mdict-parser.js
function read_keyword_index(input, keyword_summary) {
      var scanner = Scanner(input).readBlock(keyword_summary.key_index_comp_len, keyword_summary.key_index_decomp_len, _decryptors[1]),
          keyword_index = Array(keyword_summary.num_blocks),
          offset = 0;
      for (var i = 0, size; i < keyword_summary.num_blocks; i++) {
        keyword_index[i] = {
          num_entries: conseq(scanner.readNum(), size = scanner.readShort()),
// UNUSED, can be ignored        
//          first_size:  size = scanner.readShort(),
          first_word:  conseq(scanner.readTextSized(size), size = scanner.readShort()),
// UNUSED, can be ignored
//          last_size:   size = scanner.readShort(),
          last_word:   scanner.readTextSized(size),
          comp_size:   size = scanner.readNum(),
          decomp_size: scanner.readNum(),
          // extra fields
          offset: offset,     // offset of the first byte for the target key block in mdx/mdd file
          index: i            // index of this key index, used to search previous/next block
        };
        offset += size;
      }
      return spreadus(keyword_summary, keyword_index);
    }
function read_keyword_index(input, keyword_summary) {
      var scanner = Scanner(input).readBlock(keyword_summary.key_index_comp_len, keyword_summary.key_index_decomp_len, _decryptors[1]),
          keyword_index = Array(keyword_summary.num_blocks),
          offset = 0;
      for (var i = 0, size; i < keyword_summary.num_blocks; i++) {
        keyword_index[i] = {
          num_entries: conseq(scanner.readNum(), size = scanner.readShort()),
// UNUSED, can be ignored        
//          first_size:  size = scanner.readShort(),
          first_word:  conseq(scanner.readTextSized(size), size = scanner.readShort()),
// UNUSED, can be ignored
//          last_size:   size = scanner.readShort(),
          last_word:   scanner.readTextSized(size),
          comp_size:   size = scanner.readNum(),
          decomp_size: scanner.readNum(),
          // extra fields
          offset: offset,     // offset of the first byte for the target key block in mdx/mdd file
          index: i            // index of this key index, used to search previous/next block
        };
        offset += size;
      }
      return spreadus(keyword_summary, keyword_index);
    }
Read keyword index part of keyword section.
@see https://github.com/zhansliu/writemdict/blob/master/fileformat.md#keyword-header-encryption
@see https://github.com/zhansliu/writemdict/blob/master/fileformat.md#keyword-index
@param input sliced file, remained part of keyword section after keyword summary which can also be used to read following key blocks.
@param keyword_summary
@return [keyword_summary, array of keyword index]