lorem ipsum generator in C

lorem_ipsum_generator.c

#include <assert.h>
#include <ctype.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

typedef struct {
    char* text;
    int32_t count; // at least 1KB
    int32_t min_paragraphs; // at least 1
    int32_t max_paragraphs;
    int32_t min_sentences; // at least 1
    int32_t max_sentences;
    int32_t min_words; // at least 2
    int32_t max_words;
} lorem_ipsum_generator_params_t;

#define countof(array) (sizeof(array) / sizeof(array[0]))

static void lorem_ipsum_generator(lorem_ipsum_generator_params_t p) {
    assert(p.count >= 1024); // at least 1KB expected
    assert(0 < p.min_paragraphs && p.min_paragraphs <= p.max_paragraphs);
    assert(0 < p.min_sentences && p.min_sentences <= p.max_sentences);
    assert(2 < p.min_words && p.min_words <= p.max_words);
    static const char* words[] = { "lorem", "ipsum", "dolor", "sit", "amet",
        "consectetur", "adipiscing", "elit", "quisque", "faucibus", "ex", "sapien",
        "vitae", "pellentesque", "sem", "placerat", "in", "id", "cursus", "mi",
        "pretium", "tellus", "duis", "convallis", "tempus", "leo", "eu", "aenean",
        "sed", "diam", "urna", "tempor", "pulvinar", "vivamus", "fringilla", "lacus",
        "nec", "metus", "bibendum", "egestas", "iaculis", "massa", "nisl",
        "malesuada", "lacinia", "integer", "nunc", "posuere", "ut", "hendrerit",
        "semper", "vel", "class", "aptent", "taciti", "sociosqu", "ad", "litora",
        "torquent", "per", "conubia", "nostra", "inceptos", "himenaeos", "orci",
        "varius", "natoque", "penatibus", "et", "magnis", "dis", "parturient",
        "montes", "nascetur", "ridiculus", "mus", "donec", "rhoncus", "eros",
        "lobortis", "nulla", "molestie", "mattis", "scelerisque", "maximus", "eget",
        "fermentum", "odio", "phasellus", "non", "purus", "est", "efficitur",
        "laoreet", "mauris", "pharetra", "vestibulum", "fusce", "dictum", "risus",
        "blandit", "quis", "suspendisse", "aliquet", "nisi", "sodales", "consequat",
        "magna", "ante", "condimentum", "neque", "at", "luctus", "nibh", "finibus",
        "facilisis", "dapibus", "etiam", "interdum", "tortor", "ligula", "congue",
        "sollicitudin", "erat", "viverra", "ac", "tincidunt", "nam", "porta",
        "elementum", "a", "enim", "euismod", "quam", "justo", "lectus", "commodo",
        "augue", "arcu", "dignissim", "velit", "aliquam", "imperdiet", "mollis",
        "nullam", "volutpat", "porttitor", "ullamcorper", "rutrum", "gravida",
        "cras", "eleifend", "turpis", "fames", "primis", "vulputate", "ornare",
        "sagittis", "vehicula", "praesent", "dui", "felis", "venenatis", "ultrices",
        "proin", "libero", "feugiat", "tristique", "accumsan", "maecenas", "potenti",
        "ultricies", "habitant", "morbi", "senectus", "netus", "suscipit", "auctor",
        "curabitur", "facilisi", "cubilia", "curae", "hac", "habitasse", "platea",
        "dictumst"
    };
    char* s = p.text;
    char* end = p.text + p.count - 64;
    uint32_t paragraphs = p.min_paragraphs +
        (p.min_paragraphs == p.max_paragraphs ? 0 :
         random() % (p.max_paragraphs - p.min_paragraphs + 1));
    while (paragraphs > 0 && s < end) {
        uint32_t sentences_in_paragraph = p.min_sentences +
            (p.min_sentences == p.max_sentences ? 0 :
             random() % (p.max_sentences - p.min_sentences + 1));
        while (sentences_in_paragraph > 0 && s < end) {
            const uint32_t words_in_sentence = p.min_words +
                (p.min_words == p.max_words ? 0 :
                 random() % (p.max_words - p.min_words + 1));
            for (uint32_t i = 0; i < words_in_sentence && s < end; i++) {
                const char* word = words[random() % countof(words)];
                memcpy(s, word, strlen(word));
                if (i == 0) { *s = (char)toupper(*s); }
                s += strlen(word);
                if (i < words_in_sentence - 1 && s < end) {
                    const char* delimiter = "\x20";
                    int32_t punctuation = random() % 128;
                    switch (punctuation) {
                        case 0:
                        case 1:
                        case 2: delimiter = ", "; break;
                        case 3:
                        case 4: delimiter = "; "; break;
                        case 6: delimiter = ": "; break;
                        case 7: delimiter = " - "; break;
                        default: break;
                    }
                    memcpy(s, delimiter, strlen(delimiter));
                    s += strlen(delimiter);
                }
            }
            if (sentences_in_paragraph > 1 && s < end) {
                memcpy(s, ".\x20", 2);
                s += 2;
            } else {
                *s++ = '.';
            }
            sentences_in_paragraph--;
        }
        if (paragraphs > 1 && s < end) {
            *s++ = '\n';
        }
        paragraphs--;
    }
    *s = 0;
}

int main() {
    static char text[64 * 1024];
    lorem_ipsum_generator_params_t p = {
        .text = text,
        .count = countof(text),
        .min_paragraphs = 4,
        .max_paragraphs = 15,
        .min_sentences  = 4,
        .max_sentences  = 20,
        .min_words      = 8,
        .max_words      = 16
    };
    srandom(time(NULL));
    lorem_ipsum_generator(p);
    printf("%s\n", p.text);
    return 0;
}