COMMON: Added LSHIFT and RSHIFT bit shift operators

Author: chrisws

ChangeLog

@@ -3,6 +3,7 @@
 	Removed BALLOC, MALLOC and VADR keywords. Removed duplicate ENVIRON
 	Removed system constants BPP and VIDADR, OSNAME, LINECHART, BARCHART
 	Added TIMESTAMP to return the modified-datetime of a file
+	Added LSHIFT and RSHIFT bit shift operators
 	SBVER now includes build information
 	TICKS now returns millisecond intervals
 	Refactor eval() for performance

samples/distro-examples/libs/base64.bas

@@ -0,0 +1,75 @@
+'
+' Base64 encoding and decoding
+' see: https://tools.ietf.org/html/rfc4648
+'
+
+Unit Base64
+Export encode
+
+const alphabet="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
+const padding="="
+
+func encode(message)
+  local result=""
+  local in_len = len(message)
+  local offset = 1
+  local group, group_len
+  local b_a, b_b, b_c
+
+  while offset <= in_len
+    group_len = min(3, (in_len - offset + 1))
+    select case group_len
+    case 1
+      ' final unit of encoded output will be two characters followed by two "=" padding characters.
+      b_a = mid(message, offset, 1)
+      result += mid(alphabet, (asc(b_a) rshift 2) + 1, 1)
+      result += mid(alphabet, ((asc(b_a) band 0x3) lshift 4) + 1, 1)
+      result += padding
+      result += padding
+    case 2
+      ' final unit of encoded output will be three characters followed by one "=" padding character.
+      b_a = mid(message, offset, 1)
+      b_b = mid(message, offset + 1, 1)
+      result += mid(alphabet, (asc(b_a) rshift 2) + 1, 1)
+      result += mid(alphabet, (((asc(b_a) band 0x3) lshift 4) + (asc(b_b) rshift 4)) + 1, 1)
+      result += mid(alphabet, ((asc(b_b) band 0xf) lshift 2) + 1, 1)
+      result += padding
+    case else
+      b_a = mid(message, offset, 1)
+      b_b = mid(message, offset + 1, 1)
+      b_c = mid(message, offset + 2, 1)
+      result += mid(alphabet, (asc(b_a) rshift 2) + 1, 1)
+      result += mid(alphabet, (((asc(b_a) band 0x3) lshift 4) + (asc(b_b) rshift 4)) + 1, 1)
+      result += mid(alphabet, (((asc(b_b) band 0xf) lshift 2) + (asc(b_c) rshift 6)) + 1, 1)
+      result += mid(alphabet, (asc(b_c) band 0x3f) + 1, 1)
+    end select
+    offset += group_len
+  wend
+  encode = result
+end
+  
+func decode(message)
+  local result = ""
+  decode = result
+end
+
+sub test
+  if (len(alphabet) != 64) then
+    throw "Invalid alphaet length"
+  fi
+  if (encode("foobar") != "Zm9vYmFy") then
+    throw "base64 encoding error 1"
+  endif
+  if (encode("This is a longer string") != "VGhpcyBpcyBhIGxvbmdlciBzdHJpbmc=") then
+    throw "base64 encoding error 2"
+  endif
+  if (encode("This result will end with two equals.") != "VGhpcyByZXN1bHQgd2lsbCBlbmQgd2l0aCB0d28gZXF1YWxzLg==") then
+    throw "base64 encoding error 3"
+  endif
+'  if (base64_dec("Zm9vYmEy") != "foobar") then
+'    throw "base64 encoding error"
+'  endif
+end
+
+test
+

samples/distro-examples/tests/eval-test.bas

@@ -203,3 +203,7 @@ assertEq 0xcccccccc Eqv 0xaaaaaaaa, 0x99999999, PROGLINE
 assertEq 0xcccc Eqv 0xaaaa, 0x9999, PROGLINE
 assertEq 0xcc Eqv 0xaa, 0x99, PROGLINE
 assertEq 0xc Eqv 0xa, 0x9, PROGLINE
+
+' bit shift operators
+assertEq 0xFF  LSHIFT 1, 0x1FE, PROGLINE
+assertEq 0x1FE RSHIFT 1, 0xFF,  PROGLINE

src/common/eval.c

@@ -534,6 +534,12 @@ static inline void oper_log(var_t *r, var_t *left, byte op) {
   case OPLOG_XOR:
     ri = li ^ ri;
     break;
+  case OPLOG_LSHIFT:
+    ri = li << ri;
+    break;
+  case OPLOG_RSHIFT:
+    ri = li >> ri;
+    break;
   }
 
