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#include "../command.h"
static long cast_long(const char* arg) {
char* end;
long l = strtol(arg, &end, 10);
if (end == arg) {
return 0;
} else {
return l;
}
}
static double cast_double(const char* arg) {
char* end;
double d = strtod(arg, &end);
if (end == arg) {
return 0.0;
} else {
return d;
}
}
#define NUMBER(name, type, arg) \
long l = cast_long(arg); \
type* t = (type*) &l; \
type name = *t;
static void handle_percent(char n, const char* arg) {
switch (n) {
case 'd':
case 'z': {
NUMBER(i, int, arg)
printf("%d", i);
break;
}
case 'u': {
NUMBER(u, unsigned int, arg);
printf("%u", u);
break;
}
case 'f': {
double d = cast_double(arg);
printf("%lf", d);
break;
}
case 'c': {
putchar(arg[0]);
break;
}
case 's': {
printf("%s", arg);
break;
}
default: {
putchar('%');
putchar(n);
}
}
}
static void handle_slash(char n) {
switch (n) {
case 'n':
putchar('\n');
break;
case 't':
putchar('\t');
break;
case 'v':
putchar('\v');
break;
case 'b':
putchar('\b');
break;
default:
putchar('\\');
putchar(n);
}
}
static void help() {
printf("Usage printf FORMAT [ARG]...\n\n");
printf("Format and print ARG(s) according to FORMAT (a-la C prinf)\n");
exit(EXIT_SUCCESS);
}
COMMAND(print) {
if (argc < 1) {
error("usage: printf FORMAT [ARG]...\n");
}
if (streql("--help", argv[0])) help();
size_t index = 0;
int arg_index = 0;
while (true) {
char c = argv[0][index];
index++;
if (c == '\0') break;
if (c != '%' && c != '\\') {
putchar(c);
continue;
}
char n = argv[0][index];
index++;
char* arg = NULL;
if (arg_index < argc) {
arg = argv[arg_index + 1];
}
if (c == '%') {
handle_percent(n, arg);
} else {
handle_slash(n);
}
arg_index++;
}
return EXIT_SUCCESS;
}
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