mirror of
git://git.psyc.eu/libpsyc
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397 lines
11 KiB
C
397 lines
11 KiB
C
#include <stdint.h>
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/** @brief isGlyph
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*
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* @todo: document this function
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*/
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inline char isGlyph(uint8_t g)
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{
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switch(g)
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{
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case ':':
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case '-':
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case '+':
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case '=':
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return 1;
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default:
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return 0;
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}
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}
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inline char isAlphaNumeric(uint8_t c)
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{
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return
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(( c >= 'a' && c <= 'z' )||
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( c >= 'A' && c <= 'Z' )||
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( c >= '0' && c <= '9' ))
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;
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}
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inline int PSYC_parseElement(
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unsigned int* cursor,
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const uint8_t * data, unsigned int dlength,
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const uint8_t** name, unsigned int *nlength,
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const uint8_t** value, unsigned int *vlength,
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char inHeader);
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/** @brief parses a routerVariable
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*
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* This function parses one routing variable,
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* advances the cursor after the variable,
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* writes the variables name, value and their
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* lengths in the corresponding out parameters
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* and returns 0 or an errorcode.
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*
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*
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*
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*
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* @param data pointer to the packet data
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* @param dlength length of the data (amount of bytes)
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* @param cursor pointer to the current parsing position.
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* should be initialized to 0.
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* @param name pointer-pointer, used to return the position
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* of the name string
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* @param nlength pointer to which the length of
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* the name string will be written
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* @param value pointer-pointer, used to retrun the position
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* of the value string
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* @param vlength pointer to which the length of
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* the value string will be written
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*
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* @returns 0 on success
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* 1 on insufficient data.
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* This does not advance
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* the cursor.
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* 2 when no longer in the header,
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* This advances the cursor to the
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* body/entity section, but leaves
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* the other out parameters invalid.
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* 3 the packet is complete.
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* >3 on a context error,
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* <0 on a parsing error.
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* This invalidates all but the cursor
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* out paramater. */
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inline int PSYC_parseHeader(
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unsigned int* cursor,
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const uint8_t * data, unsigned int dlength,
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const uint8_t** name, unsigned int *nlength,
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const uint8_t** value, unsigned int *vlength)
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{
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return PSYC_parseElement(cursor,data,dlength,name,nlength,value,vlength,1);
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}
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/** @brief parses one bodyelement
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*
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* This function is nearly identical to
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* its brother parseClosedBody. *
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*
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* It assumes that we don’t know the
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* real length of the packet and thus
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* searches for the terminator.
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*/
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inline int PSYC_parseOpenBody(
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unsigned int* cursor,
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const uint8_t * data, unsigned int dlength,
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const uint8_t** name, unsigned int *nlength,
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const uint8_t** value, unsigned int *vlength)
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{
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return PSYC_parseElement(cursor,data,dlength,name,nlength,value,vlength,0);
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}
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/** @brief generalized linebased parser */
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inline int PSYC_parseElement(
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unsigned int* cursor,
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const uint8_t * data, unsigned int dlength,
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const uint8_t** name, unsigned int *nlength,
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const uint8_t** value, unsigned int *vlength,
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char inHeader)
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{
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/* first we test if we can access the first char */
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if(dlength<*cursor) // cursor is not inside the length
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return 1; // return insufficient data.
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// in case we return insufficent, we rewind to the start.
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unsigned int startc=*cursor;
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/* each line of the header starts with a glyph.
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* iE :_name, -_name +_name etc, so just test if
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* the first char is a glyph. */
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if(1==inHeader && !isGlyph(data[*cursor])) // is the first char not a glyph?
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{
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// the only other possibility now is that the packet
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// is complete(empty packet) or that the method started.
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if(isAlphaNumeric(data[*cursor]))
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return 2; // return header finished
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if(data[*cursor] == '|')
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{
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if(dlength<++(*cursor)) // incremented cursor inside lenght?
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{
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*cursor=startc; // set to start value
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return 1; // return insufficient
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}
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if(data[*cursor]=='\n')
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{
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++(*cursor);
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return 3; // return packet finished
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}
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}
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return -6; // report error
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}
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char method=0;
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/* in the body, the same applies, only that the
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* method does not start with a glyph.*/
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if(0==inHeader && !isGlyph(data[*cursor]))
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if(!isAlphaNumeric(data[*cursor]))
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{
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// the body rule is optional, which means
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// that now also just |\n can follow.
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if(data[*cursor] == '|')
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{
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if(dlength<++(*cursor)) // incremented cursor inside lenght?
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{
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*cursor=startc; // set to start value
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return 1; // return insufficient
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}
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if(data[*cursor]=='\n')
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{
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++(*cursor);
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return 3; // return packet finished
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}
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}
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return -5; // report error
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}
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else
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method=1;
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/* validate the incremented cursor */
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if(dlength<++(*cursor))
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{
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*cursor=startc;
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return 1;
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}
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/* what follows is the name. At least one char.
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* allowed is alphanumeric and _ */
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// first char must exist.
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if(!isAlphaNumeric(data[*cursor]) // is it not alphanum
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&& data[*cursor] != '_') // AND not '_'. must be invalid then
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return -1; // return parser error.
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*name=data+*cursor; // the name starts here.
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*nlength=1; // the initial length is 1.
