Zoltan Hudak
/
MQTT_Hello
MQTT client to test the ENC28J60-EMAC on NUCLEO-F446RE.
MQTT/MQTTPacket/MQTTPacket.c@0:238f0d0c0ba3, 2021-03-26 (annotated)
- Committer:
- hudakz
- Date:
- Fri Mar 26 16:15:14 2021 +0000
- Revision:
- 0:238f0d0c0ba3
MQTT client to test the ENC28J60-EMAC on NUCLEO-F446RE.
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
hudakz | 0:238f0d0c0ba3 | 1 | /******************************************************************************* |
hudakz | 0:238f0d0c0ba3 | 2 | * Copyright (c) 2014 IBM Corp. |
hudakz | 0:238f0d0c0ba3 | 3 | * |
hudakz | 0:238f0d0c0ba3 | 4 | * All rights reserved. This program and the accompanying materials |
hudakz | 0:238f0d0c0ba3 | 5 | * are made available under the terms of the Eclipse Public License v1.0 |
hudakz | 0:238f0d0c0ba3 | 6 | * and Eclipse Distribution License v1.0 which accompany this distribution. |
hudakz | 0:238f0d0c0ba3 | 7 | * |
hudakz | 0:238f0d0c0ba3 | 8 | * The Eclipse Public License is available at |
hudakz | 0:238f0d0c0ba3 | 9 | * http://www.eclipse.org/legal/epl-v10.html |
hudakz | 0:238f0d0c0ba3 | 10 | * and the Eclipse Distribution License is available at |
hudakz | 0:238f0d0c0ba3 | 11 | * http://www.eclipse.org/org/documents/edl-v10.php. |
hudakz | 0:238f0d0c0ba3 | 12 | * |
hudakz | 0:238f0d0c0ba3 | 13 | * Contributors: |
hudakz | 0:238f0d0c0ba3 | 14 | * Ian Craggs - initial API and implementation and/or initial documentation |
hudakz | 0:238f0d0c0ba3 | 15 | * Sergio R. Caprile - non-blocking packet read functions for stream transport |
hudakz | 0:238f0d0c0ba3 | 16 | *******************************************************************************/ |
hudakz | 0:238f0d0c0ba3 | 17 | |
hudakz | 0:238f0d0c0ba3 | 18 | #include "StackTrace.h" |
hudakz | 0:238f0d0c0ba3 | 19 | #include "MQTTPacket.h" |
hudakz | 0:238f0d0c0ba3 | 20 | |
hudakz | 0:238f0d0c0ba3 | 21 | #include <string.h> |
hudakz | 0:238f0d0c0ba3 | 22 | |
hudakz | 0:238f0d0c0ba3 | 23 | /** |
hudakz | 0:238f0d0c0ba3 | 24 | * Encodes the message length according to the MQTT algorithm |
hudakz | 0:238f0d0c0ba3 | 25 | * @param buf the buffer into which the encoded data is written |
hudakz | 0:238f0d0c0ba3 | 26 | * @param length the length to be encoded |
hudakz | 0:238f0d0c0ba3 | 27 | * @return the number of bytes written to buffer |
hudakz | 0:238f0d0c0ba3 | 28 | */ |
hudakz | 0:238f0d0c0ba3 | 29 | int MQTTPacket_encode(unsigned char* buf, int length) |
hudakz | 0:238f0d0c0ba3 | 30 | { |
hudakz | 0:238f0d0c0ba3 | 31 | int rc = 0; |
hudakz | 0:238f0d0c0ba3 | 32 | |
hudakz | 0:238f0d0c0ba3 | 33 | FUNC_ENTRY; |
hudakz | 0:238f0d0c0ba3 | 34 | do |
hudakz | 0:238f0d0c0ba3 | 35 | { |
hudakz | 0:238f0d0c0ba3 | 36 | char d = length % 128; |
hudakz | 0:238f0d0c0ba3 | 37 | length /= 128; |
hudakz | 0:238f0d0c0ba3 | 38 | /* if there are more digits to encode, set the top bit of this digit */ |
hudakz | 0:238f0d0c0ba3 | 39 | if (length > 0) |
hudakz | 0:238f0d0c0ba3 | 40 | d |= 0x80; |
hudakz | 0:238f0d0c0ba3 | 41 | buf[rc++] = d; |
