From ffbbfef499c25fa382271c89b42401e3423df503 Mon Sep 17 00:00:00 2001
From: Jon Michael Aanes <jonjmaa@gmail.com>
Date: Tue, 4 Apr 2017 16:19:22 +0200
Subject: [PATCH] Beginning work on more advanced cdata inspection.

---
 cdata.lua            | 83 ++++++++++++++++++++++++++++++++++++++++++++
 pretty.lua           |  8 ++++-
 test/test_pretty.lua | 32 +++++++++++++----
 3 files changed, 116 insertions(+), 7 deletions(-)
 create mode 100644 cdata.lua

diff --git a/cdata.lua b/cdata.lua
new file mode 100644
index 0000000..ac12575
--- /dev/null
+++ b/cdata.lua
@@ -0,0 +1,83 @@
+
+-- Import
+
+local ffi = require 'ffi'
+
+-- Constants
+
+--------------------------------------------------------------------------------
+-- Util
+
+local NUMBER_TO_HEX = {
+	[00] = '0', [01] = '1', [02] = '2', [03] = '3', [04] = '4', [05] = '5',
+	[06] = '6', [07] = '7', [08] = '8', [09] = '9', [10] = 'A', [11] = 'B',
+	[12] = 'C', [13] = 'D', [14] = 'E', [15] = 'F',
+}
+
+local function to_hex (str)
+	local l = {}
+	for i = 1, #str do
+		local v = str:byte(i)
+		l[#l+1] = NUMBER_TO_HEX[math.floor(v / 16)]
+		l[#l+1] = NUMBER_TO_HEX[v % 16]
+		l[#l+1] = ' '
+	end
+	l[#l] = nil
+	return table.concat(l, '')
+end
+
+local function is_nice_ascii_string (str)
+	for i = 1, #str do
+		local byte = str:byte(i)
+		if not (32 <= byte and byte <= 126) then  return false  end
+	end
+	return true
+end
+
+local function get_type_and_size_of_singular ( ctype )
+	local nr_elements  =  1
+	while true do
+		local etype, elements  =  ctype:match('(.+)%[(%d*)%]$')
+		if not elements then  break  end
+		ctype, nr_elements  =  etype, nr_elements * elements
+	end
+	return ctype, nr_elements
+end
+
+--------------------------------------------------------------------------------
+
+local CDATA_REPR_MATCHER = 'cdata<(.+)>: (0x%w+)'
+
+return function (value, options, depth, l)
+	local native_repr  =  tostring(value)
+	local data_length  =  ffi.sizeof(value)
+	local ctype, addr  =  native_repr:match(CDATA_REPR_MATCHER)
+
+	l[#l+1] = 'cdata {'
+	--l[#l+1] = '\n\tnative = \''   .. native_repr .. '\','
+	l[#l+1] = '\n\ttype   = '   .. ctype .. ','
+	l[#l+1] = '\n\taddr   = '   .. addr .. ','
+	if data_length then
+		-- Size
+		local str = ffi.string(value, data_length)
+		l[#l+1] = '\n\tsize   = '   .. data_length .. ','
+
+		-- Element size and type
+		local element_type, nr_elements  =  get_type_and_size_of_singular(ctype)
+		local element_size = data_length / nr_elements
+		l[#l+1] = '\n\tnr_e   = ' .. nr_elements .. ','
+		l[#l+1] = '\n\ttype_e = '   .. element_type .. ','
+		l[#l+1] = '\n\tsize_e = '   .. element_size .. ','
+
+		--
+		if is_nice_ascii_string(str) then
+			l[#l+1] = '\n\tstr    = ' .. str .. ','
+		end
+		l[#l+1] = '\n\tbin    = ' .. to_hex(str) .. ','
+
+
+
+
+	end
+	l[#l+1] = '\n}'
+end
diff --git a/pretty.lua b/pretty.lua
index 8653637..19d6824 100644
--- a/pretty.lua
+++ b/pretty.lua
@@ -9,6 +9,7 @@ do
     -- Load number and function formatting
     format_number      =  select(2, pcall(require, thispath..'number'))
     format_function    =  select(2, pcall(require, thispath..'function'))
+    format_cdata       =  select(2, pcall(require, thispath..'cdata'))
 
     -- Load other stuff
     local was_loaded
@@ -480,6 +481,11 @@ if not format_function then
     end
 end
 
+if not format_cdata then
+    -- Very simple cdata formatting, if cdata.lua is not available.
+    format_cdata = format_primitive
+end
+
 local TYPE_TO_FORMAT_FUNC = {
     ['nil']      =  format_primitive,
     ['boolean']  =  format_primitive,
@@ -491,7 +497,7 @@ local TYPE_TO_FORMAT_FUNC = {
     -- TODO
     ['function'] =  format_function,
     ['userdata'] =  format_primitive,
-    ['cdata']    =  format_primitive,  -- Luajit exclusive ?
+    ['cdata']    =  format_cdata,     -- Luajit exclusive ?
 }
 
 function format_value (value, _, depth, l)
diff --git a/test/test_pretty.lua b/test/test_pretty.lua
index 7bf2bd6..87968bc 100644
--- a/test/test_pretty.lua
+++ b/test/test_pretty.lua
@@ -377,15 +377,35 @@ if type(jit) == 'table' then
 
     format_test {
         input  = ffi.C.poll,
-        approx = true,
         expect = 'cdata<.+>: 0x%x+',
     }
 
-    format_test {
-        input  = ffi.new('int[10]'),
-        approx = true,
-        expect = 'cdata<.+>: 0x%x+',
-    }
+    do
+        local list = ffi.new('char [17]')
+        for i = 0, 16 do  list[i] = i end
+        format_test {
+            input  = list,
+            expect = 'cdata<.+>: 0x%x+',
+        }
+    end
+
+    do
+        local list = ffi.new('char [10]')
+        for i = 0, 10-1 do  list[i] = i + 65 end
+        format_test {
+            input  = list,
+            expect = 'cdata<.+>: 0x%x+',
+        }
+    end
+
+    do
+        local mat = ffi.new('char [3][3]')
+        for x = 0, 2 do for y = 0, 2 do mat[x][y] = x * 16 + y end end
+        format_test {
+            input  = mat,
+            expect = 'cdata<.+>: 0x%x+',
+        }
+    end
 end
 
 --------------------------------------------------------------------------------