zig/std/event/io.zig
Andrew Kelley b883bc873d
breaking API changes to all readInt/writeInt functions & more
* add `@bswap` builtin function. See #767
 * comptime evaluation facilities are improved to be able to
   handle a `@ptrCast` with a backing array.
 * `@truncate` allows "truncating" a u0 value to any integer
   type, and the result is always comptime known to be `0`.
 * when specifying pointer alignment in a type expression,
   the alignment value of pointers which do not have addresses
   at runtime is ignored, and always has the default/ABI alignment
 * threw in a fix to freebsd/x86_64.zig to update syntax from
   language changes
 * some improvements are pending #863

closes #638
closes #1733

std lib API changes
 * io.InStream().readIntNe renamed to readIntNative
 * io.InStream().readIntLe renamed to readIntLittle
 * io.InStream().readIntBe renamed to readIntBig
 * introduced io.InStream().readIntForeign
 * io.InStream().readInt has parameter order changed
 * io.InStream().readVarInt has parameter order changed
 * io.InStream().writeIntNe renamed to writeIntNative
 * introduced io.InStream().writeIntForeign
 * io.InStream().writeIntLe renamed to writeIntLittle
 * io.InStream().writeIntBe renamed to writeIntBig
 * io.InStream().writeInt has parameter order changed
 * mem.readInt has different parameters and semantics
 * introduced mem.readIntNative
 * introduced mem.readIntForeign
 * mem.readIntBE renamed to mem.readIntBig and different API
 * mem.readIntLE renamed to mem.readIntLittle and different API
 * introduced mem.readIntSliceNative
 * introduced mem.readIntSliceForeign
 * introduced mem.readIntSliceLittle
 * introduced mem.readIntSliceBig
 * introduced mem.readIntSlice
 * mem.writeInt has different parameters and semantics
 * introduced mem.writeIntNative
 * introduced mem.writeIntForeign
 * mem.writeIntBE renamed to mem.readIntBig and different semantics
 * mem.writeIntLE renamed to mem.readIntLittle and different semantics
 * introduced mem.writeIntSliceForeign
 * introduced mem.writeIntSliceNative
 * introduced mem.writeIntSliceBig
 * introduced mem.writeIntSliceLittle
 * introduced mem.writeIntSlice
 * removed mem.endianSwapIfLe
 * removed mem.endianSwapIfBe
 * removed mem.endianSwapIf
 * added mem.littleToNative
 * added mem.bigToNative
 * added mem.toNative
 * added mem.nativeTo
 * added mem.nativeToLittle
 * added mem.nativeToBig
2018-12-12 20:35:04 -05:00

78 lines
3.1 KiB
Zig

const std = @import("../index.zig");
const builtin = @import("builtin");
const Allocator = std.mem.Allocator;
const assert = std.debug.assert;
const mem = std.mem;
pub fn InStream(comptime ReadError: type) type {
return struct {
const Self = @This();
pub const Error = ReadError;
/// Return the number of bytes read. It may be less than buffer.len.
/// If the number of bytes read is 0, it means end of stream.
/// End of stream is not an error condition.
readFn: async<*Allocator> fn (self: *Self, buffer: []u8) Error!usize,
/// Return the number of bytes read. It may be less than buffer.len.
/// If the number of bytes read is 0, it means end of stream.
/// End of stream is not an error condition.
pub async fn read(self: *Self, buffer: []u8) !usize {
return await (async self.readFn(self, buffer) catch unreachable);
}
/// Return the number of bytes read. If it is less than buffer.len
/// it means end of stream.
pub async fn readFull(self: *Self, buffer: []u8) !usize {
var index: usize = 0;
while (index != buf.len) {
const amt_read = try await (async self.read(buf[index..]) catch unreachable);
if (amt_read == 0) return index;
index += amt_read;
}
return index;
}
/// Same as `readFull` but end of stream returns `error.EndOfStream`.
pub async fn readNoEof(self: *Self, buf: []u8) !void {
const amt_read = try await (async self.readFull(buf[index..]) catch unreachable);
if (amt_read < buf.len) return error.EndOfStream;
}
pub async fn readIntLittle(self: *Self, comptime T: type) !T {
var bytes: [@sizeOf(T)]u8 = undefined;
try await (async self.readNoEof(bytes[0..]) catch unreachable);
return mem.readIntLittle(T, &bytes);
}
pub async fn readIntBe(self: *Self, comptime T: type) !T {
var bytes: [@sizeOf(T)]u8 = undefined;
try await (async self.readNoEof(bytes[0..]) catch unreachable);
return mem.readIntBig(T, &bytes);
}
pub async fn readInt(self: *Self, comptime T: type, endian: builtin.Endian) !T {
var bytes: [@sizeOf(T)]u8 = undefined;
try await (async self.readNoEof(bytes[0..]) catch unreachable);
return mem.readInt(T, &bytes, endian);
}
pub async fn readStruct(self: *Self, comptime T: type) !T {
// Only extern and packed structs have defined in-memory layout.
comptime assert(@typeInfo(T).Struct.layout != builtin.TypeInfo.ContainerLayout.Auto);
var res: [1]T = undefined;
try await (async self.readNoEof(@sliceToBytes(res[0..])) catch unreachable);
return res[0];
}
};
}
pub fn OutStream(comptime WriteError: type) type {
return struct {
const Self = @This();
pub const Error = WriteError;
writeFn: async<*Allocator> fn (self: *Self, buffer: []u8) Error!void,
};
}