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Add a tool module to decode integers of any size and signedness

Natasha Kerensikova authored on23/03/2016 20:42:54
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src/dict_tools.c
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+/*
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+ * Copyright (c) 2016, Natacha Porté
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+ *
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+ * Permission to use, copy, modify, and distribute this software for any
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+ * purpose with or without fee is hereby granted, provided that the above
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+ * copyright notice and this permission notice appear in all copies.
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+ *
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+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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+ */
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+
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+#include <inttypes.h>
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+
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+#include "dict_tools.h"
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+
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+static bool
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+check_length(Tuple *tuple, const char *context) {
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+	if (tuple->length == 1 || tuple->length == 2 || tuple->length == 4) {
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+		return true;
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+	}
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+
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+	APP_LOG(APP_LOG_LEVEL_ERROR,
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+	    "Unexpected length %" PRIu16 " in %s dictionary entry",
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+	    tuple->length, context);
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+	return false;
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+}
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+
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+static int32_t
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+raw_read_int(Tuple *tuple) {
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+	switch (tuple->length) {
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+	    case 1:
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+		return tuple->value->int8;
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+	    case 2:
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+		return tuple->value->int16;
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+	    case 4:
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+		return tuple->value->int32;
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+	    default:
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+		return 0;
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+	}
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+}
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+
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+static uint32_t
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+raw_read_uint(Tuple *tuple) {
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+	switch (tuple->length) {
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+	    case 1:
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+		return tuple->value->uint8;
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+	    case 2:
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+		return tuple->value->uint16;
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+	    case 4:
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+		return tuple->value->uint32;
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+	    default:
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+		return 0;
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+	}
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+}
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+
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+int32_t
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+tuple_int(Tuple *tuple) {
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+	if (!tuple) return 0;
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+	switch (tuple->type) {
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+	    case TUPLE_INT:
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+		if (!check_length(tuple, "integer")) return 0;
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+		return raw_read_int(tuple);
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+	    case TUPLE_UINT:
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+		if (!check_length(tuple, "integer")) return 0;
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+		uint32_t u = raw_read_uint(tuple);
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+		if (u > 2147483647) {
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+			APP_LOG(APP_LOG_LEVEL_ERROR,
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+			    "Integer overflow in signed dictionary entry %"
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+			    PRIu32, u);
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+			return 0;
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+		}
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+		return u;
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+	    default:
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+		APP_LOG(APP_LOG_LEVEL_ERROR,
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+		    "Unexpected type %d for integer dictionary entry",
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+		    (int)tuple->type);
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+		return 0;
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+	}
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+}
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+
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+uint32_t
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+tuple_uint(Tuple *tuple) {
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+	if (!tuple) return 0;
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+	switch (tuple->type) {
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+	    case TUPLE_UINT:
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+		if (!check_length(tuple, "unsigned")) return 0;
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+		return raw_read_uint(tuple);
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+	    case TUPLE_INT:
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+		if (!check_length(tuple, "unsigned")) return 0;
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+		int32_t i = raw_read_int(tuple);
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+		if (i < 0) {
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+			APP_LOG(APP_LOG_LEVEL_ERROR,
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+			    "Integer underflow in unsigned dictionary entry %"
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+			    PRIi32, i);
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+			return 0;
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+		}
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+		return i;
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+	    default:
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+		APP_LOG(APP_LOG_LEVEL_ERROR,
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+		    "Unexpected type %d for unsigned dictionary entry",
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+		    (int)tuple->type);
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+		return 0;
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+	}
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+}
src/dict_tools.h
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0 110 
new file mode 100644
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+/*
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+ * Copyright (c) 2016, Natacha Porté
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+ *
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+ * Permission to use, copy, modify, and distribute this software for any
5 
+ * purpose with or without fee is hereby granted, provided that the above
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+ * copyright notice and this permission notice appear in all copies.
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+ *
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+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9 
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10 
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11 
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12 
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13 
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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+ */
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+
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+#include <pebble.h>
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+
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+int32_t
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+tuple_int(Tuple *tuple);
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+
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+uint32_t
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+tuple_uint(Tuple *tuple);