hudakz | 0:238f0d0c0ba3 | 42 | } while (length > 0); |
hudakz | 0:238f0d0c0ba3 | 43 | FUNC_EXIT_RC(rc); |
hudakz | 0:238f0d0c0ba3 | 44 | return rc; |
hudakz | 0:238f0d0c0ba3 | 45 | } |
hudakz | 0:238f0d0c0ba3 | 46 | |
hudakz | 0:238f0d0c0ba3 | 47 | |
hudakz | 0:238f0d0c0ba3 | 48 | /** |
hudakz | 0:238f0d0c0ba3 | 49 | * Decodes the message length according to the MQTT algorithm |
hudakz | 0:238f0d0c0ba3 | 50 | * @param getcharfn pointer to function to read the next character from the data source |
hudakz | 0:238f0d0c0ba3 | 51 | * @param value the decoded length returned |
hudakz | 0:238f0d0c0ba3 | 52 | * @return the number of bytes read from the socket |
hudakz | 0:238f0d0c0ba3 | 53 | */ |
hudakz | 0:238f0d0c0ba3 | 54 | int MQTTPacket_decode(int (*getcharfn)(unsigned char*, int), int* value) |
hudakz | 0:238f0d0c0ba3 | 55 | { |
hudakz | 0:238f0d0c0ba3 | 56 | unsigned char c; |
hudakz | 0:238f0d0c0ba3 | 57 | int multiplier = 1; |
hudakz | 0:238f0d0c0ba3 | 58 | int len = 0; |
hudakz | 0:238f0d0c0ba3 | 59 | #define MAX_NO_OF_REMAINING_LENGTH_BYTES 4 |
hudakz | 0:238f0d0c0ba3 | 60 | |
hudakz | 0:238f0d0c0ba3 | 61 | FUNC_ENTRY; |
hudakz | 0:238f0d0c0ba3 | 62 | *value = 0; |
hudakz | 0:238f0d0c0ba3 | 63 | do |
hudakz | 0:238f0d0c0ba3 | 64 | { |
hudakz | 0:238f0d0c0ba3 | 65 | int rc = MQTTPACKET_READ_ERROR; |
hudakz | 0:238f0d0c0ba3 | 66 | |
hudakz | 0:238f0d0c0ba3 | 67 | if (++len > MAX_NO_OF_REMAINING_LENGTH_BYTES) |
hudakz | 0:238f0d0c0ba3 | 68 | { |
hudakz | 0:238f0d0c0ba3 | 69 | rc = MQTTPACKET_READ_ERROR; /* bad data */ |
hudakz | 0:238f0d0c0ba3 | 70 | goto exit; |
hudakz | 0:238f0d0c0ba3 | 71 | } |
hudakz | 0:238f0d0c0ba3 | 72 | rc = (*getcharfn)(&c, 1); |
hudakz | 0:238f0d0c0ba3 | 73 | if (rc != 1) |
hudakz | 0:238f0d0c0ba3 | 74 | goto exit; |
hudakz | 0:238f0d0c0ba3 | 75 | *value += (c & 127) * multiplier; |
hudakz | 0:238f0d0c0ba3 | 76 | multiplier *= 128; |
hudakz | 0:238f0d0c0ba3 | 77 | } while ((c & 128) != 0); |
hudakz | 0:238f0d0c0ba3 | 78 | exit: |
hudakz | 0:238f0d0c0ba3 | 79 | FUNC_EXIT_RC(len); |
hudakz | 0:238f0d0c0ba3 | 80 | return len; |
hudakz | 0:238f0d0c0ba3 | 81 | } |
hudakz | 0:238f0d0c0ba3 | 82 | |
hudakz | 0:238f0d0c0ba3 | 83 | |
hudakz | 0:238f0d0c0ba3 | 84 | int MQTTPacket_len(int rem_len) |
hudakz | 0:238f0d0c0ba3 | 85 | { |
hudakz | 0:238f0d0c0ba3 | 86 | rem_len += 1; /* header byte */ |
hudakz | 0:238f0d0c0ba3 | 87 | |
hudakz | 0:238f0d0c0ba3 | 88 | /* now remaining_length field */ |
hudakz | 0:238f0d0c0ba3 | 89 | if (rem_len < 128) |
hudakz | 0:238f0d0c0ba3 | 90 | rem_len += 1; |
hudakz | 0:238f0d0c0ba3 | 91 | else if (rem_len < 16384) |
hudakz | 0:238f0d0c0ba3 | 92 | rem_len += 2; |
hudakz | 0:238f0d0c0ba3 | 93 | else if (rem_len < 2097151) |
hudakz | 0:238f0d0c0ba3 | 94 | rem_len += 3; |
hudakz | 0:238f0d0c0ba3 | 95 | else |
hudakz | 0:238f0d0c0ba3 | 96 | rem_len += 4; |
hudakz | 0:238f0d0c0ba3 | 97 | return rem_len; |
hudakz | 0:238f0d0c0ba3 | 98 | } |
hudakz | 0:238f0d0c0ba3 | 99 | |
hudakz | 0:238f0d0c0ba3 | 100 | |
