nanofish 0.11.4

//! HTTP protocol constants and shared utilities.

/// Carriage Return + Line Feed
pub const CRLF: &[u8] = b"\r\n";

/// Length of CRLF
pub const CRLF_LEN: usize = CRLF.len();

/// Double CRLF — separates HTTP headers from body
pub const DOUBLE_CRLF: &[u8] = b"\r\n\r\n";

/// Length of double CRLF
pub const DOUBLE_CRLF_LEN: usize = DOUBLE_CRLF.len();

/// Chunked transfer encoding final chunk marker
pub const CHUNKED_END_MARKER: &[u8] = b"0\r\n\r\n";

/// HTTP/1.1 version string
pub const HTTP_VERSION: &str = "HTTP/1.1";

/// HTTP/1.1 version as bytes with leading space and trailing CRLF (for request line)
pub const HTTP_VERSION_LINE_SUFFIX: &str = " HTTP/1.1\r\n";

/// Default HTTP port
pub const DEFAULT_HTTP_PORT: u16 = 80;

/// Default HTTPS port
pub const DEFAULT_HTTPS_PORT: u16 = 443;

/// Transfer-Encoding header name
pub const TRANSFER_ENCODING: &str = "Transfer-Encoding";

/// Chunked transfer encoding value
pub const CHUNKED: &str = "chunked";

/// Maximum number of headers allowed in requests and responses
pub const MAX_HEADERS: usize = 16;

/// Maximum URL path segments
pub const MAX_URL_PARTS: usize = 8;

/// Find the position of the double CRLF sequence in raw bytes.
/// Returns the byte index of the start of `\r\n\r\n`.
#[must_use]
pub fn find_double_crlf(data: &[u8]) -> Option<usize> {
    data.windows(DOUBLE_CRLF_LEN).position(|w| w == DOUBLE_CRLF)
}

/// Find the position of CRLF in raw bytes starting from a given slice.
/// Returns the byte index relative to the start of the provided slice.
#[must_use]
pub fn find_crlf(data: &[u8]) -> Option<usize> {
    data.windows(CRLF_LEN).position(|w| w == CRLF)
}

/// Check if a header name matches (case-insensitive) and return its value.
#[must_use]
pub fn find_header_value<'a>(headers_str: &'a str, target_name: &str) -> Option<&'a str> {
    for line in headers_str.split("\r\n") {
        if let Some(colon_pos) = line.find(':') {
            let name = line[..colon_pos].trim();
            let value = line[colon_pos + 1..].trim();
            if name.eq_ignore_ascii_case(target_name) {
                return Some(value);
            }
        }
    }
    None
}