Wrote basic makefile, wrote tests, and then fixed them

.gitignore

 *.o
 *~
+*.a
+src/test_suite

common.mk

+CFLAGS := $(shell pkg-config --cflags glib-2.0)
+LDFLAGS := $(shell pkg-config --libs glib-2.0)
+CC := gcc
+
+CFLAGS += -DINCLUDE_TESTS
+
+.SUFFIX:
+
+%.a:
+	-rm -f $@
+	ar crv $@ $^
+
+%.o: %.c
+	$(CC) $(CFLAGS) -c -o $@ $<
\ No newline at end of file

config.mk

-CFLAGS := $(shell pkg-config --cflags glib-2.0)
-LDFLAGS := $(shell pkg-config --libs glib-2.0)
\ No newline at end of file

lib/Makefile

-include ../config.mk
+include ../common.mk
 
 all: allocator.o
 
-%.o: %.c
-	gcc $(CFLAGS) -c -o $@ $^
\ No newline at end of file

lib/allocator.h

@@ -5,7 +5,7 @@
 typedef struct arena* arena_t; // hidden implementation
 
 arena_t new_arena(size_t block_size); // pass 0 for default...
-void* arena_malloc(arena_t arena, size_t count); // TODO: needs the malloc attribute
+void* arena_malloc(arena_t arena, size_t count) __attribute__(( malloc, alloc_size(2) ));
 void delete_arena(arena_t arena);
 
 

src/Makefile

+-include ../common.mk
+
+all: libhammer.a test_suite
+
+test_suite: test_suite.o libhammer.a
+	$(CC) $(LDFLAGS) -o $@ $^
+
+libhammer.a: bitreader.o
+
+bitreader.o: test_suite.h

src/bitreader.c

 #include <stdint.h>
+#include <stdio.h>
 #include "internal.h"
 #include "hammer.h"
+#include "test_suite.h"
 
 #define LSB(range) (0:range)
 #define MSB(range) (1:range)
 #define LDB(range,i) (((i)>>LSB(range))&((1<<(MSB(range)-LSB(range)+1))-1))
 
-long long read_bits(parse_state_t* state, int count) {
+long long read_bits(input_stream_t* state, int count, char signed_p) {
   long long out = 0;
   int offset = 0;
+  long long msb = (!!signed_p) << (count - 1); // 0 if unsigned, else 1 << (nbits - 1)
   while (count) {
     int segment, segment_len;
     // Read a segment...
@@ -45,5 +48,65 @@ long long read_bits(parse_state_t* state, int count) {
     }
     count -= segment_len;
   }
-  return out;
+  return (out ^ msb) - msb; // perform sign extension
 }
+
+#ifdef INCLUDE_TESTS
+
+#define MK_INPUT_STREAM(buf,len,endianness_)   \
+  {					      \
+    .input = buf,						\
+      .length = len,						\
+      .index = 0,						\
+      .bit_offset = (((endianness_) & BIT_BIG_ENDIAN) ? 8 : 0),	\
+      .endianness = endianness_					\
+      }
+
+static void test_bitreader_be(void) {
+  input_stream_t is = MK_INPUT_STREAM("\x6A\x5A", 2, BIT_BIG_ENDIAN | BYTE_BIG_ENDIAN);
+  g_check_cmpint(read_bits(&is, 3, false), ==, 0x03);
+  g_check_cmpint(read_bits(&is, 8, false), ==, 0x52);
+  g_check_cmpint(read_bits(&is, 5, false), ==, 0x1A);
+}
+static void test_bitreader_le(void) {
+  input_stream_t is = MK_INPUT_STREAM("\x6A\x5A", 2, BIT_LITTLE_ENDIAN | BYTE_LITTLE_ENDIAN);
+  g_check_cmpint(read_bits(&is, 3, false), ==, 0x02);
+  g_check_cmpint(read_bits(&is, 8, false), ==, 0x4D);
+  g_check_cmpint(read_bits(&is, 5, false), ==, 0x0B);
+}
+
+static void test_largebits_be(void) {
+  input_stream_t is = MK_INPUT_STREAM("\x6A\x5A", 2, BIT_BIG_ENDIAN | BYTE_BIG_ENDIAN);
+  g_check_cmpint(read_bits(&is, 11, false), ==, 0x352);
+  g_check_cmpint(read_bits(&is, 5, false), ==, 0x1A);
+}
+  
+static void test_largebits_le(void) {
+  input_stream_t is = MK_INPUT_STREAM("\x6A\x5A", 2, BIT_LITTLE_ENDIAN | BYTE_LITTLE_ENDIAN);
+  g_check_cmpint(read_bits(&is, 11, false), ==, 0x26A);
+  g_check_cmpint(read_bits(&is, 5, false), ==, 0x0B);
+}
+
+static void test_offset_largebits_be(void) {
+  input_stream_t is = MK_INPUT_STREAM("\x6A\x5A", 2, BIT_BIG_ENDIAN | BYTE_BIG_ENDIAN);
+  g_check_cmpint(read_bits(&is, 5, false), ==, 0xD);
+  g_check_cmpint(read_bits(&is, 11, false), ==, 0x25A);
+}
+  
+static void test_offset_largebits_le(void) {
+  input_stream_t is = MK_INPUT_STREAM("\x6A\x5A", 2, BIT_LITTLE_ENDIAN | BYTE_LITTLE_ENDIAN);
+  g_check_cmpint(read_bits(&is, 5, false), ==, 0xA);
+  g_check_cmpint(read_bits(&is, 11, false), ==, 0x2D3);
+}
+
+
+void register_bitreader_tests(void)  {
+  g_test_add_func("/core/bitreader/be", test_bitreader_be);
+  g_test_add_func("/core/bitreader/le", test_bitreader_le);
+  g_test_add_func("/core/bitreader/largebits-be", test_largebits_be);
+  g_test_add_func("/core/bitreader/largebits-le", test_largebits_le);
+  g_test_add_func("/core/bitreader/offset-largebits-be", test_offset_largebits_be);
+  g_test_add_func("/core/bitreader/offset-largebits-le", test_offset_largebits_le);
+}
+
+#endif // #ifdef INCLUDE_TESTS

