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Fix resizing issues

This commit is contained in:
Stephen Akinyemi 2019-10-05 16:25:47 +01:00
parent 74050e7c8c
commit 93de321471
1 changed files with 18 additions and 8 deletions
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26
src/memory/virtualalloc_bytebuf.rs
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@ -41,8 +41,6 @@ impl VAlloc {
/// - `VirtualAlloc` returns an error when committing pages. /// - `VirtualAlloc` returns an error when committing pages.
/// - `initial pages` cannot be committed. /// - `initial pages` cannot be committed.
fn new(len: usize) -> Result<Self, &'static str> { fn new(len: usize) -> Result<Self, &'static str> {
println!("windows vm new = {:?}", len);
if len > isize::max_value() as usize { if len > isize::max_value() as usize {
return Err("`len` should not exceed `isize::max_value()`"); return Err("`len` should not exceed `isize::max_value()`");
} }
@ -95,7 +93,7 @@ impl VAlloc {
) )
}; };
// Checking if there is an error with allocating memory pages. // Checking if there is an error with committing memory pages.
if ptr == NULL { if ptr == NULL {
return Err("VirtualAlloc couldn't commit initial pages"); return Err("VirtualAlloc couldn't commit initial pages");
} }
@ -105,13 +103,12 @@ impl VAlloc {
Ok(Self { ptr: base_ptr, len }) Ok(Self { ptr: base_ptr, len })
} }
/// Commits more pages `new_len` to be used by /// Commits more pages
///
fn grow(&mut self, new_len: usize) -> Result<(), &'static str> { fn grow(&mut self, new_len: usize) -> Result<(), &'static str> {
// Pointer to memory base // Pointer to memory base
let base_ptr = self.ptr.as_ptr() as LPVOID; let base_ptr = self.ptr.as_ptr() as LPVOID;
// Commit initial pages. // Commit pages.
let ptr = unsafe { let ptr = unsafe {
// Even though we are committing, actual physical pages are not allocated until // Even though we are committing, actual physical pages are not allocated until
// they are accessed. // they are accessed.
@ -132,11 +129,14 @@ impl VAlloc {
) )
}; };
// Checking if there is an error with allocating memory pages. // Checking if there is an error with committing memory pages.
if ptr == NULL { if ptr == NULL {
return Err("VirtualAlloc couldn't commit pages on grow"); return Err("VirtualAlloc couldn't commit pages on grow");
} }
// Update length.
self.len = new_len;
Ok(()) Ok(())
} }
@ -195,7 +195,11 @@ pub struct ByteBuf {
impl ByteBuf { impl ByteBuf {
pub fn new(len: usize) -> Result<Self, &'static str> { pub fn new(len: usize) -> Result<Self, &'static str> {
let region = Some(VAlloc::new(len)?); let region = if len == 0 {
None
} else {
Some(VAlloc::new(len)?)
};
Ok(Self { region }) Ok(Self { region })
} }
@ -219,6 +223,12 @@ impl ByteBuf {
if new_len > region.len { if new_len > region.len {
region.grow(new_len)?; region.grow(new_len)?;
} }
} else {
// On the other hand, if region has not been allocated and new length
// is greater than zero, then a new memory needs to be allocated.
if new_len > 0 {
self.region = Some(VAlloc::new(new_len)?);
}
} }
Ok(()) Ok(())