pptx 0.1.0

A Rust library for creating and manipulating PowerPoint (.pptx) files
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66

//! Utility functions for HTML export.

use crate::units::Emu;

pub(super) const EMUS_PER_PX: f64 = 9525.0; // 914400 / 96

pub(super) fn emu_to_px(emu: Emu) -> f64 {
    #[allow(clippy::cast_precision_loss)] // i64→f64 acceptable for pixel conversion
    let val = emu.0 as f64;
    val / EMUS_PER_PX
}

pub(super) fn html_escape(s: &str) -> String {
    let mut out = String::with_capacity(s.len());
    for ch in s.chars() {
        match ch {
            '&' => out.push_str("&"),
            '<' => out.push_str("&lt;"),
            '>' => out.push_str("&gt;"),
            '"' => out.push_str("&quot;"),
            '\'' => out.push_str("&#39;"),
            _ => out.push(ch),
        }
    }
    out
}

// ---------------------------------------------------------------------------
// Minimal base64 encoder (no external dependency)
// ---------------------------------------------------------------------------

const BASE64_CHARS: &[u8; 64] = b"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

pub(super) fn base64_encode(data: &[u8]) -> String {
    let mut result = String::with_capacity(data.len().div_ceil(3) * 4);
    let chunks = data.chunks(3);
    for chunk in chunks {
        let b0 = u32::from(chunk[0]);
        let b1 = if chunk.len() > 1 {
            u32::from(chunk[1])
        } else {
            0
        };
        let b2 = if chunk.len() > 2 {
            u32::from(chunk[2])
        } else {
            0
        };
        let triple = (b0 << 16) | (b1 << 8) | b2;

        result.push(BASE64_CHARS[((triple >> 18) & 0x3F) as usize] as char);
        result.push(BASE64_CHARS[((triple >> 12) & 0x3F) as usize] as char);

        if chunk.len() > 1 {
            result.push(BASE64_CHARS[((triple >> 6) & 0x3F) as usize] as char);
        } else {
            result.push('=');
        }
        if chunk.len() > 2 {
            result.push(BASE64_CHARS[(triple & 0x3F) as usize] as char);
        } else {
            result.push('=');
        }
    }
    result
}