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Bitset array - project 1

Usage

As all my other projects, also this one has Makefile. Just use make:

make run

to run prime numbers calculation.

make steg-decode
./steg-decode du1-obrazek.ppm

to run decoder.

Assignment

Bitset array (up to 7 points)

To interface bitset.h define structure array of bits:
Types:

• typedef <YOUR-TYPE> bitset_t - structure of bit array
• typedef unsigned long bitset_index_t - type for index to item in array

Macros:

• bitset_create(name, size) - defines and initializes variable name
  • be sure, your implementation supports both static and local arrays.
  • examples: static bitset_create(p, 100); // p = array of 100 bits, initialized, bitset_create(q, 100000L); // q = array of 100000 bits, initialized and bitset_create(q,-100); // compilation error
• bitset_alloc(name, size) - defines variable name in compatible way with array defined with bitset_create but heap needs to be used
  • bitset_alloc(q, 100000L); // q = array of 100000 bits, initialized
  • Use assert for maximum size check.
  • In case of allocation fail throw bitset_alloc: Chyba alokace paměti error
• bitset_free(name)
• bitset_size(name) - returns size of bit array (saved in array)
• bitset_setbit(name, index, value) - sets index bit to value
• bitset_getbit(name, index) - returns value of index bit in name array

For testing purposes, implement sieve of Eratosthenes for prime numbers calculation. Function Eratosthenes() have to calculate prime numbers and prints it to the stdout.

Decoder (up to 8 points)

Implement module error.c with interface defined in error.h which defines function:

• void warning_msg(const char *fmt, ...)
• void error_exit(const char *fmt, ...)

These functions support same parameters as print(). It should print formatted error message to stderr and ends program.

Implement module ppm.c with interface ppm.h where you define type:

struct ppm {
    unsigned xsize;
    unsigned ysize;
    char data[];    // RGB bytes, total of 3*xsize*ysize
};

and functions:

• struct ppm * ppm_read(const char * filename) - it loads content of PPM file to dynamically allocated structure.
  • in case invalid PPM file format, use your warning_msg() function and return NULL
• void ppm_free(struct ppm *p) - frees dynamically allocated memory from ppm_read()

Implement just binary variant P6 of PPM with 256 colors support without comments inside:

"P6" <ws>+
<xsizetxt> <ws>+ <ysizetxt> <ws>+
"255" <ws>
<binary data, 3*xsize*ysize bytes RGB>
<EOF>

Use ppm_read() and ppm_free() functions in steg-decode.c file that implements message decoder from ppm file (du1-obrazek.ppm. The secret is sequence of chars that consists of bits saved as LSb on prime indexes starts at 29. Use your implementation of sieve of Eratosthenes for prime numbers calculation.

Evaluation

15 / 15 points :)