zedbar 0.2.3

//! Codabar barcode decoder
//!
//! This module implements decoding for Codabar barcodes.

use crate::{SymbolType, color::Color, img_scanner::ImageScanner};

// Buffer constants
const NIBUF: usize = 6;

// Assertion macro
macro_rules! zassert {
    ($condition:expr, $retval:expr, $($arg:tt)*) => {
        if !$condition {
            return $retval;
        }
    };
}

// ============================================================================
// Codabar lookup tables
// ============================================================================

static CODABAR_LO: [i8; 12] = [0x0, 0x1, 0x4, 0x5, 0x2, 0xa, 0xb, 0x9, 0x6, 0x7, 0x8, 0x3];

static CODABAR_HI: [u8; 8] = [0x1, 0x4, 0x7, 0x6, 0x2, 0x3, 0x0, 0x5];

static CODABAR_CHARACTERS: &[u8; 20] = b"0123456789-$:/.+ABCD";

// ============================================================================
// Helper functions from decoder.h
// ============================================================================

/// Sort 3 like-colored elements and return ordering
fn decode_sort3(dcode: &ImageScanner, i0: u8) -> u32 {
    let w0 = dcode.get_width(i0);
    let w2 = dcode.get_width(i0 + 2);
    let w4 = dcode.get_width(i0 + 4);

    if w0 < w2 {
        if w2 < w4 {
            ((i0 as u32) << 8) | (((i0 + 2) as u32) << 4) | ((i0 + 4) as u32)
        } else if w0 < w4 {
            ((i0 as u32) << 8) | (((i0 + 4) as u32) << 4) | ((i0 + 2) as u32)
        } else {
            (((i0 + 4) as u32) << 8) | ((i0 as u32) << 4) | ((i0 + 2) as u32)
        }
    } else if w4 < w2 {
        (((i0 + 4) as u32) << 8) | (((i0 + 2) as u32) << 4) | (i0 as u32)
    } else if w0 < w4 {
        (((i0 + 2) as u32) << 8) | ((i0 as u32) << 4) | ((i0 + 4) as u32)
    } else {
        (((i0 + 2) as u32) << 8) | (((i0 + 4) as u32) << 4) | (i0 as u32)
    }
}

/// Sort N like-colored elements and return ordering
fn decode_sortn(dcode: &ImageScanner, n: i32, i0: u8) -> u32 {
    let mut mask: u32 = 0;
    let mut sort: u32 = 0;

    for _i in (0..n).rev() {
        let mut wmin = u32::MAX;
        let mut jmin: i32 = -1;

        for j in (0..n).rev() {
            if (mask >> j) & 1 != 0 {
                continue;
            }
            let w = dcode.get_width(i0 + (j as u8) * 2);
            if wmin >= w {
                wmin = w;
                jmin = j;
            }
        }
        zassert!(jmin >= 0, 0, "sortn({},{}) jmin={}", n, i0, jmin);
        sort <<= 4;
        mask |= 1 << jmin;
        sort |= (i0 as u32) + (jmin as u32) * 2;
    }
    sort
}

// ============================================================================
// Codabar Decoder functions
// ============================================================================

/// Check width against reference
fn check_width(ref_width: u32, w: u32) -> bool {
    let dref = ref_width;
    let ref_4 = ref_width * 4;
    let w_4 = w * 4;
    ref_4.wrapping_sub(dref) <= w_4 && w_4 <= ref_4.wrapping_add(dref)
}

/// Decode 7 elements into a character
fn codabar_decode7(dcode: &ImageScanner) -> i8 {
    let codabar = &dcode.codabar;
    let s = codabar.s7;
    if s < 7 {
        return -1;
    }

