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const assert = @import("debug.zig").assert;
const math = @import("math.zig");
const os = @import("os.zig");
const io = @import("io.zig");
pub const Cmp = math.Cmp;
pub error NoMem;
pub type Context = u8;
pub struct Allocator {
allocFn: fn (self: &Allocator, n: usize) -> %[]u8,
reallocFn: fn (self: &Allocator, old_mem: []u8, new_size: usize) -> %[]u8,
freeFn: fn (self: &Allocator, mem: []u8),
context: ?&Context,
/// Aborts the program if an allocation fails.
fn checkedAlloc(self: &Allocator, inline T: type, n: usize) -> []T {
alloc(self, T, n) %% |err| {
// TODO var args printf
%%io.stderr.write("allocation failure: ");
%%io.stderr.write(@errorName(err));
%%io.stderr.printf("\n");
os.abort()
}
}
fn alloc(self: &Allocator, inline T: type, n: usize) -> %[]T {
const byte_count = %return math.mulOverflow(usize, @sizeOf(T), n);
([]T)(%return self.allocFn(self, byte_count))
}
fn realloc(self: &Allocator, inline T: type, old_mem: []T, n: usize) -> %[]T {
const byte_count = %return math.mulOverflow(usize, @sizeOf(T), n);
([]T)(%return self.reallocFn(self, ([]u8)(old_mem), byte_count))
}
// TODO mem: []var and get rid of 2nd param
fn free(self: &Allocator, inline T: type, mem: []T) {
self.freeFn(self, ([]u8)(mem));
}
}
/// Copy all of source into dest at position 0.
/// dest.len must be >= source.len.
pub fn copy(inline T: type, dest: []T, source: []const T) {
assert(dest.len >= source.len);
@memcpy(dest.ptr, source.ptr, @sizeOf(T) * source.len);
}
/// Return < 0, == 0, or > 0 if memory a is less than, equal to, or greater than,
/// memory b, respectively.
pub fn cmp(inline T: type, a: []const T, b: []const T) -> Cmp {
const n = math.min(a.len, b.len);
var i: usize = 0;
while (i < n; i += 1) {
if (a[i] == b[i]) continue;
return if (a[i] > b[i]) Cmp.Greater else if (a[i] < b[i]) Cmp.Less else Cmp.Equal;
}
return if (a.len > b.len) Cmp.Greater else if (a.len < b.len) Cmp.Less else Cmp.Equal;
}
pub fn sliceAsInt(buf: []u8, is_be: bool, inline T: type) -> T {
var result: T = zeroes;
const result_slice = ([]u8)((&result)[0...1]);
const padding = @sizeOf(T) - buf.len;
if (is_be == @compileVar("is_big_endian")) {
copy(u8, result_slice, buf);
} else {
for (buf) |b, i| {
const index = result_slice.len - i - 1 - padding;
result_slice[index] = b;
}
}
return result;
}
fn testSliceAsInt() {
@setFnTest(this, true);
{
const buf = []u8{0x00, 0x00, 0x12, 0x34};
const answer = sliceAsInt(buf[0...], true, u64);
assert(answer == 0x00001234);
}
{
const buf = []u8{0x12, 0x34, 0x00, 0x00};
const answer = sliceAsInt(buf[0...], false, u64);
assert(answer == 0x00003412);
}
}
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