src/hammer.h

@@ -37,14 +37,21 @@
  */
 #define BYTE_BIG_ENDIAN 0x1
 #define BIT_BIG_ENDIAN 0x2
+#define BIT_LITTLE_ENDIAN 0x0
+#define BYTE_LITTLE_ENDIAN 0x0
 
-typedef struct parse_state {
+typedef struct input_stream {
+  // This should be considered to be a really big value type.
   const uint8_t *input;
-  GHashTable *cache; 
   size_t index;
   size_t length;
   char bit_offset;
   char endianness;
+} input_stream_t;
+  
+typedef struct parse_state {
+  GHashTable *cache; 
+  input_stream_t input_stream;
 } parse_state_t;
 
 typedef struct parse_result {

src/internal.h

@@ -2,6 +2,9 @@
 #define HAMMER_INTERNAL__H
 #include "hammer.h"
 
-long long read_bits(parse_state_t* state, int count);
+#define false 0
+#define true 1
+
+long long read_bits(input_stream_t* state, int count, char signed_p);
 
 #endif // #ifndef HAMMER_INTERNAL__H

src/test_suite.c

+#include "hammer.h"
+#include "test_suite.h"
+
+extern void register_bitreader_tests();
+
+int main(int argc, char** argv) {
+  g_test_init(&argc, &argv, NULL);
+
+  // register various test suites...
+  register_bitreader_tests();
+
+  g_test_run();
+}
+

src/test_suite.h

+#ifndef HAMMER_TEST_SUITE__H
+#define HAMMER_TEST_SUITE__H
+
+// Equivalent to g_assert_*, but not using g_assert...
+#define g_check_cmpint(n1, op, n2) {			\
+  typeof (n1) _n1 = (n1);				\
+  typeof (n2) _n2 = (n2);				\
+  if (!(_n1 op _n2)) {					\
+    g_test_message("Check failed: (%s): (%d %s %d)",	\
+		   #n1 " " #op " " #n2,			\
+		   _n1, #op, _n2);			\
+    g_test_fail();					\
+  }							\
+  }
+
+
+#endif // #ifndef HAMMER_TEST_SUITE__H