[PATCH] Add MsgPack ext types handling.
Serge Petrenko
sergepetrenko at tarantool.org
Tue Apr 23 14:37:32 MSK 2019
Add the ability to encode/decode MsgPack ext types,
introduce the first extension type: MP_EXT_DECIMAL: it will be used to
store decimals in tarantool.
Needed-for tarantool/tarantool#692
---
https://github.com/tarantool/msgpuck/tree/sp/add-extension-types
https://github.com/tarantool/tarantool/issues/692
hints.c | 24 +++++++++
msgpuck.c | 20 +++++++-
msgpuck.h | 133 +++++++++++++++++++++++++++++++++++++++++++++++++
test/msgpuck.c | 7 ++-
4 files changed, 178 insertions(+), 6 deletions(-)
diff --git a/hints.c b/hints.c
index be859e9..0ab4f4d 100644
--- a/hints.c
+++ b/hints.c
@@ -672,3 +672,27 @@ const char *mp_char2escape[128] = {
NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
NULL, NULL, NULL, NULL, NULL, NULL, NULL, "\\u007f"
};
+
+/*
+ * This lookup table is used by mp_encode_ext() to
+ * determine ext code (fixext 1, fixext 2, fixext 4, fixext 8,
+ * fixext 16) to encode using size.
+ */
+const uint8_t mp_ext_hint[16] = {
+ 0xd4, /* 1 */
+ 0xd5, /* 2 */
+ 0xd6, /* 3 */
+ 0xd6, /* 4 */
+ 0xd7, /* 5 */
+ 0xd7, /* 6 */
+ 0xd7, /* 7 */
+ 0xd7, /* 8 */
+ 0xd8, /* 9 */
+ 0xd8, /* 10 */
+ 0xd8, /* 11 */
+ 0xd8, /* 12 */
+ 0xd8, /* 13 */
+ 0xd8, /* 14 */
+ 0xd8, /* 15 */
+ 0xd8 /* 16 */
+};
diff --git a/msgpuck.c b/msgpuck.c
index d0ffb83..04aeb0f 100644
--- a/msgpuck.c
+++ b/msgpuck.c
@@ -33,6 +33,17 @@
#define MP_LIBRARY 1
#include "msgpuck.h"
+const char *
+mp_ext_type_str(enum mp_ext_type type)
+{
+ switch(type) {
+ case MP_EXT_DECIMAL:
+ return "decimal";
+ default:
+ return "undefined";
+ }
+}
+
size_t
mp_vformat(char *data, size_t data_size, const char *format, va_list vl)
{
@@ -298,9 +309,14 @@ next: \
PRINTF("%lg", mp_decode_double(&data)); \
break; \
case MP_EXT: \
- mp_next(&data); \
- PRINTF("undefined"); \
+ { \
+ uint8_t type; \
+ uint32_t len; \
+ len = mp_decode_ext(&data, &len, &type); \
+ PRINTF("%s", mp_ext_type_str(type)); \
+ data += len; \
break; \
+ } \
default: \
mp_unreachable(); \
return -1; \
diff --git a/msgpuck.h b/msgpuck.h
index 6b29cd6..0a7d230 100644
--- a/msgpuck.h
+++ b/msgpuck.h
@@ -382,6 +382,13 @@ enum mp_type {
MP_EXT
};
+/**
+ * \brief MsgPack extension data types.
+ */
+enum mp_ext_type {
+ MP_EXT_DECIMAL = 0
+};
+
/**
* \brief Determine MsgPack type by a first byte \a c of encoded data.
*
@@ -532,6 +539,49 @@ mp_check_map(const char *cur, const char *end);
MP_PROTO uint32_t
mp_decode_map(const char **data);
+/**
+ * \brief calculate exact buffer size needed to store
+ * ext value of length \a len.
+ * \param len value length in bytes.
+ * \retval buffer size in bytes
+ */
+MP_PROTO uint32_t
+mp_sizeof_ext(uint32_t len);
+
+/**
+ * \brief Encode extension header with \a type and
+ * value length \a len.
+ * The value must be encoded after the header.
+ * \return \a data + \link mp_sizeof_ext() mp_sizeof_ext(size)\endlink
+ */
+MP_PROTO char *
+mp_encode_ext(char *data, uint8_t type, uint32_t len);
+
+/**
+ * \brief Check that \a cur buffer has enough bytes to decode a map header.
+ * \param cur buffer
+ * \param end end of the buffer
+ * \retval 0 - buffer has enough bytes
+ * \retval > 0 - the numbeer of remaining bytes to read
+ * \pre cur < end
+ * \pre mp_typeof(*cur) == MP_EXT
+ */
+MP_PROTO MP_PURE ptrdiff_t
+mp_check_ext(const char *cur, const char *end);
+
+/**
+ * \brief Decode an extension header from MsgPack \a data.
+ *
+ * The extension type value must be decoded after the header.
+ * \param data - the pointer to a buffer.
+ * \param len - decoded length of the following value.
