skeeto

Question 2: Steganography using 4-bit LSB algorithm
Scope: File Processing, Pointers, Dynamic Memory Allocation (No arrays)
File to use: stego_lsb.c

Preliminary:

This question should be solved using dynamic memory  allocation  along  with
pointers.  Any  submitted  work  which  includes  an  array  will  be  given
automatically a zero mark. To view pgm files, you can use the  “Irfan  View”

skeeto

#include <assert.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define new(a, n, t)  (t *)alloc(a, n, sizeof(t), _Alignof(t))
#define S(s)          (Str){(uint8_t *)s, sizeof(s)-1}

skeeto

// Slim Reader/Writer Condition Variable Demo / Test
//   $ cc -nostartfiles -o main.exe demo.cpp
//   $ cl /GS- demo.cpp /link /subsystem:console kernel32.lib
// This is free and unencumbered software released into the public domain.

#define assert(c)  while (!(c)) *(volatile i32 *)-4 = 0

using b32 = signed;
using i32 = signed;
using uz  = decltype(sizeof(0));

skeeto

// Quick test of environment variable passing
//   $ cc -nostartfiles -o testenv testenv.cpp
//   $ cl testenv.cpp /link /subsystem:console kernel32.lib
//
// Spawns a copy of itself with a custom-built environment block, and
// the spawned child examines/probes that block.
//
// This is free and unencumbered software released into the public domain.

typedef int I;

skeeto

// Ref: https://old.reddit.com/r/C_Programming/comments/1e30ce8/
#include <stddef.h>
#include <stdio.h>

#define S(s) (str){s, sizeof(s)-1}

typedef struct {
    char     *data;
    ptrdiff_t len;
} str;

skeeto

// Quilt layout solver (example)
// $ cc -o quilt quilt.c
// Ref: https://old.reddit.com/r/algorithms/comments/1dn97c0
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>

#define countof(a) (ptrdiff_t)(sizeof(a) / sizeof(*(a)))

skeeto

// Ref: https://old.reddit.com/r/C_Programming/comments/1dlc4kw
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define new(n, t)  (t *)calloc(n, sizeof(t))

typedef struct node node;
struct node {

skeeto

// Flawless Squares
// $ cc -fopenmp -O2 -o squares squares.c
// Ref: https://old.reddit.com/r/C_Programming/comments/1de40e0
// This is free and unencumbered software released into the public domain.
#include <stdio.h>

int main(void)
{
    #pragma omp parallel for schedule(dynamic, 100000)
    for (long long root = 1; root < 3037000500; root++) {

skeeto

// $ c++ -o kanzi kanzi.cpp
#define WIN32_LEAN_AND_MEAN  // avoids std::byte conflicts
#include "src/app/BlockDecompressor.cpp"
#include "src/app/Kanzi.cpp"
#include "src/app/InfoPrinter.cpp"
#include "src/app/BlockCompressor.cpp"
#include "src/transform/BWTS.cpp"
#include "src/transform/BWTBlockCodec.cpp"
#include "src/transform/SBRT.cpp"
#include "src/transform/ZRLT.cpp"

skeeto

#define assert(c)     while (!(c)) __builtin_unreachable()
#define new(a, n, t)  (t *)alloc(a, n, sizeof(t), _Alignof(t))

enum { PAGESIZE = 1<<12 };

typedef   signed int       b32;
typedef   signed int       i32;
typedef          char      byte;
typedef   signed long long iz;
typedef unsigned long long uz;