Self-compiling C implementation of Spark https://git.zx2c4.com/spark/tree/spark.c https://zachholman.com/spark/

spark.c.sh

#!/usr/bin/env bash
#if 0
# Original spark: https://zachholman.com/spark/
# C implementation (reproduced below): https://git.zx2c4.com/spark/tree/spark.c
# The first time this file is executed it will compile itself.
echo -n "Compiling for the first time... "
BAK=/tmp/$(basename $0).bak
cp $0 $BAK
sed '1s;^;//;' $0 | gcc -o $0 -xc - -lm
echo "Done. Original code backed up at $BAK."
$0 $@
exit

cat <<//C_SRC >/dev/null
#endif
#define _POSIX_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <float.h>
#include <string.h>
#include <unistd.h>

int main(int argc, char* argv[]) {
    if (isatty(fileno(stdin)) &&
        (argc < 2 || !strcmp(argv[1], "-h") || !strcmp(argv[1], "--help"))) {
        fprintf(stderr, "Spark\n  by Jason A. Donenfeld <[email protected]>\n\n");
        fprintf(stderr, "Usage: %s [number] [number] [number] ...\n", argv[0]);
        fprintf(stderr,
                "If no arguments are given, read from stdin numbers delimited "
                "by\n");
        fprintf(stderr, "any characters except 0 1 2 3 4 5 6 7 8 9 . - e E.\n");
        return 1;
    }
    if(argc >= 2 && (strcmp(argv[1], "-w") || strcmp(argv[1], "--where"))) {
        fprintf(stderr, "Self-compiling source can be found at https://gist.github.com/armarti/dd1dd8b63ee701c4c7147282157cc79e\n");
        return 1;
    }
    double* values;
    int total;
    double max = DBL_MIN;
    double min = DBL_MAX;
    if (argc > 1) {
        total = argc - 1;
        values = malloc(sizeof(double) * total);
        if (!values) {
            perror("malloc");
            return 2;
        }
        for (int i = 0; i < total; ++i) {
            values[i] = atof(argv[i + 1]);
            if (values[i] > max)
                max = values[i];
            if (values[i] < min)
                min = values[i];
        }
    } else {
        char buffer[32];
        int i = 0;
        int c = 0;
        int size = 16;
        total = 0;
        values = malloc(sizeof(double) * size);
        if (!values) {
            perror("malloc");
            return 2;
        }
        while (c != EOF) {
            for (;;) {
                c = getchar();
                if ((c >= '0' && c <= '9') || c == '.' || c == '-' ||
                    c == 'e' || c == 'E')
                    buffer[i++] = c;
                else
                    break;
                if (i == 31)
                    break;
            }
            buffer[i] = '\0';
            if (i) {
                if (total == size) {
                    size *= 2;
                    values = realloc(values, sizeof(double) * size);
                    if (!values) {
                        perror("realloc");
                        return 2;
                    }
                }
                values[total] = atof(buffer);
                if (values[total] > max)
                    max = values[total];
                if (values[total] < min)
                    min = values[total];
                ++total;
            }
            i = 0;
        }
    }

    double difference = max - min + 1;
    if (difference < 1)
        difference = 1;
    const int levels = 8;
    for (int i = 0; i < total; ++i) {
        putchar('\xe2');
        putchar('\x96');
        putchar('\x81' +
                (int)round((values[i] - min + 1) / difference * (levels - 1)));
    }
    putchar('\n');

    free(values);
    return 0;
}
//C_SRC