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feat: Improve coordinate parsing (no SIMD) (#13)
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@sbernauer
sbernauer committed Jun 19, 2023
1 parent a0d86d0 commit 8680fb1
Showing 1 changed file with 73 additions and 74 deletions.
147 changes: 73 additions & 74 deletions src/parser.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -75,56 +75,53 @@ pub async fn parse_pixelflut_commands(
let current_command = unsafe { (buffer.as_ptr().add(i) as *const u64).read_unaligned() };
if current_command & 0x00ff_ffff == string_to_number(b"PX \0\0\0\0\0") {
i += 3;
// Parse first x coordinate char
if buffer[i] >= b'0' && buffer[i] <= b'9' {
x = (buffer[i] - b'0') as usize;
i += 1;
// Parse x coordinate
let digits =
unsafe { (buffer.as_ptr().add(i) as *const u32).read_unaligned() } as usize;

// Parse optional second x coordinate char
if buffer[i] >= b'0' && buffer[i] <= b'9' {
// TODO: Test bitshifts and add instead of multiplication
// i = (i << 3) + (i << 1);
// i = (i * 8) + (i * 2);
// i = 8i + 2i
// i = 10i
x = 10 * x + (buffer[i] - b'0') as usize;
let mut digit = digits & 0xff;
if digit >= b'0' as usize && digit <= b'9' as usize {
x = digit - b'0' as usize;
i += 1;
digit = (digits >> 8) & 0xff;
if digit >= b'0' as usize && digit <= b'9' as usize {
x = 10 * x + digit - b'0' as usize;
i += 1;

// Parse optional third x coordinate char
if buffer[i] >= b'0' && buffer[i] <= b'9' {
x = 10 * x + (buffer[i] - b'0') as usize;
digit = (digits >> 16) & 0xff;
if digit >= b'0' as usize && digit <= b'9' as usize {
x = 10 * x + digit - b'0' as usize;
i += 1;

// Parse optional forth x coordinate char
if buffer[i] >= b'0' && buffer[i] <= b'9' {
x = 10 * x + (buffer[i] - b'0') as usize;
digit = (digits >> 24) & 0xff;
if digit >= b'0' as usize && digit <= b'9' as usize {
x = 10 * x + digit - b'0' as usize;
i += 1;
}
}
}

// Separator between x and y
if buffer[i] == b' ' {
if unsafe { *buffer.get_unchecked(i) } == b' ' {
i += 1;

// Parse first y coordinate char
if buffer[i] >= b'0' && buffer[i] <= b'9' {
y = (buffer[i] - b'0') as usize;
i += 1;
// Parse y coordinate
let digits =
unsafe { (buffer.as_ptr().add(i) as *const u32).read_unaligned() } as usize;

// Parse optional second y coordinate char
if buffer[i] >= b'0' && buffer[i] <= b'9' {
y = 10 * y + (buffer[i] - b'0') as usize;
digit = digits & 0xff;
if digit >= b'0' as usize && digit <= b'9' as usize {
y = digit - b'0' as usize;
i += 1;
digit = (digits >> 8) & 0xff;
if digit >= b'0' as usize && digit <= b'9' as usize {
y = 10 * y + digit - b'0' as usize;
i += 1;

// Parse optional third y coordinate char
if buffer[i] >= b'0' && buffer[i] <= b'9' {
y = 10 * y + (buffer[i] - b'0') as usize;
digit = (digits >> 16) & 0xff;
if digit >= b'0' as usize && digit <= b'9' as usize {
y = 10 * y + digit - b'0' as usize;
i += 1;

// Parse optional forth y coordinate char
if buffer[i] >= b'0' && buffer[i] <= b'9' {
y = 10 * y + (buffer[i] - b'0') as usize;
digit = (digits >> 24) & 0xff;
if digit >= b'0' as usize && digit <= b'9' as usize {
y = 10 * y + digit - b'0' as usize;
i += 1;
}
}
Expand All @@ -134,14 +131,14 @@ pub async fn parse_pixelflut_commands(
y += connection_y_offset;

// Separator between coordinates and color
if buffer[i] == b' ' {
if unsafe { *buffer.get_unchecked(i) } == b' ' {
i += 1;

// TODO: Determine what clients use more: RGB, RGBA or gg variant.
// If RGBA is used more often move the RGB code below the RGBA code

// Must be followed by 6 bytes RGB and newline or ...
if buffer[i + 6] == b'\n' {
if unsafe { *buffer.get_unchecked(i + 6) } == b'\n' {
last_byte_parsed = i + 6;
i += 7; // We can advance one byte more than normal as we use continue and therefore not get incremented at the end of the loop

Expand All @@ -153,7 +150,7 @@ pub async fn parse_pixelflut_commands(

// ... or must be followed by 8 bytes RGBA and newline
#[cfg(not(feature = "alpha"))]
if buffer[i + 8] == b'\n' {
if unsafe { *buffer.get_unchecked(i + 8) } == b'\n' {
last_byte_parsed = i + 8;
i += 9; // We can advance one byte more than normal as we use continue and therefore not get incremented at the end of the loop