hudakz | 0:238f0d0c0ba3 | 101 | static unsigned char* bufptr; |
hudakz | 0:238f0d0c0ba3 | 102 | |
hudakz | 0:238f0d0c0ba3 | 103 | int bufchar(unsigned char* c, int count) |
hudakz | 0:238f0d0c0ba3 | 104 | { |
hudakz | 0:238f0d0c0ba3 | 105 | int i; |
hudakz | 0:238f0d0c0ba3 | 106 | |
hudakz | 0:238f0d0c0ba3 | 107 | for (i = 0; i < count; ++i) |
hudakz | 0:238f0d0c0ba3 | 108 | *c = *bufptr++; |
hudakz | 0:238f0d0c0ba3 | 109 | return count; |
hudakz | 0:238f0d0c0ba3 | 110 | } |
hudakz | 0:238f0d0c0ba3 | 111 | |
hudakz | 0:238f0d0c0ba3 | 112 | |
hudakz | 0:238f0d0c0ba3 | 113 | int MQTTPacket_decodeBuf(unsigned char* buf, int* value) |
hudakz | 0:238f0d0c0ba3 | 114 | { |
hudakz | 0:238f0d0c0ba3 | 115 | bufptr = buf; |
hudakz | 0:238f0d0c0ba3 | 116 | return MQTTPacket_decode(bufchar, value); |
hudakz | 0:238f0d0c0ba3 | 117 | } |
hudakz | 0:238f0d0c0ba3 | 118 | |
hudakz | 0:238f0d0c0ba3 | 119 | |
hudakz | 0:238f0d0c0ba3 | 120 | /** |
hudakz | 0:238f0d0c0ba3 | 121 | * Calculates an integer from two bytes read from the input buffer |
hudakz | 0:238f0d0c0ba3 | 122 | * @param pptr pointer to the input buffer - incremented by the number of bytes used & returned |
hudakz | 0:238f0d0c0ba3 | 123 | * @return the integer value calculated |
hudakz | 0:238f0d0c0ba3 | 124 | */ |
hudakz | 0:238f0d0c0ba3 | 125 | int readInt(unsigned char** pptr) |
hudakz | 0:238f0d0c0ba3 | 126 | { |
hudakz | 0:238f0d0c0ba3 | 127 | unsigned char* ptr = *pptr; |
hudakz | 0:238f0d0c0ba3 | 128 | int len = 256*(*ptr) + (*(ptr+1)); |
hudakz | 0:238f0d0c0ba3 | 129 | *pptr += 2; |
hudakz | 0:238f0d0c0ba3 | 130 | return len; |
hudakz | 0:238f0d0c0ba3 | 131 | } |
hudakz | 0:238f0d0c0ba3 | 132 | |
hudakz | 0:238f0d0c0ba3 | 133 | |
hudakz | 0:238f0d0c0ba3 | 134 | /** |
hudakz | 0:238f0d0c0ba3 | 135 | * Reads one character from the input buffer. |
hudakz | 0:238f0d0c0ba3 | 136 | * @param pptr pointer to the input buffer - incremented by the number of bytes used & returned |
hudakz | 0:238f0d0c0ba3 | 137 | * @return the character read |
hudakz | 0:238f0d0c0ba3 | 138 | */ |
hudakz | 0:238f0d0c0ba3 | 139 | char readChar(unsigned char** pptr) |
hudakz | 0:238f0d0c0ba3 | 140 | { |
hudakz | 0:238f0d0c0ba3 | 141 | char c = **pptr; |
hudakz | 0:238f0d0c0ba3 | 142 | (*pptr)++; |
hudakz | 0:238f0d0c0ba3 | 143 | return c; |
hudakz | 0:238f0d0c0ba3 | 144 | } |
hudakz | 0:238f0d0c0ba3 | 145 | |
hudakz | 0:238f0d0c0ba3 | 146 | |
hudakz | 0:238f0d0c0ba3 | 147 | /** |
hudakz | 0:238f0d0c0ba3 | 148 | * Writes one character to an output buffer. |
hudakz | 0:238f0d0c0ba3 | 149 | * @param pptr pointer to the output buffer - incremented by the number of bytes used & returned |
hudakz | 0:238f0d0c0ba3 | 150 | * @param c the character to write |
hudakz | 0:238f0d0c0ba3 | 151 | */ |
hudakz | 0:238f0d0c0ba3 | 152 | void writeChar(unsigned char** pptr, char c) |
hudakz | 0:238f0d0c0ba3 | 153 | { |
hudakz | 0:238f0d0c0ba3 | 154 | **pptr = c; |
hudakz | 0:238f0d0c0ba3 | 155 | (*pptr)++; |
hudakz | 0:238f0d0c0ba3 | 156 | } |
