# HG changeset patch
# User Mychaela Falconia <falcon@freecalypso.org>
# Date 1616630648 0
# Node ID c5e7c9e1d857ba8deb448445e37b528c9153cc8a
# Parent  1b905e730abdfd1d2b37e768a09d6c4b8f1c0cdc
GSM7 to qstring decoding: rework in a new way, emit \E for Euro

diff -r 1b905e730abd -r c5e7c9e1d857 libutil/gsm7_decode.c
--- a/libutil/gsm7_decode.c	Wed Mar 24 23:30:14 2021 +0000
+++ b/libutil/gsm7_decode.c	Thu Mar 25 00:04:08 2021 +0000
@@ -1,39 +1,41 @@
 /*
- * This module contains functions for decoding GSM7 strings
- * that exist in various SIM files.
+ * This module implements a function for decoding GSM7 strings
+ * to ASCII with output to a stdio file; it is an implementation
+ * of lossless conversion per our SIM-data-formats spec
+ * in freecalypso-docs.
  */
 
 #include <sys/types.h>
 #include <stdio.h>
 
-static char gsm7_decode_table[128] = {
-	'@', 0,   '$',  0,   0,   0,    0,   0,
-	0,   0,   '\n', 0,   0,   '\r', 0,   0,
-	0,   '_', 0,    0,   0,   0,    0,   0,
-	0,   0,   0,    0,   0,   0,    0,   0,
-	' ', '!', '"',  '#', 0,   '%',  '&', 0x27,
-	'(', ')', '*',  '+', ',', '-',  '.', '/',
-	'0', '1', '2',  '3', '4', '5',  '6', '7',
-	'8', '9', ':',  ';', '<', '=',  '>', '?',
-	0,   'A', 'B',  'C', 'D', 'E',  'F', 'G',
-	'H', 'I', 'J',  'K', 'L', 'M',  'N', 'O',
-	'P', 'Q', 'R',  'S', 'T', 'U',  'V', 'W',
-	'X', 'Y', 'Z',  0,   0,   0,    0,   0,
-	0,   'a', 'b',  'c', 'd', 'e',  'f', 'g',
-	'h', 'i', 'j',  'k', 'l', 'm',  'n', 'o',
-	'p', 'q', 'r',  's', 't', 'u',  'v', 'w',
-	'x', 'y', 'z',  0,   0,   0,    0,   0
+static char basic_table[128] = {
+	'@', 0,   '$',      0,   0,   0,        0,   0,
+	0,   0,   'n'|0x80, 0,   0,   'r'|0x80, 0,   0,
+	0,   '_', 0,        0,   0,   0,        0,   0,
+	0,   0,   0,        0,   0,   0,        0,   0,
+	' ', '!', '"'|0x80, '#', 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 char escape_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,   '\\'|0x80,
+	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,'E'|0x80,0, 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
 };
 
 void
@@ -58,30 +60,22 @@
 				continue;
 			}
 			b = *dp++;
-			c = gsm7ext_decode_table[b];
+			c = escape_table[b];
 			if (!c) {
 				fprintf(outf, "\\e\\%02X", b);
 				continue;
 			}
 		} else {
-			c = gsm7_decode_table[b];
+			c = basic_table[b];
 			if (!c) {
 				fprintf(outf, "\\%02X", b);
 				continue;
 			}
 		}
-		if (c == '\n') {
+		if (c & 0x80) {
 			putc('\\', outf);
-			putc('n', outf);
-			continue;
+			c &= 0x7F;
 		}
-		if (c == '\r') {
-			putc('\\', outf);
-			putc('r', outf);
-			continue;
-		}
-		if (c == '"' || c == '\\')
-			putc('\\', outf);
 		putc(c, outf);
 	}
 	putc('"', outf);