Initial implementation

.gitignore

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+bin/*

Makefile

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+BIN = bin
+
+$(BIN)/inet.so: \
+	$(BIN) \
+	inet.c \
+
+	gcc -Wall -g -fPIC -shared inet.c -o $(BIN)/inet.so
+
+
+$(BIN):
+	mkdir $(BIN)
+
+clean:
+	rm -rf $(BIN)/*
+
+test: \
+	$(BIN)/inet.so
+
+	./testsuite.sh

README.md

@@ -1,2 +1,32 @@
 # sqlite-inet
-Converting IP addresses between string and numeric representation
+
+This Sqlite extension provides `inet_aton()` and `inet_ntoa()` functions
+for converting IP adresses between their string and numeric representation.
+
+## Usage
+
+```
+$ make
+$ sqlite3
+sqlite> .load bin/inet.so
+sqlite> select inet_ntoa(3232235777);
+192.168.1.1
+```
+
+If you don't want to compile code yourself you can download binaries from here:
+
+| Operating System                                                    | SHA256 |
+| ------------------------------------------------------------------- | ------ |
+| [Linux 64-bit](https://tznvy.eu/download/sqlite-inet/amd64/inet.so) | `4147cf5226184a5761cbe87d6a06bdf22289db57819069667cf46362c4e58fad` |
+| [Linux 32-bit](https://tznvy.eu/download/sqlite-inet/i386/inet.so)  | `5912909bb63640c80b08b83e53e36c672c6474be98d56922525bae57923b718f` |
+
+## Misc
+
+The functions behave like their [MariaDB analogs](https://mariadb.com/kb/en/mariadb/inet_ntoa/), that is,
+they expect integers in host byte order,
+rather than network byte order as expected by [C functions](https://linux.die.net/man/3/inet_ntoa).
+For more info, see [this bug report](https://bugs.mysql.com/bug.php?id=34030#c197546).
+
+When invoked with NULL, NULL is returned.
+
+When invoked with otherwise incorrect data, an error is raised.

inet.c

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+/*
+** 2017-05-12
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** This SQLite extension implements inet_aton() and inet_ntoa() functions.
+*/
+#include <sqlite3ext.h>
+SQLITE_EXTENSION_INIT1
+#include <arpa/inet.h>
+#include <assert.h>
+#include <string.h>
+
+static void inet_aton_impl(
+    sqlite3_context *context,
+    int argc,
+    sqlite3_value **argv)
+{
+    const char *zIn;
+    struct in_addr sInAddr;
+
+    assert(argc == 1);
+    if (sqlite3_value_type(argv[0]) == SQLITE_NULL)
+    {
+        return;
+    }
+
+    zIn = (const char*)sqlite3_value_text(argv[0]);
+
+    if (inet_aton(zIn, &sInAddr) == 0)
+    {
+        sqlite3_result_error(context, "Passed a malformed IP address", -1);
+        return;
+    }
+
+    sqlite3_result_int(context, ntohl(sInAddr.s_addr));
+}
+
+static void inet_ntoa_impl(
+    sqlite3_context *context,
+    int argc,
+    sqlite3_value **argv)
+{
+    struct in_addr sInAddr;
+    int nIn;
+    char* zOut;
+    int nOut = 0;
+
+    assert(argc == 1);
+    if (sqlite3_value_type(argv[0]) == SQLITE_NULL)
+    {
+        return;
+    }
+
+    nIn = sqlite3_value_int(argv[0]);
+    sInAddr.s_addr = htonl(nIn);
+    zOut = inet_ntoa(sInAddr);
+    nOut = strlen(zOut);
+    sqlite3_result_text(context, (char*)zOut, nOut, SQLITE_TRANSIENT);
+}
+
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+
+int sqlite3_inet_init(
+    sqlite3 *db,
+    char **pzErrMsg,
+    const sqlite3_api_routines *pApi)
+{
+    int rc = SQLITE_OK;
+
+    SQLITE_EXTENSION_INIT2(pApi);
+    (void)pzErrMsg;  /* Unused parameter */
+
+    rc = sqlite3_create_function(
+        db,
+        "inet_aton",
+        1,
+        SQLITE_UTF8,
+        0,
+        inet_aton_impl,
+        0,
+        0);
+
+    if (rc != SQLITE_OK) {
+        return rc;
+    }
+
+    rc = sqlite3_create_function(
+        db,
+        "inet_ntoa",
+        1,
+        SQLITE_UTF8,
+        0,
+        inet_ntoa_impl,
+        0,
+        0);
+
+    return rc;
+}

testsuite.sh

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+#!/bin/bash
+
+ANY_FAILED=0
+
+main() {
+    ANY_FAILED="0"
+
+    testcase "inet_ntoa and inet_aton are inverse" \
+        "select inet_ntoa(inet_aton('33.44.55.66'));" \
+        "33.44.55.66"
+
+    if [ "$?" != "0" ]; then ANY_FAILED="1"; fi
+
+    testcase "inet_aton converts valid string address to number" \
+        "select inet_aton('12.34.56.78');" \
+        "203569230"
+
+    if [ "$?" != "0" ]; then ANY_FAILED="1"; fi
+
+    testcase "inet_ntoa converts valid numeric address to string" \
+        "select inet_ntoa(1924046976);" \
+        "114.174.160.128"
+
+    if [ "$?" != "0" ]; then ANY_FAILED="1"; fi
+
+    testcase "inet_ntoa ignores NULLs" \
+        "select inet_ntoa(NULL);" \
+        ""
+
+    if [ "$?" != "0" ]; then ANY_FAILED="1"; fi
+
+    testcase "inet_aton ignores NULLs" \
+        "select inet_aton(NULL);" \
+        ""
+
+    if [ "$?" != "0" ]; then ANY_FAILED="1"; fi
+
+    testcase "inet_aton fails when fed arbitrary strings" \
+        "select inet_aton('999.999.999.999');" \
+        "Error: near line 2: Passed a malformed IP address"
+
+    if [ "$?" != "0" ]; then ANY_FAILED="1"; fi
+
+    return $ANY_FAILED
+}
+
+testcase() {
+    CASE_NAME="$1"
+    CODE="$2"
+    EXPECTED="$3"
+
+    FAILED="0"
+
+    printf "$CASE_NAME\t-\t"
+
+    OUTPUT=$(
+        sqlite3 2>&1 << EOF
+.load bin/inet
+$CODE
+EOF
+    )
+
+    RC="$?"
+
+    if [ "$EXPECTED" != "$OUTPUT" ]; then
+        printf "FAILED\n"
+        printf "\tAssertion failed. Expected: '$EXPECTED', Actual: '$OUTPUT'\n"
+        FAILED="1"
+    else
+        printf "OK\n"
+    fi
+
+    return $FAILED
+}
+
+main