change to sign-folded rice coding, add golomb coder

diff --git a/src/libFLAC/bitbuffer.c b/src/libFLAC/bitbuffer.c
index 5f618a9..2feef7b 100644 (file)
--- a/src/libFLAC/bitbuffer.c
+++ b/src/libFLAC/bitbuffer.c
@@ -33,6 +33,15 @@ static const unsigned FLAC__BITBUFFER_DEFAULT_CAPACITY = 65536; /* bytes */
 #endif
 #define max(x,y) ((x)>(y)?(x):(y))
 
+static unsigned ilog2_(unsigned v)
+{
+       unsigned l = 0;
+       assert(v > 0);
+       while(v >>= 1)
+               l++;
+       return l;
+}
+
 static bool bitbuffer_resize_(FLAC__BitBuffer *bb, unsigned new_capacity)
 {
        byte *new_buffer;
@@ -391,43 +400,125 @@ bool FLAC__bitbuffer_write_raw_int64(FLAC__BitBuffer *bb, int64 val, unsigned bi
        return FLAC__bitbuffer_write_raw_uint64(bb, (uint64)val, bits);
 }
 
-bool FLAC__bitbuffer_write_rice_signed(FLAC__BitBuffer *bb, int val, unsigned parameter)
+unsigned FLAC__bitbuffer_rice_bits(int val, unsigned parameter)
+{
+       unsigned msbs, uval;
+
+       /* convert signed to unsigned */
+       if(val < 0)
+               /* equivalent to
+                *     (unsigned)(((--val) << 1) - 1);
+                * but without the overflow problem at -MAXINT
+                */
+               uval = (unsigned)(((-(++val)) << 1) + 1);
+       else
+               uval = (unsigned)(val << 1);
+
+       msbs = uval >> parameter;
+
+       return 1 + parameter + msbs;
+}
+
+unsigned FLAC__bitbuffer_golomb_bits_signed(int val, unsigned parameter)
+{
+       unsigned bits, msbs, uval;
+       unsigned k;
+
+       assert(parameter > 0);
+
+       /* convert signed to unsigned */
+       if(val < 0)
+               /* equivalent to
+                *     (unsigned)(((--val) << 1) - 1);
+                * but without the overflow problem at -MAXINT
+                */
+               uval = (unsigned)(((-(++val)) << 1) + 1);
+       else
+               uval = (unsigned)(val << 1);
+
+       k = ilog2_(parameter);
+       if(parameter == 1u<<k) {
+               assert(k <= 30);
+
+               msbs = uval >> k;
+               bits = 1 + k + msbs;
+       }
+       else {
+               unsigned q, r, d;
+
+               d = (1 << (k+1)) - parameter;
+               q = uval / parameter;
+               r = uval - (q * parameter);
+
+               bits = 1 + q + k;
+               if(r >= d)
+                       bits++;
+       }
+       return bits;
+}
+
+unsigned FLAC__bitbuffer_golomb_bits_unsigned(unsigned uval, unsigned parameter)
 {
        unsigned bits, msbs;
+       unsigned k;
+
+       assert(parameter > 0);
+
+       k = ilog2_(parameter);
+       if(parameter == 1u<<k) {
+               assert(k <= 30);
+
+               msbs = uval >> k;
+               bits = 1 + k + msbs;
+       }
+       else {
+               unsigned q, r, d;
+
+               d = (1 << (k+1)) - parameter;
+               q = uval / parameter;
+               r = uval - (q * parameter);
+
+               bits = 1 + q + k;
+               if(r >= d)
+                       bits++;
+       }
+       return bits;
+}
+
+bool FLAC__bitbuffer_write_rice_signed(FLAC__BitBuffer *bb, int val, unsigned parameter)
+{
+       unsigned bits, msbs, uval;
        uint32 pattern;
 
        assert(bb != 0);
        assert(bb->buffer != 0);
-
-       /* init pattern with sign bit */
-       if(val < 0) {
-               pattern = 1;
-               val = -val;
-       }
+       assert(parameter <= 30);
+
+       /* convert signed to unsigned */
+       if(val < 0)
+               /* equivalent to
+                *     (unsigned)(((--val) << 1) - 1);
+                * but without the overflow problem at -MAXINT
+                */
+               uval = (unsigned)(((-(++val)) << 1) + 1);
        else
-               pattern = 0;
+               uval = (unsigned)(val << 1);
 
