Merge pull request #722 from nanobowers/string_unpack_s

include/natalie/string_unpacker.hpp

@@ -9,6 +9,7 @@ namespace Natalie {
 class StringUnpacker : public Cell {
     using Tokenizer = ArrayPacker::Tokenizer;
     using Token = ArrayPacker::Token;
+    using Endianness = ArrayPacker::Endianness;
 
 public:
     StringUnpacker(const StringObject *source, String directives, nat_int_t offset)
@@ -66,6 +67,12 @@ class StringUnpacker : public Cell {
             case 'p':
                 unpack_p();
                 break;
+            case 'S':
+                unpack_s<uint16_t>(token);
+                break;
+            case 's':
+                unpack_s<int16_t>(token);
+                break;
             case 'U':
                 unpack_U(env, token);
                 break;
@@ -175,6 +182,30 @@ class StringUnpacker : public Cell {
         }
     }
 
+    template <typename T>
+    void unpack_s(Token &token) {
+        bool little_endian = (token.endianness == ArrayPacker::Endianness::Little) || (token.endianness == Endianness::Native && system_is_little_endian());
+        nat_int_t consumed = 0;
+        if (token.count == -1) token.count = 1;
+        while (token.star ? !at_end() : consumed < token.count) {
+            if ((m_index + 2) > m_source->length()) {
+                if (!token.star)
+                    m_unpacked->push(NilObject::the());
+                m_index++;
+            } else {
+                unsigned char c0 = next_char();
+                unsigned char c1 = next_char();
+                T result;
+                if (little_endian)
+                    result = (c1 << 8) + c0;
+                else
+                    result = (c0 << 8) + c1;
+                m_unpacked->push(Value::integer(result));
+            }
+            consumed++;
+        }
+    }
+
     void unpack_b(Token &token) {
         auto out = String();
 
@@ -580,6 +611,11 @@ class StringUnpacker : public Cell {
 
     bool at_end() { return m_index >= m_source->length(); }
 
+    bool system_is_little_endian() {
+        int i = 1;
+        return *((char *)&i) == 1;
+    }
+
     const StringObject *m_source;
     TM::Vector<Token> *m_directives;
     ArrayObject *m_unpacked { new ArrayObject };

