| 0,0 → 1,72 |
|---|
| /* |
| * unpacks a http "chunked" transfer into a raw data stream. |
| * this file is part of the pkgnet tool from the SvarDOS project. |
| * |
| * Copyright (C) 2021 Mateusz Viste |
| */ |
| |
| #include <stdlib.h> /* atol() */ |
| #include <string.h> |
| |
| #include "unchunk.h" |
| |
| /* transforms a http CHUNKED stream into actual data, returns the amount of raw data to read */ |
| int unchunk(unsigned char *buff, int bufflen) { |
| static long bytesleft; /* how many bytes are expected yet in the ongoing chunk */ |
| static char partial_hdr[16]; /* a small buffer for storing partial chunk headers, if these are transmitted in separate parts */ |
| int hdrstart, hdrend; |
| |
| /* if chunk header was being in progress, try to decode it now */ |
| if (bytesleft == -1) { |
| int partial_hdr_len = strlen(partial_hdr); |
| /* locate header terminator, if available */ |
| for (hdrend = 0; (hdrend < bufflen) && (buff[hdrend] != '\n'); hdrend++); |
| if (partial_hdr_len + hdrend > 15) return(-1); /* error: chunk header too long */ |
| |
| /* copy header to buffer */ |
| memcpy(partial_hdr + partial_hdr_len, buff, hdrend); |
| partial_hdr[partial_hdr_len + hdrend] = 0; |
| |
| /* quit if header still no complete */ |
| if (hdrend >= bufflen) return(0); |
| |
| /* good, got whole header */ |
| bufflen -= hdrend + 1; |
| memmove(buff, buff + hdrend + 1, bufflen); |
| bytesleft = strtol(partial_hdr, NULL, 16); |
| } |
| |
| AGAIN: |
| |
| if (bufflen <= bytesleft) { /* bufflen <= bytesleft */ |
| bytesleft -= bufflen; |
| return(bufflen); |
| } |
| |
| /* else bufflen > bytesleft */ |
| |
| /* skip trailing \r\n after chunk */ |
| for (hdrstart = bytesleft; hdrstart < bufflen; hdrstart++) if ((buff[hdrstart] != '\r') && (buff[hdrstart] != '\n')) break; |
| /* skip chunk size (look for its \n terminator) */ |
| for (hdrend = hdrstart; (hdrend < bufflen) && (buff[hdrend] != '\n'); hdrend++); |
| |
| if (hdrend < bufflen) { /* full header found */ |
| long newchunklen; |
| /* read the header length */ |
| newchunklen = strtol((char *)buff + hdrstart, NULL, 16); |
| /* move data over header to get a contiguous block of data */ |
| memmove(buff + bytesleft, buff + hdrend + 1, bufflen - (hdrend + 1)); |
| bufflen -= (hdrend + 1 - bytesleft); |
| /* update bytesleft */ |
| bytesleft += newchunklen; |
| /* loop again */ |
| goto AGAIN; |
| } else { /* partial header */ |
| if ((bufflen - bytesleft) > 15) return(-1); /* error: chunk header appears to be longer than 15 characters */ |
| memset(partial_hdr, 0, sizeof(partial_hdr)); |
| memcpy(partial_hdr, buff + bytesleft, bufflen - bytesleft); |
| bufflen -= (bufflen - bytesleft); |
| bytesleft = -1; /* "header in progress" */ |
| return(bufflen); |
| } |
| } |