put_bits: add av_assert2() to check out of array writes.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/put_bits.h

@@ -142,6 +142,7 @@ static inline void put_bits(PutBitContext *s, int n, unsigned int value)
 #ifdef BITSTREAM_WRITER_LE
     bit_buf |= value << (32 - bit_left);
     if (n >= bit_left) {
+        av_assert2(s->buf_ptr+3<s->buf_end);
         AV_WL32(s->buf_ptr, bit_buf);
         s->buf_ptr+=4;
         bit_buf = (bit_left==32)?0:value >> bit_left;
@@ -155,6 +156,7 @@ static inline void put_bits(PutBitContext *s, int n, unsigned int value)
     } else {
         bit_buf<<=bit_left;
         bit_buf |= value >> (n - bit_left);
+        av_assert2(s->buf_ptr+3<s->buf_end);
         AV_WB32(s->buf_ptr, bit_buf);
         //printf("bitbuf = %08x\n", bit_buf);
         s->buf_ptr+=4;