spec/core/string/unpack/s_spec.rb

@@ -0,0 +1,152 @@
+require_relative '../../../spec_helper'
+require_relative '../fixtures/classes'
+require_relative 'shared/basic'
+require_relative 'shared/integer'
+
+describe "String#unpack with format 'S'" do
+  describe "with modifier '<'" do
+    it_behaves_like :string_unpack_16bit_le, 'S<'
+    it_behaves_like :string_unpack_16bit_le_unsigned, 'S<'
+  end
+
+  describe "with modifier '<' and '_'" do
+    it_behaves_like :string_unpack_16bit_le, 'S<_'
+    it_behaves_like :string_unpack_16bit_le, 'S_<'
+    it_behaves_like :string_unpack_16bit_le_unsigned, 'S_<'
+    it_behaves_like :string_unpack_16bit_le_unsigned, 'S<_'
+  end
+
+  describe "with modifier '<' and '!'" do
+    it_behaves_like :string_unpack_16bit_le, 'S<!'
+    it_behaves_like :string_unpack_16bit_le, 'S!<'
+    it_behaves_like :string_unpack_16bit_le_unsigned, 'S!<'
+    it_behaves_like :string_unpack_16bit_le_unsigned, 'S<!'
+  end
+
+  describe "with modifier '>'" do
+    it_behaves_like :string_unpack_16bit_be, 'S>'
+    it_behaves_like :string_unpack_16bit_be_unsigned, 'S>'
+  end
+
+  describe "with modifier '>' and '_'" do
+    it_behaves_like :string_unpack_16bit_be, 'S>_'
+    it_behaves_like :string_unpack_16bit_be, 'S_>'
+    it_behaves_like :string_unpack_16bit_be_unsigned, 'S>_'
+    it_behaves_like :string_unpack_16bit_be_unsigned, 'S_>'
+  end
+
+  describe "with modifier '>' and '!'" do
+    it_behaves_like :string_unpack_16bit_be, 'S>!'
+    it_behaves_like :string_unpack_16bit_be, 'S!>'
+    it_behaves_like :string_unpack_16bit_be_unsigned, 'S>!'
+    it_behaves_like :string_unpack_16bit_be_unsigned, 'S!>'
+  end
+end
+
+describe "String#unpack with format 's'" do
+  describe "with modifier '<'" do
+    it_behaves_like :string_unpack_16bit_le, 's<'
+    it_behaves_like :string_unpack_16bit_le_signed, 's<'
+  end
+
+  describe "with modifier '<' and '_'" do
+    it_behaves_like :string_unpack_16bit_le, 's<_'
+    it_behaves_like :string_unpack_16bit_le, 's_<'
+    it_behaves_like :string_unpack_16bit_le_signed, 's<_'
+    it_behaves_like :string_unpack_16bit_le_signed, 's_<'
+  end
+
+  describe "with modifier '<' and '!'" do
+    it_behaves_like :string_unpack_16bit_le, 's<!'
+    it_behaves_like :string_unpack_16bit_le, 's!<'
+    it_behaves_like :string_unpack_16bit_le_signed, 's<!'
+    it_behaves_like :string_unpack_16bit_le_signed, 's!<'
+  end
+
+  describe "with modifier '>'" do
+    it_behaves_like :string_unpack_16bit_be, 's>'
+    it_behaves_like :string_unpack_16bit_be_signed, 's>'
+  end
+
+  describe "with modifier '>' and '_'" do
+    it_behaves_like :string_unpack_16bit_be, 's>_'
+    it_behaves_like :string_unpack_16bit_be, 's_>'
+    it_behaves_like :string_unpack_16bit_be_signed, 's>_'
+    it_behaves_like :string_unpack_16bit_be_signed, 's_>'
+  end
+
+  describe "with modifier '>' and '!'" do
+    it_behaves_like :string_unpack_16bit_be, 's>!'
+    it_behaves_like :string_unpack_16bit_be, 's!>'
+    it_behaves_like :string_unpack_16bit_be_signed, 's>!'
+    it_behaves_like :string_unpack_16bit_be_signed, 's!>'
+  end
+end
+
+little_endian do
+  describe "String#unpack with format 'S'" do
+    it_behaves_like :string_unpack_basic, 'S'
+    it_behaves_like :string_unpack_16bit_le, 'S'
+    it_behaves_like :string_unpack_16bit_le_unsigned, 'S'
+  end
+
+  describe "String#unpack with format 'S' with modifier '_'" do
+    it_behaves_like :string_unpack_16bit_le, 'S_'
+    it_behaves_like :string_unpack_16bit_le_unsigned, 'S_'
+  end
+
+  describe "String#unpack with format 'S' with modifier '!'" do
+    it_behaves_like :string_unpack_16bit_le, 'S!'
+    it_behaves_like :string_unpack_16bit_le_unsigned, 'S!'
+  end
+
+  describe "String#unpack with format 's'" do
+    it_behaves_like :string_unpack_basic, 's'
+    it_behaves_like :string_unpack_16bit_le, 's'
+    it_behaves_like :string_unpack_16bit_le_signed, 's'
+  end
+
+  describe "String#unpack with format 's' with modifier '_'" do
+    it_behaves_like :string_unpack_16bit_le, 's_'
+    it_behaves_like :string_unpack_16bit_le_signed, 's_'
+  end
+
+  describe "String#unpack with format 's' with modifier '!'" do
+    it_behaves_like :string_unpack_16bit_le, 's!'
+    it_behaves_like :string_unpack_16bit_le_signed, 's!'
+  end
+end
+
+big_endian do
+  describe "String#unpack with format 'S'" do
+    it_behaves_like :string_unpack_basic, 'S'
+    it_behaves_like :string_unpack_16bit_be, 'S'
+    it_behaves_like :string_unpack_16bit_be_unsigned, 'S'
+  end
+
+  describe "String#unpack with format 'S' with modifier '_'" do
+    it_behaves_like :string_unpack_16bit_be, 'S_'
+    it_behaves_like :string_unpack_16bit_be_unsigned, 'S_'
+  end
+
+  describe "String#unpack with format 'S' with modifier '!'" do
+    it_behaves_like :string_unpack_16bit_be, 'S!'
+    it_behaves_like :string_unpack_16bit_be_unsigned, 'S!'
+  end
+
+  describe "String#unpack with format 's'" do
+    it_behaves_like :string_unpack_basic, 's'
+    it_behaves_like :string_unpack_16bit_be, 's'
+    it_behaves_like :string_unpack_16bit_be_signed, 's'
+  end
+
+  describe "String#unpack with format 's' with modifier '_'" do
+    it_behaves_like :string_unpack_16bit_be, 's_'
+    it_behaves_like :string_unpack_16bit_be_signed, 's_'
+  end
+
+  describe "String#unpack with format 's' with modifier '!'" do
+    it_behaves_like :string_unpack_16bit_be, 's!'
+    it_behaves_like :string_unpack_16bit_be_signed, 's!'
+  end
+end