From 896478de2dd7064189731ac008263ccbc48d57d3 Mon Sep 17 00:00:00 2001
From: orange <mike@sprachgewalt.de>
Date: Sun, 16 Jun 2013 19:00:09 +0200
Subject: [PATCH] add fnv32_1 implementation

---
 .gitignore |  1 +
 Makefile   |  2 +-
 bloom.c    | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 48 insertions(+), 1 deletion(-)
 create mode 100644 bloom.c

diff --git a/.gitignore b/.gitignore
index 5245adb..d742c39 100644
--- a/.gitignore
+++ b/.gitignore
@@ -13,3 +13,4 @@ ncurses-pong
 checkcheck
 multibrot
 multibrot.png
+bloom
diff --git a/Makefile b/Makefile
index 5918cef..ae17d0a 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
 CFLAGS=-std=c99 -Wall -g -O2
 INDENTOPTS=-kr --no-tabs --braces-on-func-def-line --indent-level2
 
-TARGETS=approximate-pi linked-list mandelbrot threads circular-buffer structs ncurses-pong bit-fuckery bit-fuckery2 checkcheck multibrot
+TARGETS=approximate-pi linked-list mandelbrot threads circular-buffer structs ncurses-pong bit-fuckery bit-fuckery2 checkcheck multibrot bloom
 EXTRAS=mandelbrot.bmp multibrot.png
 
 .PHONY: all
diff --git a/bloom.c b/bloom.c
new file mode 100644
index 0000000..7aa0f60
--- /dev/null
+++ b/bloom.c
@@ -0,0 +1,46 @@
+#include <assert.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+/*
+ * FNV-1 hash implementation (32-bit aka FNV32_1).
+ *
+ * See http://isthe.com/chongo/tech/comp/fnv/
+ */
+uint32_t fnv32_1(uint8_t *data, size_t data_len) {
+  uint32_t hash;
+
+  /* Constants, for 32-bit only. */
+  uint32_t offset_basis = (uint32_t) 2166136261UL;
+  uint32_t FNV_prime = (uint32_t) 16777619UL;
+
+  hash = offset_basis;
+  for (size_t i = 0; i < data_len; i++) {
+     hash = hash * FNV_prime; /* implictly modulo 2^32 */
+     hash = hash ^ data[i];   /* implictly only on lower octet. */
+  }
+  return hash;
+}
+
+/* Compute FNV-1 hash for the given string (without NUL byte). */
+uint32_t fnv32_1_str(char *string) {
+  return fnv32_1((uint8_t *) string, strlen(string));
+}
+
+int main(void) {
+  /* Test FNV32_1 */
+  assert(fnv32_1_str("03SB[")  == 0x00000000UL);
+  assert(fnv32_1_str("")       == 0x811c9dc5UL);
+  assert(fnv32_1_str("a")      == 0x050c5d7eUL);
+  assert(fnv32_1_str("b")      == 0x050c5d7dUL);
+  assert(fnv32_1_str("c")      == 0x050c5d7cUL);
+  assert(fnv32_1_str("d")      == 0x050c5d7bUL);
+  assert(fnv32_1_str("e")      == 0x050c5d7aUL);
+  assert(fnv32_1_str("f")      == 0x050c5d79UL);
+  assert(fnv32_1_str("fo")     == 0x6b772514UL);
+  assert(fnv32_1_str("foo")    == 0x408f5e13UL);
+  assert(fnv32_1_str("foob")   == 0xb4b1178bUL);
+  assert(fnv32_1_str("fooba")  == 0xfdc80fb0UL);
+  assert(fnv32_1_str("foobar") == 0x31f0b262UL);
+}