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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package runtime
#include "runtime.h"
#include "arch_GOARCH.h"
#include "type.h"
#include "typekind.h"
#include "malloc.h"
#include "race.h"
#include "stack.h"
#include "../../cmd/ld/textflag.h"
enum
{
debug = 0
};
static void makeslice1(SliceType*, intgo, intgo, Slice*);
static void growslice1(SliceType*, Slice, intgo, Slice *);
// see also unsafe·NewArray
func makeslice(t *SliceType, len int64, cap int64) (ret Slice) {
// NOTE: The len > MaxMem/elemsize check here is not strictly necessary,
// but it produces a 'len out of range' error instead of a 'cap out of range' error
// when someone does make([]T, bignumber). 'cap out of range' is true too,
// but since the cap is only being supplied implicitly, saying len is clearer.
// See issue 4085.
if(len < 0 || (intgo)len != len || t->elem->size > 0 && len > MaxMem / t->elem->size)
runtime·panicstring("makeslice: len out of range");
if(cap < len || (intgo)cap != cap || t->elem->size > 0 && cap > MaxMem / t->elem->size)
runtime·panicstring("makeslice: cap out of range");
makeslice1(t, len, cap, &ret);
if(debug) {
runtime·printf("makeslice(%S, %D, %D); ret=",
*t->string, len, cap);
runtime·printslice(ret);
}
}
// Dummy word to use as base pointer for make([]T, 0).
// Since you cannot take the address of such a slice,
// you can't tell that they all have the same base pointer.
uintptr runtime·zerobase;
static void
makeslice1(SliceType *t, intgo len, intgo cap, Slice *ret)
{
ret->len = len;
ret->cap = cap;
ret->array = runtime·cnewarray(t->elem, cap);
}
// growslice(type *Type, x, []T, n int64) []T
func growslice(t *SliceType, old Slice, n int64) (ret Slice) {
int64 cap;
void *pc;
if(n < 1)
runtime·panicstring("growslice: invalid n");
cap = old.cap + n;
if((intgo)cap != cap || cap < (int64)old.cap || (t->elem->size > 0 && cap > MaxMem/t->elem->size))
runtime·panicstring("growslice: cap out of range");
if(raceenabled) {
pc = runtime·getcallerpc(&t);
runtime·racereadrangepc(old.array, old.len*t->elem->size, pc, runtime·growslice);
}
growslice1(t, old, cap, &ret);
if(debug) {
runtime·printf("growslice(%S,", *t->string);
runtime·printslice(old);
runtime·printf(", new cap=%D) =", cap);
runtime·printslice(ret);
}
}
static void
growslice1(SliceType *t, Slice x, intgo newcap, Slice *ret)
{
intgo newcap1;
uintptr capmem, lenmem;
int32 flag;
Type *typ;
typ = t->elem;
if(typ->size == 0) {
*ret = x;
ret->cap = newcap;
return;
}
newcap1 = x.cap;
// Using newcap directly for m+m < newcap handles
// both the case where m == 0 and also the case where
// m+m/4 wraps around, in which case the loop
// below might never terminate.
if(newcap1+newcap1 < newcap)
newcap1 = newcap;
else {
do {
if(x.len < 1024)
newcap1 += newcap1;
else
newcap1 += newcap1/4;
} while(newcap1 < newcap);
}
if(newcap1 > MaxMem/typ->size)
runtime·panicstring("growslice: cap out of range");
capmem = runtime·roundupsize(newcap1*typ->size);
flag = 0;
// Can't use FlagNoZero w/o FlagNoScan, because otherwise GC can scan unitialized memory.
if(typ->kind&KindNoPointers)
flag = FlagNoScan|FlagNoZero;
ret->array = runtime·mallocgc(capmem, (uintptr)typ|TypeInfo_Array, flag);
ret->len = x.len;
ret->cap = capmem/typ->size;
lenmem = x.len*typ->size;
runtime·memmove(ret->array, x.array, lenmem);
if(typ->kind&KindNoPointers)
runtime·memclr(ret->array+lenmem, capmem-lenmem);
}
#pragma textflag NOSPLIT
func copy(to Slice, fm Slice, width uintptr) (ret int) {
void *pc;
if(fm.len == 0 || to.len == 0 || width == 0) {
ret = 0;
goto out;
}
ret = fm.len;
if(to.len < ret)
ret = to.len;
if(raceenabled) {
pc = runtime·getcallerpc(&to);
runtime·racewriterangepc(to.array, ret*width, pc, runtime·copy);
runtime·racereadrangepc(fm.array, ret*width, pc, runtime·copy);
}
if(ret == 1 && width == 1) { // common case worth about 2x to do here
*to.array = *fm.array; // known to be a byte pointer
} else {
runtime·memmove(to.array, fm.array, ret*width);
}
out:
if(debug) {
runtime·prints("main·copy: to=");
runtime·printslice(to);
runtime·prints("; fm=");
runtime·printslice(fm);
runtime·prints("; width=");
runtime·printint(width);
runtime·prints("; ret=");
runtime·printint(ret);
runtime·prints("\n");
}
}
#pragma textflag NOSPLIT
func slicestringcopy(to Slice, fm String) (ret int) {
void *pc;
if(fm.len == 0 || to.len == 0) {
ret = 0;
goto out;
}
ret = fm.len;
if(to.len < ret)
ret = to.len;
if(raceenabled) {
pc = runtime·getcallerpc(&to);
runtime·racewriterangepc(to.array, ret, pc, runtime·slicestringcopy);
}
runtime·memmove(to.array, fm.str, ret);
out:;
}
func printslice(a Slice) {
runtime·prints("[");
runtime·printint(a.len);
runtime·prints("/");
runtime·printint(a.cap);
runtime·prints("]");
runtime·printpointer(a.array);
}
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