    // Check width
    if !check_width(codabar.width, s) {
        return -1;
    }

    // Extract min/max bar
    let ibar = decode_sortn(dcode, 4, 1);

    let wbmax = dcode.get_width((ibar & 0xf) as u8);
    let wbmin = dcode.get_width((ibar >> 12) as u8);
    if 8 * wbmin < wbmax || 3 * wbmin > 2 * wbmax {
        return -1;
    }

    let wb1 = dcode.get_width(((ibar >> 8) & 0xf) as u8);
    let wb2 = dcode.get_width(((ibar >> 4) & 0xf) as u8);
    let b0b3 = wbmin * wbmax;
    let b1b2 = wb1 * wb2;

    let ibar = if b1b2 + b1b2 / 8 < b0b3 {
        // Single wide bar combinations
        if 8 * wbmin < 5 * wb1
            || 8 * wb1 < 5 * wb2
            || 4 * wb2 > 3 * wbmax
            || wb2 * wb2 >= wb1 * wbmax
        {
            return -1;
        }
        (ibar >> 1) & 0x3
    } else if b1b2 > b0b3 + b0b3 / 8 {
        // Three wide bars, no wide spaces
        if 4 * wbmin > 3 * wb1
            || 8 * wb1 < 5 * wb2
            || 8 * wb2 < 5 * wbmax
            || wbmin * wb2 >= wb1 * wb1
        {
            return -1;
        }
        (ibar >> 13) + 4
    } else {
        return -1;
    };

    let ispc = decode_sort3(dcode, 2);

    let wsmax = dcode.get_width((ispc & 0xf) as u8);
    let wsmid = dcode.get_width(((ispc >> 4) & 0xf) as u8);
    let wsmin = dcode.get_width(((ispc >> 8) & 0xf) as u8);

    if ibar >> 2 != 0 {
        // Verify no wide spaces
        if 8 * wsmin < wsmax || 8 * wsmin < 5 * wsmid || 8 * wsmid < 5 * wsmax {
            return -1;
        }
        let mut ibar = ibar & 0x3;
        if codabar.direction() {
            ibar = 3 - ibar;
        }
        let c = (0xfcde >> (ibar << 2)) & 0xf;
        return c as i8;
    }
    if 8 * wsmin < wsmax || 3 * wsmin > 2 * wsmax {
        return -1;
    }

    let s0s2 = wsmin * wsmax;
    let s1s1 = wsmid * wsmid;

    if s1s1 + s1s1 / 8 < s0s2 {
        // Single wide space
        if 8 * wsmin < 5 * wsmid || 4 * wsmid > 3 * wsmax {
            return -1;
        }
        let ispc = (((ispc & 0xf) as u8) >> 1) - 1;
        let mut ic = ((ispc as u32) << 2) | ibar;
        if codabar.direction() {
            ic = 11 - ic;
        }

        CODABAR_LO[ic as usize]
    } else if s1s1 > s0s2 + s0s2 / 8 {
        // Two wide spaces, check start/stop
        if 4 * wsmin > 3 * wsmid || 8 * wsmid < 5 * wsmax {
            return -1;
        }
        if (ispc >> 8) == 4 {
            return -1;
        }
        let ispc = ispc >> 10;
        let ic = ispc * 4 + ibar;
        zassert!(ic < 8, -1, "ic={} ispc={} ibar={}", ic, ispc, ibar);
        let c = CODABAR_HI[ic as usize];
        if (c >> 2) != (codabar.direction() as u8) {
            return -1;
        }
        let c = (c & 0x3) | 0x10;
        c as i8
    } else {
        -1
    }
}

/// Decode start pattern
fn codabar_decode_start(dcode: &mut ImageScanner) -> SymbolType {
    let s = dcode.codabar.s7;
    if s < 8 {
        return SymbolType::None;
    }

    // Check leading quiet zone - spec is 10x
    let qz = dcode.get_width(8);
    if (qz != 0 && qz * 2 < s) || 4 * dcode.get_width(0) > 3 * s {
        return SymbolType::None;
    }

