Minor Reader tweaks

1- Remove `parser.trim`, it was only being used in 1 place. All other places
   are using `std.mem.trim(u8, X, &std.ascii.whitespace)`, so i updated MIME to
   use this as well

2- Use slightly more meaningful field name, i => pos, s = data

3- Leverage std.mem.indexOfScalarPos which can be more efficient for longer
   inputs (since it leverages SIMD)

src/browser/mime.zig

@@ -19,9 +19,7 @@
 const std = @import("std");
 const testing = std.testing;
 
-const strparser = @import("../str/parser.zig");
-const Reader = strparser.Reader;
-const trim = strparser.trim;
+const Reader = @import("../str/parser.zig").Reader;
 
 const Self = @This();
 
@@ -70,7 +68,7 @@ pub fn parse(s: []const u8) Self.MimeError!Self {
     if (ln > 255) return MimeError.TooBig;
 
     var res = Self{ .mtype = "", .msubtype = "" };
-    var r = Reader{ .s = s };
+    var r = Reader{ .data = s };
 
     res.mtype = trim(r.until('/'));
     if (res.mtype.len == 0) return MimeError.Invalid;
@@ -87,7 +85,7 @@ pub fn parse(s: []const u8) Self.MimeError!Self {
 
     // parse well known parameters.
     // don't check invalid parameter format.
-    var rp = Reader{ .s = res.params };
+    var rp = Reader{ .data = res.params };
     while (true) {
         const name = trim(rp.until('='));
         if (!rp.skip()) return res;
@@ -106,6 +104,10 @@ pub fn parse(s: []const u8) Self.MimeError!Self {
     return res;
 }
 
+fn trim(s: []const u8) []const u8 {
+    return std.mem.trim(u8, s, &std.ascii.whitespace);
+}
+
 test "parse valid" {
     for ([_][]const u8{
         "text/html",

src/str/parser.zig

@@ -18,89 +18,70 @@
 
 // some utils to parser strings.
 const std = @import("std");
-const testing = std.testing;
 
 pub const Reader = struct {
-    s: []const u8,
-    i: usize = 0,
+    pos: usize = 0,
+    data: []const u8,
 
     pub fn until(self: *Reader, c: u8) []const u8 {
-        const ln = self.s.len;
-        const start = self.i;
-        while (self.i < ln) {
-            if (c == self.s[self.i]) return self.s[start..self.i];
-            self.i += 1;
-        }
+        const pos = self.pos;
+        const data = self.data;
 
-        return self.s[start..self.i];
+        const index = std.mem.indexOfScalarPos(u8, data, pos, c) orelse data.len;
+        self.pos = index;
+        return data[pos..index];
     }
 
     pub fn tail(self: *Reader) []const u8 {
-        if (self.i > self.s.len) return "";
-        defer self.i = self.s.len;
-        return self.s[self.i..];
+        const pos = self.pos;
+        const data = self.data;
+        if (pos > data.len)  {
+            return "";
+        }
+        self.pos = data.len;
+        return data[pos..];
     }
 
     pub fn skip(self: *Reader) bool {
-        if (self.i >= self.s.len) return false;
-        self.i += 1;
+        const pos = self.pos;
+        if (pos >= self.data.len) {
+            return false;
+        }
+        self.pos = pos + 1;
         return true;
     }
 };
 
-test "Reader.skip" {
-    var r = Reader{ .s = "foo" };
-    try testing.expect(r.skip());
-    try testing.expect(r.skip());
-    try testing.expect(r.skip());
-    try testing.expect(!r.skip());
-    try testing.expect(!r.skip());
+const testing = std.testing;
+test "parser.Reader: skip" {
+    var r = Reader{ .data = "foo" };
+    try testing.expectEqual(true, r.skip());
+    try testing.expectEqual(true, r.skip());
+    try testing.expectEqual(true, r.skip());
+    try testing.expectEqual(false, r.skip());
+    try testing.expectEqual(false, r.skip());
 }
 
-test "Reader.tail" {
-    var r = Reader{ .s = "foo" };
+test "parser.Reader: tail" {
+    var r = Reader{ .data = "foo" };
     try testing.expectEqualStrings("foo", r.tail());
     try testing.expectEqualStrings("", r.tail());
+    try testing.expectEqualStrings("", r.tail());
 }
 
-test "Reader.until" {
-    var r = Reader{ .s = "foo.bar.baz" };
+test "parser.Reader: until" {
+    var r = Reader{ .data = "foo.bar.baz" };
     try testing.expectEqualStrings("foo", r.until('.'));
     _ = r.skip();
     try testing.expectEqualStrings("bar", r.until('.'));
     _ = r.skip();
     try testing.expectEqualStrings("baz", r.until('.'));
 
-    r = Reader{ .s = "foo" };
+    r = Reader{ .data = "foo" };
     try testing.expectEqualStrings("foo", r.until('.'));
+    try testing.expectEqualStrings("", r.tail());
 
-    r = Reader{ .s = "" };
+    r = Reader{ .data = "" };
     try testing.expectEqualStrings("", r.until('.'));
-}
-
-pub fn trim(s: []const u8) []const u8 {
-    const ln = s.len;
-    if (ln == 0) {
-        return "";
-    }
-    var start: usize = 0;
-    while (start < ln) {
-        if (!std.ascii.isWhitespace(s[start])) break;
-        start += 1;
-    }
-
-    var end: usize = ln;
-    while (end > 0) {
-        if (!std.ascii.isWhitespace(s[end - 1])) break;
-        end -= 1;
-    }
-
-    return s[start..end];
-}
-
-test "trim" {
-    try testing.expectEqualStrings("", trim(""));
-    try testing.expectEqualStrings("foo", trim("foo"));
-    try testing.expectEqualStrings("foo", trim(" \n\tfoo"));
-    try testing.expectEqualStrings("foo", trim("foo \n\t"));
+    try testing.expectEqualStrings("", r.tail());
 }

src/url/query.zig

@@ -199,12 +199,12 @@ pub fn parseQuery(alloc: std.mem.Allocator, s: []const u8) !Values {
     const ln = s.len;
     if (ln == 0) return values;
 
-    var r = Reader{ .s = s };
+    var r = Reader{ .data = s };
     while (true) {
         const param = r.until('&');
         if (param.len == 0) break;
 
-        var rr = Reader{ .s = param };
+        var rr = Reader{ .data = param };
         const k = rr.until('=');
         if (k.len == 0) continue;