(mynewt-core) 05/07: libc/baselibc: Fix sscanf character set conversion

[ja...@apache.org]

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sjanc pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/mynewt-core.git

commit 880fe222c6a64864e4235d8014a9202f00dba825
Author: Szymon Janc <sz...@codecoup.pl>
AuthorDate: Sun Oct 25 23:23:27 2026 +0100

    libc/baselibc: Fix sscanf character set conversion
    
    Field width was ignored for %[ conversion, so all matching input
    characters were stored regardless of buffer size given by width.
    Ranges in character set, e.g. %[a-z], started at '-' instead of the
    character preceding it and did not include the last character.
    
    Assisted-by: Claude:claude-opus-5-5
---
 libc/baselibc/src/vsscanf.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/libc/baselibc/src/vsscanf.c b/libc/baselibc/src/vsscanf.c
index ddd3d7e91..bc631fb57 100644
--- a/libc/baselibc/src/vsscanf.c
+++ b/libc/baselibc/src/vsscanf.c
@@ -343,6 +343,7 @@ int vsscanf(const char *buffer, const char *format, va_list ap)
 				matchinv = 1;
 			} else {
 				set_bit(matchmap, (unsigned char)ch);
+				range_start = (unsigned char)ch;
 				state = st_match;
 			}
 			break;
@@ -351,10 +352,11 @@ int vsscanf(const char *buffer, const char *format, va_list ap)
 			if (ch == ']') {
 				goto match_run;
 			} else if (ch == '-') {
-				range_start = (unsigned char)ch;
+				/* range_start holds previous character */
 				state = st_match_range;
 			} else {
 				set_bit(matchmap, (unsigned char)ch);
+				range_start = (unsigned char)ch;
 			}
 			break;
 
@@ -365,9 +367,10 @@ int vsscanf(const char *buffer, const char *format, va_list ap)
 				goto match_run;
 			} else {
 				int i;
-				for (i = range_start; i < (unsigned char)ch;
+				for (i = range_start; i <= (unsigned char)ch;
 				     i++)
 					set_bit(matchmap, i);
+				range_start = (unsigned char)ch;
 				state = st_match;
 			}
 			break;
@@ -380,6 +383,7 @@ int vsscanf(const char *buffer, const char *format, va_list ap)
 				if (sarg)
 					*sarg++ = uc;
 				q++;
+				width--;
 			}
 			if (q != qq && sarg) {
 				*sarg = '\0';