diff mbox series

[v4,3/6] stdlib: qsort: Move some macros to inline function

Message ID 20230711190722.4028821-4-adhemerval.zanella@linaro.org
State New
Headers show
Series Use introsort for qsort | expand

Commit Message

Adhemerval Zanella Netto July 11, 2023, 7:07 p.m. UTC 
---
 stdlib/qsort.c | 33 +++++++++++++++++++++++----------
 1 file changed, 23 insertions(+), 10 deletions(-)

Comments

Noah Goldstein July 11, 2023, 11:44 p.m. UTC | #1 
On Tue, Jul 11, 2023 at 2:10 PM Adhemerval Zanella via Libc-alpha
<libc-alpha@sourceware.org> wrote:
>
> ---
>  stdlib/qsort.c | 33 +++++++++++++++++++++++----------
>  1 file changed, 23 insertions(+), 10 deletions(-)
>
> diff --git a/stdlib/qsort.c b/stdlib/qsort.c
> index 00637208ab..134e784bd1 100644
> --- a/stdlib/qsort.c
> +++ b/stdlib/qsort.c
> @@ -118,15 +118,28 @@ typedef struct
>      char *hi;
>    } 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
>     log(MAX_THRESH)).  Since total_elements has type size_t, we get as
>     upper bound for log (total_elements):
>     bits per byte (CHAR_BIT) * sizeof(size_t).  */
> -#define 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)))
> -#define        STACK_NOT_EMPTY (stack < top)
> +enum { STACK_SIZE = CHAR_BIT * sizeof (size_t) };
> +
> +static inline stack_node *
> +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;
> +}
>
>
>  /* Order size using quicksort.  This implementation incorporates
> @@ -232,9 +245,9 @@ _quicksort (void *const pbase, size_t total_elems, size_t size,
>        stack_node stack[STACK_SIZE];
>        stack_node *top = stack;
>
> -      PUSH (NULL, NULL);
> +      top = push (top, NULL, NULL);
>
You could also drop this push and just set `top = stack + 1;`
> -      while (STACK_NOT_EMPTY)
> +      while (stack < top)
>          {
>            char *left_ptr;
>            char *right_ptr;
> @@ -299,7 +312,7 @@ _quicksort (void *const pbase, size_t total_elems, size_t size,
>              {
>                if ((size_t) (hi - left_ptr) <= max_thresh)
>                 /* Ignore both small partitions. */
> -                POP (lo, hi);
> +                top = pop (top, &lo, &hi);
>                else
>                 /* Ignore small left partition. */
>                  lo = left_ptr;
> @@ -310,13 +323,13 @@ _quicksort (void *const pbase, size_t total_elems, size_t size,
>            else if ((right_ptr - lo) > (hi - left_ptr))
>              {
>               /* Push larger left partition indices. */
> -              PUSH (lo, right_ptr);
> +              top = push (top, lo, right_ptr);
>                lo = left_ptr;
>              }
>            else
>              {
>               /* Push larger right partition indices. */
> -              PUSH (left_ptr, hi);
> +              top = push (top, left_ptr, hi);
>                hi = right_ptr;
>              }
>          }
> --
> 2.34.1
>
Adhemerval Zanella Netto July 12, 2023, 8:45 p.m. UTC | #2 
On 11/07/23 20:44, Noah Goldstein wrote:
> On Tue, Jul 11, 2023 at 2:10 PM Adhemerval Zanella via Libc-alpha
> <libc-alpha@sourceware.org> wrote:
>>
>> ---
>>  stdlib/qsort.c | 33 +++++++++++++++++++++++----------
>>  1 file changed, 23 insertions(+), 10 deletions(-)
>>
>> diff --git a/stdlib/qsort.c b/stdlib/qsort.c
>> index 00637208ab..134e784bd1 100644
>> --- a/stdlib/qsort.c
>> +++ b/stdlib/qsort.c
>> @@ -118,15 +118,28 @@ typedef struct
>>      char *hi;
>>    } 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
>>     log(MAX_THRESH)).  Since total_elements has type size_t, we get as
>>     upper bound for log (total_elements):
>>     bits per byte (CHAR_BIT) * sizeof(size_t).  */
>> -#define 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)))
>> -#define        STACK_NOT_EMPTY (stack < top)
>> +enum { STACK_SIZE = CHAR_BIT * sizeof (size_t) };
>> +
>> +static inline stack_node *
>> +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;
>> +}
>>
>>
>>  /* Order size using quicksort.  This implementation incorporates
>> @@ -232,9 +245,9 @@ _quicksort (void *const pbase, size_t total_elems, size_t size,
>>        stack_node stack[STACK_SIZE];
>>        stack_node *top = stack;
>>
>> -      PUSH (NULL, NULL);
>> +      top = push (top, NULL, NULL);
>>
> You could also drop this push and just set `top = stack + 1;`

Ack.
diff mbox series

Patch

diff --git a/stdlib/qsort.c b/stdlib/qsort.c
index 00637208ab..134e784bd1 100644
--- a/stdlib/qsort.c
+++ b/stdlib/qsort.c
@@ -118,15 +118,28 @@  typedef struct
     char *hi;
   } 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
    log(MAX_THRESH)).  Since total_elements has type size_t, we get as
    upper bound for log (total_elements):
    bits per byte (CHAR_BIT) * sizeof(size_t).  */
-#define 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)))
-#define	STACK_NOT_EMPTY	(stack < top)
+enum { STACK_SIZE = CHAR_BIT * sizeof (size_t) };
+
+static inline stack_node *
+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;
+}
 
 
 /* Order size using quicksort.  This implementation incorporates
@@ -232,9 +245,9 @@  _quicksort (void *const pbase, size_t total_elems, size_t size,
       stack_node stack[STACK_SIZE];
       stack_node *top = stack;
 
-      PUSH (NULL, NULL);
+      top = push (top, NULL, NULL);
 
-      while (STACK_NOT_EMPTY)
+      while (stack < top)
         {
           char *left_ptr;
           char *right_ptr;
@@ -299,7 +312,7 @@  _quicksort (void *const pbase, size_t total_elems, size_t size,
             {
               if ((size_t) (hi - left_ptr) <= max_thresh)
 		/* Ignore both small partitions. */
-                POP (lo, hi);
+                top = pop (top, &lo, &hi);
               else
 		/* Ignore small left partition. */
                 lo = left_ptr;
@@ -310,13 +323,13 @@  _quicksort (void *const pbase, size_t total_elems, size_t size,
           else if ((right_ptr - lo) > (hi - left_ptr))
             {
 	      /* Push larger left partition indices. */
-              PUSH (lo, right_ptr);
+              top = push (top, lo, right_ptr);
               lo = left_ptr;
             }
           else
             {
 	      /* Push larger right partition indices. */
-              PUSH (left_ptr, hi);
+              top = push (top, left_ptr, hi);
               hi = right_ptr;
             }
         }