Add support for signed and unsigned LEB128 to pack/unpack.

This commit adds a new pack format command `R` and `r` for unsigned and
signed LEB128 encoding.  The "r" mnemonic is because this is a
"vaRiable" length encoding scheme.

LEB128 is used in various formats including DWARF, WebAssembly, MQTT,
and Protobuf.

[Feature #21785]

3 files changed, 26 insertions, 3 deletions

diff --git a/spec/ruby/core/array/pack/r_spec.rb b/spec/ruby/core/array/pack/r_spec.rb
new file mode 100644
index 0000000000..22be6fa640
--- /dev/null
+++ b/spec/ruby/core/array/pack/r_spec.rb
@@ -0,0 +1,23 @@
+require_relative '../../../spec_helper'
+require_relative '../fixtures/classes'
+require_relative 'shared/basic'
+require_relative 'shared/numeric_basic'
+require_relative 'shared/integer'
+
+ruby_version_is "4.0" do
+  describe "Array#pack with format 'R'" do
+    it_behaves_like :array_pack_basic, 'R'
+    it_behaves_like :array_pack_basic_non_float, 'R'
+    it_behaves_like :array_pack_arguments, 'R'
+    it_behaves_like :array_pack_numeric_basic, 'R'
+    it_behaves_like :array_pack_integer, 'R'
+  end
+
+  describe "Array#pack with format 'r'" do
+    it_behaves_like :array_pack_basic, 'r'
+    it_behaves_like :array_pack_basic_non_float, 'r'
+    it_behaves_like :array_pack_arguments, 'r'
+    it_behaves_like :array_pack_numeric_basic, 'r'
+    it_behaves_like :array_pack_integer, 'r'
+  end
+end
diff --git a/spec/ruby/core/array/pack/shared/basic.rb b/spec/ruby/core/array/pack/shared/basic.rb
index ebd9f75d9d..77d7f2f71c 100644
--- a/spec/ruby/core/array/pack/shared/basic.rb
+++ b/spec/ruby/core/array/pack/shared/basic.rb
@@ -37,7 +37,7 @@ describe :array_pack_basic_non_float, shared: true do
     # NOTE: it's just a plan of the Ruby core team
     it "warns that a directive is unknown" do
       # additional directive ('a') is required for the X directive
-      -> { [@obj, @obj].pack("a R" + pack_format) }.should complain(/unknown pack directive 'R'/)
+      -> { [@obj, @obj].pack("a K" + pack_format) }.should complain(/unknown pack directive 'K'/)
       -> { [@obj, @obj].pack("a 0" + pack_format) }.should complain(/unknown pack directive '0'/)
       -> { [@obj, @obj].pack("a :" + pack_format) }.should complain(/unknown pack directive ':'/)
     end
@@ -48,7 +48,7 @@ describe :array_pack_basic_non_float, shared: true do
     # NOTE: Added this case just to not forget about the decision in the ticket
     it "raise ArgumentError when a directive is unknown" do
       # additional directive ('a') is required for the X directive
-      -> { [@obj, @obj].pack("a R" + pack_format) }.should raise_error(ArgumentError, /unknown pack directive 'R'/)
+      -> { [@obj, @obj].pack("a K" + pack_format) }.should raise_error(ArgumentError, /unknown pack directive 'K'/)
       -> { [@obj, @obj].pack("a 0" + pack_format) }.should raise_error(ArgumentError, /unknown pack directive '0'/)
       -> { [@obj, @obj].pack("a :" + pack_format) }.should raise_error(ArgumentError, /unknown pack directive ':'/)
     end
diff --git a/spec/ruby/core/string/unpack/shared/basic.rb b/spec/ruby/core/string/unpack/shared/basic.rb
index b37a447683..0ac2a951ed 100644
--- a/spec/ruby/core/string/unpack/shared/basic.rb
+++ b/spec/ruby/core/string/unpack/shared/basic.rb
@@ -12,7 +12,7 @@ describe :string_unpack_basic, shared: true do
   ruby_version_is "3.3" do
     # https://bugs.ruby-lang.org/issues/19150
     it 'raise ArgumentError when a directive is unknown' do
-      -> { "abcdefgh".unpack("a R" + unpack_format) }.should raise_error(ArgumentError, /unknown unpack directive 'R'/)
+      -> { "abcdefgh".unpack("a K" + unpack_format) }.should raise_error(ArgumentError, /unknown unpack directive 'K'/)
       -> { "abcdefgh".unpack("a 0" + unpack_format) }.should raise_error(ArgumentError, /unknown unpack directive '0'/)
       -> { "abcdefgh".unpack("a :" + unpack_format) }.should raise_error(ArgumentError, /unknown unpack directive ':'/)
     end