// Copyright 2021 The Libc Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// +build !libc.membrk,!libc.memgrind

package libc // import "modernc.org/libc"

import (
	"modernc.org/libc/errno"
	"modernc.org/libc/sys/types"
	"modernc.org/memory"
)

const memgrind = false

var (
	allocator memory.Allocator
)

// void *malloc(size_t size);
func Xmalloc(t *TLS, n types.Size_t) uintptr {
	if n == 0 {
		return 0
	}

	allocMu.Lock()

	defer allocMu.Unlock()

	p, err := allocator.UintptrMalloc(int(n))
	if err != nil {
		t.setErrno(errno.ENOMEM)
		return 0
	}

	return p
}

// void *calloc(size_t nmemb, size_t size);
func Xcalloc(t *TLS, n, size types.Size_t) uintptr {
	rq := int(n * size)
	if rq == 0 {
		return 0
	}

	allocMu.Lock()

	defer allocMu.Unlock()

	p, err := allocator.UintptrCalloc(int(n * size))
	if err != nil {
		t.setErrno(errno.ENOMEM)
		return 0
	}

	return p
}

// void *realloc(void *ptr, size_t size);
func Xrealloc(t *TLS, ptr uintptr, size types.Size_t) uintptr {
	allocMu.Lock()

	defer allocMu.Unlock()

	p, err := allocator.UintptrRealloc(ptr, int(size))
	if err != nil {
		t.setErrno(errno.ENOMEM)
		return 0
	}

	return p
}

// void free(void *ptr);
func Xfree(t *TLS, p uintptr) {
	if p == 0 {
		return
	}

	allocMu.Lock()

	defer allocMu.Unlock()

	allocator.UintptrFree(p)
}

func UsableSize(p uintptr) types.Size_t {
	allocMu.Lock()

	defer allocMu.Unlock()

	return types.Size_t(memory.UintptrUsableSize(p))
}

// MemAuditStart locks the memory allocator, initializes and enables memory
// auditing. Finaly it unlocks the memory allocator.
//
// Some memory handling errors, like double free or freeing of unallocated
// memory, will panic when memory auditing is enabled.
//
// This memory auditing functionality has to be enabled using the libc.memgrind
// build tag.
//
// It is intended only for debug/test builds. It slows down memory allocation
// routines and it has additional memory costs.
func MemAuditStart() {}

// MemAuditReport locks the memory allocator, reports memory leaks, if any.
// Finally it disables memory auditing and unlocks the memory allocator.
//
// This memory auditing functionality has to be enabled using the libc.memgrind
// build tag.
//
// It is intended only for debug/test builds. It slows down memory allocation
// routines and it has additional memory costs.
func MemAuditReport() error { return nil }