1 files changed, 151 insertions, 0 deletions
diff --git a/strings/Attic/ptr_cmp.c b/strings/Attic/ptr_cmp.c
new file mode 100644
index 00000000000..d3d4a36a054
--- /dev/null
+++ b/strings/Attic/ptr_cmp.c
@@ -0,0 +1,151 @@
+/*
+  get_ptr_compare(len) returns a pointer to a optimal byte-compare function
+  for a array of stringpointer where all strings have size len.
+  The bytes are compare as unsigned chars.
+  Because the size is saved in a static variable.
+  When using threads the program must have called my_init and the thread
+  my_init_thread()
+  */
+
+#include <global.h>
+#include "m_string.h"
+
+static int ptr_compare(uchar **a, uchar **b);
+static int ptr_compare_0(uchar **a, uchar **b);
+static int ptr_compare_1(uchar **a, uchar **b);
+static int ptr_compare_2(uchar **a, uchar **b);
+static int ptr_compare_3(uchar **a, uchar **b);
+
+#ifdef THREAD
+#include <my_pthread.h>
+#define compare_length my_thread_var->cmp_length
+#else
+static uint compare_length;
+#endif
+
+	/* Get a pointer to a optimal byte-compare function for a given size */
+
+qsort_cmp get_ptr_compare (uint size)
+{
+  compare_length=size;			/* Remember for loop */
+
+  if (size < 4)
+    return (qsort_cmp) ptr_compare;
+  switch (size & 3) {
+    case 0: return (qsort_cmp) ptr_compare_0;
+    case 1: return (qsort_cmp) ptr_compare_1;
+    case 2: return (qsort_cmp) ptr_compare_2;
+    case 3: return (qsort_cmp) ptr_compare_3;
+    }
+  return 0;					/* Impossible */
+}
+
+
+	/*
+	  Compare to keys to see witch is smaller.
+	  Loop unrolled to make it quick !!
+	*/
+
+#define cmp(N) if (first[N] != last[N]) return (int) first[N] - (int) last[N]
+
+static int ptr_compare(uchar **a, uchar **b)
+{
+  reg3 int length= compare_length;
+  reg1 uchar *first,*last;
+
+  first= *a; last= *b;
+  while (--length)
+  {
+    if (*first++ != *last++)
+      return (int) first[-1] - (int) last[-1];
+  }
+  return (int) first[0] - (int) last[0];
+}
+
+
+static int ptr_compare_0(uchar **a, uchar **b)
+{
+  reg3 int length= compare_length;
+  reg1 uchar *first,*last;
+
+  first= *a; last= *b;
+ loop:
+  cmp(0);
+  cmp(1);
+  cmp(2);
+  cmp(3);
+  if ((length-=4))
+  {
+    first+=4;
+    last+=4;
+    goto loop;
+  }
+  return (0);
+}
+
+
+static int ptr_compare_1(uchar **a, uchar **b)
+{
+  reg3 int length= compare_length-1;
+  reg1 uchar *first,*last;
+
+  first= *a+1; last= *b+1;
+  cmp(-1);
+ loop:
+  cmp(0);
+  cmp(1);
+  cmp(2);
+  cmp(3);
+  if ((length-=4))
+  {
+    first+=4;
+    last+=4;
+    goto loop;
+  }
+  return (0);
+}
+
+static int ptr_compare_2(uchar **a, uchar **b)
+{
+  reg3 int length= compare_length-2;
+  reg1 uchar *first,*last;
+
+  first= *a +2 ; last= *b +2;
+  cmp(-2);
+  cmp(-1);
+ loop:
+  cmp(0);
+  cmp(1);
+  cmp(2);
+  cmp(3);
+  if ((length-=4))
+  {
+    first+=4;
+    last+=4;
+    goto loop;
+  }
+  return (0);
+}
+
+static int ptr_compare_3(uchar **a, uchar **b)
+{
+  reg3 int length= compare_length-3;
+  reg1 uchar *first,*last;
+
+  first= *a +3 ; last= *b +3;
+  cmp(-3);
+  cmp(-2);
+  cmp(-1);
+ loop:
+  cmp(0);
+  cmp(1);
+  cmp(2);
+  cmp(3);
+  if ((length-=4))
+  {
+    first+=4;
+    last+=4;
+    goto loop;
+  }
+  return (0);
+}