initial commit <3

Makefile

@@ -0,0 +1,5 @@
+all: main.c strtoui.h
+	gcc -Wall main.c strtoui.h -o chars -lsodium
+
+clean:
+	rm chars main.o

main.c

@@ -0,0 +1,44 @@
+#include "stdio.h"
+#include "stdlib.h"
+#include "limits.h"
+#include "sodium.h"
+#include "strtoui.h"
+
+int map(int i, int i_min, int i_max, int o_min, int o_max) {
+    double r = (double)(o_max - o_min) / (double)(i_max - i_min);
+    int j = (double) (i - i_min) * r + o_min;
+    return j;
+}
+
+int main(int argc, char *argv[]) {
+    if(argc == 1) {
+        puts("Usage: chars [length]");
+        puts("       Max length is 1024");
+        exit(EXIT_SUCCESS);
+    }
+
+    unsigned int len;
+    enum strtoui_error error = strtoui(&len, argv[1], 10);
+    if(error != STRTOUI_SUCCESS){
+        fputs("Bad input\n", stderr);
+        exit(EXIT_FAILURE);
+    }else if (len > 1024) {
+        fputs("The length is to big\n", stderr);
+        exit(EXIT_FAILURE);
+    }
+
+    char lower_range = 0x20;
+    char upper_range= 0x7e;
+
+    char data[len];
+    randombytes_buf(data, sizeof len);
+
+    for(int i = 0; i < len; i++) {
+        int random = randombytes_uniform(upper_range);
+        data[i] = map(random, 0, upper_range, lower_range, upper_range);
+        printf("%c", data[i]);
+    }
+    printf("\n");
+
+    exit(EXIT_SUCCESS);
+}

strtoui.h

@@ -0,0 +1,31 @@
+#ifndef STRTOUI_H
+#define STRTOUI_H
+
+#include "stdlib.h"
+#include "ctype.h"
+#include "limits.h"
+#include "errno.h"
+
+enum strtoui_error{
+    STRTOUI_SUCCESS,
+    STRTOUI_OVERFLOW,
+    STRTOUI_UNDERFLOW,
+    STRTOUI_INCONVERTIBLE
+};
+
+enum strtoui_error strtoui(unsigned int *out, char *s, int base) {
+    char *end;
+    if(s[0] == '\0' || isspace(s[0]))
+        return STRTOUI_INCONVERTIBLE;
+    long l =  strtol(s, &end, base);
+    if(l > INT_MAX || (errno == ERANGE && l == LONG_MAX))
+        return STRTOUI_OVERFLOW;
+    if(l < 0|| (errno == ERANGE && l == LONG_MIN))
+        return STRTOUI_UNDERFLOW;
+    if(*end != '\0')
+        return STRTOUI_INCONVERTIBLE;
+    *out = l;
+    return STRTOUI_SUCCESS;
+}
+
+#endif