cleanup lut ~800ms

3 files changed, 21 insertions, 19 deletions

diff --git a/Makefile b/Makefile
index 7d75e27..537381f 100644
--- a/Makefile
+++ b/Makefile
@@ -7,6 +7,9 @@ build: calc.c lut
 bench: build
 	./calc 10.0.0.0/8 2
 
+bigbench: build
+	./calc 10.0.0.0/6 2
+
 lut: itoa_gen.py
 	python3 ./itoa_gen.py
 
diff --git a/calc.c b/calc.c
index fee64a2..fb0a5a4 100644
--- a/calc.c
+++ b/calc.c
@@ -32,20 +32,20 @@ uint32_t subnetmask_for_netspace(unsigned int desired_netspace) {
 void write_ip(char **chunk_ptr, uint32_t ip) {
     // local ptr so we don't have to deref every time
     char *ptr = *chunk_ptr;
-    LutEntry e = {.bits = itoa_lut[(ip >> 24) & 0xff]};
-    WRITE_STR(ptr, e.fields.chars, e.fields.len)
+    LutEntry e = itoa_lut[(ip >> 24) & 0xff];
+    WRITE_STR(ptr, e.chars, e.len)
     ptr[0] = '.';
     ptr += 1;
-    e.bits = itoa_lut[(ip >> 16) & 0xff];
-    WRITE_STR(ptr, e.fields.chars, e.fields.len)
+    e = itoa_lut[(ip >> 16) & 0xff];
+    WRITE_STR(ptr, e.chars, e.len)
     ptr[0] = '.';
     ptr += 1;
-    e.bits = itoa_lut[(ip >> 8) & 0xff];
-    WRITE_STR(ptr, e.fields.chars, e.fields.len)
+    e = itoa_lut[(ip >> 8) & 0xff];
+    WRITE_STR(ptr, e.chars, e.len)
     ptr[0] = '.';
     ptr += 1;
-    e.bits = itoa_lut[ip & 0xff];
-    WRITE_STR(ptr, e.fields.chars, e.fields.len)
+    e = itoa_lut[ip & 0xff];
+    WRITE_STR(ptr, e.chars, e.len)
     *chunk_ptr = ptr;
 }
 
@@ -106,8 +106,8 @@ int main(int argc, char** argv) {
         write_ip(&chunk_ptr, broadcast);
         WRITE_STR(chunk_ptr,  "\",\n", 3)
         WRITE_STR(chunk_ptr,  "\t\t\"Nbr\": \"", 10)
-        LutEntry e = {.bits = itoa_lut[ips_per_subnet - 2]};
-        WRITE_STR(chunk_ptr, e.fields.chars, e.fields.len);
+        LutEntry e = itoa_lut[ips_per_subnet - 2];
+        WRITE_STR(chunk_ptr, e.chars, e.len);
         if (i+1 == req.count) {
             WRITE_STR(chunk_ptr,  "\"\n\t}\n", 5)
         }else {
diff --git a/itoa_gen.py b/itoa_gen.py
index 0437c62..2c62ed5 100644
--- a/itoa_gen.py
+++ b/itoa_gen.py
@@ -1,15 +1,14 @@
 with open("itoa_lut.h", "w") as f:
     f.write("#include <stdint.h>\n")
-    f.write("typedef union { struct { char chars[3]; uint8_t len; } fields; uint32_t bits; } LutEntry;\n")
-    f.write("const uint32_t itoa_lut[256] = {")
+    f.write("typedef struct { char chars[3]; uint8_t len; } LutEntry;\n")
+    f.write("const LutEntry itoa_lut[256] = {\n")
     out = []
     for i in range(0, 256):
         running=len(str(i))
-        for j in reversed(range(3)):
-            running = running << 8
-            if j < len(str(i)):
-                running += ord(str(i)[j])
-        out.append(hex(running))
-    f.write(", ".join(out))
-    f.write("};")
+        s = str(i)
+        while len(s) < 3:
+            s=s+chr(69)
+        out.append("{{"+",".join(map(lambda x: f"'{x}'", s))+"}, "+str(len(str(i)))+"}")
+    f.write(",\n".join(out))
+    f.write("\n};")