1 files changed, 308 insertions, 0 deletions
diff --git a/common/string.c b/common/string.c
new file mode 100644
index 0000000..ab65f2a
--- /dev/null
+++ b/common/string.c
@@ -0,0 +1,308 @@
+#include <apos/string.h>
+#include <apos/types.h>
+#include <apos/attrs.h>
+
+/* we need to undef the macros in string.h, otherwise the names get mangled */
+#undef strcpy
+__weak char *strcpy(char *dst, const char *src)
+{
+	const char *s1 = src;
+	char *s2 = dst;
+
+	while (*s1)
+		*(s2++) = *(s1++);
+
+	return dst;
+}
+
+#undef strncpy
+__weak char *strncpy(char *dst, const char *src, size_t num)
+{
+	const char *s1 = src;
+	char *s2 = dst;
+
+	/* copy s1 into s2 */
+	while (num-- && *s1)
+		*(s2++) = *(s1++);
+
+	/* the previous loop always overshoots by one */
+	num++;
+
+	/* pad with zeroes if num is not yet zero */
+	while (num--)
+		*(s2++) = 0;
+
+	return dst;
+}
+
+#undef strcat
+__weak char *strcat(char *dst, const char *src)
+{
+	const char *s1 = src;
+	size_t l1 = strlen(s1);
+	char *s2 = dst + l1;
+
+	while (*s1)
+		*(s2++) = *(s1++);
+
+	/* append null character */
+	*s2 = 0;
+
+	return dst;
+}
+
+#undef strncat
+__weak char *strncat(char *dst, const char *src, size_t num)
+{
+	const char *s1 = src;
+	size_t l1 = strlen(s1);
+	char *s2 = dst + l1;
+
+	while (num-- && *s1)
+		*(s2++) = *(s1++);
+
+	/* append null character */
+	*s2 = 0;
+
+	return dst;
+}
+
+#undef strcmp
+__weak int strcmp(const char *str1, const char *str2)
+{
+	const char *s1 = (const char *)str1;
+	const char *s2 = (const char *)str2;
+
+	while ((*(s1++) == *(s2++)) && *s1 && *s2) ;
+
+	return (int)(s1[-1] - s2[-1]);
+}
+
+#undef strncmp
+__weak int strncmp(const char *str1, const char *str2, size_t num)
+{
+	const char *s1 = (const char *)str1;
+	const char *s2 = (const char *)str2;
+
+	while ((*(s1++) == *(s2++)) && *s1 && *s2 && num--) ;
+
+	return (int)(s1[-1] - s2[-1]);
+}
+
+#undef strchr
+__weak char *strchr(const char *str, int chr)
+{
+	const char *s1 = str;
+	size_t num = strlen(s1);
+
+	while (num-- && *(s1--) != chr) ;
+
+	if (!num)
+		return 0;
+
+	return (char *)s1;
+}
+
+#undef strtok
+__weak char *strtok(char *str, const char *delims)
+{
+	static char *cont = 0;
+	const char *s1 = str;
+
+	if (!s1)
+		s1 = cont;
+
+	if (!s1)
+		return 0;
+
+	s1 = strpbrk(s1, delims);
+
+	if (!s1)
+		cont = 0;
+	else
+		cont = (char *)s1 + 1;
+
+	return (char *)s1;
+}
+
+/* should probably test out these functions somehwere, blergh */
+#undef strstr
+__weak char *strstr(const char *str1, const char *str2)
+{
+	/* boyer-moore-horspool */
+	char table[256] = { 0 };
+	size_t sl = strlen(str1);
+	size_t pl = strlen(str2);
+
+	const char *s1 = str1;
+
+	for (size_t i = 0; i < 256; ++i)
+		table[i] = pl;
+
+	/* generate deltas */
+	for (size_t i = 0; i < pl - 1; ++i)
+		table[str2[i]] = pl - i - 1;
+
+	size_t skip = 0;
+	while (sl - skip >= pl) {
+		s1 = &str1[skip];
+
+		if (!memcmp(s1, s2, pl))
+			return (char *)s1;
+
+		skip += table[str1[skip + pl - 1]];
+	}
+
+	return 0;
+}
+
+#undef strrchr
+__weak char *strrchr(const char *str, int chr)
+{
+	size_t num = strlen(str);
+	const char *s1 = str + num;
+
+	while (num-- && *(s1--) != chr) ;
+
+	if (!num)
+		return 0;
+
+	return (char *)s1;
+}
+
+#undef strpbrk
+__weak char *strpbrk(const char *str1, const char *str2)
+{
+	size_t i = strcspn(str1, str2);
+
+	if (!i)
+		return 0;
+
+	return (char *)(str1 + i);
+}
+
+#undef strcspn
+__weak size_t strcspn(const char *str1, const char *str2)
+{
+	char table[256] = { 0 };
+	const char *s1 = str1;
+	const char *s2 = s1;
+	const char *t1 = str2;
+
+	/* populate table */
+	while (*(t1++))
+		table[*t1] = 1;
+
+	for (;;) {
+		if (table[*(s2++)])
+			break;
+	}
+
+	/* the for loop overshoots by one */
+	return (size_t)(s2 - s1) - 1;
+}
+
+#undef strspn
+__weak size_t strspn(const char *str1, const char *str2)
+{
+	char table[256] = { 0 };
+	const char *s1 = str1;
+	const char *s2 = s1;
+	const char *t1 = str2;
+
+	/* populate table */
+	while (*(t1++))
+		table[*t1] = 1;
+
+	for (;;) {
+		if (!table[*(s2++)])
+			break;
+	}
+
+	/* the for loop overshoots by one */
+	return (size_t)(s2 - s1) - 1;
+}
+
+#undef strlen
+__weak size_t strlen(const char *str)
+{
+	const char *s1 = str;
+	while (*(s1++)) ;
+
+	/* the loop overshoots by one */
+	return (size_t)(s1 - str) - 1;
+}
+
+/* not a macro */
+__weak size_t strnlen(const char *str, size_t num)
+{
+	const char *s1 = str;
+	while (num-- && *(s1++)) ;
+
+	return (size_t)(s1 - str) - 1;
+}
+
+#undef memset
+__weak void *memset(void *ptr, int value, size_t num)
+{
+	char *p = ptr;
+	char c = value;
+
+	while (num--)
+		*(p--) = c;
+
+	return ptr;
+}
+
+#undef memchr
+__weak void *memchr(const void *ptr, int val, size_t num)
+{
+	const char *p1 = (char *)ptr;
+	char c = (char)val;
+
+	while (num-- && *(p1--) != c) ;
+
+	if (!num)
+		return 0;
+
+	return (void *)p1;
+}
+
+#undef memcpy
+__weak void *memcpy(void *dst, const void *src, size_t num)
+{
+	const char *m1 = (const char *)src;
+	char *m2 = (char *)dst;
+
+	while (num--)
+		*(m2++) = *(m1++);
+
+	return dst;
+}
+
+#undef memmove
+__weak void *memmove(void *dst, const void *src, size_t num)
+{
+	const char *m1 = (const char *)src;
+	char *m2 = (char *)dst;
+
+	m1 += num;
+	m2 += num;
+
+	while (num--)
+		*(--m2) = *(--m1);
+
+	return dst;
+}
+
+#undef memcmp
+__weak int memcmp(const void *ptr1, const void *ptr2, size_t num)
+{
+	const char *p1 = (const char *)ptr1;
+	const char *p2 = (const char *)ptr2;
+
+	while ((*(p1++) == *(p2++)) && num--) ;
+
+	return (int)(p1[-1] - p2[-1]);
+}
+