[glibutil] Added range utilities

New functions are useful for parsing binary data: gutil_range_init_with_bytes() gutil_range_has_prefix() gutil_range_skip_prefix()
sailfishos · May 22, 2021 · b6d240c · b6d240c
1 parent b5359fb
commit b6d240c
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diff --git a/include/gutil_misc.h b/include/gutil_misc.h
@@ -136,6 +136,21 @@ gutil_memdup(
     const void* ptr,
     gsize size); /* Since 1.0.52 */
 
+gsize
+gutil_range_init_with_bytes(
+    GUtilRange* range,
+    GBytes* bytes); /* Since 1.0.55 */
+
+gboolean
+gutil_range_has_prefix(
+    const GUtilRange* range,
+    const GUtilData* prefix); /* Since 1.0.55 */
+
+gboolean
+gutil_range_skip_prefix(
+    GUtilRange* range,
+    const GUtilData* prefix); /* Since 1.0.55 */
+
 G_END_DECLS
 
 #endif /* GUTIL_MISC_H */

diff --git a/src/gutil_misc.c b/src/gutil_misc.c
@@ -502,6 +502,52 @@ gutil_memdup(
     }
 }
 
+gsize
+gutil_range_init_with_bytes(
+    GUtilRange* range,
+    GBytes* bytes) /* Since 1.0.55 */
+{
+    gsize size = 0;
+
+    if (G_LIKELY(range)) {
+        if (G_LIKELY(bytes)) {
+            range->ptr = (const guint8*) g_bytes_get_data(bytes, &size);
+            range->end = range->ptr + size;
+        } else {
+            memset(range, 0, sizeof(*range));
+        }
+    }
+    return size;
+}
+
+gboolean
+gutil_range_has_prefix(
+    const GUtilRange* range,
+    const GUtilData* prefix) /* Since 1.0.55 */
+{
+    if (G_LIKELY(range) && G_LIKELY(range->ptr) && G_LIKELY(prefix)) {
+        if (range->end > range->ptr) {
+            return (gsize)(range->end - range->ptr) >= prefix->size &&
+                !memcmp(range->ptr, prefix->bytes, prefix->size);
+        } else {
+            return !prefix->size;
+        }
+    }
+    return FALSE;
+}
+
+gboolean
+gutil_range_skip_prefix(
+    GUtilRange* range,
+    const GUtilData* prefix) /* Since 1.0.55 */
+{
+    if (gutil_range_has_prefix(range, prefix)) {
+        range->ptr += prefix->size;
+        return TRUE;
+    }
+    return FALSE;
+}
+
 /*
  * Local Variables:
  * mode: C

diff --git a/test/test_misc/test_misc.c b/test/test_misc/test_misc.c
@@ -581,6 +581,82 @@ test_memdup(
     g_assert(!gutil_memdup(NULL, 1));
 }
 
+/*==========================================================================*
+ * range_init
+ *==========================================================================*/
+
+static
+void
+test_range_init(
+    void)
+{
+    static const guint8 data[] = { 0x01, 0x02, 0x03 };
+    GBytes* bytes = g_bytes_new_static(data, sizeof(data));
+    GUtilRange range;
+
+    g_assert(!gutil_range_init_with_bytes(NULL, NULL));
+    g_assert(!gutil_range_init_with_bytes(&range, NULL));
+    g_assert(!range.ptr);
+    g_assert(!range.end);
+
+    g_assert(gutil_range_init_with_bytes(&range, bytes) == sizeof(data));
+    g_assert(range.ptr == data);
+    g_assert(range.end == (data + sizeof(data)));
+    g_bytes_unref(bytes);
+}
+
+/*==========================================================================*
+ * range_prefix
+ *==========================================================================*/
+
+static
+void
+test_range_prefix(
+    void)
+{
+    static const guint8 data[] = { 0x01, 0x02, 0x03, 0x04 };
+    static const guint8 prefix[] = { 0x01, 0x02 };
+    static const guint8 not_prefix[] = { 0x03, 0x04 };
+    static const guint8 too_long[] = { 0x01, 0x02, 0x03, 0x04, 0x05 };
+    GUtilData prefix_data, not_prefix_data, too_long_data;
+    GUtilRange range;
+
+    memset(&range, 0, sizeof(range));
+    g_assert(!gutil_range_has_prefix(NULL, NULL));
+    g_assert(!gutil_range_has_prefix(&range, NULL));
+
+    not_prefix_data.bytes = not_prefix;
+    not_prefix_data.size = sizeof(not_prefix);
+    too_long_data.bytes = too_long;
+    too_long_data.size = sizeof(too_long);
+
+    range.end = range.ptr = data; /* Empty range */
+    memset(&prefix_data, 0, sizeof(prefix_data)); /* Empty prefix */
+    /* Empty range doesn't have NULL prefix */
+    g_assert(!gutil_range_has_prefix(&range, NULL));
+    /* But does have empty prefix */
+    g_assert(gutil_range_has_prefix(&range, &prefix_data));
+
+    /* And doesn't have non-empty prefix */
+    g_assert(!gutil_range_has_prefix(&range, &not_prefix_data));
+    prefix_data.bytes = prefix;
+    prefix_data.size = sizeof(prefix);
+    g_assert(!gutil_range_has_prefix(&range, &prefix_data));
+
+    range.end = range.ptr + sizeof(data);
+
+    g_assert(gutil_range_has_prefix(&range, &prefix_data));
+    g_assert(!gutil_range_has_prefix(&range, &not_prefix_data));
+    g_assert(!gutil_range_has_prefix(&range, &too_long_data));
+
+    /* Test skipping */
+    g_assert(!gutil_range_skip_prefix(&range, &not_prefix_data));
+    g_assert(range.ptr == data);
+
+    g_assert(gutil_range_skip_prefix(&range, &prefix_data));
+    g_assert(range.ptr == (data + prefix_data.size));
+}
+
 /*==========================================================================*
  * Common
  *==========================================================================*/
@@ -614,6 +690,8 @@ int main(int argc, char* argv[])
     g_test_add_func(TEST_("ptrv_lenght"), test_ptrv_length);
     g_test_add_func(TEST_("ptrv_free"), test_ptrv_free);
     g_test_add_func(TEST_("memdup"), test_memdup);
+    g_test_add_func(TEST_("range_init"), test_range_init);
+    g_test_add_func(TEST_("range_prefix"), test_range_prefix);
     test_init(&test_opt, argc, argv);
     return g_test_run();
 }