    // Check space ratios first
    let ispc = decode_sort3(dcode, 2);
    if (ispc >> 8) == 4 {
        return SymbolType::None;
    }

    // Require 2 wide and 1 narrow spaces
    let wsmax = dcode.get_width((ispc & 0xf) as u8);
    let wsmin = dcode.get_width((ispc >> 8) as u8);
    let wsmid = dcode.get_width(((ispc >> 4) & 0xf) as u8);
    if 8 * wsmin < wsmax
        || 3 * wsmin > 2 * wsmax
        || 4 * wsmin > 3 * wsmid
        || 8 * wsmid < 5 * wsmax
        || wsmid * wsmid <= wsmax * wsmin
    {
        return SymbolType::None;
    }
    let ispc = ispc >> 10;

    // Check bar ratios
    let ibar = decode_sortn(dcode, 4, 1);

    let wbmax = dcode.get_width((ibar & 0xf) as u8);
    let wbmin = dcode.get_width((ibar >> 12) as u8);
    if 8 * wbmin < wbmax || 3 * wbmin > 2 * wbmax {
        return SymbolType::None;
    }

    // Require 1 wide & 3 narrow bars
    let wb1 = dcode.get_width(((ibar >> 8) & 0xf) as u8);
    let wb2 = dcode.get_width(((ibar >> 4) & 0xf) as u8);
    if 8 * wbmin < 5 * wb1
        || 8 * wb1 < 5 * wb2
        || 4 * wb2 > 3 * wbmax
        || wb1 * wb2 >= wbmin * wbmax
        || wb2 * wb2 >= wb1 * wbmax
    {
        return SymbolType::None;
    }
    let ibar = (((ibar & 0xf) as u8) - 1) >> 1;

    // Decode combination
    let ic = ispc * 4 + (ibar as u32);
    zassert!(
        ic < 8,
        SymbolType::None,
        "ic={} ispc={} ibar={}",
        ic,
        ispc,
        ibar
    );
    let c = CODABAR_HI[ic as usize];
    dcode.codabar.buf[0] = (c & 0x3) | 0x10;

    // Set character direction
    dcode.codabar.set_direction((c >> 2) != 0);

    dcode.codabar.set_element(4);
    dcode.codabar.set_character(1);
    dcode.codabar.width = dcode.codabar.s7;
    SymbolType::Partial
}

/// Post-process decoded buffer
fn codabar_postprocess(dcode: &mut ImageScanner) -> SymbolType {
    let dir = dcode.codabar.direction();
    dcode.direction = 1 - 2 * (dir as i32);
    let mut n = dcode.codabar.character() as usize;

    // Cache all values we need from dcode before taking mutable borrow of buffer
    let copy_len = n.min(NIBUF);
    let temp_buf = dcode.codabar.buf; // Copy the small array
    let has_checksum = dcode.should_validate_checksum(SymbolType::Codabar);
    let emit_check = dcode.should_emit_checksum(SymbolType::Codabar);

    // Get a mutable slice to the buffer, ensuring it has space for n bytes plus null terminator
    let buffer = match dcode.buffer_mut_slice(n + 1) {
        Ok(buf) => buf,
        Err(_) => return SymbolType::None,
    };

    // Copy from holding buffer to main buffer
    buffer[..copy_len].copy_from_slice(&temp_buf[..copy_len]);

    if dir {
        // Reverse buffer
        buffer[..n].reverse();
    }

    if has_checksum {
        // Validate checksum (read-only operation on buffer)
        let mut chk: u32 = 0;
        for c in buffer.iter().take(n) {
            chk += *c as u32;
        }
        if (chk & 0xf) != 0 {
            return SymbolType::None;
        }
        if !emit_check {
            buffer[n - 2] = buffer[n - 1];
            n -= 1;
        }
    }

    // Translate character codes to ASCII
    for c in buffer.iter_mut().take(n) {
        *c = *CODABAR_CHARACTERS.get(*c as usize).unwrap_or(&b'?');
    }

