Link against libuuid

  * replaces UUID struct with uuid_t array type
  * uses libuuid to generate version 1 and 4 UUIDs in a cross-platform
    manner

Author: benwebber

Makefile

@@ -2,31 +2,26 @@
 
 NAME	  = uuid
 PLATFORM := $(shell uname -s)
-CFLAGS    = -fPIC -Wall -Wextra -O2 -c
+CFLAGS    = -g -fPIC -Wall -Wextra -O2
 LDFLAGS   = -shared
-BUILD_DIR = build
 DIST_DIR  = dist
 SOURCES  := $(wildcard src/*.c)
-OBJECTS  := $(patsubst src/%.c, $(BUILD_DIR)/%.o, $(SOURCES))
 
 ifeq ($(PLATFORM), Darwin)
 	SO_EXT = dylib
 else
-	SO_EXT = so
+	SO_EXT   = so
+	LDFLAGS += -luuid
 endif
 
 all: $(DIST_DIR)/$(NAME).$(SO_EXT)
 
 clean:
-	$(RM) -r $(BUILD_DIR) $(DIST_DIR)
+	$(RM) -r $(DIST_DIR)
 
 print-%:
 	@echo '$*=$($*)'
 
-$(BUILD_DIR)/%.o: src/%.c
-	mkdir -p $(BUILD_DIR)
-	$(CC) $(CFLAGS) -o "$@" $<
-
-$(DIST_DIR)/$(NAME).$(SO_EXT): $(OBJECTS)
+$(DIST_DIR)/$(NAME).$(SO_EXT): $(SOURCES)
 	mkdir -p $(DIST_DIR)
-	$(CC) $(LDFLAGS) -o $@ $<
+	$(CC) $< $(CFLAGS) $(LDFLAGS) -o $@

README.md

@@ -4,18 +4,18 @@ This SQLite extension implements functions for creating [RFC 4122](https://www.i
 
 ## Installation
 
-1. Install the SQLite development headers. Mac OS X ships with SQLite and the development headers, but you may need to install them on Linux.
+1. Install the necessary development headers. Mac OS X ships with SQLite and the development headers, but you may need to install them on Linux.
 
     * Debian / Ubuntu:
 
         ```
-        sudo apt-get install libsqlite3-dev
+        sudo apt-get install libsqlite3-dev uuid-dev
         ```
 
     * Red Hat / CentOS:
 
         ```
-        sudo yum install sqlite-devel
+        sudo yum install sqlite-devel uuid-devel
         ```
 
 2. Build the extension. The build will produce a shared library for your platform under `dist/`.
@@ -41,6 +41,15 @@ This SQLite extension implements functions for creating [RFC 4122](https://www.i
 
 ## Usage
 
+### `uuid1()`
+
+Generate a version 1 UUID, based on the time and host machine's MAC address.
+
+```sql
+SELECT uuid1();
+d5a80b20-0d8f-11e5-b8cb-080027b6ec40
+```
+
 ### `uuid4()`
 
 Generate a version 4 (random) UUID.

src/uuid.c

@@ -15,94 +15,67 @@
 #include <sqlite3ext.h>
 SQLITE_EXTENSION_INIT1
 #include <assert.h>
-#include <fcntl.h>
-#include <unistd.h>
-#include <stdio.h>
-#include <stdlib.h>
+#include <uuid/uuid.h>
 
 /*
-** A UUID represents an RFC 4122 UUID.
+** Implementation of uuid1() function.
 */
-typedef struct UUID {
-  unsigned char bytes[16];
-} UUID;
-
-/*
-** Set the UUID version.
-*/
-void set_uuid_version(UUID* u, char version) {
-  u->bytes[6] = (u->bytes[6] & 0x0f) | (version << 4);
+static void uuid1func(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  assert(argc==0);
+  uuid_t uuid;
+  uuid_generate_time(uuid);
+  char uuid_str[37];
+  uuid_unparse_lower(uuid, uuid_str);
+  sqlite3_result_text(context, uuid_str, 37, SQLITE_TRANSIENT);
 }
 
