X-Git-Url: https://sigrok.org/gitweb/?a=blobdiff_plain;f=datastore.c;h=30d1d9b3f535b3fd91683f3926644812912278b0;hb=c73d2ea421c2b425c3f0ae33bce2bfd0c448ca5f;hp=443ab1539d96c0bbf920f8da369488f9905cd684;hpb=1b452b8510922bac08db87f8ea769515c795e22f;p=libsigrok.git

diff --git a/datastore.c b/datastore.c
index 443ab153..30d1d9b3 100644
--- a/datastore.c
+++ b/datastore.c
@@ -1,7 +1,7 @@
 /*
  * This file is part of the sigrok project.
  *
- * Copyright (C) 2010 Bert Vermeulen <bert@biot.com>
+ * Copyright (C) 2010-2012 Bert Vermeulen <bert@biot.com>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -21,55 +21,168 @@
 #include <stdint.h>
 #include <string.h>
 #include <glib.h>
-#include <sigrok.h>
+#include "sigrok.h"
+#include "sigrok-internal.h"
 
-static gpointer new_chunk(struct datastore **ds);
+static gpointer new_chunk(struct sr_datastore **ds);
 
-struct datastore *datastore_new(int unitsize)
+/**
+ * Create a new datastore with the specified unit size.
+ *
+ * The unit size is fixed once the datastore is created, and cannot be
+ * changed later on, neither can data be added to the datastore with
+ * different unit sizes later.
+ *
+ * It is the caller's responsibility to free the allocated memory of the
+ * datastore via the sr_datastore_destroy() function, if no longer needed.
+ *
+ * TODO: Unitsize should probably be unsigned int or uint32_t or similar.
+ * TODO: This function should have a 'chunksize' parameter, and
+ *       struct sr_datastore a 'chunksize' field.
+ *
+ * @param unitsize The unit size (>= 1) to be used for this datastore.
+ * @param ds Pointer to a variable which will hold the newly created
+ *           datastore structure.
+ *           
+ * @return SR_OK upon success, SR_ERR_MALLOC upon memory allocation errors,
+ *         or SR_ERR_ARG upon invalid arguments. If something other than SR_OK
+ *         is returned, the value of 'ds' is undefined.
+ */
+SR_API int sr_datastore_new(int unitsize, struct sr_datastore **ds)
 {
-	struct datastore *ds;
+	if (!ds) {
+		sr_err("ds: %s: ds was NULL", __func__);
+		return SR_ERR_ARG;
+	}
 
-	ds = g_malloc(sizeof(struct datastore));
-	ds->ds_unitsize = unitsize;
-	ds->num_units = 0;
-	ds->chunklist = NULL;
+	if (unitsize <= 0) {
+		sr_err("ds: %s: unitsize was %d, but it must be >= 1",
+		       __func__, unitsize);
+		return SR_ERR_ARG;
+	}
+
+	if (!(*ds = g_try_malloc(sizeof(struct sr_datastore)))) {
+		sr_err("ds: %s: ds malloc failed", __func__);
+		return SR_ERR_MALLOC;
+	}
 
-	return ds;
+	(*ds)->ds_unitsize = unitsize;
+	(*ds)->num_units = 0;
+	(*ds)->chunklist = NULL;
+
+	return SR_OK;
 }
 
-void datastore_destroy(struct datastore *ds)
+/**
+ * Destroy the specified datastore and free the memory used by it.
+ *
+ * This will free the memory used by the data in the datastore's 'chunklist',
+ * by the chunklist data structure itself, and by the datastore struct.
+ *
+ * @param ds The datastore to destroy.
+ *
+ * @return SR_OK upon success, SR_ERR_ARG upon invalid arguments.
+ */
+SR_API int sr_datastore_destroy(struct sr_datastore *ds)
 {
 	GSList *chunk;
 
+	if (!ds) {
+		sr_err("ds: %s: ds was NULL", __func__);
+		return SR_ERR_ARG;
+	}
+
 	for (chunk = ds->chunklist; chunk; chunk = chunk->next)
 		g_free(chunk->data);
 	g_slist_free(ds->chunklist);
 	g_free(ds);
+
+	/* TODO: Set ds = NULL? */
+
+	return SR_OK;
 }
 
