commit 0e64de8ac00b13a58fd449a628ef521565f0fd90
parent 66bf45d4e933e7d6d91f612cc4bb560ca24a8692
Author: ssnf <ssnf@ssnf.xyz>
Date: Sun, 31 Aug 2025 21:00:13 +0000
use file descriptor instead of Biobuf in Strgets
Diffstat:
4 files changed, 39 insertions(+), 43 deletions(-)
diff --git a/include/str.h b/include/str.h
@@ -17,7 +17,7 @@ void Strdelc(String*);
void Strdelete(String*, Posn, Posn);
void Strdup(String*, String);
void Strgetf(String*, int);
-int Strgets(String*, Biobuf*);
+int Strgets(String*, int);
void Strinit(String*);
void Strinsert(String*, String, Posn);
void Strinsure(String*, ulong);
diff --git a/man/man3/str.3 b/man/man3/str.3
@@ -47,7 +47,7 @@ void Strdup(String *p, String s)
void Strgetf(String *s, int fd)
.PP
.B
-int Strgets(String *s, Biobuf *b)
+int Strgets(String *s, int fd)
.PP
.B
void Strinit(String *s)
@@ -70,28 +70,33 @@ void Strzero(String *s)
This library provides a dynamic string implementation that is
mutually exclusive with Plan 9's standard libString.
It offers a simpler, more lightweight alternative focused on ease of use.
+.PP
A
.B String
contains a pointer to the string data, its current length, and its allocated size.
+.PP
+When
+.I size
+is 0, the string cannot be shrunk or grown.
.SS "Comparison with libString"
This library differs from Plan 9's standard libString in several key ways:
-.IP \(bu
+.IP -
.B No locking:
libString includes locking mechanisms for thread safety, while this library omits them for simplicity.
-.IP \(bu
+.IP -
.B Stack allocation:
.I Str
and
.I Strn
create stack-allocated strings that reference existing data,
while libString requires heap allocation for all strings.
-.IP \(bu
+.IP -
.B Direct formatting:
.I Strprint
provides direct formatted output using
.IR vsmprint ,
while libString requires separate formatting steps.
-.IP \(bu
+.IP -
.B Simpler structure:
Uses a 3-field structure (s, n, size) compared to libString's
6-field structure with reference counting and locking.
@@ -101,22 +106,21 @@ Both libraries provide similar Biobuf integration for reading operations.
.I Str
creates a
.B String
-from a null-terminated C string.
-The resulting string references the original data and should not be modified.
+that references a null-terminated C string, with size set to 0.
.PP
.I Strn
creates a
.B String
-from the first
+that references
.I n
-characters of a C string.
-The resulting string references the original data and should not be modified.
+characters of a C string, with size set to 0.
+It does not modify the data to guarantee a valid C string, but libstr
+functions will respect the length it claims to have.
.PP
.I Strinit
initializes a
.B String
for use as a dynamic string.
-The string is initially empty but has space allocated for growth.
.PP
.I Strdup
copies string
@@ -138,14 +142,12 @@ appends character
.I c
to string
.IR p .
-The string grows automatically if necessary.
.PP
.I Stradds
appends string
.I s
to string
.IR p .
-The string grows automatically if necessary.
.PP
.I Strinsert
inserts string
@@ -154,9 +156,6 @@ into string
.I s
at position
.IR p .
-Characters after position
-.I p
-are shifted to make room.
The behavior is undefined if
.I s
and
@@ -183,7 +182,6 @@ ensures that string
has space for at least
.I n
characters.
-This can be used to preallocate space for better performance.
.PP
.I Strprint
appends formatted text to string
@@ -200,14 +198,13 @@ into string
Any existing content is replaced.
.PP
.I Strgets
-reads a line from
-.I Biobuf
-.I b
+reads a line from an open file descriptor
+.IR fd
into string
.IR s .
The newline character is removed if present.
-It returns the number of characters read (excluding any newline),
-or 0 on end of file.
+It returns the number of characters read, or 0 on end of file.
+Any existing content is replaced.
.PP
.I Strtok
tokenizes string
@@ -293,14 +290,7 @@ Strclose(&s);
Functions call
.I sysfatal
if memory allocation fails.
-.SH NOTES
-Strings created with
-.I Str
-and
-.I Strn
-reference the original data and should not be modified
-or passed to
-.IR Strclose .
-Use
-.I Strdup
-to create a modifiable copy.
+.PP
+Strinsure calls
+.I sysfatal
+when size is 0.
diff --git a/src/libstr/Strgets.c b/src/libstr/Strgets.c
@@ -1,18 +1,25 @@
#include "std.h"
+#include <bio.h>
+
int
-Strgets(String *p, Biobuf *b)
+Strgets(String *p, int fd)
{
- char *s;
+ Biobuf b;
ulong n;
+ char *s;
Strzero(p);
- s = Brdstr(b, '\n', '\n');
- if (!s)
- return 0;
- n = Blinelen(b);
- Stradds(p, Strn(s, n));
- free(s);
+ Binit(&b, fd, OREAD);
+ n = 0;
+ s = Brdstr(&b, '\n', 1);
+ if (s) {
+ free(p->s);
+ n = Blinelen(&b) + 1;
+ *p = Strn(s, n - 1);
+ p->size = n;
+ }
+ Bterm(&b);
return n;
}
diff --git a/src/libstr/std.h b/src/libstr/std.h
@@ -1,4 +1,3 @@
#include <u.h>
#include <libc.h>
-#include <bio.h>
#include <str.h>
