Method parseBfRange

src/fontbox/cmap/parser.ts:237–290

(count: number, result: CMap)

  }

  private parseBfRange(count: number, result: CMap): void {
    for (let i = 0; i < count; i++) {
      const startToken = this.parseNextToken();

      if (isOperator(startToken)) {
        break;
      }

      if (!(startToken instanceof Uint8Array)) {
        throw new Error("Expected hex string for bfrange start");
      }

      const endToken = this.parseNextToken();

      if (isOperator(endToken)) {
        break;
      }

      if (!(endToken instanceof Uint8Array)) {
        throw new Error("Expected hex string for bfrange end");
      }

      const start = bytesToInt(startToken);
      const end = bytesToInt(endToken);

      if (end < start) {
        // Corrupt range - skip
        break;
      }

      const mappingToken = this.parseNextToken();

      if (Array.isArray(mappingToken)) {
        // Array of mappings
        this.addBfRangeFromArray(result, startToken, mappingToken);
      } else if (mappingToken instanceof Uint8Array) {
        if (mappingToken.length > 0) {
          // Special case: identity mapping <0000> <ffff> <0000>
          // Handle this by breaking into 256 chunks of 256 to avoid strict mode overflow
          if (
            mappingToken.length === 2 &&
            start === 0 &&
            end === 0xffff &&
            mappingToken[0] === 0 &&
            mappingToken[1] === 0
          ) {
            this.addIdentityBfRange(result, startToken);
          } else {
            this.addBfRangeFromBytes(result, startToken, end - start + 1, mappingToken);
          }
        }
      }
    }
  }

  /**
   * Handle identity bfrange <0000> <ffff> <0000> by breaking into 256 chunks.