打印一段utf-8字符

print_utf8_range.c

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

void write_value(char *c, int value, int head, int tail, int len)
{
    int high = value >> 8;
    int low = (1 << 8) - 1 & value;
    if (len == 1) {
        c[0] = low | head;
    }
    else if(len == 2) {
        c[0] = head | ((high & 7) << 2) | (low >> 6);
        c[1] = tail | ((1 << 6) - 1 & low);
    }
    else if(len == 3) {
        c[0] = head | (high >> 4);
        c[1] = tail | ((high & 15) << 2) | (low >> 6);
        c[2] = tail | ((1 << 6) - 1 & low);
    }
    printf("unicode=%#x, char:%.*s\n", value, len, c);
}

void print_char(char *c, int start, int end)
{
    if (start > end) {
        int tmp = start;
        start = end;
        end = tmp;
    }

    int head, tail, len;

    int value = 0;
    int i = 0;
    for(; i < end - start; i++) {
        value = start + i;
        if (value > 0 && value <= 0x7f) {
            head = tail = 0;
            len = 1;
        }
        else if (value >= 0x80 && value <= 0x7ff) {
            head = 0xc0;
            tail = 0x80;
            len = 2;
        }
        else if (value >= 0x800 && value <= 0xffff) {
            head = 0xe0;
            tail = 0x80;
            len = 3;
        }
        write_value(c + i * len, value, head, tail, len);
    }
}

int main(void)
{
    char c[10000];
    print_char(c, 15000, 15200);

    return 0;
}