sllibc/string.c

// Copyright (c) 2025, Zak Fenton
// Zak Fenton's libc is licensed under the Mulan PSL v2. You can use this
// software according to the terms and conditions of the Mulan PSL v2.
// You may obtain a copy of Mulan PSL v2 at:
// http://license.coscl.org.cn/MulanPSL2
// THIS SOFTWARE IS PROVIDED ON AN “AS IS” BASIS, WITHOUT warranties of
// any kind, either express or implied, including but not limited to
// non-infringement, merchantability or fit for a particular purpose.
// See the Mulan PSL v2 for more details.

// For auditing purposes, this is NEW CODE

#ifdef KERNEL_MODE
#define size_t long
#define NULL ((void*)0ULL)
#else
#include <string.h>
#include "internal.h"
#endif


//ifdef _ZCC
#ifdef NOT_USED_YET
/* Works like memset except assumes n is a multiple of 8 and src>=dst+8.
 * Doesn't return a useful value.
 */
void __naked memset_quick64(void* dst, uint64 v, uint64 n) __asm {
    add a3, a0, a2
  .setloop:
    sd a1, 0(a0)
    addi a0, a0, 8
    bne a0, a3, .setloop
    ret
}
void __naked memset_quick(void* dst, uint64 v, uint64 n) __asm {
    add a3, a0, a2
  .setloopa:
    sb a1, 0(a0)
    addi a0, a0, 1
    bne a0, a3, .setloopa
    ret
}
void* __naked memset_opt(void* dst, uint64 v, uint64 n) __asm {
    add a3, a0, a2
    add a4, a0, zero
	beq a2, zero, .endopt
	addi a6, zero, 16
	blt a2, a6, .setloopoptshort
	addi a6, zero, 128
	blt a6, a2, .setloopoptlong
  .setloopopt:
    sb a1, 0(a4)
    addi a4, a4, 1
    andi a5, a4, 7
    beq a5, zero, .setloopopt64
  .setloopstartopt:
    bne a4, a3, .setloopopt
  .endopt:
    ret
  .setloopoptshort:
    sb a1, 0(a4)
    addi a4, a4, 1
    bne a4, a3, .setloopoptshort
    ret
  .setloopopt64adjust:
    addi a3, a3, -1
    sb a1, 0(a3)
  .setloopopt64:
    bne a1, zero, .setloopstartopt
    andi a6, a3, 7
    bne a6, zero, .setloopopt64adjust
    //addi a6, zero, 8
  .setloopopt64b:
    //sub a5, a3, a4
    //blt a5, a6, .setloopstartopt
    sd a1, 0(a4)
    addi a4, a4, 8
    blt a4, a3, .setloopopt64b
    //j .setloopstartopt
    ret
  .setloopoptlong:
    bne a1, zero, .setloopstartopt
    andi a6, a2, 127
    bne a6, zero, .setloopstartopt
  .setloopoptlongb:
    sd zero, 0(a4)
    sd zero, 8(a4)
    sd zero, 16(a4)
    sd zero, 24(a4)
    sd zero, 32(a4)
    sd zero, 40(a4)
    sd zero, 48(a4)
    sd zero, 56(a4)
    sd zero, 64(a4)
    sd zero, 72(a4)
    sd zero, 80(a4)
    sd zero, 88(a4)
    sd zero, 96(a4)
    sd zero, 104(a4)
    sd zero, 112(a4)
    sd zero, 120(a4)
    addi a4, a4, 128
    bne a4, a3, .setloopoptlongb
    ret
}
void* __naked memcpy_opt(void* dst, void* src, uint64 n) __asm {
    add a3, a0, a2
    add a4, a0, zero
	beq a2, zero, .endcpy
	addi a6, zero, 16
	blt a2, a6, .cpyloopoptshort
	addi a6, zero, 128
	blt a6, a2, .cpyloopoptlong
  .cpyloopopt:
    lb a6, 0(a1)
    sb a6, 0(a4)
    addi a4, a4, 1
    addi a1, a1, 1
    andi a5, a4, 7
    beq a5, zero, .cpyloopopt64
  .cpyloopstartopt:
    bne a4, a3, .cpyloopopt
  .endcpy:
    ret
  .cpyloopoptshort:
    lb a6, 0(a1)
    sb a6, 0(a4)
    addi a4, a4, 1
    addi a1, a1, 1
    bne a4, a3, .cpyloopoptshort
    ret
  .cpyloopopt64adjust:
    addi a3, a3, -1
    sub a5, a3, a4
    add a5, a5, a1
    lb a6, 0(a5)
    sb a6, 0(a3)
  .cpyloopopt64:
    andi a6, a3, 7
    bne a6, zero, .cpyloopopt64adjust
    //addi a6, zero, 8
  .cpyloopopt64b:
    //sub a5, a3, a4
    //blt a5, a6, .setloopstartopt
    ld a6, 0(a1)
    sd a6, 0(a4)
    addi a4, a4, 8
    addi a1, a1, 8
    blt a4, a3, .cpyloopopt64b
    //j .setloopstartopt
    ret
  .cpyloopoptlong:
    andi a6, a2, 127
    bne a6, zero, .cpyloopstartopt
  .cpyloopoptlongb:
    ld a6, 0(a1)
    sd a6, 0(a4)
    ld a6, 8(a1)
    sd a6, 8(a4)
    ld a6, 16(a1)
    sd a6, 16(a4)
    ld a6, 24(a1)
    sd a6, 24(a4)
    ld a6, 32(a1)
    sd a6, 32(a4)
    ld a6, 40(a1)
    sd a6, 40(a4)
    ld a6, 48(a1)
    sd a6, 48(a4)
    ld a6, 56(a1)
    sd a6, 56(a4)
    ld a6, 64(a1)
    sd a6, 64(a4)
    ld a6, 72(a1)
    sd a6, 72(a4)
    ld a6, 80(a1)
    sd a6, 80(a4)
    ld a6, 88(a1)
    sd a6, 88(a4)
    ld a6, 96(a1)
    sd a6, 96(a4)
    ld a6, 104(a1)
    sd a6, 104(a4)
    ld a6, 112(a1)
    sd a6, 112(a4)
    ld a6, 120(a1)
    sd a6, 120(a4)
    addi a4, a4, 128
    addi a1, a1, 128
    bne a4, a3, .cpyloopoptlongb
    ret
}
// Works like memcpy except assumes n is a multiple of 8 and src>=dst+8.
// Doesn't return a useful value.
void __naked memcpy_quick64(void* dst, void* src, uint64 n) __asm {
    add a3, a0, a2
  .cpyloop:
    ld a4, 0(a1)
    addi a1, a1, 8
    sd a4, 0(a0)
    addi a0, a0, 8
    bne a0, a3, .cpyloop
    ret
}
// Expands a byte to a word.
uint64 __naked expandbyte_quick64(int b) __asm {
    andi a1, a0, 255
    slli a0, a0, 8
    or a0, a0, a1
    slli a0, a0, 8
    or a0, a0, a1
    slli a0, a0, 8
    or a0, a0, a1
    slli a0, a0, 8
    or a0, a0, a1
    slli a0, a0, 8
    or a0, a0, a1
    slli a0, a0, 8
    or a0, a0, a1
    slli a0, a0, 8
    or a0, a0, a1
    ret
}
#endif

