[FFmpeg-cvslog] avcodec/cbs: add helper functions and macros to read and write signed values
James Almer
git at videolan.org
Wed Apr 17 02:47:56 EEST 2019
ffmpeg | branch: master | James Almer <jamrial at gmail.com> | Mon Apr 15 17:46:53 2019 -0300| [5006dcdf9af177444e3e0185640d7d84629e4215] | committer: James Almer
avcodec/cbs: add helper functions and macros to read and write signed values
Reviewed-by: Mark Thompson <sw at jkqxz.net>
Signed-off-by: James Almer <jamrial at gmail.com>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=5006dcdf9af177444e3e0185640d7d84629e4215
---
libavcodec/cbs.c | 79 +++++++++++++++++++++++++++++++++++++++++++++++
libavcodec/cbs_internal.h | 20 +++++++++++-
2 files changed, 98 insertions(+), 1 deletion(-)
diff --git a/libavcodec/cbs.c b/libavcodec/cbs.c
index c388be896b..0260ba6f67 100644
--- a/libavcodec/cbs.c
+++ b/libavcodec/cbs.c
@@ -504,6 +504,85 @@ int ff_cbs_write_unsigned(CodedBitstreamContext *ctx, PutBitContext *pbc,
return 0;
}
+int ff_cbs_read_signed(CodedBitstreamContext *ctx, GetBitContext *gbc,
+ int width, const char *name,
+ const int *subscripts, int32_t *write_to,
+ int32_t range_min, int32_t range_max)
+{
+ int32_t value;
+ int position;
+
+ av_assert0(width > 0 && width <= 32);
+
+ if (get_bits_left(gbc) < width) {
+ av_log(ctx->log_ctx, AV_LOG_ERROR, "Invalid value at "
+ "%s: bitstream ended.\n", name);
+ return AVERROR_INVALIDDATA;
+ }
+
+ if (ctx->trace_enable)
+ position = get_bits_count(gbc);
+
+ value = get_sbits_long(gbc, width);
+
+ if (ctx->trace_enable) {
+ char bits[33];
+ int i;
+ for (i = 0; i < width; i++)
+ bits[i] = value & (1U << (width - i - 1)) ? '1' : '0';
+ bits[i] = 0;
+
+ ff_cbs_trace_syntax_element(ctx, position, name, subscripts,
+ bits, value);
+ }
+
+ if (value < range_min || value > range_max) {
+ av_log(ctx->log_ctx, AV_LOG_ERROR, "%s out of range: "
+ "%"PRId32", but must be in [%"PRId32",%"PRId32"].\n",
+ name, value, range_min, range_max);
+ return AVERROR_INVALIDDATA;
+ }
+
+ *write_to = value;
+ return 0;
+}
+
+int ff_cbs_write_signed(CodedBitstreamContext *ctx, PutBitContext *pbc,
+ int width, const char *name,
+ const int *subscripts, int32_t value,
+ int32_t range_min, int32_t range_max)
+{
+ av_assert0(width > 0 && width <= 32);
+
+ if (value < range_min || value > range_max) {
+ av_log(ctx->log_ctx, AV_LOG_ERROR, "%s out of range: "
+ "%"PRId32", but must be in [%"PRId32",%"PRId32"].\n",
+ name, value, range_min, range_max);
+ return AVERROR_INVALIDDATA;
+ }
+
+ if (put_bits_left(pbc) < width)
+ return AVERROR(ENOSPC);
+
+ if (ctx->trace_enable) {
+ char bits[33];
+ int i;
+ for (i = 0; i < width; i++)
+ bits[i] = value & (1U << (width - i - 1)) ? '1' : '0';
+ bits[i] = 0;
+
+ ff_cbs_trace_syntax_element(ctx, put_bits_count(pbc),
+ name, subscripts, bits, value);
+ }
+
+ if (width < 32)
+ put_sbits(pbc, width, value);
+ else
+ put_bits32(pbc, value);
+
+ return 0;
+}
+
int ff_cbs_alloc_unit_content(CodedBitstreamContext *ctx,
CodedBitstreamUnit *unit,
diff --git a/libavcodec/cbs_internal.h b/libavcodec/cbs_internal.h
index 53f2e5d187..dd4babf092 100644
--- a/libavcodec/cbs_internal.h
+++ b/libavcodec/cbs_internal.h
@@ -81,10 +81,28 @@ int ff_cbs_write_unsigned(CodedBitstreamContext *ctx, PutBitContext *pbc,
const int *subscripts, uint32_t value,
uint32_t range_min, uint32_t range_max);
-// The largest value representable in N bits, suitable for use as
+int ff_cbs_read_signed(CodedBitstreamContext *ctx, GetBitContext *gbc,
+ int width, const char *name,
+ const int *subscripts, int32_t *write_to,
+ int32_t range_min, int32_t range_max);
+
+int ff_cbs_write_signed(CodedBitstreamContext *ctx, PutBitContext *pbc,
+ int width, const char *name,
+ const int *subscripts, int32_t value,
+ int32_t range_min, int32_t range_max);
+
+// The largest unsigned value representable in N bits, suitable for use as
// range_max in the above functions.
#define MAX_UINT_BITS(length) ((UINT64_C(1) << (length)) - 1)
+// The largest signed value representable in N bits, suitable for use as
+// range_max in the above functions.
+#define MAX_INT_BITS(length) ((INT64_C(1) << ((length) - 1)) - 1)
+
+// The smallest signed value representable in N bits, suitable for use as
+// range_min in the above functions.
+#define MIN_INT_BITS(length) (-(INT64_C(1) << ((length) - 1)))
+
extern const CodedBitstreamType ff_cbs_type_av1;
extern const CodedBitstreamType ff_cbs_type_h264;
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