rfc1867

Hello, I am writing custom rfc1867 code on a http server so in php application code I can just use the file directly instead of being processed by rfc1867.c. I went through the rfc1867 code but the code is hard to understand. When data comes as chunks from the browser, whats a good logic to detect start of headers, file? In php code, I see constants like TSRMLS_CC but cant find the definitions of these and it makes hard to understand the code. Thanks