hudakz | 0:238f0d0c0ba3 | 157 | |
hudakz | 0:238f0d0c0ba3 | 158 | |
hudakz | 0:238f0d0c0ba3 | 159 | /** |
hudakz | 0:238f0d0c0ba3 | 160 | * Writes an integer as 2 bytes to an output buffer. |
hudakz | 0:238f0d0c0ba3 | 161 | * @param pptr pointer to the output buffer - incremented by the number of bytes used & returned |
hudakz | 0:238f0d0c0ba3 | 162 | * @param anInt the integer to write |
hudakz | 0:238f0d0c0ba3 | 163 | */ |
hudakz | 0:238f0d0c0ba3 | 164 | void writeInt(unsigned char** pptr, int anInt) |
hudakz | 0:238f0d0c0ba3 | 165 | { |
hudakz | 0:238f0d0c0ba3 | 166 | **pptr = (unsigned char)(anInt / 256); |
hudakz | 0:238f0d0c0ba3 | 167 | (*pptr)++; |
hudakz | 0:238f0d0c0ba3 | 168 | **pptr = (unsigned char)(anInt % 256); |
hudakz | 0:238f0d0c0ba3 | 169 | (*pptr)++; |
hudakz | 0:238f0d0c0ba3 | 170 | } |
hudakz | 0:238f0d0c0ba3 | 171 | |
hudakz | 0:238f0d0c0ba3 | 172 | |
hudakz | 0:238f0d0c0ba3 | 173 | /** |
hudakz | 0:238f0d0c0ba3 | 174 | * Writes a "UTF" string to an output buffer. Converts C string to length-delimited. |
hudakz | 0:238f0d0c0ba3 | 175 | * @param pptr pointer to the output buffer - incremented by the number of bytes used & returned |
hudakz | 0:238f0d0c0ba3 | 176 | * @param string the C string to write |
hudakz | 0:238f0d0c0ba3 | 177 | */ |
hudakz | 0:238f0d0c0ba3 | 178 | void writeCString(unsigned char** pptr, const char* string) |
hudakz | 0:238f0d0c0ba3 | 179 | { |
hudakz | 0:238f0d0c0ba3 | 180 | int len = strlen(string); |
hudakz | 0:238f0d0c0ba3 | 181 | writeInt(pptr, len); |
hudakz | 0:238f0d0c0ba3 | 182 | memcpy(*pptr, string, len); |
hudakz | 0:238f0d0c0ba3 | 183 | *pptr += len; |
hudakz | 0:238f0d0c0ba3 | 184 | } |
hudakz | 0:238f0d0c0ba3 | 185 | |
hudakz | 0:238f0d0c0ba3 | 186 | |
hudakz | 0:238f0d0c0ba3 | 187 | int getLenStringLen(char* ptr) |
hudakz | 0:238f0d0c0ba3 | 188 | { |
hudakz | 0:238f0d0c0ba3 | 189 | int len = 256*((unsigned char)(*ptr)) + (unsigned char)(*(ptr+1)); |
hudakz | 0:238f0d0c0ba3 | 190 | return len; |
hudakz | 0:238f0d0c0ba3 | 191 | } |
hudakz | 0:238f0d0c0ba3 | 192 | |
hudakz | 0:238f0d0c0ba3 | 193 | |
hudakz | 0:238f0d0c0ba3 | 194 | void writeMQTTString(unsigned char** pptr, MQTTString mqttstring) |
hudakz | 0:238f0d0c0ba3 | 195 | { |
hudakz | 0:238f0d0c0ba3 | 196 | if (mqttstring.lenstring.len > 0) |
hudakz | 0:238f0d0c0ba3 | 197 | { |
hudakz | 0:238f0d0c0ba3 | 198 | writeInt(pptr, mqttstring.lenstring.len); |
hudakz | 0:238f0d0c0ba3 | 199 | memcpy(*pptr, mqttstring.lenstring.data, mqttstring.lenstring.len); |
hudakz | 0:238f0d0c0ba3 | 200 | *pptr += mqttstring.lenstring.len; |
hudakz | 0:238f0d0c0ba3 | 201 | } |
hudakz | 0:238f0d0c0ba3 | 202 | else if (mqttstring.cstring) |
hudakz | 0:238f0d0c0ba3 | 203 | writeCString(pptr, mqttstring.cstring); |
hudakz | 0:238f0d0c0ba3 | 204 | else |
hudakz | 0:238f0d0c0ba3 | 205 | writeInt(pptr, 0); |
hudakz | 0:238f0d0c0ba3 | 206 | } |
hudakz | 0:238f0d0c0ba3 | 207 | |
hudakz | 0:238f0d0c0ba3 | 208 | |
hudakz | 0:238f0d0c0ba3 | 209 | /** |
