NMERandomGen.c

Go to the documentation of this file.

/* License: new BSD license (see NME.h) */

/* To compile: gcc -o nmerandom NMERandomGen.c */

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#define rnd() (seed = 1664525 * seed + 1013904223, (seed >> 24) & 0xff)

int main(int argc, char **argv)
{
    int i;
    int size = 1024;
    int maxLineLength = 60;
    enum { Random, CR, LF, CRLF } eol = Random;
    int ascii = 0;
    int count;  // number of characters generated
    int countForLine;   // number of characters generated
    unsigned long seed = 1;
    unsigned char c;
    
    for (i = 1; i < argc; i++)
        if (!strcmp(argv[i], "--size") && i + 1 < argc)
            size = strtol(argv[++i], NULL, 0);
        else if (!strcmp(argv[i], "--maxlinelength") && i + 1 < argc)
            maxLineLength = strtol(argv[++i], NULL, 0);
        else if (!strcmp(argv[i], "--ascii"))
            ascii = 1;
        else if (!strcmp(argv[i], "--cr"))
            eol = CR;
        else if (!strcmp(argv[i], "--lf"))
            eol = LF;
        else if (!strcmp(argv[i], "--crlf"))
            eol = CRLF;
        else if (!strcmp(argv[i], "--seed") && i + 1 < argc)
            seed = strtol(argv[++i], NULL, 0);
        else
        {
            if (strcmp(argv[i], "--help"))
                fprintf(stderr, "Unknown option %s\n", argv[i]);
            fprintf(stderr, "Usage: %s [options]\n"
                    "Generate random input for testing Nyctergatis Markup Engine.\n"
                    "--ascii           ASCII output (default: random bytes)\n"
                    "--cr              CR (0x0D) for end-of-line (default: random)\n"
                    "--crlf            CRLF (0x0D 0x0A) for end-of-line (default: random)\n"
                    "--help            display this help message and exit\n"
                    "--lf              LF (0x0A) for end-of-line (default: random)\n"
                    "--maxlinelength   max number of characters per line, or 0 for no limit\n"
                    "--seed            seed of the pseudorandom generator (default: 1)\n"
                    "--size            approximate size of output in bytes\n",
                argv[0]);
            exit(0);
        }
    
    // skip first pseudorandom number to avoid zeros
    rnd();
    
    for (count = countForLine = 0; count < size; )
    {
        c = rnd();
        
        // eol: p = 2 %, or 20 % after an eol
        if (maxLineLength > 0 && countForLine >= maxLineLength
                || c < 5 || countForLine == 0 && c < 51)
        {
            switch (eol)
            {
                case CR:
                    printf("\x0d");
                    count++;
                    break;
                case LF:
                    printf("\x0a");
                    count++;
                    break;
                case CRLF:
                    printf("\x0d\x0a");
                    count += 2;
                    break;
                case Random:
                default:
                    c = rnd();
                    switch (c & 0xc0)
                    {
                        case 0:
                            printf("\x0d");
                            count++;
                            break;
                        case 0x80:
                            printf("\x0a");
                            count++;
                            break;
                        default:
                            printf("\x0d\x0a");
                            count += 2;
                            break;
                    }
                    break;
            }
            countForLine = 0;
            continue;
        }
        
        // random number of special characters at beg. of line: p = 20 %
        c = rnd();
        if (countForLine == 0 && c < 51)
        {
            while (count < size)
            {
                c = rnd();
                switch ((c >> 5) & 7)
                {
                    case 0:
                        printf("*");
                        break;
                    case 1:
                        printf("#");
                        break;
                    case 2:
                        printf(":");
                        break;
                    case 3:
                        printf(";");
                        break;
                    case 4:
                        printf("|");
                        break;
                    default:
                        printf("*");
                        break;
                }
                count++;
                countForLine++;
                if (rnd() > 128)    // p = 50 % to break
                    break;
            }
            continue;
        }
        
        // random style: p = 20 %
        c = rnd();
        switch (c >> 2)
        {
            case 0:
                printf("**");
                count += 2;
                countForLine += 2;
                continue;
            case 1:
                printf("//");
                count += 2;
                countForLine += 2;
                continue;
            case 2:
                printf("__");
                count += 2;
                countForLine += 2;
                continue;
            case 3:
                printf("##");
                count += 2;
                countForLine += 2;
                continue;
            case 4:
                printf(",,");
                count += 2;
                countForLine += 2;
                continue;
            case 5:
                printf("^^");
                count += 2;
                countForLine += 2;
                continue;
            case 6:
                printf("{{");
                count += 2;
                countForLine += 2;
                continue;
            case 7:
                printf("}}");
                count += 2;
                countForLine += 2;
                continue;
            case 8:
                printf("[[");
                count += 2;
                countForLine += 2;
                continue;
            case 9:
                printf("]]");
                count += 2;
                countForLine += 2;
                continue;
            case 10:
                printf("http://");
                count += 7;
                countForLine += 7;
                continue;
        }
        
        // random character
        for (;;)
        {
            c = rnd();
            if (!ascii || c >= 32 && c < 127)
            {
                printf("%c", c);
                count++;
                countForLine++;
                break;
            }
        }
    }
    
    return 0;
}