 /*
-** Set the UUID variant to match the RFC4122 specification.
-**
-** Example:
-**
-**   e462c464-d4d9-433b-b372-cc90939dbe6d
-**                      ^
-**                      one of {8, 9, a, b}
+** Implementation of the uuid4() function.
 */
-void set_uuid_variant(UUID* u) {
-  u->bytes[8] = (u->bytes[8] & 0x3f) | 0x80;
+static void uuid4func(
+  sqlite3_context *context,
+  int argc,
+  sqlite3_value **argv
+){
+  assert(argc==0);
+  uuid_t uuid;
+  uuid_generate_random(uuid);
+  char uuid_str[37];
+  uuid_unparse_lower(uuid, uuid_str);
+  sqlite3_result_text(context, uuid_str, 37, SQLITE_TRANSIENT);
 }
 
 /*
-** Represent a UUID in its canonical string form.
+** Register UUID functions to database `db`.
 */
-char* uuid_to_string(UUID* u) {
-
-  int i;
-  char* buf = sqlite3_malloc(sizeof(char)*36+1);
-
-  for (i = 0; i < 4; i++) {
-    sprintf(&buf[2*i], "%02x", u->bytes[i]);
-  }
-  sprintf(&buf[8], "-");
-  for (i = 4; i < 6; i++) {
-    sprintf(&buf[2*i + 1], "%02x", u->bytes[i]);
-  }
-  sprintf(&buf[13], "-");
-  for (i = 6; i < 8; i++) {
-    sprintf(&buf[2*i + 2], "%02x", u->bytes[i]);
-  }
-  sprintf(&buf[18], "-");
-  for (i = 8; i < 10; i++) {
-    sprintf(&buf[2*i + 3], "%02x", u->bytes[i]);
-  }
-  sprintf(&buf[23], "-");
-  for (i = 10; i < 16; i++) {
-    sprintf(&buf[2*i + 4], "%02x", u->bytes[i]);
-  }
+int register_uuid_functions(sqlite3 *db) {
+  typedef struct UUIDScalar {
+    const char *name;
+    int argc;
+    int enc;
+    void (*func)(sqlite3_context*, int, sqlite3_value**);
+  } UUIDScalar;
 
-  return buf;
-}
+  UUIDScalar scalars[] = {
+    {"uuid1", 0, SQLITE_UTF8, uuid1func},
+    {"uuid4", 0, SQLITE_UTF8, uuid4func},
+  };
 
-UUID random_uuid() {
-  UUID u;
+  int rc = SQLITE_OK;
+  int i, n;
 
-  int fd = open("/dev/urandom", O_RDONLY);
-  read(fd, u.bytes, sizeof(u.bytes));
-  close(fd);
+  n = (int)(sizeof(scalars)/sizeof(scalars[0]));
 
-  set_uuid_version(&u, 4);
-  set_uuid_variant(&u);
-  return u;
-}
+  for (i = 0; rc == SQLITE_OK && i < n; i++) {
+    UUIDScalar *s = &scalars[i];
+    rc = sqlite3_create_function(db, s->name, s->argc, s->enc, 0, s->func, 0, 0);
+  }
 
-/*
-** Implementation of the uuid4() function.
-*/
-static void uuid4func(
-  sqlite3_context *context,
-  int argc,
-  sqlite3_value **argv
-){
-  assert(argc==0);
-  UUID uuid = random_uuid();
-  char* buf = uuid_to_string(&uuid);
-  sqlite3_result_text(context, (char*)buf, 36, SQLITE_TRANSIENT);
-  sqlite3_free(buf);
+  return rc;
 }
 
 #ifdef _WIN32
@@ -113,8 +86,6 @@ int sqlite3_uuid_init(
   char **pzErrMsg,
   const sqlite3_api_routines *pApi
 ){
-  int rc = SQLITE_OK;
   SQLITE_EXTENSION_INIT2(pApi);
-  rc = sqlite3_create_function(db, "uuid4", 0, SQLITE_UTF8, 0, uuid4func, 0, 0);
-  return rc;
+  return register_uuid_functions(db);
 }