Merge pull request #150 from davidhubbard/master

Fix #44: document _ofs header fields
diff --git a/spec/basis_spec.txt b/spec/basis_spec.txt
index 3b6649e..ba9fa4b 100644
--- a/spec/basis_spec.txt
+++ b/spec/basis_spec.txt
@@ -105,11 +105,11 @@
   uint32      m_userdata1;        // For client use
 
   uint16      m_total_endpoints;          // ETC1S: The number of endpoints in the endpoint codebook 
-  uint32      m_endpoint_cb_file_ofs;     // ETC1S: The compressed endpoint codebook's file offset relative to the header
+  uint32      m_endpoint_cb_file_ofs;     // ETC1S: The compressed endpoint codebook's file offset relative to the start of the file
   uint24      m_endpoint_cb_file_size;    // ETC1S: The compressed endpoint codebook's size in bytes
 
   uint16      m_total_selectors;          // ETC1S: The number of selectors in the selector codebook 
-  uint32      m_selector_cb_file_ofs;     // ETC1S: The compressed selector codebook's file offset relative to the header
+  uint32      m_selector_cb_file_ofs;     // ETC1S: The compressed selector codebook's file offset relative to the start of the file
   uint24      m_selector_cb_file_size;    // ETC1S: The compressed selector codebook's size in bytes
 
   uint32      m_tables_file_ofs;          // ETC1S: The file offset of the compressed Huffman codelength tables.
@@ -169,7 +169,7 @@
 * m_orig_height: The original image height (may not be a multiple of 4 pixels)
 * m_num_blocks_x: The slice's block X dimensions. Each block is 4x4 pixels. The slice's pixel resolution may or may not be a power of 2.
 * m_num_blocks_y: The slice's block Y dimensions. 
-* m_file_ofs: Offset from the header to the start of the slice's data
+* m_file_ofs: Offset from the start of the file to the start of the slice's data
 * m_file_size: The size of the compressed slice data in bytes
 * m_slice_data_crc16: The CRC16 of the compressed slice data, for extra-paranoid use cases
 
diff --git a/transcoder/basisu_file_headers.h b/transcoder/basisu_file_headers.h
index e682996..a9c67f9 100644
--- a/transcoder/basisu_file_headers.h
+++ b/transcoder/basisu_file_headers.h
@@ -38,7 +38,7 @@
 		basisu::packed_uint<2> m_num_blocks_x;	// The slice's block X dimensions. Each block is 4x4 pixels. The slice's pixel resolution may or may not be a power of 2.
 		basisu::packed_uint<2> m_num_blocks_y;	// The slice's block Y dimensions. 
 
-		basisu::packed_uint<4> m_file_ofs;		// Offset from the header to the start of the slice's data
+		basisu::packed_uint<4> m_file_ofs;		// Offset from the start of the file to the start of the slice's data
 		basisu::packed_uint<4> m_file_size;		// The size of the compressed slice data in bytes
 
 		basisu::packed_uint<2> m_slice_data_crc16; // The CRC16 of the compressed slice data, for extra-paranoid use cases
@@ -107,11 +107,11 @@
 		basisu::packed_uint<4>      m_userdata1;		// For client use
 
 		basisu::packed_uint<2>      m_total_endpoints;			// The number of endpoints in the endpoint codebook 
-		basisu::packed_uint<4>      m_endpoint_cb_file_ofs;	// The compressed endpoint codebook's file offset relative to the header
+		basisu::packed_uint<4>      m_endpoint_cb_file_ofs;	// The compressed endpoint codebook's file offset relative to the start of the file
 		basisu::packed_uint<3>      m_endpoint_cb_file_size;	// The compressed endpoint codebook's size in bytes
 
 		basisu::packed_uint<2>      m_total_selectors;			// The number of selectors in the endpoint codebook 
-		basisu::packed_uint<4>      m_selector_cb_file_ofs;	// The compressed selectors codebook's file offset relative to the header
+		basisu::packed_uint<4>      m_selector_cb_file_ofs;	// The compressed selectors codebook's file offset relative to the start of the file
 		basisu::packed_uint<3>      m_selector_cb_file_size;	// The compressed selector codebook's size in bytes
 
 		basisu::packed_uint<4>      m_tables_file_ofs;			// The file offset of the compressed Huffman codelength tables, for decompressing slices