[devel] Changes to remove gcc warnings (John Bowler)
Certain optional gcc warning flags resulted in warnings in libpng code.
With these changes only -Wconversion and -Wcast-qual cannot be turned on.
Changes are trivial rearrangements of code. -Wconversion is not possible
for pngrutil.c (because of the widespread use of += et al on variables
smaller than (int) or (unsigned int)) and -Wcast-qual is not possible
with pngwio.c and pngwutil.c because the 'write' callback and zlib
compression both fail to declare their input buffers with 'const'.
diff --git a/ANNOUNCE b/ANNOUNCE
index b98b196..4ad0e31 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -442,6 +442,15 @@
Fixed atomicity of chunk header serialization (Cosmin)
Added test for io_state in pngtest.c (Cosmin)
Added "#!/bin/sh" at the top of contrib/pngminim/*/gather.sh scripts.
+ Changes to remove gcc warnings (John Bowler)
+ Certain optional gcc warning flags resulted in warnings in libpng code.
+ With these changes only -Wconversion and -Wcast-qual cannot be turned on.
+ Changes are trivial rearrangements of code. -Wconversion is not possible
+ for pngrutil.c (because of the widespread use of += et al on variables
+ smaller than (int) or (unsigned int)) and -Wcast-qual is not possible
+ with pngwio.c and pngwutil.c because the 'write' callback and zlib
+ compression both fail to declare their input buffers with 'const'.
+
Send comments/corrections/commendations to png-mng-implement at lists.sf.net:
(subscription required; visit
diff --git a/CHANGES b/CHANGES
index 5d1b443..a816a9e 100644
--- a/CHANGES
+++ b/CHANGES
@@ -3080,6 +3080,15 @@
Fixed atomicity of chunk header serialization (Cosmin)
Added test for io_state in pngtest.c (Cosmin)
Added "#!/bin/sh" at the top of contrib/pngminim/*/gather.sh scripts.
+ Changes to remove gcc warnings (John Bowler)
+ Certain optional gcc warning flags resulted in warnings in libpng code.
+ With these changes only -Wconversion and -Wcast-qual cannot be turned on.
+ Changes are trivial rearrangements of code. -Wconversion is not possible
+ for pngrutil.c (because of the widespread use of += et al on variables
+ smaller than (int) or (unsigned int)) and -Wcast-qual is not possible
+ with pngwio.c and pngwutil.c because the 'write' callback and zlib
+ compression both fail to declare their input buffers with 'const'.
+
Send comments/corrections/commendations to png-mng-implement at lists.sf.net
(subscription required; visit
diff --git a/pngpread.c b/pngpread.c
index 67455c3..c893104 100644
--- a/pngpread.c
+++ b/pngpread.c
@@ -1137,6 +1137,7 @@
break;
}
+ default:
case 6:
{
png_push_have_row(png_ptr, png_ptr->row_buf + 1);
diff --git a/pngread.c b/pngread.c
index fe180fd..30605d1 100644
--- a/pngread.c
+++ b/pngread.c
@@ -618,6 +618,7 @@
}
break;
+ default:
case 6:
if (!(png_ptr->row_number & 1))
{
diff --git a/pngrtran.c b/pngrtran.c
index 9cd85df..b3425d3 100644
--- a/pngrtran.c
+++ b/pngrtran.c
@@ -719,6 +719,11 @@
case 3:
png_ptr->transformations |= PNG_RGB_TO_GRAY_ERR;
+ break;
+
+ default:
+ png_error(png_ptr, "invalid error action to rgb_to_gray");
+ break;
}
if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
#ifdef PNG_READ_EXPAND_SUPPORTED
@@ -886,6 +891,8 @@
}
break;
+ default:
+
case 8:
case 16:
@@ -1088,6 +1095,9 @@
gs = png_reciprocal2(png_ptr->background_gamma,
png_ptr->screen_gamma);
break;
+
+ default:
+ png_error(png_ptr, "invalid background gamma type");
}
png_ptr->background_1.gray = png_gamma_correct(png_ptr,
@@ -1725,6 +1735,9 @@
}
break;
}
+
+ default:
+ break;
}
row_info->bit_depth = 8;
row_info->pixel_depth = (png_byte)(8 * row_info->channels);
@@ -1785,6 +1798,9 @@
switch (row_info->bit_depth)
{
+ default:
+ break;
+
case 2:
{
png_bytep bp;
@@ -2966,6 +2982,9 @@
}
break;
}
+
+ default:
+ break;
}
break;
}
@@ -3438,6 +3457,9 @@
}
break;
}
+
+ default:
+ break;
}
if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
@@ -3646,6 +3668,9 @@
}
break;
}
+
+ default:
+ break;
}
}
}
@@ -3744,6 +3769,9 @@
}
break;
}
+
+ default:
+ break;
}
row_info->bit_depth = 8;
row_info->pixel_depth = 8;
@@ -3901,6 +3929,9 @@
}
break;
}
+
+ default:
+ break;
}
row_info->bit_depth = 8;
diff --git a/pngrutil.c b/pngrutil.c
index 2cc0b10..38464d2 100644
--- a/pngrutil.c
+++ b/pngrutil.c
@@ -98,6 +98,11 @@
png_uint_16 (PNGAPI
png_get_uint_16)(png_const_bytep buf)
{
+ /* ANSI-C requires an int value to accomodate at least 16 bits so this
+ * works and allows the compiler not to worry about possible narrowing
+ * on 32 bit systems. (Pre-ANSI systems did not make integers smaller
+ * than 16 bits either.)
+ */
unsigned int val =
((unsigned int)(*buf) << 8) +
((unsigned int)(*(buf + 1)));
diff --git a/pngwtran.c b/pngwtran.c
index 066e1e2..1765ef8 100644
--- a/pngwtran.c
+++ b/pngwtran.c
@@ -220,6 +220,9 @@
break;
}
+
+ default:
+ break;
}
row_info->bit_depth = (png_byte)bit_depth;
diff --git a/pngwutil.c b/pngwutil.c
index 3377d38..71f2625 100644
--- a/pngwutil.c
+++ b/pngwutil.c
@@ -257,10 +257,12 @@
*/
/* Set up the compression buffers */
+ /* TODO: the following cast hides a potential overflow problem. */
png_ptr->zstream.avail_in = (uInt)text_len;
+ /* NOTE: assume zlib doesn't overwrite the input */
png_ptr->zstream.next_in = (Bytef *)text;
- png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
- png_ptr->zstream.next_out = (Bytef *)png_ptr->zbuf;
+ png_ptr->zstream.avail_out = png_ptr->zbuf_size;
+ png_ptr->zstream.next_out = png_ptr->zbuf;
/* This is the same compression loop as in png_write_row() */
do
