debug.c: new debug line information format `mrb_debug_line_packed_map`.

It uses BER number compression of delta of instruction positions and line
numbers. BER compression is a variable length number representation.

* `mrb_debug_line_ary`: array of line numbers represented in `uint16_t`.
  `[lineno, lineno, ...]`

* `mrb_debug_line_flat_map`: array of `mrb_irep_debug_info_line`, which
  is `struct {uint32_t pos; uint16_t lineno}`, for each line.

* `mrb_debug_line_packed_map` [new]: sequence of BER compressed 2
  numbers, `pos_delta, lineno_delta`. Deltas are differences from
  previous values (starting `0`). `line_entry_counts` represents total
  length of a packed map string for this type.

1 files changed, 6 insertions, 0 deletions

diff --git a/src/load.c b/src/load.c
index 2e637aa19..d7f01347c 100644
--- a/src/load.c
+++ b/src/load.c
@@ -362,6 +362,12 @@ read_debug_record(mrb_state *mrb, const uint8_t *start, mrb_irep* irep, size_t *
         }
       } break;
 
+      case mrb_debug_line_packed_map: {
+        file->lines.packed_map = (char*)mrb_calloc(mrb, 1, (size_t)file->line_entry_count);
+        memcpy(file->lines.packed_map, bin, file->line_entry_count);
+        bin += file->line_entry_count;
+      } break;
+
       default: return MRB_DUMP_GENERAL_FAILURE;
     }
   }