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/* now checking how long the name of the variable is. */
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unsigned int i=0;
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while(1)
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{
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if(dlength<++(*cursor)) // incremented cursor inside lenght?
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{
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*cursor=startc; // set to start value
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return 1; // return insufficient
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}
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// same as bevore
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if(!isAlphaNumeric(data[*cursor]) &&
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data[*cursor] != '_')
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break; // not valid? then stop the loop right here
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++(*nlength); // was a valid char, increase length
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}
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/* we now parsed the variable name successfully
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* after the name either a \n or a \t follows.
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*
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* for the method, the data starts after an \n
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* so checking for \n too here
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* We dont check if cursor inside length, because
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* the last loop iteration did that already. */
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if(data[*cursor] == '\t' || (data[*cursor] == '\n' && method==1))
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{
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/* after the \t the arg-data follows, which is
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* anything but \n. arg-data can be of length 0
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*
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* for the method: after the \n data follows,
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* which is anything but \n|\n
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*
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* arg-data=*value. we set value here so it
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* points to a valid range and so we point
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* to the first potential arg-data byte.
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* If there is no arg-data, we still have
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* the length attribute on 0. */
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*value=data+*cursor+1;
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*vlength=0;
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while(1)
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{
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if(dlength<++(*cursor)) // incremented cursor inside lenght?
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{
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*cursor=startc; // set to start value
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return 1; // return insufficient
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}
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if(data[*cursor] == '\n')
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{
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if(method==1)
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{
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if(dlength<++(*cursor)+1) // incremented cursor inside lenght?
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{
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*cursor=startc; // set to start value
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return 1; // return insufficient
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}
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/* packet finishes here */
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if(data[*cursor] == '|' &&
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data[*cursor+1] == '\n')
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return 3;
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}else
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break;
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}
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++(*vlength);
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}
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}
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/* if there was a \t, then we parsed up until the
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* \n char from the simple-arg rule ( \t arg-data \n )
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*
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* Now, if there would be no \t, we still would be at
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* the point where a \n must follow.
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*
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* So, just checking \n here will cover both cases of
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* the alternative ( simple-arg / \n ) from rule
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* routing-modifier
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*
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* again, the loop has already validated the cursors
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* position*/
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if(data[*cursor] != '\n')
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return -2; // return parser error.
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/* if a \n follows now, the an body is attached.
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* if not, a |\n must follow */
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if(dlength<++(*cursor)) // incremented cursor inside lenght?
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{
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*cursor=startc; // set to start value
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return 1; // return insufficient
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}
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if(*cursor == '\n')
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return 0; // line is complete
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else if(*cursor != '|')
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return -3;
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if(dlength<++(*cursor)) // incremented cursor inside lenght?
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{
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*cursor=startc; // set to start value
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return 1; // return insufficient
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}
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if(*cursor != '\n')
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return -4;
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return 3; // packet is complete
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}
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/** @brief parses one variable in two buffers
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*
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* This function is nearly identical to its
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* brother parseHeader. The difference is,
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* it uses two buffers and return parameters
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* for everything. It is meant to be used
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* in case parseHeader returned 2 for
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* insufficient data and you don’t
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* like to copy memory around to
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* have all the data in one buffer.
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* Using this function, you can pass two
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* data buffers. The consequence is,
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* that name and value can be distributed
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* on two different buffers and thus need
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* also two out paramaters. If only one
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* will be used, length of the second
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* will be 0.
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*
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* If your data is spread over more
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* than two buffers, you need to
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* copy that in one or two buffers.
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* Given the unlikleyness of that
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* event, we don't offer a three
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* or more buffer function here.
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*
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*/
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int PSYC_parseHeader2(
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unsigned int* cursor,
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const uint8_t * data1, unsigned int dlength1,
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const uint8_t * data2, unsigned int dlength2,
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const uint8_t** name1, unsigned int *nlength1,
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const uint8_t** name2, unsigned int *nlength2,
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const uint8_t** value1, unsigned int *vlength1,
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const uint8_t** value2, unsigned int *vlength2);
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/** @brief parses one bodyelement
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*
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* This parses one body element, that is
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* either an entity-variable or the method
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*
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* The function assumes that dlength is set
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* to the exact length of the packet
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* so that data[dlength-1] would be the
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* ending "\n" of the packet.
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*
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* The parameters are nearly the same as for
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* PSYC_routerVariable, only difference is
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* that a returnvalue of 2 means, we encountered
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* the method.
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* This means that the out paramterer
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* name contains the methodname and
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* value the content.
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* */
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int PSYC_parseClosedBody(
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unsigned int* cursor,
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const uint8_t * data, unsigned int dlength,
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const uint8_t** name, unsigned int *nlength,
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const uint8_t** value, unsigned int *vlength);
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/* @brief parses an bodyelement in two buffers
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*
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* This function is the brother of parseHeader2.
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* It behaives the same as
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* parseOpenBody and parseHeader2. */
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int PSYC_parseOpenBody2(
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unsigned int* cursor,
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const uint8_t * data1, unsigned int dlength1,
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const uint8_t * data2, unsigned int dlength2,
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const uint8_t** name1, unsigned int *nlength1,
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const uint8_t** name2, unsigned int *nlength2,
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const uint8_t** value1, unsigned int *vlength1,
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const uint8_t** value2, unsigned int *vlength2);
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