From af36529554c39a2eefcc2c8723715e2d25b401b8 Mon Sep 17 00:00:00 2001
From: jvoisin
Date: Sun, 8 Jun 2014 13:39:18 +0200
Subject: Rename the MAT folder to libmat.

This commit fixes some issues for dump operating
systems who doesn't handle capitalization.
---
 libmat/images.py | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)
 create mode 100644 libmat/images.py

(limited to 'libmat/images.py')

diff --git a/libmat/images.py b/libmat/images.py
new file mode 100644
index 0000000..67c710f
--- /dev/null
+++ b/libmat/images.py
@@ -0,0 +1,52 @@
+''' Takes care about pictures formats
+
+References:
+    - JFIF: http://www.ecma-international.org/publications/techreports/E-TR-098.htm
+    - PNG: http://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/PNG.html
+    - PNG: http://www.w3.org/TR/PNG-Chunks.html
+'''
+
+import parser
+
+
+class JpegStripper(parser.GenericParser):
+    ''' Represents a jpeg file.
+        Custom Huffman and Quantization tables
+        are stripped: they may leak
+        some info, and the quality loss is minor.
+    '''
+    def _should_remove(self, field):
+        ''' Return True if the field is compromising
+        '''
+        field_list = frozenset([
+            'start_image',  # start of the image
+            'app0',         # JFIF data
+            'start_frame',  # specify width, height, number of components
+            'start_scan',   # specify which slice of data the top-to-bottom scan contains
+            'data',         # actual data
+            'end_image'])   # end of the image
+        if field.name in field_list:
+            return False
+        elif field.name.startswith('quantization['):  # custom Quant. tables
+            return False
+        elif field.name.startswith('huffman['):  # custom Huffman tables
+            return False
+        return True
+
+
+class PngStripper(parser.GenericParser):
+    ''' Represents a png file
+    '''
+    def _should_remove(self, field):
+        ''' Return True if the field is compromising
+        '''
+        field_list = frozenset([
+            'id',
+            'header',    # PNG header
+            'physical',  # the intended pixel size or aspect ratio
+            'end'])      # end of the image
+        if field.name in field_list:
+            return False
+        if field.name.startswith('data['):  # data
+            return False
+        return True
-- 
cgit v1.3