From 10b19d747805e4fd1323455dae419091500efc18 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Sat, 23 Aug 2025 15:28:56 +0100
Subject: Add helpers for hashing values extracted from log input

zlib's crc32 used here, the interface is a bit C and as a result a bit
casty, but it'll work.
---
 src/Jamfile.jam  |  1 +
 src/ingestor.cpp | 35 +++++++++++++++++++++++++++++++++++
 src/ingestor.hpp |  1 +
 src/logTypes.hpp |  3 +++
 4 files changed, 40 insertions(+)

(limited to 'src')

diff --git a/src/Jamfile.jam b/src/Jamfile.jam
index 40ec28e..637ddb8 100644
--- a/src/Jamfile.jam
+++ b/src/Jamfile.jam
@@ -1,6 +1,7 @@
 lib webstat : ingestor.cpp logTypes.cpp :
 	<include>.
 	<library>../thirdparty//scn
+	<library>..//z
 	: :
 	<include>.
 	;
diff --git a/src/ingestor.cpp b/src/ingestor.cpp
index 5724b33..17310c2 100644
--- a/src/ingestor.cpp
+++ b/src/ingestor.cpp
@@ -1,8 +1,43 @@
 #include "ingestor.hpp"
 #include <scn/scan.h>
 #include <syslog.h>
+#include <utility>
+#include <zlib.h>
 
 namespace WebStat {
+	namespace {
+		Crc32Value
+		crc32(const std::string_view value)
+		{
+			return static_cast<Crc32Value>(::crc32(::crc32(0, Z_NULL, 0), reinterpret_cast<const Bytef *>(value.data()),
+					static_cast<uInt>(value.length())));
+		}
+
+		Entity
+		addCrc32(const std::string_view value)
+		{
+			return {crc32(value), value};
+		}
+
+		std::optional<Entity>
+		addCrc32o(const std::optional<std::string_view> value)
+		{
+			return value.transform(addCrc32);
+		}
+
+		auto
+		crc32ScanValues(const Ingestor::ScanValues & values)
+		{
+			return std::apply(
+					[](auto &&... value) {
+						return std::make_tuple(addCrc32(value...[0]), value...[1], value...[2], value...[3],
+								addCrc32(value...[4]), addCrc32o(value...[5]), value...[6], value...[7], value...[8],
+								value...[9], addCrc32o(value...[10]), addCrc32o(value...[11]));
+					},
+					values);
+		}
+	}
+
 	Ingestor::ScanResult
 	Ingestor::scanLogLine(std::string_view input)
 	{
diff --git a/src/ingestor.hpp b/src/ingestor.hpp
index 97ce9f9..3bb9ddd 100644
--- a/src/ingestor.hpp
+++ b/src/ingestor.hpp
@@ -10,6 +10,7 @@ namespace WebStat {
 		using ScanResult = decltype(scn::scan<std::string_view, std::string_view, uint64_t, std::string_view,
 				QuotedString, QueryString, std::string_view, unsigned short, unsigned int, unsigned int, CLFString,
 				CLFString>(std::declval<std::string_view>(), ""));
+		using ScanValues = std::remove_cvref_t<decltype(std::declval<WebStat::Ingestor::ScanResult>()->values())>;
 
 		[[nodiscard]] static ScanResult scanLogLine(std::string_view);
 
diff --git a/src/logTypes.hpp b/src/logTypes.hpp
index d4f1b7b..7439733 100644
--- a/src/logTypes.hpp
+++ b/src/logTypes.hpp
@@ -21,6 +21,9 @@ namespace WebStat {
 		using std::optional<std::string>::operator=;
 		bool operator<=>(const CLFString &) const = default;
 	};
+
+	using Crc32Value = uint32_t;
+	using Entity = std::pair<Crc32Value, std::string_view>;
 }
 
 namespace scn {
-- 
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