Add compile-time config

Author: chriso

.gitignore

@@ -9,3 +9,5 @@ CMakeCache.txt
 CMakeFiles
 cmake_install.cmake
 install_manifest.txt
+Makefile
+config.h

CMakeLists.txt

@@ -1,5 +1,14 @@
 cmake_minimum_required (VERSION 2.6)
+
 project (Intern)
+
+set (PAGE_SIZE 4096 CACHE STRING "Page size for allocations")
+option (MMAP_PAGES "Allocate pages with mmap(2)" OFF)
+option (INLINE_UNSIGNED "Inline unsigned integers into the ID" OFF)
+
+configure_file (config.h.in config.h)
+
 add_library (intern strings.c block.c optimize.c)
+
 install (TARGETS intern DESTINATION lib)
 install (FILES strings.h block.h optimize.h DESTINATION include/intern)

block.c

@@ -1,6 +1,7 @@
 #include <stdlib.h>
 #include <string.h>
 
+#include "config.h"
 #include "block.h"
 #include "branch.h"
 #include "page.h"

config.h.in

@@ -0,0 +1,3 @@
+#define PAGE_SIZE @PAGE_SIZE@
+#cmakedefine MMAP_PAGES
+#cmakedefine INLINE_UNSIGNED

optimize.c

@@ -1,6 +1,7 @@
 #include <stdlib.h>
 #include <string.h>
 
+#include "config.h"
 #include "optimize.h"
 #include "branch.h"
 
@@ -125,7 +126,7 @@ bool strings_frequency_add_all(struct strings_frequency *frequency,
     return true;
 }
 
-struct strings *strings_optimize(const struct strings *strings,
+struct strings *strings_optimize(struct strings *strings,
                                  struct strings_frequency *frequency) {
     struct strings *optimized = strings_new();
     if (!optimized) {

optimize.h

@@ -8,8 +8,7 @@ struct strings_frequency;
 // Create a new, optimized string repository which stores the most frequently
 // seen strings together. The string with the lowest ID (1) is the most
 // frequently seen string
-struct strings *strings_optimize(const struct strings*,
-                                 struct strings_frequency*);
+struct strings *strings_optimize(struct strings*, struct strings_frequency*);
 
 // Create a new string frequency tracker
 struct strings_frequency *strings_frequency_new(void);

page.h

@@ -1,4 +1,4 @@
-#ifdef PAGE_MMAP
+#ifdef MMAP_PAGES
 #include <sys/mman.h>
 
 static inline void *page_alloc(size_t page_size) {

strings.c

@@ -2,6 +2,7 @@
 #include <string.h>
 #include <limits.h>
 
+#include "config.h"
 #include "strings.h"
 #include "tree.h"
 #include "branch.h"
@@ -228,14 +229,12 @@ uint32_t strings_lookup(const struct strings *strings, const char *string) {
     return 0;
 }
 
-#ifdef INLINE_UNSIGNED
 const char *strings_lookup_id(struct strings *strings, uint32_t id) {
+#ifdef INLINE_UNSIGNED
     if (id & unsigned_tag) {
         unsigned_string(strings->buffer, id & ~unsigned_tag);
         return strings->buffer;
     }
-#else
-const char *strings_lookup_id(const struct strings *strings, uint32_t id) {
 #endif
 
     if (UNLIKELY(id > strings->total)) {

strings.h

@@ -5,10 +5,6 @@
 
 #include "block.h"
 
-#ifndef PAGE_SIZE
-# define PAGE_SIZE 4096
-#endif
-
 struct strings;
 
 // Create a new repository of strings
@@ -22,7 +18,8 @@ uint32_t strings_count(const struct strings*);
 
 // Intern a string and get back a unique ID. Strings must be NULL-terminated.
 // Note that IDs start at 1 and increment to either UINT_MAX or INT_MAX if
-// INLINE_UNSIGNED is defined. This function returns 0 if an error occurred
+// INLINE_UNSIGNED was defined at compile time. This function returns 0 if an
+// error occurred
 uint32_t strings_intern(struct strings*, const char *string);
 
 // Lookup the ID for a string. This function returns zero if the string
@@ -31,15 +28,11 @@ uint32_t strings_lookup(const struct strings*, const char *string);
 
 // Lookup the string associated with an ID. This function returns NULL
 // if there is no string with that ID in the repository. If INLINE_UNSIGNED
-// is defined then the repository will inline unsigned integers into the ID
-// itself. When looking up the string associated with such an ID, the integer
-// is written into an internal buffer which persists until the function is
-// called again
-#ifdef INLINE_UNSIGNED
-  const char *strings_lookup_id(struct strings*, uint32_t id);
-#else
-  const char *strings_lookup_id(const struct strings*, uint32_t id);
-#endif
+// was defined at compile time then the repository will inline unsigned
+// integers into the ID itself. When looking up the string associated with such
+// an ID, the integer is written into an internal buffer which persists until
+// the function is called again
+const char *strings_lookup_id(struct strings*, uint32_t id);
 
 struct strings_cursor {
     const struct block *strings;