    // Add null terminator at position n
    buffer[n] = 0;

    // Truncate to final length (doesn't include null terminator)
    dcode.truncate_buffer(n);

    dcode.modifiers = 0;
    dcode.codabar.set_character(-1);
    SymbolType::Codabar
}

/// Main Codabar decode function
pub(crate) fn decode_codabar(dcode: &mut ImageScanner) -> SymbolType {
    // Update latest character width
    let w8 = dcode.get_width(8);
    let w1 = dcode.get_width(1);
    dcode.codabar.s7 = dcode.codabar.s7.wrapping_sub(w8).wrapping_add(w1);

    if dcode.color() != Color::Space {
        return SymbolType::None;
    }

    if dcode.codabar.character() < 0 {
        return codabar_decode_start(dcode);
    }

    if dcode.codabar.character() < 2 && codabar_decode_start(dcode) != SymbolType::None {
        return SymbolType::Partial;
    }

    let element = dcode.codabar.element() - 1;
    dcode.codabar.set_element(element);
    if element != 0 {
        return SymbolType::None;
    }
    dcode.codabar.set_element(4);

    let c = codabar_decode7(dcode);
    if c < 0 {
        // goto reset
        let character = dcode.codabar.character();
        if character >= NIBUF as i16 {
            dcode.release_lock(SymbolType::Codabar);
        }
        dcode.codabar.set_character(-1);
        return SymbolType::None;
    }

    let character = dcode.codabar.character();
    if character < NIBUF as i16 {
        dcode.codabar.buf[character as usize] = c as u8;
    } else {
        // Write directly to the buffer using the idiomatic method
        if dcode
            .write_buffer_byte(character as usize, c as u8)
            .is_err()
        {
            // goto reset
            dcode.release_lock(SymbolType::Codabar);
            dcode.codabar.set_character(-1);
            return SymbolType::None;
        }
    }
    dcode.codabar.set_character(character + 1);

    // Lock shared resources
    if character + 1 == NIBUF as i16 && !dcode.acquire_lock(SymbolType::Codabar) {
        dcode.codabar.set_character(-1);
        return SymbolType::Partial;
    }

    let s = dcode.codabar.s7;
    if (c & 0x10) != 0 {
        let qz = dcode.get_width(0);
        if qz != 0 && qz * 2 < s {
            // goto reset
            let character = dcode.codabar.character();
            if character >= NIBUF as i16 {
                dcode.release_lock(SymbolType::Codabar);
            }
            dcode.codabar.set_character(-1);
            return SymbolType::None;
        }

        let n = dcode.codabar.character();
        let (min_len, max_len) = dcode
            .get_length_limits(SymbolType::Codabar)
            .unwrap_or((4, 0)); // Default: min=4, max=0 (unlimited)
        if n < min_len as i16 || (max_len > 0 && n > max_len as i16) {
            // goto reset
            let character = dcode.codabar.character();
            if character >= NIBUF as i16 {
                dcode.release_lock(SymbolType::Codabar);
            }
            dcode.codabar.set_character(-1);
            return SymbolType::None;
        }

        if dcode.codabar.character() < NIBUF as i16 && !dcode.acquire_lock(SymbolType::Codabar) {
            dcode.codabar.set_character(-1);
            return SymbolType::Partial;
        }

        let sym = codabar_postprocess(dcode);
        if sym <= SymbolType::Partial {
            dcode.release_lock(SymbolType::Codabar);
            dcode.codabar.set_character(-1);
        }
        return sym;
    } else if 4 * dcode.get_width(0) > 3 * s {
        // goto reset
        let character = dcode.codabar.character();
        if character >= NIBUF as i16 {
            dcode.release_lock(SymbolType::Codabar);
        }
        dcode.codabar.set_character(-1);
        return SymbolType::None;
    }

    SymbolType::None
}