// 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.

//go:build !libc.membrk && !libc.memgrind && !(linux && (amd64 || arm64 || loong64 || ppc64le || s390x || riscv64 || 386 || arm))

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

import (
	"math"
	"math/bits"

	"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 __ccgo_strace {
		trc("t=%v n=%v, (%v:)", t, n, origin(2))
	}
	if n == 0 {
		// malloc(0) should return unique pointers
		// (often expected and gnulib replaces malloc if malloc(0) returns 0)
		n = 1
	}

	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 {
	if __ccgo_strace {
		trc("t=%v n=%v size=%v, (%v:)", t, n, size, origin(2))
	}
	hi, rq0 := bits.Mul(uint(n), uint(size))
	if hi != 0 || rq0 > math.MaxInt {
		t.setErrno(errno.ENOMEM)
		return 0
	}
	rq := int(rq0)
	if rq == 0 {
		rq = 1
	}

	allocMu.Lock()

	defer allocMu.Unlock()

	p, err := allocator.UintptrCalloc(rq)
	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 {
	if __ccgo_strace {
		trc("t=%v ptr=%v size=%v, (%v:)", t, ptr, size, origin(2))
	}
	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 __ccgo_strace {
		trc("t=%v p=%v, (%v:)", t, p, origin(2))
	}
	if p == 0 {
		return
	}

	allocMu.Lock()

	defer allocMu.Unlock()

	allocator.UintptrFree(p)
}

func Xmalloc_usable_size(tls *TLS, p uintptr) (r types.Size_t) {
	if __ccgo_strace {
		trc("tls=%v p=%v, (%v:)", tls, p, origin(2))
		defer func() { trc("-> %v", r) }()
	}
	if p == 0 {
		return 0
	}

	allocMu.Lock()

	defer allocMu.Unlock()

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

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

	defer allocMu.Unlock()

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

type MemAllocatorStat struct {
	Allocs int
	Bytes  int
	Mmaps  int
}

// MemStat returns the global memory allocator statistics.
// should be compiled with the memory.counters build tag for the data to be available.
func MemStat() MemAllocatorStat {
	allocMu.Lock()
	defer allocMu.Unlock()

	return MemAllocatorStat{
		Allocs: allocator.Allocs,
		Bytes:  allocator.Bytes,
		Mmaps:  allocator.Mmaps,
	}
}

// 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 }
