STYLE.md

This style guide comes from dav1d: https://code.videolan.org/videolan/dav1d/wikis/Coding-style

Tabs vs Spaces No tabs, only spaces; 4-space indentation;

Be aware that some tools might add tabs when auto aligning the code, please check your commits with a diff tool for tabs.

for multi-line statements, the indentation of the next line depends on the context of the statement and braces around it. For example, if you have a long assignment, you can choose to either align it to the = of the first line, or (if that leads to less lines of code) just indent 1 level further from the first line's indentation level:

const int my_var = something1 &&
                   something2;

or

const int my_var = something1 +
    something2 - something3 * something4;

However, if there are braces, the first non-whitespace character of the line should be aligned with the brace level that it is part of:

const int my_var = (something1 +
                    something2) * something3;

use CamelCase for types and under_score for variable names (TypeName my_instance;) we use const where possible, except in forward function declarations in header files, where we only use it for const-arrays:

int my_func(const array *values, int arg);

[..]

int my_func(const array *const values, const int num) {
    ..
}

braces go on the same line for single-line statements, but on a new line for multi-line statements:

static void function(const int argument) {
    do_something();
}

versus

static void function(const int argument1,
                     const int argument2)
{
    do_something();
}

braces are only necessary for multi-line code blocks or multi-line condition statements;

if (condition1 && condition2)
    do_something();

and

if (condition) {
    do_something_1();
    do_something_2();
}

and

if (condition1 &&
    condition2)
{
    do_something();
}

switch/case are indented at the same level, and the code block is indented one level deeper:

switch (a) {
case 1:
    bla();
    break;
}

but for very trivial blocks, you can also put everything on one single line

switch (a) {
case 1: bla(); break;
}

lines should not be longer than 80 characters. We allow exceptions if wrapping the line would lead to exceptional ugliness, and this is done on a case-by-case basis; don't use goto except for standard error handling; use native types (int, unsigned, etc.) for scalar variables where the upper bound of a size doesn't matter; use sized types (uint8_t, int16_t, etc.) for vector/array variables where the upper bound of the size matters; use dynamic types (pixel, coef, etc.) so multi-bitdepth templating works as it should.