144 lines
3.9 KiB
C
144 lines
3.9 KiB
C
/***********************************************************************/
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/* */
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/* Objective Caml */
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/* */
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/* Xavier Leroy, projet Cristal, INRIA Rocquencourt */
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/* */
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/* Copyright 1996 Institut National de Recherche en Informatique et */
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/* Automatique. Distributed only by permission. */
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/* */
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/***********************************************************************/
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/* $Id$ */
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#include "fail.h"
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#include "memory.h"
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#include "misc.h"
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#include "mlvalues.h"
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#include "str.h"
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/* Structural comparison on trees.
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May loop on cyclic structures. */
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static long compare_val(value v1, value v2)
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{
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tag_t t1, t2;
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tailcall:
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if (v1 == v2) return 0;
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if (Is_long(v1)) {
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if (Is_long(v2))
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return Long_val(v1) - Long_val(v2);
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else
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return -1;
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}
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if (Is_long(v2)) return 1;
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/* If one of the objects is outside the heap (but is not an atom),
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use address comparison. Since both addresses are 2-aligned,
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shift lsb off to avoid overflow in subtraction. */
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if ((!Is_atom(v1) && !Is_young(v1) && !Is_in_heap(v1)) ||
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(!Is_atom(v2) && !Is_young(v2) && !Is_in_heap(v2)))
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return (v1 >> 1) - (v2 >> 1);
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t1 = Tag_val(v1);
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t2 = Tag_val(v2);
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if (t1 != t2) return (long)t1 - (long)t2;
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switch(t1) {
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case String_tag: {
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mlsize_t len1, len2, len;
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unsigned char * p1, * p2;
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len1 = string_length(v1);
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len2 = string_length(v2);
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for (len = (len1 <= len2 ? len1 : len2),
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p1 = (unsigned char *) String_val(v1),
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p2 = (unsigned char *) String_val(v2);
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len > 0;
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len--, p1++, p2++)
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if (*p1 != *p2) return (long)*p1 - (long)*p2;
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return len1 - len2;
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}
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case Double_tag: {
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double d1 = Double_val(v1);
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double d2 = Double_val(v2);
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if (d1 < d2) return -1; else if (d1 > d2) return 1; else return 0;
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}
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case Double_array_tag: {
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mlsize_t sz1 = Wosize_val(v1) / Double_wosize;
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mlsize_t sz2 = Wosize_val(v2) / Double_wosize;
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mlsize_t i;
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if (sz1 != sz2) return sz1 - sz2;
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for (i = 0; i < sz1; i++) {
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double d1 = Double_field(v1, i);
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double d2 = Double_field(v2, i);
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if (d1 < d2) return -1; else if (d1 > d2) return 1;
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}
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return 0;
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}
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case Abstract_tag:
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case Final_tag:
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invalid_argument("equal: abstract value");
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case Closure_tag:
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case Infix_tag:
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invalid_argument("equal: functional value");
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case Object_tag:
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return (Oid_val(v1) - Oid_val(v2));
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default: {
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mlsize_t sz1 = Wosize_val(v1);
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mlsize_t sz2 = Wosize_val(v2);
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value * p1, * p2;
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long res;
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if (sz1 != sz2) return sz1 - sz2;
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if (sz1 == 0) return 0;
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for(p1 = Op_val(v1), p2 = Op_val(v2);
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sz1 > 1;
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sz1--, p1++, p2++) {
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res = compare_val(*p1, *p2);
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if (res != 0) return res;
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}
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v1 = *p1;
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v2 = *p2;
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goto tailcall;
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}
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}
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}
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value compare(value v1, value v2) /* ML */
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{
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long res = compare_val(v1, v2);
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if (res < 0)
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return Val_int(-1);
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else if (res > 0)
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return Val_int(1);
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else
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return Val_int(0);
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}
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value equal(value v1, value v2) /* ML */
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{
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return Val_int(compare_val(v1, v2) == 0);
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}
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value notequal(value v1, value v2) /* ML */
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{
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return Val_int(compare_val(v1, v2) != 0);
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}
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value lessthan(value v1, value v2) /* ML */
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{
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return Val_int(compare_val(v1, v2) < 0);
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}
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value lessequal(value v1, value v2) /* ML */
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{
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return Val_int(compare_val(v1, v2) <= 0);
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}
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value greaterthan(value v1, value v2) /* ML */
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{
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return Val_int(compare_val(v1, v2) > 0);
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}
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value greaterequal(value v1, value v2) /* ML */
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{
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return Val_int(compare_val(v1, v2) >= 0);
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}
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