   // cleanup

src/common/kw.h

@@ -42,6 +42,9 @@ extern "C" {
 #define OPLOG_MOD       'M'     // MOD (remain)
 #define OPLOG_MDL       'L'     // MDL (modulus)
 #define OPLOG_LIKE      'W'     // LIKE wc
+#define OPLOG_LSHIFT    'X'     // LSHIFT
+#define OPLOG_RSHIFT    'Y'     // RSHIFT
+
 /**
  * @ingroup sys
  * @enum keyword

src/languages/keywords.en.c

@@ -133,21 +133,23 @@ struct keyword_s keyword_table[] = {
  * OPERATORS (not the symbols)
  */
 struct opr_keyword_s opr_table[] = {
-{ "AND",   kwTYPE_LOGOPR, '&' },
-{ "OR",    kwTYPE_LOGOPR, '|' },
-{ "BAND",  kwTYPE_LOGOPR, OPLOG_BAND },
-{ "BOR",   kwTYPE_LOGOPR, OPLOG_BOR },
-{ "XOR",   kwTYPE_LOGOPR, '~' },
-{ "NOT",   kwTYPE_UNROPR, '!' },
-{ "MOD",   kwTYPE_MULOPR, OPLOG_MOD },
-{ "MDL",   kwTYPE_MULOPR, OPLOG_MDL },
-{ "EQV",   kwTYPE_LOGOPR, OPLOG_EQV },
-{ "IMP",   kwTYPE_LOGOPR, OPLOG_IMP },
-{ "NAND",  kwTYPE_LOGOPR, OPLOG_NAND },
-{ "NOR",   kwTYPE_LOGOPR, OPLOG_NOR },
-{ "XNOR",  kwTYPE_LOGOPR, OPLOG_XNOR },
-{ "IN",    kwTYPE_CMPOPR, OPLOG_IN },
-{ "LIKE",  kwTYPE_CMPOPR, OPLOG_LIKE },
+{ "AND",    kwTYPE_LOGOPR, '&' },
+{ "OR",     kwTYPE_LOGOPR, '|' },
+{ "BAND",   kwTYPE_LOGOPR, OPLOG_BAND },
+{ "BOR",    kwTYPE_LOGOPR, OPLOG_BOR },
+{ "XOR",    kwTYPE_LOGOPR, '~' },
+{ "NOT",    kwTYPE_UNROPR, '!' },
+{ "MOD",    kwTYPE_MULOPR, OPLOG_MOD },
+{ "MDL",    kwTYPE_MULOPR, OPLOG_MDL },
+{ "EQV",    kwTYPE_LOGOPR, OPLOG_EQV },
+{ "IMP",    kwTYPE_LOGOPR, OPLOG_IMP },
+{ "NAND",   kwTYPE_LOGOPR, OPLOG_NAND },
+{ "NOR",    kwTYPE_LOGOPR, OPLOG_NOR },
+{ "XNOR",   kwTYPE_LOGOPR, OPLOG_XNOR },
+{ "IN",     kwTYPE_CMPOPR, OPLOG_IN },
+{ "LIKE",   kwTYPE_CMPOPR, OPLOG_LIKE },
+{ "LSHIFT", kwTYPE_LOGOPR, OPLOG_LSHIFT },
+{ "RSHIFT", kwTYPE_LOGOPR, OPLOG_RSHIFT },
 { "", 0, 0 }
 };
 

src/platform/sdl/editor.cpp

@@ -190,7 +190,7 @@ void System::editSource(String loadPath) {
         break;
       case SB_KEY_F(1):
       case SB_KEY_ALT('h'):
-        _output->setStatus("Keyword Help. Esc=Close");
+        _output->setStatus("Keyword Help. F2=online, Esc=Close");
         widget = helpWidget;
         helpWidget->createKeywordIndex();
         helpWidget->show();