// Copied from my preexisting number parser in numbered.c
unsigned long long _libc_scandec(const char** strvar) {
  unsigned long long val = 0;
  const char* s = *strvar;
  char c;
  while ((c = *s) >= '0' && c <= '9') {
    unsigned long long oldval = val;
    val = val * 10 + c - '0';
    if (val / 10 != oldval) {
      return 0;
    }
    s++;
  }
  
  *strvar = s;
  return val;
}

long long atoll(const char* str) {
  if (*str == '-') {
    str++;
    long long x = (long long) _libc_scandec(&str);
    return -x;
  } else if (*str == '+') {
    str++;
    return (long long) _libc_scandec(&str);
  } else {
    return (long long) _libc_scandec(&str);
  }
}

long atol(const char* str) {
  return (long) atoll(str);
}

int atoi(const char* str) {
  return (int) atoll(str);
}

size_t strlen(const char* foo) {
  if (foo == NULL) {
    return 0;
  } else {
    size_t i = 0;
    while (foo[i] != 0) i++;
    return i;
  }
}

void* memcpy(void* dst, const void* src, size_t nbytes) {
  char* cdst = (char*) dst;
  const char* csrc = (char*) src;
  size_t i = 0;
  for (i = 0; i < nbytes; i++) {
      cdst[i] = csrc[i];
  }
  return dst;
}

void* memset(void* mem, int byt, size_t nbytes) {
  char* tmp = mem;
  for (size_t i = 0; i < nbytes; i++) {
    tmp[i] = (char) byt;
  }
  return mem;
}

int strcmp(const char* a, const char* b) {
  while (*a == *b) {
    if (*a == 0) {
      return 0; // Got to the end, strings are equal
    }
    a++;
    b++;
  }
  return *a - *b;
}

char* strcat(char* dst, const char* src) {
  char* end = dst;
  while (*end) { // Find the terminating zero of the dst string
    end++;
  }
  while (*src) { // Overwrite the end of dst from src until it's terminating zero
    *end++ = *src++;
  }
  *end = 0; // Add terminating zero back to dst
  return dst; // Return the start of the dst string
}

char* strcpy(char *dst, const char* src) {
  char *d = dst;
  while (*src) {
    *d++ = *src++;
  }
  *d = 0;
  return dst;
}

char* strncpy(char* dst, const char* src, size_t n) {
  size_t i = 0;
  char *d = dst;
  while (*src) {
    *d++ = *src++;
    i++;
  }
  while (i < n) { // TODO: Is this right??
    dst[i] = 0;
    i++;
  }
  return dst;
}

#ifndef KERNEL_MODE
char* strdup(const char* src) {
  char* result = malloc(strlen(src) + 1);
  if (result) {
    strcpy(result, src);
  }
  return result;
}

char* strndup(const char* str, size_t n) {
  size_t resultlen = strlen(str);
  if (resultlen > n) {
    resultlen = n;
  }
  char* result = malloc(resultlen + 1);
  if (result) {
    for (size_t i = 0; i < resultlen; i++) {
      result[i] = str[i];
    }
    str[resultlen] = 0;
  }
  return result;
}
#endif

const char* strpbrk(const char* str, const char* search) {
  char c;
  while ((c = *str)) {
    const char* s = search;
    while (*s++) {
      if (c == *s) {
        return str;
      }
    }
    str++;
  }
  return NULL;
}

char *strchr(const char* str, int chr) {
  int c;
  while ((c = *str)) {
    if (c == chr) {
      return (char*) str;
    }
    str++;
  }
  return NULL;
}

char *strrchr(const char* str, int chr) {
  int c;
  char* result = NULL;
  while ((c = *str)) {
    if (c == chr) {
      result = (char*) str;
    }
    str++;
  }
  return result;
}