Use signed variables in the lookahead.

Wrap around behavior is enforced manually and we use the values in
arithmetic involving negative integers.

Change-Id: I199706b6f3af91f4fb6fe2ef302fbbc6d0cf5785

vp10/encoder/lookahead.c

@@ -20,8 +20,8 @@
 
 /* Return the buffer at the given absolute index and increment the index */
 static struct lookahead_entry *pop(struct lookahead_ctx *ctx,
-                                   unsigned int *idx) {
-  unsigned int index = *idx;
+                                   int *idx) {
+  int index = *idx;
   struct lookahead_entry *buf = ctx->buf + index;
 
   assert(index < ctx->max_sz);
@@ -35,7 +35,7 @@ static struct lookahead_entry *pop(struct lookahead_ctx *ctx,
 void vp10_lookahead_destroy(struct lookahead_ctx *ctx) {
   if (ctx) {
     if (ctx->buf) {
-      unsigned int i;
+      int i;
 
       for (i = 0; i < ctx->max_sz; i++)
         vpx_free_frame_buffer(&ctx->buf[i].img);
@@ -221,9 +221,9 @@ struct lookahead_entry *vp10_lookahead_peek(struct lookahead_ctx *ctx,
 
   if (index >= 0) {
     // Forward peek
-    if (index < (int)ctx->sz) {
+    if (index < ctx->sz) {
       index += ctx->read_idx;
-      if (index >= (int)ctx->max_sz)
+      if (index >= ctx->max_sz)
         index -= ctx->max_sz;
       buf = ctx->buf + index;
     }

vp10/encoder/lookahead.h

@@ -31,10 +31,10 @@ struct lookahead_entry {
 #define MAX_PRE_FRAMES 1
 
 struct lookahead_ctx {
-  unsigned int max_sz;         /* Absolute size of the queue */
-  unsigned int sz;             /* Number of buffers currently in the queue */
-  unsigned int read_idx;       /* Read index */
-  unsigned int write_idx;      /* Write index */
+  int max_sz;                  /* Absolute size of the queue */
+  int sz;                      /* Number of buffers currently in the queue */
+  int read_idx;                /* Read index */
+  int write_idx;               /* Write index */
   struct lookahead_entry *buf; /* Buffer list */
 };
 

vp9/encoder/vp9_lookahead.c

@@ -20,8 +20,8 @@
 
 /* Return the buffer at the given absolute index and increment the index */
 static struct lookahead_entry *pop(struct lookahead_ctx *ctx,
-                                   unsigned int *idx) {
-  unsigned int index = *idx;
+                                   int *idx) {
+  int index = *idx;
   struct lookahead_entry *buf = ctx->buf + index;
 
   assert(index < ctx->max_sz);
@@ -35,7 +35,7 @@ static struct lookahead_entry *pop(struct lookahead_ctx *ctx,
 void vp9_lookahead_destroy(struct lookahead_ctx *ctx) {
   if (ctx) {
     if (ctx->buf) {
-      unsigned int i;
+      int i;
 
       for (i = 0; i < ctx->max_sz; i++)
         vpx_free_frame_buffer(&ctx->buf[i].img);
@@ -221,9 +221,9 @@ struct lookahead_entry *vp9_lookahead_peek(struct lookahead_ctx *ctx,
 
   if (index >= 0) {
     // Forward peek
-    if (index < (int)ctx->sz) {
+    if (index < ctx->sz) {
       index += ctx->read_idx;
-      if (index >= (int)ctx->max_sz)
+      if (index >= ctx->max_sz)
         index -= ctx->max_sz;
       buf = ctx->buf + index;
     }

vp9/encoder/vp9_lookahead.h

@@ -36,10 +36,10 @@ struct lookahead_entry {
 #define MAX_PRE_FRAMES 1
 
 struct lookahead_ctx {
-  unsigned int max_sz;         /* Absolute size of the queue */
-  unsigned int sz;             /* Number of buffers currently in the queue */
-  unsigned int read_idx;       /* Read index */
-  unsigned int write_idx;      /* Write index */
+  int max_sz;                  /* Absolute size of the queue */
+  int sz;                      /* Number of buffers currently in the queue */
+  int read_idx;                /* Read index */
+  int write_idx;               /* Write index */
   struct lookahead_entry *buf; /* Buffer list */
 };