hudakz | 0:238f0d0c0ba3 | 210 | * @param mqttstring the MQTTString structure into which the data is to be read |
hudakz | 0:238f0d0c0ba3 | 211 | * @param pptr pointer to the output buffer - incremented by the number of bytes used & returned |
hudakz | 0:238f0d0c0ba3 | 212 | * @param enddata pointer to the end of the data: do not read beyond |
hudakz | 0:238f0d0c0ba3 | 213 | * @return 1 if successful, 0 if not |
hudakz | 0:238f0d0c0ba3 | 214 | */ |
hudakz | 0:238f0d0c0ba3 | 215 | int readMQTTLenString(MQTTString* mqttstring, unsigned char** pptr, unsigned char* enddata) |
hudakz | 0:238f0d0c0ba3 | 216 | { |
hudakz | 0:238f0d0c0ba3 | 217 | int rc = 0; |
hudakz | 0:238f0d0c0ba3 | 218 | |
hudakz | 0:238f0d0c0ba3 | 219 | FUNC_ENTRY; |
hudakz | 0:238f0d0c0ba3 | 220 | /* the first two bytes are the length of the string */ |
hudakz | 0:238f0d0c0ba3 | 221 | if (enddata - (*pptr) > 1) /* enough length to read the integer? */ |
hudakz | 0:238f0d0c0ba3 | 222 | { |
hudakz | 0:238f0d0c0ba3 | 223 | mqttstring->lenstring.len = readInt(pptr); /* increments pptr to point past length */ |
hudakz | 0:238f0d0c0ba3 | 224 | if (&(*pptr)[mqttstring->lenstring.len] <= enddata) |
hudakz | 0:238f0d0c0ba3 | 225 | { |
hudakz | 0:238f0d0c0ba3 | 226 | mqttstring->lenstring.data = (char*)*pptr; |
hudakz | 0:238f0d0c0ba3 | 227 | *pptr += mqttstring->lenstring.len; |
hudakz | 0:238f0d0c0ba3 | 228 | rc = 1; |
hudakz | 0:238f0d0c0ba3 | 229 | } |
hudakz | 0:238f0d0c0ba3 | 230 | } |
hudakz | 0:238f0d0c0ba3 | 231 | mqttstring->cstring = NULL; |
hudakz | 0:238f0d0c0ba3 | 232 | FUNC_EXIT_RC(rc); |
hudakz | 0:238f0d0c0ba3 | 233 | return rc; |
hudakz | 0:238f0d0c0ba3 | 234 | } |
hudakz | 0:238f0d0c0ba3 | 235 | |
hudakz | 0:238f0d0c0ba3 | 236 | |
hudakz | 0:238f0d0c0ba3 | 237 | /** |
hudakz | 0:238f0d0c0ba3 | 238 | * Return the length of the MQTTstring - C string if there is one, otherwise the length delimited string |
hudakz | 0:238f0d0c0ba3 | 239 | * @param mqttstring the string to return the length of |
hudakz | 0:238f0d0c0ba3 | 240 | * @return the length of the string |
hudakz | 0:238f0d0c0ba3 | 241 | */ |
hudakz | 0:238f0d0c0ba3 | 242 | int MQTTstrlen(MQTTString mqttstring) |
hudakz | 0:238f0d0c0ba3 | 243 | { |
hudakz | 0:238f0d0c0ba3 | 244 | int rc = 0; |
hudakz | 0:238f0d0c0ba3 | 245 | |
hudakz | 0:238f0d0c0ba3 | 246 | if (mqttstring.cstring) |
hudakz | 0:238f0d0c0ba3 | 247 | rc = strlen(mqttstring.cstring); |
hudakz | 0:238f0d0c0ba3 | 248 | else |
hudakz | 0:238f0d0c0ba3 | 249 | rc = mqttstring.lenstring.len; |
hudakz | 0:238f0d0c0ba3 | 250 | return rc; |
hudakz | 0:238f0d0c0ba3 | 251 | } |
hudakz | 0:238f0d0c0ba3 | 252 | |
hudakz | 0:238f0d0c0ba3 | 253 | |
hudakz | 0:238f0d0c0ba3 | 254 | /** |
hudakz | 0:238f0d0c0ba3 | 255 | * Compares an MQTTString to a C string |
hudakz | 0:238f0d0c0ba3 | 256 | * @param a the MQTTString to compare |
hudakz | 0:238f0d0c0ba3 | 257 | * @param bptr the C string to compare |
hudakz | 0:238f0d0c0ba3 | 258 | * @return boolean - equal or not |
hudakz | 0:238f0d0c0ba3 | 259 | */ |
