From 916aa42260290e9e864304bc7d9395b6aa693c27 Mon Sep 17 00:00:00 2001 From: Anton Kling Date: Tue, 10 Dec 2024 12:24:07 +0100 Subject: kernel: Add string view and string builder This makes write/read calls that use strings to communicate much simpler and less error prone. --- kernel/libc/ctype/isspace.c | 5 +++++ kernel/libc/include/string.h | 1 + kernel/libc/string/memmove.c | 14 ++++++++++++++ 3 files changed, 20 insertions(+) create mode 100644 kernel/libc/ctype/isspace.c create mode 100644 kernel/libc/string/memmove.c (limited to 'kernel/libc') diff --git a/kernel/libc/ctype/isspace.c b/kernel/libc/ctype/isspace.c new file mode 100644 index 0000000..a922d91 --- /dev/null +++ b/kernel/libc/ctype/isspace.c @@ -0,0 +1,5 @@ +#include + +int isspace(int c) { + return c == ' ' || (unsigned)c - '\t' < 5; +} diff --git a/kernel/libc/include/string.h b/kernel/libc/include/string.h index 89ea5ab..4425085 100644 --- a/kernel/libc/include/string.h +++ b/kernel/libc/include/string.h @@ -15,4 +15,5 @@ char *copy_and_allocate_string(const char *s); char *copy_and_allocate_user_string(const char *s); size_t strlcpy(char *dst, const char *src, size_t dsize); char *strcat(char *s1, const char *s2); +void *memmove(void *s1, const void *s2, size_t n); #endif diff --git a/kernel/libc/string/memmove.c b/kernel/libc/string/memmove.c new file mode 100644 index 0000000..5fc49f7 --- /dev/null +++ b/kernel/libc/string/memmove.c @@ -0,0 +1,14 @@ +#include + +// copy bytes in memory with overlapping areas +// https://pubs.opengroup.org/onlinepubs/9699919799/functions/memmove.html +void *memmove(void *s1, const void *s2, size_t n) { + // Copying takes place as if the n bytes from the object pointed to by s2 are + // first copied into a temporary array of n bytes that does not overlap the + // objects pointed to by s1 and s2, and then the n bytes from the temporary + // array are copied into the object pointed to by s1. + unsigned char tmp[n]; + memcpy(tmp, s2, n); + memcpy(s1, tmp, n); + return s1; +} -- cgit v1.2.3