/* printf.c - Format and Print the data. * * Copyright 2014 Sandeep Sharma <sandeep.jack2756@gmail.com> * Copyright 2014 Kyungwan Han <asura321@gmail.com> * * See http://pubs.opengroup.org/onlinepubs/9699919799/utilities/printf.html * * todo: *m$ ala printf("%1$d:%2$.*3$d:%4$.*3$d\n", hour, min, precision, sec); USE_PRINTF(NEWTOY(printf, "<1?^", TOYFLAG_USR|TOYFLAG_BIN)) config PRINTF bool "printf" default y help usage: printf FORMAT [ARGUMENT...] Format and print ARGUMENT(s) according to FORMAT, using C printf syntax (% escapes for cdeEfgGiosuxX, \ escapes for abefnrtv0 or \OCTAL or \xHEX). */ #define FOR_printf #include "toys.h" // Detect matching character (return true/false) and advance pointer if match. static int eat(char **s, char c) { int x = (**s == c); if (x) ++*s; return x; } // Parse escape sequences. static int handle_slash(char **esc_val, int posix) { char *ptr = *esc_val; int len, base = 0; unsigned result = 0, num; if (*ptr == 'c') xexit(); // 0x12 hex escapes have 1-2 digits, \123 octal escapes have 1-3 digits. if (eat(&ptr, 'x')) base = 16; else { if (posix && *ptr=='0') ptr++; if (*ptr >= '0' && *ptr <= '7') base = 8; } len = (char []){0,3,2}[base/8]; // Not a hex or octal escape? (This catches trailing \) if (!len) { if (!(result = unescape(*ptr))) result = '\\'; else ++*esc_val; return result; } while (len) { num = tolower(*ptr) - '0'; if (num >= 'a'-'0') num += '0'-'a'+10; if (num >= base) { // Don't parse invalid hex value ala "\xvd", print it verbatim if (base == 16 && len == 2) { ptr--; result = '\\'; } break; } result = (result*base)+num; ptr++; len--; } *esc_val = ptr; return result; } void printf_main(void) { char **arg = toys.optargs+1; // Repeat format until arguments consumed for (;;) { int seen = 0; char *f = *toys.optargs; // Loop through characters in format while (*f) { if (eat(&f, '\\')) putchar(handle_slash(&f, 0)); else if (!eat(&f, '%') || *f == '%') putchar(*f++); // Handle %escape else { char c, *end = 0, *aa, *to = toybuf; int wp[] = {0,-1}, i = 0; // Parse width.precision between % and type indicator. *to++ = '%'; while (strchr("-+# '0", *f) && (to-toybuf)<10) *to++ = *f++; for (;;) { if (eat(&f, '*')) { if (*arg) wp[i] = atolx(*arg++); } else while (*f >= '0' && *f <= '9') wp[i] = (wp[i]*10)+(*f++)-'0'; if (i++ || !eat(&f, '.')) break; wp[1] = 0; } c = *f++; seen = sprintf(to, "*.*%c", c);; errno = 0; aa = *arg ? *arg++ : ""; // Output %esc using parsed format string if (c == 'b') { while (*aa) putchar(eat(&aa, '\\') ? handle_slash(&aa, 1) : *aa++); continue; } else if (c == 'c') printf(toybuf, wp[0], wp[1], *aa); else if (c == 's') printf(toybuf, wp[0], wp[1], aa); else if (strchr("diouxX", c)) { long ll; if (*aa == '\'' || *aa == '"') ll = aa[1]; else ll = strtoll(aa, &end, 0); sprintf(to, "*.*ll%c", c); printf(toybuf, wp[0], wp[1], ll); } else if (strchr("feEgG", c)) { long double ld = strtold(aa, &end); sprintf(to, "*.*L%c", c); printf(toybuf, wp[0], wp[1], ld); } else error_exit("bad %%%c@%ld", c, (long)(f-*toys.optargs)); if (end && (errno || *end)) perror_msg("bad %%%c %s", c, aa); } } // Posix says to keep looping through format until we consume all args. // This only works if the format actually consumed at least one arg. if (!seen || !*arg) break; } }