X-Git-Url: https://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Fcrcsync%2Fcrcsync.c;h=b6eb65b007fb891339689ad297f9f03ae0709cfd;hp=459010a760f7e826b7a3780e8ef6491a1ee5213f;hb=2a1c08c3e86ac3a9750bfb6f77c236356a2a3f3d;hpb=c934a7a21d9ea8aa421d62a65a93f46c95adb535

diff --git a/ccan/crcsync/crcsync.c b/ccan/crcsync/crcsync.c
index 459010a7..b6eb65b0 100644
--- a/ccan/crcsync/crcsync.c
+++ b/ccan/crcsync/crcsync.c
@@ -35,8 +35,8 @@ struct crc_context {
 	int have_match;
 
 	/* Final block is special (if a different size) */
-	size_t final_size;
-	uint32_t final_crc;
+	size_t tail_size;
+	uint32_t tail_crc;
 
 	/* Uncrc tab. */
 	uint32_t uncrc_tab[256];
@@ -66,25 +66,20 @@ static void init_uncrc_tab(uint32_t uncrc_tab[], unsigned int wsize)
 
 struct crc_context *crc_context_new(size_t block_size, unsigned crcbits,
 				    const uint32_t crc[], unsigned num_crcs,
-				    size_t final_size)
+				    size_t tail_size)
 {
 	struct crc_context *ctx;
 
 	assert(num_crcs > 0);
 	assert(block_size > 0);
-	assert(final_size > 0);
-	assert(final_size <= block_size);
+	assert(tail_size < block_size);
 
 	ctx = malloc(sizeof(*ctx) + sizeof(crc[0])*num_crcs);
 	if (ctx) {
 		ctx->block_size = block_size;
-		if (final_size != block_size) {
-			ctx->final_size = final_size;
-			ctx->final_crc = crc[--num_crcs];
-		} else {
-			/* If this is 0, we never compare against it. */
-			ctx->final_size = 0;
-		}
+		ctx->tail_size = tail_size;
+		if (tail_size)
+			ctx->tail_crc = crc[--num_crcs];
 
 		/* Technically, 1 << 32 is undefined. */
 		if (crcbits >= 32)
@@ -123,12 +118,12 @@ static int crc_matches(const struct crc_context *ctx)
 	return -1;
 }
 
-static bool final_matches(const struct crc_context *ctx)
+static bool tail_matches(const struct crc_context *ctx)
 {
-	if (ctx->literal_bytes != ctx->final_size)
+	if (ctx->literal_bytes != ctx->tail_size)
 		return false;
 
-	return (ctx->running_crc & ctx->crcmask) == ctx->final_crc;
+	return (ctx->running_crc & ctx->crcmask) == ctx->tail_crc;
 }
 
 static uint32_t crc_add_byte(uint32_t crc, uint8_t newbyte)
@@ -197,7 +192,7 @@ size_t crc_read_block(struct crc_context *ctx, long *result,
 				old = buf;
 			/* We don't roll this csum, we only look for it after
 			 * a block match.  It's simpler and faster. */
-			if (final_matches(ctx)) {
+			if (tail_matches(ctx)) {
 				crcmatch = ctx->num_crcs;
 				goto have_match;
 			}
@@ -217,7 +212,7 @@ size_t crc_read_block(struct crc_context *ctx, long *result,
 		have_match:
 			*result = -crcmatch-1;
 			if (crcmatch == ctx->num_crcs)
-				assert(ctx->literal_bytes == ctx->final_size);
+				assert(ctx->literal_bytes == ctx->tail_size);
 			else
 				assert(ctx->literal_bytes == ctx->block_size);
 			ctx->literal_bytes = 0;