[libpng16] refactor: Deduplicate the interlace arrays `png_pass_*`
Move the definitions of interlace arrays to the top of their respective
translation units, to reduce their repeated copying in various places of
the codebase.
TODO:
As they still exist in three copies, in pngpread.c, in pngrutil.c, and
in pngwutil.c, they should all be further moved to a common place.
This is a cherry-pick of commit 620a2b73b22df66ed099e1faacac2d92f48252b7
from branch 'libpng18'.
diff --git a/pngpread.c b/pngpread.c
index 1a59fae..322b0cf 100644
--- a/pngpread.c
+++ b/pngpread.c
@@ -31,6 +31,21 @@
if (png_ptr->buffer_size < N) \
{ png_push_save_buffer(png_ptr); return; }
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+/* Arrays to facilitate interlacing - use pass (0 - 6) as index. */
+
+/* Start of interlace block */
+static const png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+/* Offset to next interlace block */
+static const png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+/* Start of interlace block in the y direction */
+static const png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
+/* Offset to next interlace block in the y direction */
+static const png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
+
+/* TODO: Move these arrays to a common utility module to avoid duplication. */
+#endif
+
void PNGAPI
png_process_data(png_structrp png_ptr, png_inforp info_ptr,
png_bytep buffer, size_t buffer_size)
@@ -975,27 +990,6 @@
void /* PRIVATE */
png_read_push_finish_row(png_structrp png_ptr)
{
-#ifdef PNG_READ_INTERLACING_SUPPORTED
- /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
-
- /* Start of interlace block */
- static const png_byte png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
-
- /* Offset to next interlace block */
- static const png_byte png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
-
- /* Start of interlace block in the y direction */
- static const png_byte png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
-
- /* Offset to next interlace block in the y direction */
- static const png_byte png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
-
- /* Height of interlace block. This is not currently used - if you need
- * it, uncomment it here and in png.h
- static const png_byte png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
- */
-#endif
-
png_ptr->row_number++;
if (png_ptr->row_number < png_ptr->num_rows)
return;
diff --git a/pngrutil.c b/pngrutil.c
index 16a3c62..44b3a68 100644
--- a/pngrutil.c
+++ b/pngrutil.c
@@ -17,6 +17,21 @@
#ifdef PNG_READ_SUPPORTED
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+/* Arrays to facilitate interlacing - use pass (0 - 6) as index. */
+
+/* Start of interlace block */
+static const png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+/* Offset to next interlace block */
+static const png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+/* Start of interlace block in the y direction */
+static const png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
+/* Offset to next interlace block in the y direction */
+static const png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
+
+/* TODO: Move these arrays to a common utility module to avoid duplication. */
+#endif
+
png_uint_32 PNGAPI
png_get_uint_31(png_const_structrp png_ptr, png_const_bytep buf)
{
@@ -3683,10 +3698,6 @@
png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
png_uint_32 transformations /* Because these may affect the byte layout */)
{
- /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
- /* Offset to next interlace block */
- static const unsigned int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
-
png_debug(1, "in png_do_read_interlace");
if (row != NULL && row_info != NULL)
{
@@ -4324,20 +4335,6 @@
void /* PRIVATE */
png_read_finish_row(png_structrp png_ptr)
{
- /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
-
- /* Start of interlace block */
- static const png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
-
- /* Offset to next interlace block */
- static const png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
-
- /* Start of interlace block in the y direction */
- static const png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
-
- /* Offset to next interlace block in the y direction */
- static const png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
-
png_debug(1, "in png_read_finish_row");
png_ptr->row_number++;
if (png_ptr->row_number < png_ptr->num_rows)
@@ -4389,20 +4386,6 @@
void /* PRIVATE */
png_read_start_row(png_structrp png_ptr)
{
- /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
-
- /* Start of interlace block */
- static const png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
-
- /* Offset to next interlace block */
- static const png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
-
- /* Start of interlace block in the y direction */
- static const png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
-
- /* Offset to next interlace block in the y direction */
- static const png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
-
unsigned int max_pixel_depth;
size_t row_bytes;
diff --git a/pngwutil.c b/pngwutil.c
index 9d73071..abe7b07 100644
--- a/pngwutil.c
+++ b/pngwutil.c
@@ -8,12 +8,30 @@
* This code is released under the libpng license.
* For conditions of distribution and use, see the disclaimer
* and license in png.h
+ *
+ * This file contains routines that are only called from within
+ * libpng itself during the course of writing an image.
*/
#include "pngpriv.h"
#ifdef PNG_WRITE_SUPPORTED
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+/* Arrays to facilitate interlacing - use pass (0 - 6) as index. */
+
+/* Start of interlace block */
+static const png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+/* Offset to next interlace block */
+static const png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+/* Start of interlace block in the y direction */
+static const png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
+/* Offset to next interlace block in the y direction */
+static const png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
+
+/* TODO: Move these arrays to a common utility module to avoid duplication. */
+#endif
+
#ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
/* Place a 32-bit number into a buffer in PNG byte order. We work
* with unsigned numbers for convenience, although one supported
@@ -1888,22 +1906,6 @@
void /* PRIVATE */
png_write_start_row(png_structrp png_ptr)
{
-#ifdef PNG_WRITE_INTERLACING_SUPPORTED
- /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
-
- /* Start of interlace block */
- static const png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
-
- /* Offset to next interlace block */
- static const png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
-
- /* Start of interlace block in the y direction */
- static const png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
-
- /* Offset to next interlace block in the y direction */
- static const png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
-#endif
-
png_alloc_size_t buf_size;
int usr_pixel_depth;
@@ -2003,22 +2005,6 @@
void /* PRIVATE */
png_write_finish_row(png_structrp png_ptr)
{
-#ifdef PNG_WRITE_INTERLACING_SUPPORTED
- /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
-
- /* Start of interlace block */
- static const png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
-
- /* Offset to next interlace block */
- static const png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
-
- /* Start of interlace block in the y direction */
- static const png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
-
- /* Offset to next interlace block in the y direction */
- static const png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
-#endif
-
png_debug(1, "in png_write_finish_row");
/* Next row */
@@ -2094,14 +2080,6 @@
void /* PRIVATE */
png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
{
- /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
-
- /* Start of interlace block */
- static const png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
-
- /* Offset to next interlace block */
- static const png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
-
png_debug(1, "in png_do_write_interlace");
/* We don't have to do anything on the last pass (6) */