-void datastore_put(struct datastore *ds, void *data, unsigned int length,
-		   int in_unitsize, int *probelist)
+/**
+ * Append some data to the specified datastore.
+ *
+ * TODO: More elaborate function description.
+ *
+ * TODO: This function should use the (not yet available) 'chunksize' field
+ *       of struct sr_datastore (instead of hardcoding DATASTORE_CHUNKSIZE).
+ * TODO: in_unitsize and probelist are unused?
+ * TODO: A few of the parameters can be const.
+ * TODO: Handle new_chunk() returning NULL.
+ * TODO: Ideally, 'ds' should be unmodified upon errors.
+ *
+ * @param ds Pointer to the datastore which shall receive the data.
+ *           Must not be NULL.
+ * @param data Pointer to the memory buffer containing the data to add.
+ *             Must not be NULL. TODO: Data format?
+ * @param length Length of the data to add (in number of bytes).
+ *               TODO: Should 0 be allowed as length?
+ * @param in_unitsize The unit size (>= 1) of the input data.
+ * @param probelist Pointer to a list of integers (probe numbers). The probe
+ *                  numbers in this list are 1-based, i.e. the first probe
+ *                  is expected to be numbered 1 (not 0!). Must not be NULL.
+ *
+ * @return SR_OK upon success, SR_ERR_MALLOC upon memory allocation errors,
+ *         or SR_ERR_ARG upon invalid arguments. If something other than SR_OK
+ *         is returned, the value/state of 'ds' is undefined.
+ */
+SR_API int sr_datastore_put(struct sr_datastore *ds, void *data,
+		unsigned int length, int in_unitsize, int *probelist)
 {
 	unsigned int stored;
 	int capacity, size, num_chunks, chunk_bytes_free, chunk_offset;
 	gpointer chunk;
 
-	/* QUICK HACK */
-	in_unitsize = in_unitsize;
-	probelist = probelist;
+	/* Avoid compiler warnings. */
+	(void)in_unitsize;
+	(void)probelist;
 
+	if (!ds) {
+		sr_err("ds: %s: ds was NULL", __func__);
+		return SR_ERR_ARG;
+	}
+
+	/* Unitsize must not be 0, we'll divide by 0 otherwise. */
+	if (ds->ds_unitsize == 0) {
+		sr_err("ds: %s: ds->ds_unitsize was 0", __func__);
+		return SR_ERR_ARG;
+	}
+
+	if (!data) {
+		sr_err("ds: %s: data was NULL", __func__);
+		return SR_ERR_ARG;
+	}
+
+	if (in_unitsize < 1) {
+		sr_err("ds: %s: in_unitsize was %d, but it must be >= 1",
+		       __func__, in_unitsize);
+		return SR_ERR_ARG;
+	}
+
+	if (!probelist) {
+		sr_err("ds: %s: probelist was NULL", __func__);
+		return SR_ERR_ARG;
+	}
+
+	/* Get the last chunk in the list, or create a new one if needed. */
 	if (ds->chunklist == NULL)
 		chunk = new_chunk(&ds);
 	else
 		chunk = g_slist_last(ds->chunklist)->data;
 
+	/* Get/calculate number of chunks, free space, etc. */
 	num_chunks = g_slist_length(ds->chunklist);
 	capacity = (num_chunks * DATASTORE_CHUNKSIZE);
 	chunk_bytes_free = capacity - (ds->ds_unitsize * ds->num_units);
 	chunk_offset = capacity - (DATASTORE_CHUNKSIZE * (num_chunks - 1))
 		       - chunk_bytes_free;
+
 	stored = 0;
 	while (stored < length) {
+		/* No more free space left, allocate a new chunk. */
 		if (chunk_bytes_free == 0) {
 			chunk = new_chunk(&ds);
 			chunk_bytes_free = DATASTORE_CHUNKSIZE;
@@ -86,15 +199,45 @@ void datastore_put(struct datastore *ds, void *data, unsigned int length,
 		chunk_bytes_free -= size;
 		stored += size;
 	}
+
 	ds->num_units += stored / ds->ds_unitsize;
+
+	return SR_OK;
 }
 
-static gpointer new_chunk(struct datastore **ds)
+/**
+ * Allocate a new memory chunk, append it to the datastore's chunklist.
+ *
+ * The newly allocated chunk is added to the datastore's chunklist by this
+ * function, and the return value additionally points to the new chunk.
+ *
+ * The allocated memory is guaranteed to be cleared.
+ *
+ * TODO: This function should use the datastore's 'chunksize' field instead
+ *       of hardcoding DATASTORE_CHUNKSIZE.
+ * TODO: Return int, so we can return SR_OK / SR_ERR_ARG / SR_ERR_MALLOC?
+ *
+ * @param ds Pointer to a variable which holds the datastore structure.
+ *           Must not be NULL. The contents of 'ds' are modified in-place.
+ *
+ * @return Pointer to the newly allocated chunk, or NULL upon failure.
+ */
+static gpointer new_chunk(struct sr_datastore **ds)
 {
 	gpointer chunk;
 
-	chunk = g_malloc(DATASTORE_CHUNKSIZE * (*ds)->ds_unitsize);
+	if (!ds) {
+		sr_err("ds: %s: ds was NULL", __func__);
+		return NULL; /* TODO: SR_ERR_ARG later? */
+	}
+
+	chunk = g_try_malloc0(DATASTORE_CHUNKSIZE * (*ds)->ds_unitsize);
+	if (!chunk) {
+		sr_err("ds: %s: chunk malloc failed", __func__);
+		return NULL; /* TODO: SR_ERR_MALLOC later? */
+	}
+
 	(*ds)->chunklist = g_slist_append((*ds)->chunklist, chunk);
 
-	return chunk;
+	return chunk; /* TODO: SR_OK later? */
 }