Add VLQ

axl.h

@@ -5,5 +5,6 @@
 #include "axl_memory.h"
 #include "axl_string.h"
 #include "axl_io.h"
+#include "axl_vlq.h"
 
 #endif

axl_types.h

@@ -15,4 +15,21 @@ typedef unsigned long long  u64;
 #define false 0
 #define NULL ((void*)0)
 
+// Minimum and maximum values for integer types
+#define I8_MIN   (-128)
+#define I8_MAX   127
+#define U8_MAX   255
+
+#define I16_MIN  (-32768)
+#define I16_MAX  32767
+#define U16_MAX  65535
+
+#define I32_MIN  (-2147483647 - 1)
+#define I32_MAX  2147483647
+#define U32_MAX  4294967295U
+
+#define I64_MIN  (-9223372036854775807LL - 1LL)
+#define I64_MAX  9223372036854775807LL
+#define U64_MAX  18446744073709551615ULL
+
 #endif // !AXL_TYPES_H

axl_vlq.c

@@ -0,0 +1,57 @@
+#include "axl_vlq.h"
+
+u32 axl_vlq_encode(u32 num, u8* out)
+{
+    u8 buf[5];
+    int pos = 0;
+
+    if(num == 0)
+    {
+        out[0] = 0;
+        return 1;
+    }
+
+    while(num > 0)
+    {
+        buf[pos] = num & 0x7F;
+        num >>= 7;
+        pos++;
+    }
+
+    for(int j = pos - 1; j > 0; j--)
+    {
+        buf[j] |= 0x80;
+    }
+    
+    for(int j = pos - 1; j >= 0; j--) 
+    {
+        *out++ = buf[j];
+    }
+    
+    return pos;
+}
+
+u32 axl_vlq_decode(const u8* in, u32* num) 
+{
+    *num = 0;
+    u32 pos = 0;
+
+    while(pos < AXL_VLQ_MAX_LEN) 
+    {
+        u8 b = in[pos++];
+    
+        *num = (*num << 7) | (b & 0x7F);
+        
+        if(!(b & 0x80)) 
+        {
+            return pos;
+        }
+        
+        if(*num > (U32_MAX >> 7)) 
+        {  
+            return 0;
+        }
+    }
+
+    return 0;
+}

axl_vlq.h

@@ -0,0 +1,11 @@
+#ifndef AXL_VLQ_H
+#define AXL_VLQ_H
+
+#include "axl_types.h"
+
+#define AXL_VLQ_MAX_LEN 5
+
+u32 axl_vlq_encode(u32 num, u8* out);
+u32 axl_vlq_decode(const u8* in, u32* num);
+
+#endif // !AXL_VLQ_H

axl_vlq_test.c

@@ -0,0 +1,30 @@
+#include "axl_koan.h"
+#include "axl_memory.h"
+#include "axl_types.h"
+#include "axl_vlq.h"
+
+KOAN(vlq_basic_encode_decode)
+{
+    u32 expected[] =     {0, 126, 129, 256, 65535, 70000, 9999999, U32_MAX};
+    u32 expected_len[] = {1, 1,   2,   2,   3,     3,     4,       5      };
+
+    u8 encoded[AXL_VLQ_MAX_LEN];
+
+    for(u32 i = 0; i < sizeof(expected) / sizeof(expected[0]); i++)
+    {
+        u32 encoded_len = axl_vlq_encode(expected[i], encoded);
+
+        u32 decoded = 0;
+        u32 decoded_len = axl_vlq_decode(encoded, &decoded);
+
+        ASSERT_UINT_EQ(expected_len[i], encoded_len);
+        ASSERT_UINT_EQ(expected_len[i], decoded_len);
+        ASSERT_UINT_EQ(expected[i], decoded);
+    }
+}
+
+int main(void)
+{
+    axl_init();
+    return koan_run_all();
+}

main.c

@@ -1,4 +1,5 @@
 #include "axl.h"
+#include "axl_vlq.h"
 #include <windows.h>
 
 int _start(void)
@@ -29,5 +30,23 @@ int _start(void)
     (void)fds;
     (void)f;
 
+
+    u32 new_len = 0;
+    u8 src[] = "Bonjour le monde!";
+    u32 src_len = axl_strlen((i8*)src);
+    for(u32 i = 0; i < src_len; i += 4)
+    {
+        u8 buff[AXL_VLQ_MAX_LEN + 1];
+
+        u32 encoded_l = axl_vlq_encode(*((u32*)(src + i)), buff);
+        new_len += encoded_l;
+
+        buff[encoded_l] = '\0'; 
+
+        axl_puts((i8*)buff);
+    }
+    (void)new_len;
+
+
     return 0;
 }