implement incbin directive

README.md

@@ -237,6 +237,11 @@ include an external assembly file as-is at this position.
 lips will look for the included file
 in the directory of the file using the directive.
 
+* `.incbin {filename}`  
+write an external binary file as-is at this position.
+lips will look for the included file
+in the directory of the file using the directive.
+
 * `.ascii "some\ntext\0"`  
 writes a string using its characters' ASCII values.
 a few escapes are currently supported: `\ " a b f n r t v 0`
@@ -249,5 +254,3 @@ same as ascii, but with a null byte added to the end.
 * FLOAT: writes a list of 32-bit floating point numbers until end-of-line.
 this may not get implemented due to a lack of aliasing in vanilla Lua,
 and thus accuracy issues.
-
-* INCBIN: write an external binary file as-is at this position.

lips/Lexer.lua

@@ -278,6 +278,24 @@ function Lexer:lex_include(_yield)
     sublexer:lex(_yield)
 end
 
+function Lexer:lex_include_binary(_yield)
+    self:read_spaces()
+    local fn
+    self:lex_string_naive(function(tt, tok)
+        fn = tok
+    end)
+    if self.options.path then
+        fn = self.options.path..fn
+    end
+    -- NOTE: this allocates two tables for each byte.
+    --       this could easily cause performance issues on big files.
+    local data = util.readfile(fn, true)
+    for b in string.gfind(data, '.') do
+        _yield('DIR', 'BYTE', fn, 0)
+        _yield('NUM', string.byte(b), fn, 0)
+    end
+end
+
 function Lexer:lex(_yield)
     local function yield(tt, tok)
         return _yield(tt, tok, self.fn, self.line)
@@ -338,6 +356,9 @@ function Lexer:lex(_yield)
             if up == 'INC' or up == 'INCASM' or up == 'INCLUDE' then
                 yield('DIR', 'INC')
                 self:lex_include(_yield)
+            elseif up == 'INCBIN' then
+                yield('DIR', 'INCBIN')
+                self:lex_include_binary(_yield)
             else
                 yield('DIR', up)
             end

lips/Parser.lua

@@ -54,7 +54,7 @@ function Parser:directive()
             add(name, self:const().tok)
         end
         self:expect_EOL()
-    elseif name == 'INC' then
+    elseif name == 'INC' or name == 'INCBIN' then
         -- noop, handled by lexer
     elseif name == 'ASCII' or name == 'ASCIIZ' then
         local bytes = self:string()
@@ -65,8 +65,6 @@ function Parser:directive()
             add('BYTE', 0)
         end
         self:expect_EOL()
-    elseif name == 'INCBIN' then
-        self:error('unimplemented')
     elseif name == 'FLOAT' then
         self:error('unimplemented')
     else

lips/util.lua

@@ -16,14 +16,16 @@ local function Class(inherit)
     return setmetatable(class, mt_class)
 end
 
-local function readfile(fn)
-    local f = open(fn, 'r')
+local function readfile(fn, binary)
+    local mode = binary and 'rb' or 'r'
+    local f = open(fn, mode)
     if not f then
-        error('could not open assembly file for reading: '..tostring(fn), 2)
+        local kind = binary and 'binary' or 'assembly'
+        error('could not open '..kind..' file for reading: '..tostring(fn), 2)
     end
-    local asm = f:read('*a')
+    local data = f:read('*a')
     f:close()
-    return asm
+    return data
 end
 
 local function bitrange(x, lower, upper)