Remove top-level const from function-scope variables
As per the const correctness rules, top-level const-ness of data
in automatic scopes does not propagate outside of these scopes
(unlike const-ness at lower levels, such as pointers to const data).
Previously, const was used liberally, but inconsistently across the
libpng codebase. Using const wherever applicable is not incorrect.
However, _consistent_ use of const is difficult to maintain in such
conditions.
In conclusion, we shall continue to use const only where doing so is
strictly necessary:
1. If a function guarantees that it will not modify an argument
passed by pointer, the corresponding function parameter should be
a pointer-to-const (const T *).
2. Static data should not be modified, therefore it should be const.
Reference:
Google C++ Style Guide
https://google.github.io/styleguide/cppguide.html#Use_of_const
diff --git a/pngwutil.c b/pngwutil.c
index 5a4ded5..16345e4 100644
--- a/pngwutil.c
+++ b/pngwutil.c
@@ -2101,7 +2101,7 @@
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};
+ static const png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
png_debug(1, "in png_do_write_interlace");
@@ -2276,7 +2276,7 @@
#ifdef PNG_WRITE_FILTER_SUPPORTED
static size_t /* PRIVATE */
-png_setup_sub_row(png_structrp png_ptr, const png_uint_32 bpp,
+png_setup_sub_row(png_structrp png_ptr, png_uint_32 bpp,
size_t row_bytes, size_t lmins)
{
png_bytep rp, dp, lp;
@@ -2315,7 +2315,7 @@
}
static void /* PRIVATE */
-png_setup_sub_row_only(png_structrp png_ptr, const png_uint_32 bpp,
+png_setup_sub_row_only(png_structrp png_ptr, png_uint_32 bpp,
size_t row_bytes)
{
png_bytep rp, dp, lp;
@@ -2380,7 +2380,7 @@
}
static size_t /* PRIVATE */
-png_setup_avg_row(png_structrp png_ptr, const png_uint_32 bpp,
+png_setup_avg_row(png_structrp png_ptr, png_uint_32 bpp,
size_t row_bytes, size_t lmins)
{
png_bytep rp, dp, pp, lp;
@@ -2420,7 +2420,7 @@
return (sum);
}
static void /* PRIVATE */
-png_setup_avg_row_only(png_structrp png_ptr, const png_uint_32 bpp,
+png_setup_avg_row_only(png_structrp png_ptr, png_uint_32 bpp,
size_t row_bytes)
{
png_bytep rp, dp, pp, lp;
@@ -2442,7 +2442,7 @@
}
static size_t /* PRIVATE */
-png_setup_paeth_row(png_structrp png_ptr, const png_uint_32 bpp,
+png_setup_paeth_row(png_structrp png_ptr, png_uint_32 bpp,
size_t row_bytes, size_t lmins)
{
png_bytep rp, dp, pp, cp, lp;
@@ -2503,7 +2503,7 @@
return (sum);
}
static void /* PRIVATE */
-png_setup_paeth_row_only(png_structrp png_ptr, const png_uint_32 bpp,
+png_setup_paeth_row_only(png_structrp png_ptr, png_uint_32 bpp,
size_t row_bytes)
{
png_bytep rp, dp, pp, cp, lp;
