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Reduce memory usage of fast-import. 

Some structs are allocated rather frequently, but were using integer
types which were far larger than required to actually store their
full value range.

As packfiles are limited to 4 GiB we don't need more than 32 bits to
store the offset of an object within that packfile, an `unsigned long`
on a 64 bit system is likely a 64 bit unsigned value.  Saving 4 bytes
per object on a 64 bit system can add up fast on any sizable import.

As atom strings are strictly single components in a path name these
are probably limited to just 255 bytes by the underlying OS.  Going
to that short of a string is probably too restrictive, but certainly
`unsigned int` is far too large for their lengths.  `unsigned short`
is a reasonable limit.

Modes within a tree really only need two bytes to store their whole
value; using `unsigned int` here is vast overkill.  Saving 4 bytes
per file entry in an active branch can add up quickly on a project
with a large number of files.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
This commit is contained in:
Shawn O. Pearce 2007-02-05 16:34:56 -05:00
parent 8c1f22da9f
commit 10831c5513
1 changed files with 12 additions and 12 deletions
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24
fast-import.c
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@ -130,7 +130,7 @@ Format of STDIN stream:
struct object_entry
{
struct object_entry *next;
unsigned long offset;
uint32_t offset;
unsigned type : TYPE_BITS;
unsigned pack_id : PACK_ID_BITS;
unsigned char sha1[20];
@ -157,7 +157,7 @@ struct last_object
{
void *data;
unsigned long len;
unsigned long offset;
uint32_t offset;
unsigned int depth;
unsigned no_free:1;
};
@ -173,7 +173,7 @@ struct mem_pool
struct atom_str
{
struct atom_str *next_atom;
unsigned int str_len;
unsigned short str_len;
char str_dat[FLEX_ARRAY]; /* more */
};
@ -184,7 +184,7 @@ struct tree_entry
struct atom_str* name;
struct tree_entry_ms
{
unsigned int mode;
uint16_t mode;
unsigned char sha1[20];
} versions[2];
};
@ -464,7 +464,7 @@ static struct object_entry* find_mark(uintmax_t idnum)
return oe;
}
static struct atom_str* to_atom(const char *s, size_t len)
static struct atom_str* to_atom(const char *s, unsigned short len)
{
unsigned int hc = hc_str(s, len) % atom_table_sz;
struct atom_str *c;
@ -993,10 +993,10 @@ static void *gfi_unpack_entry(
return unpack_entry(p, oe->offset, type, sizep);
}
static const char *get_mode(const char *str, unsigned int *modep)
static const char *get_mode(const char *str, uint16_t *modep)
{
unsigned char c;
unsigned int mode = 0;
uint16_t mode = 0;
while ((c = *str++) != ' ') {
if (c < '0' || c > '7')
@ -1046,7 +1046,7 @@ static void load_tree(struct tree_entry *root)
if (!c)
die("Corrupt mode in %s", sha1_to_hex(sha1));
e->versions[0].mode = e->versions[1].mode;
e->name = to_atom(c, strlen(c));
e->name = to_atom(c, (unsigned short)strlen(c));
c += e->name->str_len + 1;
hashcpy(e->versions[0].sha1, (unsigned char*)c);
hashcpy(e->versions[1].sha1, (unsigned char*)c);
@ -1098,7 +1098,7 @@ static void mktree(struct tree_content *t,
struct tree_entry *e = t->entries[i];
if (!e->versions[v].mode)
continue;
c += sprintf(c, "%o", e->versions[v].mode);
c += sprintf(c, "%o", (unsigned int)e->versions[v].mode);
*c++ = ' ';
strcpy(c, e->name->str_dat);
c += e->name->str_len + 1;
@ -1161,7 +1161,7 @@ static int tree_content_set(
struct tree_entry *root,
const char *p,
const unsigned char *sha1,
const unsigned int mode)
const uint16_t mode)
{
struct tree_content *t = root->tree;
const char *slash1;
@ -1207,7 +1207,7 @@ static int tree_content_set(
if (t->entry_count == t->entry_capacity)
root->tree = t = grow_tree_content(t, 8);
e = new_tree_entry();
e->name = to_atom(p, n);
e->name = to_atom(p, (unsigned short)n);
e->versions[0].mode = 0;
hashclr(e->versions[0].sha1);
t->entries[t->entry_count++] = e;
@ -1458,7 +1458,7 @@ static void file_change_m(struct branch *b)
const char *endp;
struct object_entry *oe;
unsigned char sha1[20];
unsigned int mode, inline_data = 0;
uint16_t mode, inline_data = 0;
char type[20];
p = get_mode(p, &mode);