iir_filter: Change type of array stride parameters to ptrdiff_t

ptrdiff_t is the correct type for array strides and similar.

libavcodec/iirfilter.c

@@ -28,6 +28,7 @@
 
 #include "libavutil/attributes.h"
 #include "libavutil/common.h"
+#include "libavutil/log.h"
 
 #include "iirfilter.h"
 
@@ -278,7 +279,8 @@ av_cold struct FFIIRFilterState *ff_iir_filter_init_state(int order)
 
 void ff_iir_filter(const struct FFIIRFilterCoeffs *c,
                    struct FFIIRFilterState *s, int size,
-                   const int16_t *src, int sstep, int16_t *dst, int dstep)
+                   const int16_t *src, ptrdiff_t sstep,
+                   int16_t *dst, ptrdiff_t dstep)
 {
     if (c->order == 2) {
         FILTER_O2(int16_t, S16)
@@ -291,7 +293,8 @@ void ff_iir_filter(const struct FFIIRFilterCoeffs *c,
 
 void ff_iir_filter_flt(const struct FFIIRFilterCoeffs *c,
                        struct FFIIRFilterState *s, int size,
-                       const float *src, int sstep, float *dst, int dstep)
+                       const float *src, ptrdiff_t sstep,
+                       float *dst, ptrdiff_t dstep)
 {
     if (c->order == 2) {
         FILTER_O2(float, FLT)

libavcodec/iirfilter.h

@@ -27,7 +27,8 @@
 #ifndef AVCODEC_IIRFILTER_H
 #define AVCODEC_IIRFILTER_H
 
-#include "avcodec.h"
+#include <stddef.h>
+#include <stdint.h>
 
 struct FFIIRFilterCoeffs;
 struct FFIIRFilterState;
@@ -102,7 +103,7 @@ void ff_iir_filter_free_state(struct FFIIRFilterState *state);
  * @param dstep  destination stride
  */
 void ff_iir_filter(const struct FFIIRFilterCoeffs *coeffs, struct FFIIRFilterState *state,
-                   int size, const int16_t *src, int sstep, int16_t *dst, int dstep);
+                   int size, const int16_t *src, ptrdiff_t sstep, int16_t *dst, ptrdiff_t dstep);
 
 /**
  * Perform IIR filtering on floating-point input samples.
@@ -117,6 +118,7 @@ void ff_iir_filter(const struct FFIIRFilterCoeffs *coeffs, struct FFIIRFilterSta
  */
 void ff_iir_filter_flt(const struct FFIIRFilterCoeffs *coeffs,
                        struct FFIIRFilterState *state, int size,
-                       const float *src, int sstep, float *dst, int dstep);
+                       const float *src, ptrdiff_t sstep,
+                       float *dst, ptrdiff_t dstep);
 
 #endif /* AVCODEC_IIRFILTER_H */