commit 5872ff742edb773beccd2856d92c5bf1b1327b38
parent ea2e9f1b20e531d79e79218c5f0561737c5a5f3b
Author: Drew DeVault <sir@cmpwn.com>
Date: Fri, 26 Mar 2021 09:34:45 -0400
endian: complete earlier API expansions
Diffstat:
2 files changed, 37 insertions(+), 0 deletions(-)
diff --git a/endian/endian.ha b/endian/endian.ha
@@ -1,17 +1,26 @@
// The set of functions used for endian-aware encoding.
export type endian = struct {
+ getu16: *fn(buf: []u8) u16,
+ putu16: *fn(buf: []u8, in: u16) void,
+ getu32: *fn(buf: []u8) u32,
putu32: *fn(buf: []u8, in: u32) void,
putu64: *fn(buf: []u8, in: u64) void,
};
// Big endian; MSB first.
export const big: endian = endian {
+ getu16 = &begetu16,
+ putu16 = &beputu16,
+ getu32 = &begetu32,
putu32 = &beputu32,
putu64 = &beputu64,
};
// Little endian; LSB first.
export const little: endian = endian {
+ getu16 = &legetu16,
+ putu16 = &leputu16,
+ getu32 = &legetu32,
putu32 = &leputu32,
putu64 = &leputu64,
};
diff --git a/endian/little.ha b/endian/little.ha
@@ -1,3 +1,25 @@
+// Reads a u16 from a buffer in little-endian order.
+export fn legetu16(buf: []u8) u16 = {
+ return
+ (buf[1] << 8u16) |
+ (buf[0] << 0);
+};
+
+// Writes a u16 into a buffer in little-endian order.
+export fn leputu16(buf: []u8, in: u16) void = {
+ buf[0] = (in >> 0): u8;
+ buf[1] = (in >> 8): u8;
+};
+
+// Reads a u32 from a buffer in little-endian order.
+export fn legetu32(buf: []u8) u32 = {
+ return
+ (buf[3] << 24u32) |
+ (buf[2] << 16u32) |
+ (buf[1] << 8u32) |
+ (buf[0] << 0);
+};
+
// Writes a u32 into a buffer in big-endian order.
export fn leputu32(buf: []u8, in: u32) void = {
buf[0] = (in): u8;
@@ -20,9 +42,15 @@ export fn leputu64(buf: []u8, in: u64) void = {
@test fn little() void = {
let buf: [8]u8 = [0...];
+ leputu16(buf, 0x1234);
+ assert(buf[0] == 0x34 && buf[1] == 0x12);
+ assert(legetu16(buf) == 0x1234);
+
leputu32(buf, 0x12345678);
assert(buf[0] == 0x78 && buf[1] == 0x56
&& buf[2] == 0x34 && buf[3] == 0x12);
+ assert(legetu32(buf) == 0x12345678);
+
leputu64(buf, 0x1234567887654321);
assert(buf[0] == 0x21 && buf[1] == 0x43
&& buf[2] == 0x65 && buf[3] == 0x87
