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Add strndup

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char* __fastcall__ strndup (const char* S, size_t maxlen);
This commit is contained in:
Colin Leroy-Mira
2025-07-03 23:43:23 +02:00
parent fcbc253bf9
commit 90e1ac374b
4 changed files with 148 additions and 0 deletions
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31
doc/funcref.sgml
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@@ -785,6 +785,7 @@ communication, see also <tt>testcode/lib/ser-test.c</tt>.
<item><ref id="strcpy" name="strcpy">
<item><ref id="strcspn" name="strcspn">
<item><ref id="strdup" name="strdup">
<item><ref id="strndup" name="strndup">
<item><ref id="strerror" name="strerror">
<item><ref id="stricmp" name="stricmp">
<item><ref id="strlen" name="strlen">
@@ -5621,6 +5622,7 @@ be used in presence of a prototype.
<ref id="free" name="free">,
<ref id="realloc" name="realloc">,
<ref id="strdup" name="strdup">
<ref id="strndup" name="strndup">
<tag/Example/None.
</descrip>
</quote>
@@ -7774,6 +7776,35 @@ be used in presence of a prototype.
<tag/See also/
<ref id="free" name="free">,
<ref id="malloc" name="malloc">
<ref id="strndup" name="strndup">
<tag/Example/None.
</descrip>
</quote>
<sect1>strndup<label id="strndup"><p>
<quote>
<descrip>
<tag/Function/Allocate a copy of a string on the heap, of a given maximum length.
<tag/Header/<tt/<ref id="string.h" name="string.h">/
<tag/Declaration/<tt/char* __fastcall__ strndup (const char* s, size_t maxlen);/
<tag/Description/<tt/strndup/ allocates a memory block on the heap, big enough
to hold a copy of <tt/s/ including the terminating zero. If the allocation
fails, <tt/NULL/ is returned, otherwise <tt/s/ is copied into the allocated
memory block, maxlen characters are kept, and a pointer to the block is returned.
<tag/Notes/<itemize>
<item>The function is only available as fastcall function, so it may only
be used in presence of a prototype.
<item>It is up to the caller to free the allocated memory block.
</itemize>
<tag/Availability/ISO 9899
<tag/See also/
<ref id="free" name="free">,
<ref id="malloc" name="malloc">
<ref id="strndup" name="strndup">
<tag/Example/None.
</descrip>
</quote>

1
include/string.h
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@@ -79,6 +79,7 @@ void* __fastcall__ __bzero (void* ptr, size_t n);
#if __CC65_STD__ == __CC65_STD_CC65__
void __fastcall__ bzero (void* ptr, size_t n); /* BSD */
char* __fastcall__ strdup (const char* s); /* SYSV/BSD */
char* __fastcall__ strndup (const char* s, size_t maxlen); /* SYSV/BSD */
int __fastcall__ stricmp (const char* s1, const char* s2); /* DOS/Windows */
int __fastcall__ strcasecmp (const char* s1, const char* s2); /* Same for Unix */
char* __fastcall__ strcasestr (const char* str, const char* substr);

56
libsrc/common/strndup.s Normal file
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@@ -0,0 +1,56 @@
;
; Colin Leroy-Mira, 03.07.2025
;
; char* __fastcall__ strndup (const char* S, size_t maxlen);
;
.importzp ptr4, c_sp
.import _strdup, _strlen, pushax, popax, _realloc
.export _strndup
_strndup:
sta maxlen ; Remember maxlen
stx maxlen+1
jsr popax ; Duplicate string
jsr _strdup
jsr pushax ; Remember result
jsr _strlen ; Check length,
cpx maxlen+1
bcc out ; Return directly if < maxlen
bne :+
cmp maxlen
bcc out
: ldy #$00 ; Otherwise, point to end of string,
lda maxlen
clc
adc (c_sp),y
sta ptr4
lda maxlen+1
iny
adc (c_sp),y
sta ptr4+1
dey ; Cut it short,
tya
sta (ptr4),y
ldx maxlen+1 ; And finally, realloc to maxlen+1
ldy maxlen
iny
tya
bne :+
inx
: jsr _realloc ; TOS still contains result
; We consider realloc will not fail,
; as the block shrinks.
jsr pushax ; push/pop for size optimisation
out:
jmp popax
.bss
maxlen: .res 2

60
test/val/lib_common_strndup.c Normal file
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@@ -0,0 +1,60 @@
#include <string.h>
#include "unittest.h"
#define SHORT_STR "abcdefghijklmnopqrstuvwxyz"
#define MID_STR_LEN 700 /* Two pages and something */
#define LONG_STR_LEN 40000UL /* Two long to duplicate */
TEST
{
char *dst;
char *src;
int i;
dst = strndup("", 0);
ASSERT_IsTrue(dst != NULL, "strndup returned NULL")
ASSERT_IsTrue(!strcmp(dst, ""), "strings differ");
free(dst);
for (i = 0; i < 30; i+=10) {
dst = strndup(SHORT_STR, i);
ASSERT_IsTrue(dst != NULL, "strndup returned NULL");
printf("strlen %s = %d (%d expected)\n", dst, strlen(dst), i);
ASSERT_IsTrue(strlen(dst) == i, "string lengths differ");
ASSERT_IsTrue(!strncmp(dst, SHORT_STR, i), "strings differ");
free(dst);
}
dst = strndup(SHORT_STR, 50);
ASSERT_IsTrue(dst != NULL, "strndup returned NULL");
printf("strlen %s = %d (%d expected)\n", dst, strlen(dst), i);
ASSERT_IsTrue(strlen(dst) == 26, "string lengths differ");
ASSERT_IsTrue(!strcmp(dst, SHORT_STR), "strings differ");
free(dst);
src = malloc(MID_STR_LEN+1);
ASSERT_IsTrue(src != NULL, "Could not allocate source string");
memset(src, 'a', MID_STR_LEN);
src[MID_STR_LEN] = '\0';
for (i = 0; i < MID_STR_LEN -1; i+=10) {
dst = strndup(src, i);
ASSERT_IsTrue(dst != NULL, "strndup returned NULL");
printf("strlen %s = %d (%d expected)\n", dst, strlen(dst), i);
ASSERT_IsTrue(strlen(dst) == i, "string lengths differ");
ASSERT_IsTrue(!strncmp(dst, src, i), "strings differ");
free(dst);
}
for (i = MID_STR_LEN; i < MID_STR_LEN * 2; i+=10) {
dst = strndup(src, i);
ASSERT_IsTrue(dst != NULL, "strndup returned NULL");
printf("%d, strlen %s = %d (%d expected)\n", i, dst, strlen(dst), strlen(src));
ASSERT_IsTrue(strlen(dst) == strlen(src), "string lengths differ");
ASSERT_IsTrue(!strcmp(dst, src), "strings differ");
free(dst);
}
}
ENDTEST