+ * \param type - decoded type of the following value.
+ * \retval - the length of the following ext value.
+ * \post *data = *data + mp_sizeof_ext(length)
+ */
+MP_PROTO uint32_t
+mp_decode_ext(const char **data, uint32_t *len, uint8_t *type);
+
/**
* \brief Calculate exact buffer size needed to store an integer \a num.
* Maximum return value is 9. For performance reasons you can preallocate
@@ -1326,6 +1376,7 @@ mp_frame_advance(struct mp_frame *frame);
extern const enum mp_type mp_type_hint[];
extern const int8_t mp_parser_hint[];
extern const char *mp_char2escape[];
+extern const uint8_t mp_ext_hint[];
MP_IMPL MP_ALWAYSINLINE enum mp_type
mp_typeof(const char c)
@@ -1462,6 +1513,88 @@ mp_decode_map(const char **data)
}
}
+MP_IMPL uint32_t
+mp_sizeof_ext(uint32_t len)
+{
+ if (len <= 16) return 2;
+ if (len <= UINT8_MAX) return 3;
+ if (len <= UINT16_MAX) return 4;
+ else return 5;
+}
+
+MP_IMPL char *
+mp_encode_ext(char *data, uint8_t type, uint32_t len)
+{
+ /*
+ * zero-length should be encoded in EXT 8, because
+ * fixext always assumes exact length (1, 2, 4, 8 and 16).
+ */
+ if (len <= 16 && len > 0) {
+ data = mp_store_u8(data, mp_ext_hint[len-1]);
+ } else if (len <= UINT8_MAX) {
+ data = mp_store_u8(data, 0xc7);
+ data = mp_store_u8(data, (uint8_t) len);
+ } else if (len <= UINT16_MAX) {
+ data = mp_store_u8(data, 0xc8);
+ data = mp_store_u16(data, (uint16_t) len);
+ } else {
+ data = mp_store_u8(data, 0xc9);
+ data = mp_store_u32(data, (uint32_t) len);
+ }
+ data = mp_store_u8(data, type);
+ return data;
+}
+
+MP_IMPL ptrdiff_t
+mp_check_ext(const char *cur, const char *end)
+{
+ assert(cur < end);
+ assert(mp_typeof(*cur) == MP_EXT);
+ uint8_t c = mp_load_u8(&cur);
+ switch (c) {
+ case 0xd4:
+ case 0xd5:
+ case 0xd6:
+ case 0xd7:
+ case 0xd8:
+ return 1 - (end - cur);
+ case 0xc7:
+ case 0xc8:
+ return c - 0xc4 - (end - cur);
+ case 0xc9:
+ return 6 - (end - cur);
+ default:
+ mp_unreachable();
+ }
+}
+
+MP_IMPL uint32_t
+mp_decode_ext(const char **data, uint32_t *len, uint8_t *type) {
+ uint8_t c = mp_load_u8(data);
+ switch (c) {
+ case 0xd4:
+ case 0xd5:
+ case 0xd6:
+ case 0xd7:
+ case 0xd8:
+ *len = 1u << (c - 0xd4);
+ break;
+ case 0xc7:
+ *len = mp_load_u8(data);
+ break;
+ case 0xc8:
+ *len = mp_load_u16(data);
+ break;
+ case 0xc9:
+ *len = mp_load_u32(data);
+ break;
+ default:
+ mp_unreachable();
+ }
+ *type = mp_load_u8(data);
+ return *len;
+}
+
MP_IMPL uint32_t
mp_sizeof_uint(uint64_t num)
{
diff --git a/test/msgpuck.c b/test/msgpuck.c
index 3b31bfc..5ddaba7 100644
--- a/test/msgpuck.c
+++ b/test/msgpuck.c
@@ -789,9 +789,8 @@ test_mp_print()
d = mp_encode_double(d, 3.14);
d = mp_encode_uint(d, 100);
d = mp_encode_uint(d, 500);
- *d++ = 0xd4; /* let's pack smallest fixed ext */
- *d++ = 0;
- *d++ = 0;
+ /* let's pack zero-length ext */
+ d = mp_encode_ext(d, MP_EXT_DECIMAL, 0);
char bin[] = "\x12test\x34\b\t\n\"bla\\-bla\"\f\r";
d = mp_encode_bin(d, bin, sizeof(bin));
d = mp_encode_map(d, 0);
@@ -800,7 +799,7 @@ test_mp_print()
const char *expected =
"[-5, 42, \"kill bill\", [], "
"{\"bool true\": true, \"bool false\": false, \"null\": null, "
- "\"float\": 3.14, \"double\": 3.14, 100: 500}, undefined, "
+ "\"float\": 3.14, \"double\": 3.14, 100: 500}, decimal, "
"\"\\u0012test4\\b\\t\\n\\\"bla\\\\-bla\\\"\\f\\r\\u0000\", {}]";
int esize = strlen(expected);
--
2.20.1 (Apple Git-117)
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