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//go:build tinygo.wasm && !custommalloc
package runtime
import "unsafe"
// The below functions override the default allocator of wasi-libc. This ensures
// code linked from other languages can allocate memory without colliding with
// our GC allocations.
var allocs = make(map[uintptr][]byte)
//export malloc
func libc_malloc(size uintptr) unsafe.Pointer {
if size == 0 {
return nil
}
buf := make([]byte, size)
ptr := unsafe.Pointer(&buf[0])
allocs[uintptr(ptr)] = buf
return ptr
}
//export free
func libc_free(ptr unsafe.Pointer) {
if ptr == nil {
return
}
if _, ok := allocs[uintptr(ptr)]; ok {
delete(allocs, uintptr(ptr))
} else {
panic("free: invalid pointer")
}
}
//export calloc
func libc_calloc(nmemb, size uintptr) unsafe.Pointer {
// No difference between calloc and malloc.
return libc_malloc(nmemb * size)
}
//export realloc
func libc_realloc(oldPtr unsafe.Pointer, size uintptr) unsafe.Pointer {
if size == 0 {
libc_free(oldPtr)
return nil
}
// It's hard to optimize this to expand the current buffer with our GC, but
// it is theoretically possible. For now, just always allocate fresh.
buf := make([]byte, size)
if oldPtr != nil {
if oldBuf, ok := allocs[uintptr(oldPtr)]; ok {
copy(buf, oldBuf)
delete(allocs, uintptr(oldPtr))
} else {
panic("realloc: invalid pointer")
}
}
ptr := unsafe.Pointer(&buf[0])
allocs[uintptr(ptr)] = buf
return ptr
}
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