From 10cbc36b6bd4a8f283239a0a2c0e9780fc6e054c Mon Sep 17 00:00:00 2001
From: Elara6331 <elara@elara.ws>
Date: Mon, 25 Dec 2023 12:50:17 -0800
Subject: [PATCH] Add gpioset command

---
 build.zig       |  1 +
 src/cmd/set.zig | 53 +++++++++++++++++++++++++++++++++++++++++++++++++
 src/gpio.zig    | 40 ++++++++++++++++++++++++++++++++++++-
 3 files changed, 93 insertions(+), 1 deletion(-)
 create mode 100644 src/cmd/set.zig

diff --git a/build.zig b/build.zig
index 0f66566..c1fa711 100644
--- a/build.zig
+++ b/build.zig
@@ -16,6 +16,7 @@ const commands = [_]Item{
     .{ .name = "gpiodetect", .src = "src/cmd/detect.zig" },
     .{ .name = "gpioinfo", .src = "src/cmd/info.zig" },
     .{ .name = "gpioget", .src = "src/cmd/get.zig" },
+    .{ .name = "gpioset", .src = "src/cmd/set.zig" },
 };
 
 pub fn build(b: *std.Build) !void {
diff --git a/src/cmd/set.zig b/src/cmd/set.zig
new file mode 100644
index 0000000..5bc44f7
--- /dev/null
+++ b/src/cmd/set.zig
@@ -0,0 +1,53 @@
+const std = @import("std");
+const gpio = @import("gpio");
+
+pub fn main() !void {
+    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
+    defer std.debug.assert(gpa.deinit() == .ok);
+    const alloc = gpa.allocator();
+
+    var args = try std.process.argsAlloc(alloc);
+    defer std.process.argsFree(alloc, args);
+
+    const stdout = std.io.getStdOut().writer();
+
+    if (args.len < 3) {
+        try stdout.print("Usage: {s} <gpiochip> <line=value...>\n\n", .{args[0]});
+        return error.InsufficientArguments;
+    }
+
+    var path: []const u8 = if (hasPrefix(args[1], "gpiochip"))
+        try std.mem.concat(alloc, u8, &.{ "/dev/", args[1] })
+    else
+        try std.mem.concat(alloc, u8, &.{ "/dev/gpiochip", args[1] });
+    defer alloc.free(path);
+
+    var chip = try gpio.getChip(path);
+    defer chip.close();
+    try chip.setConsumer("gpioset");
+
+    var values = std.AutoArrayHashMap(u32, bool).init(alloc);
+    defer values.deinit();
+
+    // Iterate over each argument starting from the second one
+    for (args[2..args.len]) |argument| {
+        // Get the index of the equals sign in the argument
+        const eqIndex = std.mem.indexOf(u8, argument, "=") orelse return error.InvalidArgument;
+        // Parse each argument's offset and value, and add it to the values map
+        var offset = try std.fmt.parseUnsigned(u32, argument[0..eqIndex], 10);
+        var value = try std.fmt.parseUnsigned(u1, argument[eqIndex + 1 .. argument.len], 10);
+        try values.put(offset, value != 0);
+    }
+
+    var lines = try chip.requestLines(values.keys(), .{ .output = true });
+    defer lines.close();
+
+    var vals = gpio.uapi.LineValueBitset{ .mask = 0 };
+    for (0.., values.values()) |i, val| vals.setValue(i, val);
+    try lines.setAllValues(vals);
+}
+
+fn hasPrefix(s: []const u8, prefix: []const u8) bool {
+    if (s.len < prefix.len) return false;
+    return (std.mem.eql(u8, s[0..prefix.len], prefix));
+}
diff --git a/src/gpio.zig b/src/gpio.zig
index e22c229..3083d91 100644
--- a/src/gpio.zig
+++ b/src/gpio.zig
@@ -209,13 +209,44 @@ pub const Lines = struct {
         try gpio.uapi.setLineConfig(self.handle, lc);
     }
 
+    /// Sets the values of the lines at the given indices.
+    ///
+    /// Note that this function takes indices and not offsets.
+    /// The indices correspond to the index of the offset in your request.
+    /// For example, if you requested `&.{22, 20, 23}`,
+    /// `22` will correspond to `0`, `20` will correspond to `1`,
+    /// and `23` will correspond to `2`.
+    pub fn setValues(self: Lines, indices: []const u32, vals: gpio.uapi.LineValueBitset) !void {
+        if (self.closed) return error.LineClosed;
+        var lv = gpio.uapi.LineValues{ .bits = vals };
+        for (indices) |index| {
+            if (index >= self.num_lines) return error.IndexOutOfRange;
+            lv.mask.set(index);
+        }
+        return try gpio.uapi.setLineValues(self.handle, lv);
+    }
+
+    /// Sets the values of all the controlled lines
+    pub fn setAllValues(self: Lines, vals: gpio.uapi.LineValueBitset) !void {
+        if (self.closed) return error.LineClosed;
+        var lv = gpio.uapi.LineValues{ .bits = vals };
+
+        // Add all the indices to the bitset of values to set
+        var i: u32 = 0;
+        while (i < self.num_lines) : (i += 1) lv.mask.set(i);
+
+        return try gpio.uapi.setLineValues(self.handle, lv);
+    }
+
     /// Gets the values of all the controlled lines as a bitset
     pub fn getValues(self: Lines) !gpio.uapi.LineValueBitset {
         if (self.closed) return error.LineClosed;
         var vals = gpio.uapi.LineValueBitset{ .mask = 0 };
+
+        // Add all the indices to the bitset of values to get
         var i: u32 = 0;
-        // Add all the indices to the list of values to get
         while (i < self.num_lines) : (i += 1) vals.set(i);
+
         return try gpio.uapi.getLineValues(self.handle, vals);
     }
 
@@ -242,6 +273,13 @@ pub const Line = struct {
         try self.lines.setLow(&.{0});
     }
 
+    // Sets the value of the line.
+    pub fn setValue(self: Line, value: bool) !void {
+        var vals = gpio.uapi.LineValueBitset{ .mask = 0 };
+        vals.setValue(0, value);
+        try self.lines.setValues(&.{0}, vals);
+    }
+
     /// Sets the configuration flags of the line.
     pub fn reconfigure(self: Line, flags: gpio.uapi.LineFlags) !void {
         try self.lines.reconfigure(&.{0}, flags);