WORD TCPFindEx( TCP_SOCKET hTCP, BYTE cFind, WORD wStart, WORD wSearchLen, BOOL bTextCompare );
This function finds the first occurrance of a byte in the TCP RX buffer. It can be used by an application to abstract searches out of their own application code. For increased efficiency, the function is capable of limiting the scope of search to a specific range of bytes. It can also perform a case-insensitive search if required.
For example, if the buffer contains "I love PIC MCUs!" and the cFind byte is ' ', a value of 1 will be returned.
TCP is initialized.
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Parameters |
Description |
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hTCP |
The socket to search within. |
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cFind |
The byte to find in the buffer. |
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wStart |
Zero-indexed starting position within the buffer. |
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wSearchLen |
Length from wStart to search in the buffer. |
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bTextCompare |
TRUE for case-insensitive text search, FALSE for binary search |
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Return Values |
Description |
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0xFFFF |
Search array not found |
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Otherwise |
Zero-indexed position of the first occurrance |
Since this function usually must transfer data from external storage to internal RAM for comparison, its performance degrades significantly when the buffer is full and the array is not found. For better performance, try to search for characters that are expected to exist or limit the scope of the search as much as possible. The HTTP2 module, for example, uses this function to parse headers. However, it searches for newlines, then the separating colon, then reads the header name to RAM for final comparison. This has proven to be significantly faster than searching for full header name strings outright.