Function mc_compress

modules/compression/compression.c:1034–1116

* Compression function * 1) Only mandatory headers will be kept * 2) The rest of the headers along with the body * will form the new body which will be use for compression * 3) The Content-Encoding Header will set to gzip, probably * base64 also */

 * base64 also
 */
static int mc_compress(struct sip_msg* msg, int *algo_p, int *flags_p,
		mc_whitelist_p wh_list)
{
	int ret = -1;
	int index;
	int algo = (algo_p? *algo_p: 0);
	int flags = *flags_p;
	struct mc_comp_args* args;

	/* first check if anyone else has called mc_compact() on this msg */
	if (GET_GLOBAL_CTX(compress_ctx_pos))
		return -1;

	if (!(flags&BODY_COMP_FLG) && !(flags&HDR_COMP_FLG)) {
		LM_WARN("nothing requested to compress! "
				"please choose at least one of the 'b' or 'h' flags\n");
		return -1;
	}

	if (wh_list)
		wh_list = mc_dup_whitelist(wh_list);

	/* Simulate a whitelist which will contain only the Content-Length
		header in case BODY_COMP_FLG is set */
	if (flags&HDR_COMP_FLG && wh_list) {
		/* Remove mandatory headers if they have been set */
		for (index=0; index < veclen(mnd_hdrs, int); index++) {
			if (wh_list->hdr_mask[mnd_hdrs[index]/MC_BYTE_SIZE]
						& (1 << mnd_hdrs[index]%MC_BYTE_SIZE)) {
				wh_list->hdr_mask[mnd_hdrs[index]/MC_BYTE_SIZE] ^=
								1 << (mnd_hdrs[index]%MC_BYTE_SIZE);
			}
		}
	}


	/* Content Length must be encoded if asked for body to be encoded*/
	if (flags&BODY_COMP_FLG) {
		if (!wh_list && parse_whitelist(NULL, &wh_list, NULL) < 0) {
			LM_ERR("could not allocate new list!\n");
			goto end;
		}
		wh_list->hdr_mask[HDR_CONTENTLENGTH_T/MC_BYTE_SIZE] |=
					1 << (HDR_CONTENTLENGTH_T%MC_BYTE_SIZE);
	}

	args=pkg_malloc(sizeof(struct mc_comp_args));
	if (args==NULL) {
		LM_ERR("no more pkg mem\n");
		goto end;
	}

	args->hdr2compress_list = wh_list;
	args->flags = flags;
	args->algo = algo;
	SET_GLOBAL_CTX(compress_ctx_pos, (void*)args);

	/* register stateless callbacks */