From 0395886e11624982aac4c103733ff95e86148559 Mon Sep 17 00:00:00 2001
From: "bernard.xiong@gmail.com" <bernard.xiong@gmail.com>
Date: Fri, 15 Oct 2010 23:31:11 +0000
Subject: [PATCH] add rand function in minilibc.

git-svn-id: https://rt-thread.googlecode.com/svn/trunk@1011 bbd45198-f89e-11dd-88c7-29a3b14d5316
---
 components/libc/minilibc/ctype.c     |  5 ++++
 components/libc/minilibc/ctype.h     |  1 +
 components/libc/minilibc/rand.c      | 35 ++++++++++++++++++++++++++++
 components/libc/minilibc/stdlib.h    |  4 ++++
 components/libc/minilibc/sys/types.h |  3 +++
 5 files changed, 48 insertions(+)
 create mode 100644 components/libc/minilibc/rand.c

diff --git a/components/libc/minilibc/ctype.c b/components/libc/minilibc/ctype.c
index 8e02e1a90..786ff472f 100644
--- a/components/libc/minilibc/ctype.c
+++ b/components/libc/minilibc/ctype.c
@@ -29,4 +29,9 @@ int isalpha(int ch)
 	return (unsigned int)((ch | 0x20) - 'a') < 26u;
 }
 
+int isdigit (int ch)
+{
+    return (unsigned int)(ch - '0') < 10u;
+}
+
 #endif
diff --git a/components/libc/minilibc/ctype.h b/components/libc/minilibc/ctype.h
index fdbf7bf00..9a773b69a 100644
--- a/components/libc/minilibc/ctype.h
+++ b/components/libc/minilibc/ctype.h
@@ -16,5 +16,6 @@
 
 int isprint(int c) __attribute__ ((__const__));
 int isalpha (int c) __attribute__ ((__const__));
+int isdigit (int ch) __attribute__ ((__const__));
 
 #endif
diff --git a/components/libc/minilibc/rand.c b/components/libc/minilibc/rand.c
new file mode 100644
index 000000000..46a96ac5b
--- /dev/null
+++ b/components/libc/minilibc/rand.c
@@ -0,0 +1,35 @@
+#include <stdlib.h>
+#include <sys/types.h>
+
+static unsigned int seed=1;
+
+/* Knuth's TAOCP section 3.6 */
+#define	M	((1U<<31) -1)
+#define	A	48271
+#define	Q	44488		// M/A
+#define	R	3399		// M%A; R < Q !!!
+
+// FIXME: ISO C/SuS want a longer period
+int rand_r(unsigned int* seed)
+{   int32_t X;
+
+    X = *seed;
+    X = A*(X%Q) - R * (int32_t) (X/Q);
+    if (X < 0)
+	X += M;
+
+    *seed = X;
+    return X;
+}
+
+int rand(void) {
+  return rand_r(&seed);
+}
+
+void srand(unsigned int i)
+{ 
+	seed=i;
+}
+
+int random(void) __attribute__((alias("rand")));
+void srandom(unsigned int i) __attribute__((alias("srand")));
diff --git a/components/libc/minilibc/stdlib.h b/components/libc/minilibc/stdlib.h
index 89318b30d..93c9b19b5 100644
--- a/components/libc/minilibc/stdlib.h
+++ b/components/libc/minilibc/stdlib.h
@@ -24,4 +24,8 @@ int atoi(const char *nptr);
 #define realloc rt_realloc
 #define calloc  rt_calloc
 
+int rand(void);
+int rand_r(unsigned int *seed);
+void srand(unsigned int seed);
+
 #endif
diff --git a/components/libc/minilibc/sys/types.h b/components/libc/minilibc/sys/types.h
index a9a1dafa2..2be1f3440 100644
--- a/components/libc/minilibc/sys/types.h
+++ b/components/libc/minilibc/sys/types.h
@@ -14,6 +14,9 @@ typedef rt_uint32_t u_long;
 typedef rt_uint8_t 	u_int8_t;
 typedef rt_uint16_t u_int16_t;
 typedef rt_uint32_t u_int32_t;
+typedef rt_int8_t 	int8_t;
+typedef rt_int16_t  int16_t;
+typedef rt_int32_t  int32_t;
 
 typedef rt_time_t time_t;
 
-- 
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