken.
 */
export function determineBranch(decodeTree, current, nodeIdx, char) {
    const branchCount = (current & BinTrieFlags.BRANCH_LENGTH) >> 7;
    const jumpOffset = current & BinTrieFlags.JUMP_TABLE;
    // Case 1: Single branch encoded in jump offset
    if (branchCount === 0) {
        return jumpOffset !== 0 && char === jumpOffset ? nodeIdx : -1;
    }
    // Case 2: Multiple branches encoded in jump table
    if (jumpOffset) {
        const value = char - jumpOffset;
        return value < 0 || value >= branchCount
            ? -1
            : decodeTree[nodeIdx + value] - 1;
    }
    // Case 3: Multiple branches encoded in dictionary
    // Binary search for the character.
    let lo = nodeIdx;
    let hi = lo + branchCount - 1;
    while (lo <= hi) {
        const mid = (lo + hi) >>> 1;
        const midVal = decodeTree[mid];
        if (midVal < char) {
            lo = mid + 1;
        }
        else if (midVal > char) {
            hi = mid - 1;
        }
        else {
            return decodeTree[mid + branchCount];
        }
    }
    return -1;
}
const htmlDecoder = getDecoder(htmlDecodeTree);
const xmlDecoder = getDecoder(xmlDecodeTree);
/**
 * Decodes an HTML string.
 *
 * @param str The string to decode.
 * @param mode The decoding mode.
 * @returns The decoded string.
 */
export function decodeHTML(str, mode = DecodingMode.Legacy) {
    return htmlDecoder(str, mode);
}
/**
 * Decodes an HTML string in an attribute.
 *
 * @param str The string to decode.
 * @returns The decoded string.
 */
export function decodeHTMLAttribute(str) {
    return htmlDecoder(str, DecodingMode.Attribute);
}
/**
 * Decodes an HTML string, requiring all entities to be terminated by a semicolon.
 *
 * @param str The string to decode.
 * @returns The decoded string.
 */
export function decodeHTMLStrict(str) {
    return htmlDecoder(str, DecodingMode.Strict);
}
/**
 * Decodes an XML string, requiring all entities to be terminated by a semicolon.
 *
 * @param str The string to decode.
 * @returns The decoded string.
 */
export function decodeXML(str) {
    return xmlDecoder(str, DecodingMode.Strict);
}
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