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use crate::memory::{allocation::WasmAllocation, MemoryInt};
use std::{ffi::CStr, os::raw::c_char};

/// reads are always from a WasmAllocation
impl WasmAllocation {
    fn read_str_raw<'a>(ptr_data: *mut c_char) -> &'a str {
        let ptr_safe_c_str = unsafe { CStr::from_ptr(ptr_data) };
        ptr_safe_c_str.to_str().unwrap()
    }

    /// Retrieve a stored string from an allocation.
    /// Return error code if encoded_allocation is invalid.
    pub fn read_to_string(self) -> String {
        WasmAllocation::read_str_raw(MemoryInt::from(self.offset()) as *mut c_char).to_string()
    }
}

#[cfg(test)]
pub mod tests {

    use memory::allocation::WasmAllocation;
    use std::{ffi::CString, os::raw::c_char};

    #[test]
    pub fn read_str_raw_test() {
        let s = "foo";
        let c_string = CString::new(s).expect("could not create cstring");
        let ptr = c_string.as_ptr();

        assert_eq!(s, WasmAllocation::read_str_raw(ptr as *mut c_char),);
    }
}