From b1e837afb44f9053763d6a654a5f7bb2757a39d4 Mon Sep 17 00:00:00 2001
From: pommicket <pommicket@gmail.com>
Date: Wed, 16 Feb 2022 19:41:44 -0500
Subject: string.h

---
 05/main.c   |  16 ++++++--
 05/string.h | 120 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++---
 2 files changed, 128 insertions(+), 8 deletions(-)

diff --git a/05/main.c b/05/main.c
index 6757ec7..2dc7b81 100644
--- a/05/main.c
+++ b/05/main.c
@@ -15,9 +15,19 @@ int compar(const void *a, const void *b) {
 
 int main(int argc, char **argv) {
 	char buf[36];
-	memset(buf, 'a', sizeof buf);
-	strncpy(buf, "hello, world!\n",36);
-	printf("%d\n",strcmp(buf, "hello, world!\n"));
+	strcpy(buf, "Hello there there!");
+/* 	buf[36]='b'; */
+	printf("%s\n",strstr(buf," ther"));
+	
+         static char str[] = "?a???b,,,#c";
+         char *t;
+        
+         printf("%s\n", strtok(str, "?"));      /* t  points to the token "a" */
+         printf("%s\n", strtok(NULL, ",")); 
+         printf("%s\n", strtok(NULL, "#,")); 
+         printf("%s\n", strtok(NULL, "?")); 
+         
+
 	return 0;
 }
 
diff --git a/05/string.h b/05/string.h
index 9b59637..02216b5 100644
--- a/05/string.h
+++ b/05/string.h
@@ -59,17 +59,127 @@ int memcmp(const void *s1, const void *s2, size_t n) {
 
 int strcmp(const char *s1, const char *s2) {
 	char *p = s1, *q = s2;
-	for (; *p && *q; ++p, ++q) {
+	for (; ; ++p, ++q) {
 		if (*p > *q)
 			return 1;
 		if (*p < *q)
 			return -1;
+		if (!*p) break;
 	}
-	if (*p > *q)
-		return 1;
-	if (*p < *q)
-		return -1;
 	return 0;
 }
 
+int strcoll(const char *s1, const char *s2) {
+	// we only support the C locale
+	return strcmp(s1, s2);
+}
+
+int strncmp(const char *s1, const char *s2, size_t n) {
+	char *p = s1, *q = s2;
+	size_t i;
+	for (i = 0; i < n; ++i, ++p, ++q) {
+		if (*p > *q)
+			return 1;
+		if (*p < *q)
+			return -1;
+		if (!*p) break;
+	}
+	return 0;
+}
+
+size_t strxfrm(char *s1, const char *s2, size_t n) {
+	// we only support the C locale
+	size_t l = strlen(s2);
+	if (l >= n) return l;
+	strcpy(s1, s2);
+	return l;
+}
+
+void *memchr(const void *s, int c, size_t n) {
+	char *p = s, *end = p + n;
+	while (p < end) {
+		if ((unsigned char)*p == c)
+			return p;
+		++p;
+	}
+	return NULL;
+}
+
+char *strchr(const char *s, int c) {
+	return memchr(s, c, strlen(s)+1);
+}
+
+
+size_t strcspn(const char *s1, const char *s2) {
+	const char *p, *q;
+	for (p = s1; *p; ++p) {
+		for (q = s2; *q; ++q) {
+			if (*p == *q)
+				goto ret;
+		}
+	}
+	ret:
+	return p - s1;
+}
+
+char *strpbrk(const char *s1, const char *s2) {
+	const char *p, *q;
+	for (p = s1; *p; ++p) {
+		for (q = s2; *q; ++q) {
+			if (*p == *q)
+				return p;
+		}
+	}
+	return NULL;
+}
+
+char *strrchr(const char *s, int c) {
+	char *p;
+	for (p = s + strlen(s); p >= s; --p) {
+		if (*p == c)
+			return p;
+	}
+	return NULL;
+}
+
+size_t strspn(const char *s1, const char *s2) {
+	const char *p, *q;
+	for (p = s1; *p; ++p) {
+		for (q = s2; *q; ++q) {
+			if (*p == *q) break;
+		}
+		if (!*q) break;
+	}
+	return p - s1;
+}
+
+char *strstr(const char *s1, const char *s2) {
+	char *p;
+	size_t l = strlen(s2);
+	for (p = s1; *p; ++p) {
+		if (memcmp(p, s2, l) == 0)
+			return p;
+	}
+	return NULL;
+}
+
+char *_strtok_str;
+char *strtok(char *s1, const char *s2) {
+	if (s1) _strtok_str = s1;
+	if (!_strtok_str) return NULL;
+	char *p = _strtok_str + strspn(_strtok_str, s2);
+	if (!*p) {
+		_strtok_str = NULL;
+		return NULL;
+	}
+	char *q = strpbrk(p, s2);
+	if (q) {
+		*q = 0;
+		_strtok_str = q + 1;
+	} else {
+		_strtok_str = NULL;
+	}
+	return p;
+}
+
 #endif // _STRING_H
-- 
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