string - Memory and string utilities

Header: libc/include/string.h
Sources: libc/string/memcmp.c, memcpy.c, memmove.c, memset.c, strlen.c

Provides the core <string.h> memory and string functions required by the kernel and its libc. All are standard C implementations with no OS-specific dependencies.

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Functions

memset

void *memset(void *s, int c, size_t n);

Fill the first n bytes of memory at s with the byte value (unsigned char)c. Returns s. Used throughout the kernel to zero buffers, the IDT, ISR handler table, and PMM bitmap.

memcpy

void *memcpy(void *restrict dst, const void *restrict src, size_t n);

Copy n bytes from src to dst. The source and destination regions must not overlap; use memmove if they may. Returns dst.

memmove

void *memmove(void *dst, const void *src, size_t n);

Copy n bytes from src to dst, handling overlapping regions correctly by choosing the copy direction based on the relative positions of dst and src. Returns dst. Used by the VESA TTY scroll routine.

memcmp

int memcmp(const void *s1, const void *s2, size_t n);

Compare the first n bytes of s1 and s2. Returns 0 if equal, a negative value if s1 < s2, or a positive value if s1 > s2.

strlen

size_t strlen(const char *s);

Return the number of characters in the null-terminated string s, not including the terminating '\0'.

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Future work

• Add strcpy, strncpy, strcmp, strncmp, strchr, strrchr, strstr for the shell and configuration parser.
• Add strtok / strtok_r for tokenising shell command lines.