hudakz | 0:238f0d0c0ba3 | 260 | int MQTTPacket_equals(MQTTString* a, char* bptr) |
hudakz | 0:238f0d0c0ba3 | 261 | { |
hudakz | 0:238f0d0c0ba3 | 262 | int alen = 0, |
hudakz | 0:238f0d0c0ba3 | 263 | blen = 0; |
hudakz | 0:238f0d0c0ba3 | 264 | char *aptr; |
hudakz | 0:238f0d0c0ba3 | 265 | |
hudakz | 0:238f0d0c0ba3 | 266 | if (a->cstring) |
hudakz | 0:238f0d0c0ba3 | 267 | { |
hudakz | 0:238f0d0c0ba3 | 268 | aptr = a->cstring; |
hudakz | 0:238f0d0c0ba3 | 269 | alen = strlen(a->cstring); |
hudakz | 0:238f0d0c0ba3 | 270 | } |
hudakz | 0:238f0d0c0ba3 | 271 | else |
hudakz | 0:238f0d0c0ba3 | 272 | { |
hudakz | 0:238f0d0c0ba3 | 273 | aptr = a->lenstring.data; |
hudakz | 0:238f0d0c0ba3 | 274 | alen = a->lenstring.len; |
hudakz | 0:238f0d0c0ba3 | 275 | } |
hudakz | 0:238f0d0c0ba3 | 276 | blen = strlen(bptr); |
hudakz | 0:238f0d0c0ba3 | 277 | |
hudakz | 0:238f0d0c0ba3 | 278 | return (alen == blen) && (strncmp(aptr, bptr, alen) == 0); |
hudakz | 0:238f0d0c0ba3 | 279 | } |
hudakz | 0:238f0d0c0ba3 | 280 | |
hudakz | 0:238f0d0c0ba3 | 281 | |
hudakz | 0:238f0d0c0ba3 | 282 | /** |
hudakz | 0:238f0d0c0ba3 | 283 | * Helper function to read packet data from some source into a buffer |
hudakz | 0:238f0d0c0ba3 | 284 | * @param buf the buffer into which the packet will be serialized |
hudakz | 0:238f0d0c0ba3 | 285 | * @param buflen the length in bytes of the supplied buffer |
hudakz | 0:238f0d0c0ba3 | 286 | * @param getfn pointer to a function which will read any number of bytes from the needed source |
hudakz | 0:238f0d0c0ba3 | 287 | * @return integer MQTT packet type, or -1 on error |
hudakz | 0:238f0d0c0ba3 | 288 | * @note the whole message must fit into the caller's buffer |
hudakz | 0:238f0d0c0ba3 | 289 | */ |
hudakz | 0:238f0d0c0ba3 | 290 | int MQTTPacket_read(unsigned char* buf, int buflen, int (*getfn)(unsigned char*, int)) |
hudakz | 0:238f0d0c0ba3 | 291 | { |
hudakz | 0:238f0d0c0ba3 | 292 | int rc = -1; |
hudakz | 0:238f0d0c0ba3 | 293 | MQTTHeader header = {0}; |
hudakz | 0:238f0d0c0ba3 | 294 | int len = 0; |
hudakz | 0:238f0d0c0ba3 | 295 | int rem_len = 0; |
hudakz | 0:238f0d0c0ba3 | 296 | |
hudakz | 0:238f0d0c0ba3 | 297 | /* 1. read the header byte. This has the packet type in it */ |
hudakz | 0:238f0d0c0ba3 | 298 | if ((*getfn)(buf, 1) != 1) |
hudakz | 0:238f0d0c0ba3 | 299 | goto exit; |
hudakz | 0:238f0d0c0ba3 | 300 | |
hudakz | 0:238f0d0c0ba3 | 301 | len = 1; |
hudakz | 0:238f0d0c0ba3 | 302 | /* 2. read the remaining length. This is variable in itself */ |
hudakz | 0:238f0d0c0ba3 | 303 | MQTTPacket_decode(getfn, &rem_len); |
hudakz | 0:238f0d0c0ba3 | 304 | len += MQTTPacket_encode(buf + 1, rem_len); /* put the original remaining length back into the buffer */ |
hudakz | 0:238f0d0c0ba3 | 305 | |
hudakz | 0:238f0d0c0ba3 | 306 | /* 3. read the rest of the buffer using a callback to supply the rest of the data */ |
hudakz | 0:238f0d0c0ba3 | 307 | if((rem_len + len) > buflen) |
hudakz | 0:238f0d0c0ba3 | 308 | goto exit; |
