Hi, On Mon, Jul 17, 2006 at 11:00:01AM +0200, Philip Van Hoof wrote: > > > I cannot change these "to, from nor subject" pointers. These are used > > > in thousands of lines of Evolution code that I don't want to change. > > > > There's no need to align access to chars. Is there something that accesses > > the saved data as shorts, longs (ints), floats or doubles? Or casts the > > char pointers e.g. into int *? (use -Wcast-align) > > Yes. But I already did something to make sure that access is correct. > > It's in the patch. Search for "get_unaligned_u32"
Why the code changes everything saved to network order? The byteorder doesn't change unless you move to a different CPU architecture and I would assume mmap files to be quite specific for one machine. :-) > http://pvanhoof.be/files/camel_folder_summary_with_mmap_fixes11_data_alignment03.diff At least this one is broken: +#define CFU_ENCODE_T(type) \ +int \ +camel_file_util_encode_##type(FILE *out, type value) \ +{ \ + return camel_file_util_encode_fixed_int32 (out, (guint32) value); \ } The original code was using sizeof(type), not blindly assuming it to be guint32. These changes are a bit strange, they change the semantics of the code: - if (camel_file_util_decode_fixed_int32(in, &cns->version) == -1) - return -1; + cns->version = g_ntohl(get_unaligned_u32(s->filepos)); s->filepos += 4; - if (camel_file_util_decode_fixed_int32(in, &cns->high) == -1 - || camel_file_util_decode_fixed_int32(in, &cns->low) == -1) - return -1; + cns->high = g_ntohl(get_unaligned_u32(s->filepos)); s->filepos += 4; + cns->low = g_ntohl(get_unaligned_u32(s->filepos)); s->filepos += 4; Btw. something like this: + if (lena % G_MEM_ALIGN) + lena += G_MEM_ALIGN - (lena % G_MEM_ALIGN); Might be slower than just aligning always: lena = (lena + (G_MEM_ALIGN-1)) & ~(G_MEM_ALIGN-1); Which can be nicely wrapped in a macro: /* assume "var" is either char/short/int/long or pointer to char * so that it doesn't need to cast into something which * increments happen in units of one */ ALIGN(var) (var = (var + (G_MEM_ALIGN-1)) & ~(G_MEM_ALIGN-1)) > Yet the patch still isn't working on ARM (and I don't have a debug > infrastructure, unless somebody can explain me how to set it up using > some emulator -- like qemu? --). You can request the kernel to give warnings about unligned access. I'm not sure whether you need to re-compile kernel for that or is there a /proc entry for that. Some other Gotchas on ARM are sign extensions. You need to watch out for compiler warnings about comparisons where chars are of different signedness I think. - Eero _______________________________________________ maemo-developers mailing list maemo-developers@maemo.org https://maemo.org/mailman/listinfo/maemo-developers
