qiurui
/
glibc
mirror of git://sourceware.org/git/glibc.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

stdlib: qsort: Move some macros to inline function 

Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
This commit is contained in:
Adhemerval Zanella 2023-10-03 09:22:48 -03:00
parent a035a9857e
commit d097f3c79b
1 changed files with 23 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

35
stdlib/qsort.c
View File

@ -100,15 +100,28 @@ typedef struct
char *hi; char *hi;
} stack_node; } stack_node;
/* The next 4 #defines implement a very fast in-line stack abstraction. */
/* The stack needs log (total_elements) entries (we could even subtract /* The stack needs log (total_elements) entries (we could even subtract
log(MAX_THRESH)). Since total_elements has type size_t, we get as log(MAX_THRESH)). Since total_elements has type size_t, we get as
upper bound for log (total_elements): upper bound for log (total_elements):
bits per byte (CHAR_BIT) * sizeof(size_t). */ bits per byte (CHAR_BIT) * sizeof(size_t). */
#define STACK_SIZE (CHAR_BIT * sizeof (size_t)) enum { STACK_SIZE = CHAR_BIT * sizeof (size_t) };
#define PUSH(low, high) ((void) ((top->lo = (low)), (top->hi = (high)), ++top))
#define POP(low, high) ((void) (--top, (low = top->lo), (high = top->hi))) static inline stack_node *
#define STACK_NOT_EMPTY (stack < top) push (stack_node *top, char *lo, char *hi)
{
top->lo = lo;
top->hi = hi;
return ++top;
}
static inline stack_node *
pop (stack_node *top, char **lo, char **hi)
{
--top;
*lo = top->lo;
*hi = top->hi;
return top;
}
static inline void static inline void
@ -212,11 +225,9 @@ _quicksort (void *const pbase, size_t total_elems, size_t size,
char *lo = base_ptr; char *lo = base_ptr;
char *hi = &lo[size * (total_elems - 1)]; char *hi = &lo[size * (total_elems - 1)];
stack_node stack[STACK_SIZE]; stack_node stack[STACK_SIZE];
stack_node *top = stack; stack_node *top = stack + 1;
PUSH (NULL, NULL); while (stack < top)
while (STACK_NOT_EMPTY)
{ {
char *left_ptr; char *left_ptr;
char *right_ptr; char *right_ptr;
@ -281,7 +292,7 @@ _quicksort (void *const pbase, size_t total_elems, size_t size,
{ {
if ((size_t) (hi - left_ptr) <= max_thresh) if ((size_t) (hi - left_ptr) <= max_thresh)
/* Ignore both small partitions. */ /* Ignore both small partitions. */
POP (lo, hi); top = pop (top, &lo, &hi);
else else
/* Ignore small left partition. */ /* Ignore small left partition. */
lo = left_ptr; lo = left_ptr;
@ -292,13 +303,13 @@ _quicksort (void *const pbase, size_t total_elems, size_t size,
else if ((right_ptr - lo) > (hi - left_ptr)) else if ((right_ptr - lo) > (hi - left_ptr))
{ {
/* Push larger left partition indices. */ /* Push larger left partition indices. */
PUSH (lo, right_ptr); top = push (top, lo, right_ptr);
lo = left_ptr; lo = left_ptr;
} }
else else
{ {
/* Push larger right partition indices. */ /* Push larger right partition indices. */
PUSH (left_ptr, hi); top = push (top, left_ptr, hi);
hi = right_ptr; hi = right_ptr;
} }
} }