hudakz | 0:238f0d0c0ba3 | 309 | if (rem_len && ((*getfn)(buf + len, rem_len) != rem_len)) |
hudakz | 0:238f0d0c0ba3 | 310 | goto exit; |
hudakz | 0:238f0d0c0ba3 | 311 | |
hudakz | 0:238f0d0c0ba3 | 312 | header.byte = buf[0]; |
hudakz | 0:238f0d0c0ba3 | 313 | rc = header.bits.type; |
hudakz | 0:238f0d0c0ba3 | 314 | exit: |
hudakz | 0:238f0d0c0ba3 | 315 | return rc; |
hudakz | 0:238f0d0c0ba3 | 316 | } |
hudakz | 0:238f0d0c0ba3 | 317 | |
hudakz | 0:238f0d0c0ba3 | 318 | /** |
hudakz | 0:238f0d0c0ba3 | 319 | * Decodes the message length according to the MQTT algorithm, non-blocking |
hudakz | 0:238f0d0c0ba3 | 320 | * @param trp pointer to a transport structure holding what is needed to solve getting data from it |
hudakz | 0:238f0d0c0ba3 | 321 | * @param value the decoded length returned |
hudakz | 0:238f0d0c0ba3 | 322 | * @return integer the number of bytes read from the socket, 0 for call again, or -1 on error |
hudakz | 0:238f0d0c0ba3 | 323 | */ |
hudakz | 0:238f0d0c0ba3 | 324 | static int MQTTPacket_decodenb(MQTTTransport *trp) |
hudakz | 0:238f0d0c0ba3 | 325 | { |
hudakz | 0:238f0d0c0ba3 | 326 | unsigned char c; |
hudakz | 0:238f0d0c0ba3 | 327 | int rc = MQTTPACKET_READ_ERROR; |
hudakz | 0:238f0d0c0ba3 | 328 | |
hudakz | 0:238f0d0c0ba3 | 329 | FUNC_ENTRY; |
hudakz | 0:238f0d0c0ba3 | 330 | if(trp->len == 0){ /* initialize on first call */ |
hudakz | 0:238f0d0c0ba3 | 331 | trp->multiplier = 1; |
hudakz | 0:238f0d0c0ba3 | 332 | trp->rem_len = 0; |
hudakz | 0:238f0d0c0ba3 | 333 | } |
hudakz | 0:238f0d0c0ba3 | 334 | do { |
hudakz | 0:238f0d0c0ba3 | 335 | int frc; |
hudakz | 0:238f0d0c0ba3 | 336 | if (trp->len >= MAX_NO_OF_REMAINING_LENGTH_BYTES) |
hudakz | 0:238f0d0c0ba3 | 337 | goto exit; |
hudakz | 0:238f0d0c0ba3 | 338 | if ((frc=(*trp->getfn)(trp->sck, &c, 1)) == -1) |
hudakz | 0:238f0d0c0ba3 | 339 | goto exit; |
hudakz | 0:238f0d0c0ba3 | 340 | if (frc == 0){ |
hudakz | 0:238f0d0c0ba3 | 341 | rc = 0; |
hudakz | 0:238f0d0c0ba3 | 342 | goto exit; |
hudakz | 0:238f0d0c0ba3 | 343 | } |
hudakz | 0:238f0d0c0ba3 | 344 | ++(trp->len); |
hudakz | 0:238f0d0c0ba3 | 345 | trp->rem_len += (c & 127) * trp->multiplier; |
hudakz | 0:238f0d0c0ba3 | 346 | trp->multiplier *= 128; |
hudakz | 0:238f0d0c0ba3 | 347 | } while ((c & 128) != 0); |
hudakz | 0:238f0d0c0ba3 | 348 | rc = trp->len; |
hudakz | 0:238f0d0c0ba3 | 349 | exit: |
hudakz | 0:238f0d0c0ba3 | 350 | FUNC_EXIT_RC(rc); |
hudakz | 0:238f0d0c0ba3 | 351 | return rc; |
hudakz | 0:238f0d0c0ba3 | 352 | } |
hudakz | 0:238f0d0c0ba3 | 353 | |
hudakz | 0:238f0d0c0ba3 | 354 | /** |
hudakz | 0:238f0d0c0ba3 | 355 | * Helper function to read packet data from some source into a buffer, non-blocking |
hudakz | 0:238f0d0c0ba3 | 356 | * @param buf the buffer into which the packet will be serialized |
hudakz | 0:238f0d0c0ba3 | 357 | * @param buflen the length in bytes of the supplied buffer |
hudakz | 0:238f0d0c0ba3 | 358 | * @param trp pointer to a transport structure holding what is needed to solve getting data from it |
