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//! View invocation - Read from attachment
const copy = @import("../../utils/mem/copy.zig");
const handler = @import("../handler.zig");
const int = @import("../../utils/types/int.zig");
const kata_attachment = @import("../../kata/attachment.zig");
const kata_limits = @import("../../common/limits/kata.zig");
const keyboard = @import("../../drivers/keyboard/keyboard.zig");
const random = @import("../../utils/random/xorshift.zig");
const result = @import("../../utils/types/result.zig");
const sensei = @import("../../kata/sensei/sensei.zig");
const slice = @import("../../utils/mem/slice.zig");
pub fn invoke(ctx: *handler.InvocationContext) void {
const kata = sensei.get_current_kata() orelse return result.set_error(ctx);
const fd = int.u32_of(ctx.rdi);
const buffer_ptr = ctx.rsi;
const count = ctx.rdx;
if (fd >= kata_limits.MAX_ATTACHMENTS) return result.set_error(ctx);
const entry = kata.attachments[fd] orelse return result.set_error(ctx);
const bytes = view_from_attachment(entry, buffer_ptr, count) catch return result.set_error(ctx);
result.set_value(ctx, bytes);
}
fn view_from_attachment(entry: *kata_attachment.Attachment, buffer_ptr: u64, count: u64) !u64 {
if (entry.attachment_type == .Device) {
const device = entry.device_type orelse return error.InvalidDevice;
return view_from_device(device, buffer_ptr, count);
}
const unit_buffer = entry.buffer orelse return 0;
const remaining = entry.unit_size - entry.position;
const to_view = @min(count, remaining);
if (to_view == 0) return 0;
const src = slice.from_ptr_const(u8, int.from_ptr(unit_buffer.ptr) + entry.position, to_view);
const dest = slice.from_ptr(u8, buffer_ptr, to_view);
copy.bytes(dest, src);
entry.position += to_view;
return to_view;
}
fn view_from_device(device: kata_attachment.DeviceType, buffer_ptr: u64, count: u64) !u64 {
const dest = slice.byte_ptr(buffer_ptr);
switch (device) {
.Source => {
var i: u64 = 0;
while (i < count) : (i += 1) {
if (keyboard.read_char()) |char| {
dest[i] = char;
} else break;
}
return i;
},
.Zero => {
copy.zero(slice.from_ptr(u8, buffer_ptr, count));
return count;
},
.Chaos => {
var i: u64 = 0;
while (i < count) : (i += 1) {
dest[i] = random.byte();
}
return count;
},
else => return error.CannotView,
}
}
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