1/* printf.c - Format and Print the data.
2 *
3 * Copyright 2014 Sandeep Sharma <sandeep.jack2756@gmail.com>
4 * Copyright 2014 Kyungwan Han <asura321@gmail.com>
5 *
6 * See http://pubs.opengroup.org/onlinepubs/9699919799/utilities/printf.html
7 *
8 * todo: *m$ ala printf("%1$d:%2$.*3$d:%4$.*3$d\n", hour, min, precision, sec);
9
10USE_PRINTF(NEWTOY(printf, "<1?^", TOYFLAG_USR|TOYFLAG_BIN))
11
12config PRINTF
13  bool "printf"
14  default y
15  help
16    usage: printf FORMAT [ARGUMENT...]
17
18    Format and print ARGUMENT(s) according to FORMAT, using C printf syntax
19    (% escapes for cdeEfgGiosuxX, \ escapes for abefnrtv0 or \OCTAL or \xHEX).
20*/
21
22#define FOR_printf
23#include "toys.h"
24
25// Detect matching character (return true/false) and advance pointer if match.
26static int eat(char **s, char c)
27{
28  int x = (**s == c);
29
30  if (x) ++*s;
31
32  return x;
33}
34
35// Parse escape sequences.
36static int handle_slash(char **esc_val, int posix)
37{
38  char *ptr = *esc_val;
39  int len, base = 0;
40  unsigned result = 0, num;
41
42  if (*ptr == 'c') xexit();
43
44  // 0x12 hex escapes have 1-2 digits, \123 octal escapes have 1-3 digits.
45  if (eat(&ptr, 'x')) base = 16;
46  else {
47    if (posix && *ptr=='0') ptr++;
48    if (*ptr >= '0' && *ptr <= '7') base = 8;
49  }
50  len = (char []){0,3,2}[base/8];
51
52  // Not a hex or octal escape? (This catches trailing \)
53  if (!len) {
54    if (!(result = unescape(*ptr))) result = '\\';
55    else ++*esc_val;
56
57    return result;
58  }
59
60  while (len) {
61    num = tolower(*ptr) - '0';
62    if (num >= 'a'-'0') num += '0'-'a'+10;
63    if (num >= base) {
64      // Don't parse invalid hex value ala "\xvd", print it verbatim
65      if (base == 16 && len == 2) {
66        ptr--;
67        result = '\\';
68      }
69      break;
70    }
71    result = (result*base)+num;
72    ptr++;
73    len--;
74  }
75  *esc_val = ptr;
76
77  return result;
78}
79
80void printf_main(void)
81{
82  char **arg = toys.optargs+1;
83
84  // Repeat format until arguments consumed
85  for (;;) {
86    int seen = 0;
87    char *f = *toys.optargs;
88
89    // Loop through characters in format
90    while (*f) {
91      if (eat(&f, '\\')) putchar(handle_slash(&f, 0));
92      else if (!eat(&f, '%') || *f == '%') putchar(*f++);
93
94      // Handle %escape
95      else {
96        char c, *end = 0, *aa, *to = toybuf;
97        int wp[] = {0,-1}, i = 0;
98
99        // Parse width.precision between % and type indicator.
100        *to++ = '%';
101        while (strchr("-+# '0", *f) && (to-toybuf)<10) *to++ = *f++;
102        for (;;) {
103          if (eat(&f, '*')) {
104            if (*arg) wp[i] = atolx(*arg++);
105          } else while (*f >= '0' && *f <= '9') wp[i] = (wp[i]*10)+(*f++)-'0';
106          if (i++ || !eat(&f, '.')) break;
107          wp[1] = 0;
108        }
109        c = *f++;
110        seen = sprintf(to, "*.*%c", c);;
111        errno = 0;
112        aa = *arg ? *arg++ : "";
113
114        // Output %esc using parsed format string
115        if (c == 'b') {
116          while (*aa) putchar(eat(&aa, '\\') ? handle_slash(&aa, 1) : *aa++);
117
118          continue;
119        } else if (c == 'c') printf(toybuf, wp[0], wp[1], *aa);
120        else if (c == 's') printf(toybuf, wp[0], wp[1], aa);
121        else if (strchr("diouxX", c)) {
122          long long ll;
123
124          if (*aa == '\'' || *aa == '"') ll = aa[1];
125          else ll = strtoll(aa, &end, 0);
126
127          sprintf(to, "*.*ll%c", c);
128          printf(toybuf, wp[0], wp[1], ll);
129        } else if (strchr("feEgG", c)) {
130          long double ld = strtold(aa, &end);
131
132          sprintf(to, "*.*L%c", c);
133          printf(toybuf, wp[0], wp[1], ld);
134        } else error_exit("bad %%%c@%ld", c, (long)(f-*toys.optargs));
135
136        if (end && (errno || *end)) perror_msg("bad %%%c %s", c, aa);
137      }
138    }
139
140    // Posix says to keep looping through format until we consume all args.
141    // This only works if the format actually consumed at least one arg.
142    if (!seen || !*arg) break;
143  }
144}
145