hudakz | 0:238f0d0c0ba3 | 359 | * @return integer MQTT packet type, 0 for call again, or -1 on error |
hudakz | 0:238f0d0c0ba3 | 360 | * @note the whole message must fit into the caller's buffer |
hudakz | 0:238f0d0c0ba3 | 361 | */ |
hudakz | 0:238f0d0c0ba3 | 362 | int MQTTPacket_readnb(unsigned char* buf, int buflen, MQTTTransport *trp) |
hudakz | 0:238f0d0c0ba3 | 363 | { |
hudakz | 0:238f0d0c0ba3 | 364 | int rc = -1, frc; |
hudakz | 0:238f0d0c0ba3 | 365 | MQTTHeader header = {0}; |
hudakz | 0:238f0d0c0ba3 | 366 | |
hudakz | 0:238f0d0c0ba3 | 367 | switch(trp->state){ |
hudakz | 0:238f0d0c0ba3 | 368 | default: |
hudakz | 0:238f0d0c0ba3 | 369 | trp->state = 0; |
hudakz | 0:238f0d0c0ba3 | 370 | /*FALLTHROUGH*/ |
hudakz | 0:238f0d0c0ba3 | 371 | case 0: |
hudakz | 0:238f0d0c0ba3 | 372 | /* read the header byte. This has the packet type in it */ |
hudakz | 0:238f0d0c0ba3 | 373 | if ((frc=(*trp->getfn)(trp->sck, buf, 1)) == -1) |
hudakz | 0:238f0d0c0ba3 | 374 | goto exit; |
hudakz | 0:238f0d0c0ba3 | 375 | if (frc == 0) |
hudakz | 0:238f0d0c0ba3 | 376 | return 0; |
hudakz | 0:238f0d0c0ba3 | 377 | trp->len = 0; |
hudakz | 0:238f0d0c0ba3 | 378 | ++trp->state; |
hudakz | 0:238f0d0c0ba3 | 379 | /*FALLTHROUGH*/ |
hudakz | 0:238f0d0c0ba3 | 380 | /* read the remaining length. This is variable in itself */ |
hudakz | 0:238f0d0c0ba3 | 381 | case 1: |
hudakz | 0:238f0d0c0ba3 | 382 | if((frc=MQTTPacket_decodenb(trp)) == MQTTPACKET_READ_ERROR) |
hudakz | 0:238f0d0c0ba3 | 383 | goto exit; |
hudakz | 0:238f0d0c0ba3 | 384 | if(frc == 0) |
hudakz | 0:238f0d0c0ba3 | 385 | return 0; |
hudakz | 0:238f0d0c0ba3 | 386 | trp->len = 1 + MQTTPacket_encode(buf + 1, trp->rem_len); /* put the original remaining length back into the buffer */ |
hudakz | 0:238f0d0c0ba3 | 387 | if((trp->rem_len + trp->len) > buflen) |
hudakz | 0:238f0d0c0ba3 | 388 | goto exit; |
hudakz | 0:238f0d0c0ba3 | 389 | ++trp->state; |
hudakz | 0:238f0d0c0ba3 | 390 | /*FALLTHROUGH*/ |
hudakz | 0:238f0d0c0ba3 | 391 | case 2: |
hudakz | 0:238f0d0c0ba3 | 392 | if(trp->rem_len){ |
hudakz | 0:238f0d0c0ba3 | 393 | /* read the rest of the buffer using a callback to supply the rest of the data */ |
hudakz | 0:238f0d0c0ba3 | 394 | if ((frc=(*trp->getfn)(trp->sck, buf + trp->len, trp->rem_len)) == -1) |
hudakz | 0:238f0d0c0ba3 | 395 | goto exit; |
hudakz | 0:238f0d0c0ba3 | 396 | if (frc == 0) |
hudakz | 0:238f0d0c0ba3 | 397 | return 0; |
hudakz | 0:238f0d0c0ba3 | 398 | trp->rem_len -= frc; |
hudakz | 0:238f0d0c0ba3 | 399 | trp->len += frc; |
hudakz | 0:238f0d0c0ba3 | 400 | if(trp->rem_len) |
hudakz | 0:238f0d0c0ba3 | 401 | return 0; |
hudakz | 0:238f0d0c0ba3 | 402 | } |
hudakz | 0:238f0d0c0ba3 | 403 | header.byte = buf[0]; |
hudakz | 0:238f0d0c0ba3 | 404 | rc = header.bits.type; |
hudakz | 0:238f0d0c0ba3 | 405 | break; |
hudakz | 0:238f0d0c0ba3 | 406 | } |
hudakz | 0:238f0d0c0ba3 | 407 | |
hudakz | 0:238f0d0c0ba3 | 408 | exit: |
hudakz | 0:238f0d0c0ba3 | 409 | trp->state = 0; |
hudakz | 0:238f0d0c0ba3 | 410 | return rc; |
hudakz | 0:238f0d0c0ba3 | 411 | } |