/*
 * This module contains functions for decoding and displaying alpha fields
 * that exist in various SIM files.
 */

#include <sys/types.h>
#include <string.h>
#include <strings.h>
#include <stdio.h>
#include <stdlib.h>

static char gsm7_decode_table[128] = {
	'@', 0,   '$',  0,   0,   0,    0,   0,
	0,   0,   '\n', 0,   0,   '\r', 0,   0,
	0,   '_', 0,    0,   0,   0,    0,   0,
	0,   0,   0,    0,   0,   0,    0,   0,
	' ', '!', '"',  '#', 0,   '%',  '&', 0x27,
	'(', ')', '*',  '+', ',', '-',  '.', '/',
	'0', '1', '2',  '3', '4', '5',  '6', '7',
	'8', '9', ':',  ';', '<', '=',  '>', '?',
	0,   'A', 'B',  'C', 'D', 'E',  'F', 'G',
	'H', 'I', 'J',  'K', 'L', 'M',  'N', 'O',
	'P', 'Q', 'R',  'S', 'T', 'U',  'V', 'W',
	'X', 'Y', 'Z',  0,   0,   0,    0,   0,
	0,   'a', 'b',  'c', 'd', 'e',  'f', 'g',
	'h', 'i', 'j',  'k', 'l', 'm',  'n', 'o',
	'p', 'q', 'r',  's', 't', 'u',  'v', 'w',
	'x', 'y', 'z',  0,   0,   0,    0,   0
};

static char gsm7ext_decode_table[128] = {
	0,   0, 0, 0, 0,   0, 0, 0, 0,   0,   0, 0, 0,   0,   0,   0,
	0,   0, 0, 0, '^', 0, 0, 0, 0,   0,   0, 0, 0,   0,   0,   0,
	0,   0, 0, 0, 0,   0, 0, 0, '{', '}', 0, 0, 0,   0,   0,   '\\',
	0,   0, 0, 0, 0,   0, 0, 0, 0,   0,   0, 0, '[', '~', ']', 0,
	'|', 0, 0, 0, 0,   0, 0, 0, 0,   0,   0, 0, 0,   0,   0,   0,
	0,   0, 0, 0, 0,   0, 0, 0, 0,   0,   0, 0, 0,   0,   0,   0,
	0,   0, 0, 0, 0,   0, 0, 0, 0,   0,   0, 0, 0,   0,   0,   0,
	0,   0, 0, 0, 0,   0, 0, 0, 0,   0,   0, 0, 0,   0,   0,   0
};

static
is_gsm7_string_ok(data, nbytes)
	u_char *data;
	unsigned nbytes;
{
	u_char *dp, *endp;
	int c;

	dp = data;
	endp = data + nbytes;
	while (dp < endp) {
		c = *dp++;
		if (c == 0x1B && dp < endp)
			c = gsm7ext_decode_table[*dp++];
		else
			c = gsm7_decode_table[c];
		if (!c)
			return(0);
	}
	return(1);
}

static void
print_alpha_field_gsmdecode(data, nbytes, outf)
	u_char *data;
	unsigned nbytes;
	FILE *outf;
{
	u_char *dp, *endp;
	int c;

	dp = data;
	endp = data + nbytes;
	putc('"', outf);
	while (dp < endp) {
		c = *dp++;
		if (c == 0x1B && dp < endp)
			c = gsm7ext_decode_table[*dp++];
		else
			c = gsm7_decode_table[c];
		if (c == '\n') {
			putc('\\', outf);
			putc('n', outf);
			continue;
		}
		if (c == '\r') {
			putc('\\', outf);
			putc('r', outf);
			continue;
		}
		if (c == '"' || c == '\\')
			putc('\\', outf);
		putc(c, outf);
	}
	putc('"', outf);
}

static void
print_alpha_field_hex(data, nbytes, outf)
	u_char *data;
	unsigned nbytes;
	FILE *outf;
{
	u_char *dp, *endp;

	fputs("HEX ", outf);
	dp = data;
	endp = data + nbytes;
	while (dp < endp)
		fprintf(outf, "%02X", *dp++);
}

void
print_alpha_field(data, nbytes, outf)
	u_char *data;
	unsigned nbytes;
	FILE *outf;
{
	if (!nbytes) {
		fputs("\"\"", outf);
		return;
	}
	if (data[0] & 0x80) {
		print_alpha_field_hex(data, nbytes, outf);
		return;
	}
	if (is_gsm7_string_ok(data, nbytes))
		print_alpha_field_gsmdecode(data, nbytes, outf);
	else
		print_alpha_field_hex(data, nbytes, outf);
}