X-Git-Url: https://sigrok.org/gitweb/?a=blobdiff_plain;f=src%2Fresource.c;h=b921d93da8df5ecef1849460f2f3df8d8b3aae0e;hb=c04ca4da177bbd718be4de11e40a4ef5cbf3df7a;hp=b29be60863b0eb83584d04bfe777f75b6a666d46;hpb=bee246665b05a59f91ff7d51040cbaee614ab0c7;p=libsigrok.git

diff --git a/src/resource.c b/src/resource.c
index b29be608..b921d93d 100644
--- a/src/resource.c
+++ b/src/resource.c
@@ -35,6 +35,47 @@
  * Access to resource files.
  */
 
+/** Retrieve the size of the open stream @a file.
+ *
+ * This function only works on seekable streams. However, the set of seekable
+ * streams is generally congruent with the set of streams that have a size.
+ * Code that needs to work with any type of stream (including pipes) should
+ * require neither seekability nor advance knowledge of the size.
+ * On failure, the return value is negative and errno is set.
+ *
+ * @param file An I/O stream opened in binary mode.
+ * @return The size of @a file in bytes, or a negative value on failure.
+ *
+ * @private
+ */
+SR_PRIV int64_t sr_file_get_size(FILE *file)
+{
+	off_t filepos, filesize;
+
+	/* ftello() and fseeko() are not standard C, but part of POSIX.1-2001.
+	 * Thus, if these functions are available at all, they can reasonably
+	 * be expected to also conform to POSIX semantics. In particular, this
+	 * means that ftello() after fseeko(..., SEEK_END) has a defined result
+	 * and can be used to get the size of a seekable stream.
+	 * On Windows, the result is fully defined only for binary streams.
+	 */
+	filepos = ftello(file);
+	if (filepos < 0)
+		return -1;
+
+	if (fseeko(file, 0, SEEK_END) < 0)
+		return -1;
+
+	filesize = ftello(file);
+	if (filesize < 0)
+		return -1;
+
+	if (fseeko(file, filepos, SEEK_SET) < 0)
+		return -1;
+
+	return filesize;
+}
+
 static FILE *try_open_file(const char *datadir, const char *subdir,
 		const char *name)
 {
@@ -58,7 +99,10 @@ static int resource_open_default(struct sr_resource *res,
 		const char *name, void *cb_data)
 {
 	int64_t filesize;
-	const char *builtindir, *subdir;
+#ifdef FIRMWARE_DIR
+	const char *builtindir;
+#endif
+	const char *subdir;
 	const char *const *datadirs;
 	FILE *file;
 
@@ -66,7 +110,9 @@ static int resource_open_default(struct sr_resource *res,
 
 	switch (res->type) {
 	case SR_RESOURCE_FIRMWARE:
+#ifdef FIRMWARE_DIR
 		builtindir = FIRMWARE_DIR;
+#endif
 		subdir = "sigrok-firmware";
 		break;
 	default:
@@ -79,9 +125,10 @@ static int resource_open_default(struct sr_resource *res,
 	 * Scan the hard-coded directory before the system directories to
 	 * avoid picking up possibly outdated files from a system install.
 	 */
+#ifdef FIRMWARE_DIR
 	if (!file)
 		file = try_open_file(builtindir, "", name);
-
+#endif
 	if (!file) {
 		datadirs = g_get_system_data_dirs();
 		while (*datadirs && !file)
@@ -126,7 +173,7 @@ static int resource_close_default(struct sr_resource *res, void *cb_data)
 	return SR_OK;
 }
 
-static ssize_t resource_read_default(const struct sr_resource *res,
+static gssize resource_read_default(const struct sr_resource *res,
 		void *buf, size_t count, void *cb_data)
 {
 	FILE *file;
@@ -139,7 +186,7 @@ static ssize_t resource_read_default(const struct sr_resource *res,
 		sr_err("%s: invalid handle.", __func__);
 		return SR_ERR_ARG;
 	}
-	if (count > SSIZE_MAX) {
+	if (count > G_MAXSSIZE) {
 		sr_err("%s: count %zu too large.", __func__, count);
 		return SR_ERR_ARG;
 	}
@@ -262,10 +309,10 @@ SR_PRIV int sr_resource_close(struct sr_context *ctx, struct sr_resource *res)
  *
  * @private
  */
-SR_PRIV ssize_t sr_resource_read(struct sr_context *ctx,
+SR_PRIV gssize sr_resource_read(struct sr_context *ctx,
 		const struct sr_resource *res, void *buf, size_t count)
 {
-	ssize_t n_read;
+	gssize n_read;
 
 	n_read = (*ctx->resource_read_cb)(res, buf, count,
 			ctx->resource_cb_data);
@@ -294,7 +341,8 @@ SR_PRIV void *sr_resource_load(struct sr_context *ctx,
 {
 	struct sr_resource res;
 	void *buf;
-	ssize_t n_read;
+	size_t res_size;
+	gssize n_read;
 
 	if (sr_resource_open(ctx, &res, type, name) != SR_OK)
 		return NULL;
@@ -305,17 +353,19 @@ SR_PRIV void *sr_resource_load(struct sr_context *ctx,
 		sr_resource_close(ctx, &res);
 		return NULL;
 	}
-	buf = g_try_malloc(res.size);
+	res_size = res.size;
+
+	buf = g_try_malloc(res_size);
 	if (!buf) {
 		sr_err("Failed to allocate buffer for '%s'.", name);
 		sr_resource_close(ctx, &res);
 		return NULL;
 	}
 
-	n_read = sr_resource_read(ctx, &res, buf, res.size);
+	n_read = sr_resource_read(ctx, &res, buf, res_size);
 	sr_resource_close(ctx, &res);
 
-	if (n_read < 0 || (size_t)n_read != res.size) {
+	if (n_read < 0 || (size_t)n_read != res_size) {
 		if (n_read >= 0)
 			sr_err("Failed to read '%s': premature end of file.",
 				name);
@@ -323,7 +373,7 @@ SR_PRIV void *sr_resource_load(struct sr_context *ctx,
 		return NULL;
 	}
 
-	*size = res.size;
+	*size = res_size;
 	return buf;
 }