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mesa,intel: use _mesa_image_offset() for PBOs 

This avoids forming invalid pointers needlessly, which even if
never dereferenced is undefined behavior. It also makes
_mesa_validate_pbo_access() more comprehensible.

Reviewed-by: Brian Paul <brianp@vmware.com>
This commit is contained in:
nobled 2011-10-19 06:35:53 +00:00
parent 4a2b9b5305
commit eefff37060
2 changed files with 19 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
src/mesa/drivers/dri/intel/intel_pixel_read.c
View File

@ -120,8 +120,9 @@ do_blit_readpixels(struct gl_context * ctx,
rowLength = -rowLength;
}
dst_offset = (GLintptr) _mesa_image_address(2, pack, pixels, width, height,
format, type, 0, 0, 0);
dst_offset = (GLintptr)pixels;
dst_offset += _mesa_image_offset(2, pack, width, height,
format, type, 0, 0, 0);
if (!_mesa_clip_copytexsubimage(ctx,
&dst_x, &dst_y,

29
src/mesa/main/pbo.c
View File

@ -68,8 +68,8 @@ _mesa_validate_pbo_access(GLuint dimensions,
GLenum format, GLenum type, GLsizei clientMemSize,
const GLvoid *ptr)
{
const GLvoid *start, *end, *offset;
const GLubyte *sizeAddr; /* buffer size, cast to a pointer */
/* unsigned, to detect overflow/wrap-around */
uintptr_t start, end, offset, size;
/* If no PBO is bound, 'ptr' is a pointer to client memory containing
'clientMemSize' bytes.
@ -78,10 +78,10 @@ _mesa_validate_pbo_access(GLuint dimensions,
*/
if (!_mesa_is_bufferobj(pack->BufferObj)) {
offset = 0;
sizeAddr = ((const GLubyte *) 0) + clientMemSize;
size = clientMemSize;
} else {
offset = ptr;
sizeAddr = ((const GLubyte *) 0) + pack->BufferObj->Size;
offset = (uintptr_t)ptr;
size = pack->BufferObj->Size;
/* The ARB_pixel_buffer_object spec says:
* "INVALID_OPERATION is generated by ColorTable, ColorSubTable,
* ConvolutionFilter2D, ConvolutionFilter1D, SeparableFilter2D,
@ -93,27 +93,30 @@ _mesa_validate_pbo_access(GLuint dimensions,
* parameter."
*/
if (type != GL_BITMAP &&
((GLintptr)offset % _mesa_sizeof_packed_type(type)))
(offset % _mesa_sizeof_packed_type(type)))
return GL_FALSE;
}
if (sizeAddr == 0)
if (size == 0)
/* no buffer! */
return GL_FALSE;
/* get the offset to the first pixel we'll read/write */
start = _mesa_image_address(dimensions, pack, offset, width, height,
format, type, 0, 0, 0);
start = _mesa_image_offset(dimensions, pack, width, height,
format, type, 0, 0, 0);
/* get the offset to just past the last pixel we'll read/write */
end = _mesa_image_address(dimensions, pack, offset, width, height,
format, type, depth-1, height-1, width);
end = _mesa_image_offset(dimensions, pack, width, height,
format, type, depth-1, height-1, width);
if ((const GLubyte *) start > sizeAddr) {
start += offset;
end += offset;
if (start > size) {
/* This will catch negative values / wrap-around */
return GL_FALSE;
}
if ((const GLubyte *) end > sizeAddr) {
if (end > size) {
/* Image read/write goes beyond end of buffer */
return GL_FALSE;
}