zig memory allocators

allocators.zig

const std = @import("std");


pub fn main() !void {
    // fixe buffer allocator
   var buffer: [1000]u8 = undefined;
    const allocator = &std.heap.FixedBufferAllocator.init(&buffer).allocator;
    
    const memory = try allocator.alloc(u8, 5);
    defer allocator.free(memory);

    memory[0] = 'b';
    memory[1] = 'o';
    memory[2] = 'b';
    std.debug.print("{s} \n", .{memory});

   
    std.mem.copy(u8,memory, "hello");
    std.debug.print("{s} \n", .{memory});

    const w = std.mem.concat(allocator, u8, &[_][]const u8{ "bobby ", "bouche" });
    std.debug.print("{s} \n", .{w});

    // general purpose allocator

    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
    const allocator1 = &gpa.allocator;
      
    const bytes = try allocator1.alloc(u8, 1);
    
    
    defer allocator1.free(bytes);
    bytes[0] = 'L';
    std.debug.print("{s} \n", .{bytes});

    // heap allocator must use 
    const allocator2 = std.heap.page_allocator;
    const bytes1 = try allocator2.alloc(u8, 25);
    defer allocator2.free(bytes1);
    

   std.mem.copy(u8, bytes1, "zig is awesome");
    std.debug.print("{s} \n", .{bytes1});

    // c heap allocator must use -lc switch
    const allocator3 = std.heap.c_allocator;
    const bytes3 = try allocator3.alloc(u8, 25);
    defer allocator3.free(bytes3);
    
    
   std.mem.copy(u8, bytes3, "zig is great");
    std.debug.print("{s} \n", .{bytes3});

    // arena allocator

     var arena = std.heap.ArenaAllocator.init(std.heap.page_allocator);
    defer arena.deinit();
    var allocator4 = &arena.allocator;

    const m1 = try allocator4.alloc(u8, 1);
    std.mem.copy(u8, m1, "I");
    const m2 = try allocator4.alloc(u8, 4);
    std.mem.copy(u8, m2, "LOVE");
    const m3 = try allocator4.alloc(u8, 3);
    std.mem.copy(u8, m3, "ZIG");

    std.debug.print("{s} {s} {s}\n", .{m1, m2, m3});


    
}