Optimize PUB and HPUB parsing

This will try to take better advantage of the buffered reading.
Instead of pushing one byte at a time to the array list for each
section, find the end index for each section, then alloc the arraylist
and copy the data into it all at once.

1 files changed, 59 insertions, 49 deletions

diff --git a/src/server/message_parser.zig b/src/server/message_parser.zig
index bf472af..fd1b5b1 100644
--- a/src/server/message_parser.zig
+++ b/src/server/message_parser.zig
@@ -404,12 +404,14 @@ fn parseSub(alloc: Allocator, in: *Reader) !Message {
             continue :sw .in_second;
         },
         .in_second => {
-            const byte = try in.peekByte();
-            if (!isWhitespace(byte)) {
-                try second.append(alloc, byte);
-                in.toss(1);
-                continue :sw .in_second;
-            }
+            for (1..in.buffer.len) |i| {
+                try in.fill(i + 1);
+                if (isWhitespace(in.buffered()[i])) {
+                    @memcpy(try second.addManyAsSlice(alloc, i), in.buffered()[0..i]);
+                    in.toss(i);
+                    break;
+                }
+            } else return error.EndOfStream;
             continue :sw .after_second;
         },
         .after_second => {
@@ -424,13 +426,15 @@ fn parseSub(alloc: Allocator, in: *Reader) !Message {
             continue :sw .in_third;
         },
         .in_third => {
-            const byte = try in.peekByte();
-            if (byte == '\r') {
-                continue :sw .in_end;
-            }
-            try third.?.append(alloc, byte);
-            in.toss(1);
-            continue :sw .in_third;
+            for (1..in.buffer.len) |i| {
+                try in.fill(i + 1);
+                if (isWhitespace(in.buffered()[i])) {
+                    @memcpy(try third.?.addManyAsSlice(alloc, i), in.buffered()[0..i]);
+                    in.toss(i);
+                    break;
+                }
+            } else return error.EndOfStream;
+            continue :sw .in_end;
         },
         .in_end => {
             try expectStreamBytes(in, "\r\n");
@@ -674,12 +678,14 @@ fn parsePub(alloc: Allocator, in: *Reader) !Message {
             continue :sw .in_second;
         },
         .in_second => {
-            const byte = try in.peekByte();
-            if (!isWhitespace(byte)) {
-                try second.append(alloc, byte);
-                in.toss(1);
-                continue :sw .in_second;
-            }
+            for (1..in.buffer.len) |i| {
+                try in.fill(i + 1);
+                if (isWhitespace(in.buffered()[i])) {
+                    @memcpy(try second.addManyAsSlice(alloc, i), in.buffered()[0..i]);
+                    in.toss(i);
+                    break;
+                }
+            } else return error.EndOfStream;
             continue :sw .after_second;
         },
         .after_second => {
@@ -694,15 +700,15 @@ fn parsePub(alloc: Allocator, in: *Reader) !Message {
             continue :sw .in_third;
         },
         .in_third => {
-            const byte = try in.peekByte();
-            if (byte == '\r') {
-                continue :sw .in_end;
-            } else if (isDigit(byte)) {
-                try third.?.append(alloc, byte);
-                in.toss(1);
-                continue :sw .in_third;
-            }
-            return error.InvalidStream;
+            for (1..in.buffer.len) |i| {
+                try in.fill(i + 1);
+                if (isWhitespace(in.buffered()[i])) {
+                    @memcpy(try third.?.addManyAsSlice(alloc, i), in.buffered()[0..i]);
+                    in.toss(i);
+                    break;
+                }
+            } else return error.EndOfStream;
+            continue :sw .in_end;
         },
         .in_end => {
             try expectStreamBytes(in, "\r\n");
@@ -847,12 +853,14 @@ fn parseHPub(alloc: Allocator, in: *Reader) !Message {
             continue :sw .in_second;
         },
         .in_second => {
-            const byte = try in.peekByte();
-            if (!isWhitespace(byte)) {
-                try second.append(alloc, byte);
-                in.toss(1);
-                continue :sw .in_second;
-            }
+            for (1..in.buffer.len) |i| {
+                try in.fill(i + 1);
+                if (isWhitespace(in.buffered()[i])) {
+                    @memcpy(try second.addManyAsSlice(alloc, i), in.buffered()[0..i]);
+                    in.toss(i);
+                    break;
+                }
+            } else return error.EndOfStream;
             continue :sw .after_second;
         },
         .after_second => {
@@ -867,12 +875,14 @@ fn parseHPub(alloc: Allocator, in: *Reader) !Message {
             continue :sw .in_third;
         },
         .in_third => {
-            const byte = try in.peekByte();
-            if (!isWhitespace(byte)) {
-                try third.append(alloc, byte);
-                in.toss(1);
-                continue :sw .in_third;
-            }
+            for (1..in.buffer.len) |i| {
+                try in.fill(i + 1);
+                if (isWhitespace(in.buffered()[i])) {
+                    @memcpy(try third.addManyAsSlice(alloc, i), in.buffered()[0..i]);
+                    in.toss(i);
+                    break;
+                }
+            } else return error.EndOfStream;
             continue :sw .after_third;
         },
         .after_third => {
@@ -887,15 +897,15 @@ fn parseHPub(alloc: Allocator, in: *Reader) !Message {
             continue :sw .in_fourth;
         },
         .in_fourth => {
-            const byte = try in.peekByte();
-            if (byte == '\r') {
-                continue :sw .in_end;
-            } else if (isDigit(byte)) {
-                try fourth.?.append(alloc, byte);
-                in.toss(1);
-                continue :sw .in_fourth;
-            }
-            return error.InvalidStream;
+            for (1..in.buffer.len) |i| {
+                try in.fill(i + 1);
+                if (isWhitespace(in.buffered()[i])) {
+                    @memcpy(try fourth.?.addManyAsSlice(alloc, i), in.buffered()[0..i]);
+                    in.toss(i);
+                    break;
+                }
+            } else return error.EndOfStream;
+            continue :sw .in_end;
         },
         .in_end => {
             try expectStreamBytes(in, "\r\n");