add osmo_escape_cstr and osmo_quote_cstr

Provide string escaping that
- returns the required buffer size, so it can be used with OSMO_STRBUF_APPEND().
- uses C compatible string constant escaping sequences.

This is intended as a replacement for all previous osmo_escape_str* and
osmo_quote_str* API. It pains me that I didn't get them right the first nor the
second time:
- The buffer functions do not return the chars needed, which is required for
  allocating sufficient memory in the *_c versions of the functions.
- Because of that, these functions are accurately usable for
  OSMO_STRBUF_APPEND(), producing truncated strings, for example when dumping a
  GSUP message.
- They do not use the C equivalent string constant escaping: for some reason I
  thought "\15" would be valid, but it should be "\x0f".
If I could, I would completely drop those mislead implementations ... but
backwards compat prohibits that.

A previous patch already provided internal static functions that accurately
return the required buffer size. Enhance these to also support C compatible
string escaping, and use them as implementation of the new functions:

osmo_escape_cstr_buf()
osmo_escape_cstr_c()
osmo_quote_cstr_buf()
osmo_quote_cstr_c()

In the tests for these, also test C string equivalence.

Naming: from API versions, it would be kind of logical to call them
osmo_escape_str_buf3() and osmo_escape_str_c2(). Since these anyway return a
different escaping, it makes sense to me to have distinct names instead.

Quasi missing are variants of the non-C-compatible weird legacy escaping that
return the required buffer size, but I refrain from adding those, because we
have enough API cruft as it is. Just always use these new cstr variants.

Change-Id: I3dfb892036e01000033dd8e7e4a6a0c32a3caa9b

1 files changed, 74 insertions, 2 deletions

diff --git a/tests/utils/utils_test.ok b/tests/utils/utils_test.ok
index 89e0fed4..baa708ee 100644
--- a/tests/utils/utils_test.ok
+++ b/tests/utils/utils_test.ok
@@ -206,7 +206,7 @@ Testing bcd to string conversion
   bcd2str(NULL, ...) -> -12
   bcd2str(dst, 0, ...) -> -12
 
-Testing string escaping
+Testing string escaping: osmo_escape_str()
 - all chars from 0 to 255 in batches of 16:
 "\0\1\2\3\4\5\6\a\b\t\n\v\f\r\14\15"
 "\16\17\18\19\20\21\22\23\24\25\26\27\28\29\30\31"
@@ -233,7 +233,7 @@ passed through unchanged "printable"
 - truncation when too long:
 "\axxxxxxE"
 
-Testing string quoting
+Testing string quoting: osmo_quote_str()
 - all chars from 0 to 255 in batches of 16:
 '"\0\1\2\3\4\5\6\a\b\t\n\v\f\r\14\15"'
 '"\16\17\18\19\20\21\22\23\24\25\26\27\28\29\30\31"'
@@ -266,6 +266,78 @@ NOT passed through. '"printable"'
 - NULL string becomes a "NULL" literal:
 'NULL'
 
+Testing string escaping: osmo_escape_cstr_buf()
+- all chars from 0 to 255 in batches of 16:
+"\0\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f"
+"\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f"
+" !\"#$%&'()*+,-./"
+"0123456789:;<=>?"
+"@ABCDEFGHIJKLMNO"
+"PQRSTUVWXYZ[\\]^_"
+"`abcdefghijklmno"
+"pqrstuvwxyz{|}~\x7f"
+"\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f"
+"\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f"
+"\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab\xac\xad\xae\xaf"
+"\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe\xbf"
+"\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf"
+"\xd0\xd1\xd2\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xdb\xdc\xdd\xde\xdf"
+"\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef"
+"\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff"
+- nul terminated:
+"termi\nated"
+- passthru:
+passed through unchanged "printable"
+- zero length:
+""
+- truncation when too long:
+"\x07xxxxx"
+- Test escaping an escaped string:
+0: '\x02\x03\n'
+1: '\\x02\\x03\\n'
+2: '\\\\x02\\\\x03\\\\n'
+3: '\\\\\\\\x02\\\\\\\\x03\\\\\\\\n'
+
+Testing string quoting: osmo_quote_cstr_buf()
+- all chars from 0 to 255 in batches of 16:
+"\0\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f"
+"\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f"
+" !\"#$%&'()*+,-./"
+"0123456789:;<=>?"
+"@ABCDEFGHIJKLMNO"
+"PQRSTUVWXYZ[\\]^_"
+"`abcdefghijklmno"
+"pqrstuvwxyz{|}~\x7f"
+"\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f"
+"\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f"
+"\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab\xac\xad\xae\xaf"
+"\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe\xbf"
+"\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf"
+"\xd0\xd1\xd2\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xdb\xdc\xdd\xde\xdf"
+"\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef"
+"\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff"
+- nul terminated:
+'"termi\nated"'
+- never passthru:
+NOT passed through. '"printable"'
+- zero length:
+'""'
+- truncation when too long:
+'"\x07xxxx'
+- always truncation, even when no escaping needed:
+'"xxxxxxxE'
+- try to feed too little buf for quoting:
+'"'
+- Test quoting a quoted+escaped string:
+0: "\x02\x03\n"
+1: "\"\\x02\\x03\\n\""
+2: "\"\\\"\\\\x02\\\\x03\\\\n\\\"\""
+3: "\"\\\"\\\\\\\"\\\\\\\\x02\\\\\\\\x03\\\\\\\\n\\\\\\\"\\\"\""
+- Test C-string equivalence:
+strcmp(OSMO_STRINGIFY_VAL(TEST_STR), osmo_quote_cstr_c(ctx, TEST_STR, 256)) == 0
+strcmp(OSMO_STRINGIFY_VAL(EMPTY_STR), osmo_quote_cstr_c(ctx, EMPTY_STR, -1)) == 0
+strcmp("NULL", osmo_quote_cstr_c(ctx, NULL, -1)) == 0
+
 Testing integer square-root
 
 osmo_sockaddr_to_str_and_uint_test