plan9port

commit 38847929a349c9fe0613c5053213f5b17e9d4d0b
parent 6c013fecdf5b447b4a09069674f60ebca9235f55
Author: ssnf <ssnf@ssnf.xyz>
Date:   Fri,  1 Aug 2025 05:03:55 +0000

libstr: fix bugs and update documentation

Diffstat:
M
man/man3/str.3
 | 
17
++++++++++++++---
M
src/libstr/Stradds.c
 | 
2
++
M
src/libstr/Strgetf.c
 | 
1
+
M
src/libstr/Strgets.c
 | 
10
+++++-----
M
src/libstr/Strinit.c
 | 
3
++-
M
src/libstr/Strprint.c
 | 
12
+++++++-----

6 files changed, 31 insertions(+), 14 deletions(-)
diff --git a/man/man3/str.3 b/man/man3/str.3
@@ -127,6 +127,11 @@ which must be initialized.
 Any existing content in
 .I p
 is replaced.
+The behavior is undefined if
+.I p
+and
+.I s
+refer to the same string.
 .PP
 .I Straddc
 appends character
@@ -152,6 +157,11 @@ at position
 Characters after position
 .I p
 are shifted to make room.
+The behavior is undefined if
+.I s
+and
+.I t
+refer to the same string.
 .PP
 .I Strdelete
 deletes characters from position
@@ -195,8 +205,9 @@ reads a line from
 .I b
 into string
 .IR s .
-The newline character is included if present.
-It returns 1 on success, 0 on end of file, and -1 on error.
+The newline character is removed if present.
+It returns the number of characters read (excluding any newline),
+or 0 on end of file.
 .PP
 .I Strtok
 tokenizes string
@@ -212,7 +223,7 @@ is set to point to the remaining string.
 .I Strzero
 empties string
 .I s
-but retains its allocated space.
+and may shrink strings larger than the initial allocation size.
 .PP
 .I Strclose
 frees the memory used by string
diff --git a/src/libstr/Stradds.c b/src/libstr/Stradds.c
@@ -22,6 +22,8 @@ Strinsure(String *p, ulong n)
 {
 	ulong size;
 
+	if (!p->size)
+		sysfatal("Strinsure: read-only");
 	assert(p->s && p->size);
 	for (size = p->size; n >= size; size *= 2);
 	if (size != p->size) {
diff --git a/src/libstr/Strgetf.c b/src/libstr/Strgetf.c
@@ -5,6 +5,7 @@ Strgetf(String *p, int fd)
 {
 	ulong n;
 
+	Strzero(p);
 	do {
 		n = read(fd, p->s + p->n, p->size - p->n);
 		p->n += n;
diff --git a/src/libstr/Strgets.c b/src/libstr/Strgets.c
@@ -7,12 +7,12 @@ Strgets(String *p, Biobuf *b)
 	ulong n;
 
 	Strzero(p);
-	s = Brdline(b, '\n');
+	s = Brdstr(b, '\n', '\n');
+	if (!s)
+		return 0;
 	n = Blinelen(b);
-	if (n && s[n - 1] == '\n')
-		--n;
-	if (n)
-		Stradds(p, Strn(s, n));
+	Stradds(p, Strn(s, n));
+	free(s);
 	return n;
 }
 
diff --git a/src/libstr/Strinit.c b/src/libstr/Strinit.c
@@ -11,6 +11,7 @@ void
 Strclose(String *s)
 {
 	free(s->s);
+	s->s = nil;
 	s->n = 0;
 	s->size = 0;
 }
@@ -30,7 +31,7 @@ Strinit(String *p)
 String
 Str(char *s)
 {
-	return !s ? Strn(NULL, 0) : Strn(s, strlen(s));
+	return !s ? Strn(nil, 0) : Strn(s, strlen(s));
 }
 
 String
diff --git a/src/libstr/Strprint.c b/src/libstr/Strprint.c
@@ -4,12 +4,14 @@ int
 Strprint(String *s, char *fmt, ...)
 {
 	va_list ap;
+	char *t;
+	ulong n;
 
-	if (s->s)
-		free(s->s);
 	va_start(ap, fmt);
-	s->s = vsmprint(fmt, ap);
+	t = vsmprint(fmt, ap);
 	va_end(ap);
-	s->n = strlen(s->s);
-	return s->n;
+	n = strlen(t);
+	Stradds(s, Strn(t, n));
+	free(t);
+	return n;
 }