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Dircache: A bit of follow-up code cleanup suggested by Amaury Pouly.

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git-svn-id: svn://svn.rockbox.org/rockbox/trunk@30040 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Thomas Martitz 2011-06-20 20:12:52 +00:00
parent 3b29aa49d3
commit 287d69d7c4
1 changed files with 27 additions and 32 deletions
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59
firmware/common/dircache.c
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@ -599,8 +599,8 @@ int dircache_load(void)
dotdot = dot - sizeof("..");
/* d_names are in reverse order, so the last entry points to the first string */
intptr_t offset_d_names = maindata.d_names_start - d_names_start;
intptr_t offset_entries = maindata.root_entry - dircache_root;
ptrdiff_t offset_d_names = maindata.d_names_start - d_names_start,
offset_entries = maindata.root_entry - dircache_root;
/* offset_entries is less likely to differ, so check if it's 0 in the loop
* offset_d_names however is almost always non-zero, since dircache_save()
@ -846,10 +846,11 @@ int dircache_build(int last_size)
return 3;
}
/* struct dircache_entrys are allocated from the beginning,
* their corresponding d_name from the end
/* We'll use the entire audiobuf to allocate the dircache
* struct dircache_entrys are allocated from the beginning
* and their corresponding d_name from the end
* after generation the buffer will be compacted with DIRCACHE_RESERVE
* free bytes in between */
* free bytes inbetween */
audiobuf = (char*)(((intptr_t)audiobuf & ~0x03) + 0x04);
dircache_root = (struct dircache_entry*)audiobuf;
d_names_start = d_names_end = audiobufend - 1;
@ -858,35 +859,29 @@ int dircache_build(int last_size)
/* Start a non-transparent rebuild. */
int res = dircache_do_rebuild();
if (res < 0)
return res;
/** compact the dircache buffer **/
if (res >= 0)
{
char* dst = ((char*)&dircache_root[entry_count] + DIRCACHE_RESERVE);
ssize_t offset = d_names_start - dst;
if (offset > 0)
{
ssize_t size_to_move = dircache_size -
entry_count*sizeof(struct dircache_entry);
/* move d_names down, use memmove if overlap */
if (offset > size_to_move)
memcpy(dst, d_names_start, size_to_move);
else
memmove(dst, d_names_start, size_to_move);
/* fix up pointers to the d_names */
for(unsigned i = 0; i < entry_count; i++)
dircache_root[i].d_name -= offset;
/* now compact the dircache buffer */
char* dst = ((char*)&dircache_root[entry_count] + DIRCACHE_RESERVE);
ptrdiff_t offset = d_names_start - dst, size_to_move;
if (offset <= 0) /* something went wrong */
return -1;
/* memmove d_names down, there's a possibility of overlap */
size_to_move = dircache_size - entry_count*sizeof(struct dircache_entry);
memmove(dst, d_names_start, size_to_move);
/* fix up pointers to the d_names */
for(unsigned i = 0; i < entry_count; i++)
dircache_root[i].d_name -= offset;
d_names_end -= offset;
/* equivalent to dircache_size + DIRCACHE_RESERVE */
allocated_size = (d_names_end - (char*)dircache_root);
reserve_used = 0;
audiobuf += allocated_size;
d_names_end -= offset;
/* equivalent to dircache_size + DIRCACHE_RESERVE */
allocated_size = (d_names_end - (char*)dircache_root);
reserve_used = 0;
audiobuf += allocated_size;
}
else /* something went wrong */
return -1;
}
return res;
}