Incorporate a few upstream doc changes; grammar police; wordsmithing; Move -arithmetic into "switches for advanced users"; Additional documentation for IDCT scaling extensions

git-svn-id: svn://svn.code.sf.net/p/libjpeg-turbo/code/trunk@765 632fc199-4ca6-4c93-a231-07263d6284db

1 files changed, 10 insertions, 10 deletions

diff --git a/structure.txt b/structure.txt
index 779233a..83f552f 100644
--- a/structure.txt
+++ b/structure.txt
@@ -1,6 +1,6 @@
 IJG JPEG LIBRARY:  SYSTEM ARCHITECTURE
 
-Copyright (C) 1991-2009, Thomas G. Lane, Guido Vollbeding.
+Copyright (C) 1991-2012, Thomas G. Lane, Guido Vollbeding.
 This file is part of the Independent JPEG Group's software.
 For conditions of distribution and use, see the accompanying README file.
 
@@ -385,8 +385,9 @@ objects:
 
 * Data destination manager: writes the output JPEG datastream to its final
   destination (e.g., a file).  The destination manager supplied with the
-  library knows how to write to a stdio stream; for other behaviors, the
-  surrounding application may provide its own destination manager.
+  library knows how to write to a stdio stream or to a memory buffer;
+  for other behaviors, the surrounding application may provide its own
+  destination manager.
 
 * Memory manager: allocates and releases memory, controls virtual arrays
   (with backing store management, where required).
@@ -454,8 +455,8 @@ shown are:
   buffered by the coefficient controller have NOT been dequantized; we
   merge dequantization and inverse DCT into a single step for speed reasons.
   When scaled-down output is asked for, simplified DCT algorithms may be used
-  that emit only 1x1, 2x2, or 4x4 samples per DCT block, not the full 8x8.
-  Works on one DCT block at a time.
+  that emit fewer samples per DCT block, not the full 8x8.  Works on one DCT
+  block at a time.
 
 * Postprocessing controller: buffer controller for the color quantization
   input buffer, when quantization is in use.  (Without quantization, this
@@ -504,9 +505,9 @@ objects:
 * Marker reading: decodes JPEG markers (except for RSTn).
 
 * Data source manager: supplies the input JPEG datastream.  The source
-  manager supplied with the library knows how to read from a stdio stream;
-  for other behaviors, the surrounding application may provide its own source
-  manager.
+  manager supplied with the library knows how to read from a stdio stream
+  or from a memory buffer;  for other behaviors, the surrounding application
+  may provide its own source manager.
 
 * Memory manager: same as for compression library.
 
@@ -586,8 +587,7 @@ as "((value) & 0xFF)" on signed-char machines and "((int) (value))" elsewhere.
 With these conventions, JSAMPLE values can be assumed to be >= 0.  This helps
 simplify correct rounding during downsampling, etc.  The JPEG standard's
 specification that sample values run from -128..127 is accommodated by
-subtracting 128 just as the sample value is copied into the source array for
-the DCT step (this will be an array of signed ints).  Similarly, during
+subtracting 128 from the sample value in the DCT step.  Similarly, during
 decompression the output of the IDCT step will be immediately shifted back to
 0..255.  (NB: different values are required when 12-bit samples are in use.
 The code is written in terms of MAXJSAMPLE and CENTERJSAMPLE, which will be