Expand All @@ -163,7 +160,7 @@ pub async fn parse_pixelflut_commands(
continue;
}
#[cfg(feature = "alpha")]
if buffer[i + 8] == b'\n' {
if unsafe { *buffer.get_unchecked(i + 8) } == b'\n' {
last_byte_parsed = i + 8;
i += 9; // We can advance one byte more than normal as we use continue and therefore not get incremented at the end of the loop

Expand Down Expand Up @@ -193,7 +190,7 @@ pub async fn parse_pixelflut_commands(
}

// ... for the efficient/lazy clients
if buffer[i + 2] == b'\n' {
if unsafe { *buffer.get_unchecked(i + 2) } == b'\n' {
last_byte_parsed = i + 2;
i += 3; // We can advance one byte more than normal as we use continue and therefore not get incremented at the end of the loop

Expand All @@ -208,7 +205,7 @@ pub async fn parse_pixelflut_commands(
}

// End of command to read Pixel value
if buffer[i] == b'\n' {
if unsafe { *buffer.get_unchecked(i) } == b'\n' {
last_byte_parsed = i;
i += 1;
if let Some(rgb) = fb.get(x, y) {
Expand Down Expand Up @@ -236,58 +233,60 @@ pub async fn parse_pixelflut_commands(
}
} else if current_command & 0x0000_ffff_ffff_ffff == string_to_number(b"OFFSET \0\0") {
i += 7;
// Parse first x coordinate char
if buffer[i] >= b'0' && buffer[i] <= b'9' {
x = (buffer[i] - b'0') as usize;
i += 1;
// Parse x coordinate
let digits =
unsafe { (buffer.as_ptr().add(i) as *const u32).read_unaligned() } as usize;

// Parse optional second x coordinate char
if buffer[i] >= b'0' && buffer[i] <= b'9' {
x = 10 * x + (buffer[i] - b'0') as usize;
let mut digit = digits & 0xff;
if digit >= b'0' as usize && digit <= b'9' as usize {
x = digit - b'0' as usize;
i += 1;
digit = (digits >> 8) & 0xff;
if digit >= b'0' as usize && digit <= b'9' as usize {
x = 10 * x + digit - b'0' as usize;
i += 1;

// Parse optional third x coordinate char
if buffer[i] >= b'0' && buffer[i] <= b'9' {
x = 10 * x + (buffer[i] - b'0') as usize;
digit = (digits >> 16) & 0xff;
if digit >= b'0' as usize && digit <= b'9' as usize {
x = 10 * x + digit - b'0' as usize;
i += 1;

// Parse optional forth x coordinate char
if buffer[i] >= b'0' && buffer[i] <= b'9' {
x = 10 * x + (buffer[i] - b'0') as usize;
digit = (digits >> 24) & 0xff;
if digit >= b'0' as usize && digit <= b'9' as usize {
x = 10 * x + digit - b'0' as usize;
i += 1;
}
}
}

// Separator between x and y
if buffer[i] == b' ' {
if unsafe { *buffer.get_unchecked(i) } == b' ' {
i += 1;

// Parse first y coordinate char
if buffer[i] >= b'0' && buffer[i] <= b'9' {
y = (buffer[i] - b'0') as usize;
i += 1;
// Parse y coordinate
let digits =
unsafe { (buffer.as_ptr().add(i) as *const u32).read_unaligned() } as usize;

// Parse optional second y coordinate char
if buffer[i] >= b'0' && buffer[i] <= b'9' {
y = 10 * y + (buffer[i] - b'0') as usize;
digit = digits & 0xff;
if digit >= b'0' as usize && digit <= b'9' as usize {
y = digit - b'0' as usize;
i += 1;
digit = (digits >> 8) & 0xff;
if digit >= b'0' as usize && digit <= b'9' as usize {
y = 10 * y + digit - b'0' as usize;
i += 1;

// Parse optional third y coordinate char
if buffer[i] >= b'0' && buffer[i] <= b'9' {
y = 10 * y + (buffer[i] - b'0') as usize;
digit = (digits >> 16) & 0xff;
if digit >= b'0' as usize && digit <= b'9' as usize {
y = 10 * y + digit - b'0' as usize;
i += 1;

// Parse optional forth y coordinate char
if buffer[i] >= b'0' && buffer[i] <= b'9' {
y = 10 * y + (buffer[i] - b'0') as usize;
digit = (digits >> 24) & 0xff;
if digit >= b'0' as usize && digit <= b'9' as usize {
y = 10 * y + digit - b'0' as usize;
i += 1;
}
}
}

// End of command to set offset
if buffer[i] == b'\n' {
if unsafe { *buffer.get_unchecked(i) } == b'\n' {
last_byte_parsed = i;
connection_x_offset = x;
connection_y_offset = y;
Expand Down

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