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-rw-r--r--proto/puzbusv1.c43
-rw-r--r--proto/puzbusv1.h37
2 files changed, 66 insertions, 14 deletions
diff --git a/proto/puzbusv1.c b/proto/puzbusv1.c
index 3ff7c63..d6cd597 100644
--- a/proto/puzbusv1.c
+++ b/proto/puzbusv1.c
@@ -1,25 +1,44 @@
#include <mpack.h>
#include <stdio.h>
+// MIN() macro
+#include <sys/param.h>
+// TODO: check if this works on pico as well
+
#include "puzbusv1.h"
-int pb_read(struct pb_msg* target, char* buf, size_t buf_sz) {
- mpack_reader_t reader;
- printf("read %lu bytes...\n", buf_sz);
+bool pb_read(struct pb_msg* target, char* buf, size_t buf_sz) {
+ // remaining bytes to be read to target->data; this is the only variable that
+ // needs to persist between buffer blocks, and is therefore static
+ static size_t rdata = 0;
+ // a new reader is used per buffer block passed to this function
+ mpack_reader_t reader;
mpack_reader_init_data(&reader, buf, buf_sz);
- uint16_t address = mpack_expect_u16(&reader);
- char data_buf[80];
- size_t data_size = mpack_expect_bin_buf(&reader, data_buf, sizeof(data_buf));
-
- printf("0x%02x\n", address);
- printf("\"%.*s\"\n", data_size, data_buf);
-
- return 0;
+ // at start of message
+ if (rdata == 0) {
+ // NOTE: This approach will crash and burn when target->addr can be read
+ // and target->length is past the end of the current buffer block. This is
+ // a highly unlikely scenario, as pb_read is called for each chunk of a TCP
+ // frame, and frames (should) include only one puzzle bus message.
+ target->addr = mpack_expect_u16(&reader);
+ target->length = rdata = mpack_expect_bin(&reader);
+ target->data = (char*) malloc(target->length);
+ }
+
+ // continue reading chunks of target->data until the amount of bytes
+ // specified in target->length
+ size_t to_read = MIN(mpack_reader_remaining(&reader, NULL), rdata);
+ char* data = target->data + target->length - rdata; // 'ol pointer arithmetic
+ mpack_read_bytes(&reader, data, to_read);
+ rdata -= to_read;
+
+ // if rdata = 0, the message was completely read
+ return rdata == 0;
}
-int pb_write(struct pb_msg* target, char** buf, size_t* buf_sz) {
+bool pb_write(struct pb_msg* target, char** buf, size_t* buf_sz) {
mpack_writer_t writer;
mpack_writer_init_growable(&writer, buf, buf_sz);
diff --git a/proto/puzbusv1.h b/proto/puzbusv1.h
index 116dbf9..814bc93 100644
--- a/proto/puzbusv1.h
+++ b/proto/puzbusv1.h
@@ -13,8 +13,41 @@ struct pb_msg {
size_t length;
};
-int pb_read(struct pb_msg* target, char* buf, size_t buf_sz);
-int pb_write(struct pb_msg* target, char** buf, size_t* buf_sz);
+/**
+ * \brief Read chunk of input stream, and store resulting message in \p target
+ *
+ * This function is called for each chunk of data from an input stream, and
+ * will parse the next puzzle bus message into \p target. The input stream is
+ * assumed to only contain messages encoded by \p pb_write()
+ *
+ * \param target pointer to struct that will contain the finished message data
+ * \param buf pointer to input stream data chunk
+ * \param buf_sz size of \p buf
+ *
+ * \returns boolean true if a message was completely read, false if more data
+ * is required
+ *
+ * \note target->data will automatically be allocated by this function, and
+ * must be `free()`d by the caller when finished
+ */
+bool pb_read(struct pb_msg* target, char* buf, size_t buf_sz);
+/**
+ * \brief Allocate and write a msgpack-formatted message to \p buf
+ *
+ * This function allocates a buffer large enough to fit the message specified
+ * in \p target, and encodes the data in \p target in a format that can be
+ * decoded later using \p pb_read()
+ *
+ * \param target pointer to struct that contains the message data
+ * \param buf pointer to \c char* that will contain the formatted message
+ * \param buf_sz pointer to \c size_t that will represent the final size of \p buf
+ *
+ * \returns boolean true if a the message could be encoded successfully, false
+ * if there was some kind of error
+ *
+ * \note the pointer stored in \p buf must be `free()`d by the caller afterwards
+ */
+bool pb_write(struct pb_msg* target, char** buf, size_t* buf_sz);
#ifdef __cplusplus
}