-       msbs = val >> parameter;
-       bits = 2 + parameter + msbs;
+       msbs = uval >> parameter;
+       bits = 1 + parameter + msbs;
+       pattern = 1 << parameter; /* the unary end bit */
+       pattern |= (uval & ((1<<parameter)-1)); /* the binary LSBs */
 
        if(bits <= 32) {
-               pattern = (pattern << parameter) | (val & ((1<<parameter)-1));
-               pattern = (pattern << (msbs+1)) | 1;
                if(!FLAC__bitbuffer_write_raw_uint32(bb, pattern, bits))
                        return false;
        }
        else {
-               /* write the sign bit */
-               if(!FLAC__bitbuffer_write_raw_uint32(bb, pattern, 1))
-                       return false;
-               /* write the binary LSBs */
-               if(!FLAC__bitbuffer_write_raw_uint32(bb, val & ((1<<parameter)-1), parameter))
-                       return false;
                /* write the unary MSBs */
                if(!FLAC__bitbuffer_write_zeroes(bb, msbs))
                        return false;
-               /* write the end bit */
-               if(!FLAC__bitbuffer_write_raw_uint32(bb, 1, 1))
+               /* write the unary end bit and binary LSBs */
+               if(!FLAC__bitbuffer_write_raw_uint32(bb, pattern, parameter+1))
                        return false;
        }
        return true;
@@ -435,28 +526,31 @@ bool FLAC__bitbuffer_write_rice_signed(FLAC__BitBuffer *bb, int val, unsigned pa
 
 bool FLAC__bitbuffer_write_rice_signed_guarded(FLAC__BitBuffer *bb, int val, unsigned parameter, unsigned max_bits, bool *overflow)
 {
-       unsigned bits, msbs;
+       unsigned bits, msbs, uval;
        uint32 pattern;
 
        assert(bb != 0);
        assert(bb->buffer != 0);
+       assert(parameter <= 30);
 
        *overflow = false;
 
-       /* init pattern with sign bit */
-       if(val < 0) {
-               pattern = 1;
-               val = -val;
-       }
+       /* convert signed to unsigned */
+       if(val < 0)
+               /* equivalent to
+                *     (unsigned)(((--val) << 1) - 1);
+                * but without the overflow problem at -MAXINT
+                */
+               uval = (unsigned)(((-(++val)) << 1) + 1);
        else
-               pattern = 0;
+               uval = (unsigned)(val << 1);
 
-       msbs = val >> parameter;
-       bits = 2 + parameter + msbs;
+       msbs = uval >> parameter;
+       bits = 1 + parameter + msbs;
+       pattern = 1 << parameter; /* the unary end bit */
+       pattern |= (uval & ((1<<parameter)-1)); /* the binary LSBs */
 
        if(bits <= 32) {
-               pattern = (pattern << parameter) | (val & ((1<<parameter)-1));
-               pattern = (pattern << (msbs+1)) | 1;
                if(!FLAC__bitbuffer_write_raw_uint32(bb, pattern, bits))
                        return false;
        }
@@ -465,18 +559,138 @@ bool FLAC__bitbuffer_write_rice_signed_guarded(FLAC__BitBuffer *bb, int val, uns
                return true;
        }
        else {
-               /* write the sign bit */
-               if(!FLAC__bitbuffer_write_raw_uint32(bb, pattern, 1))
+               /* write the unary MSBs */
+               if(!FLAC__bitbuffer_write_zeroes(bb, msbs))
                        return false;
-               /* write the binary LSBs */
-               if(!FLAC__bitbuffer_write_raw_uint32(bb, val & ((1<<parameter)-1), parameter))
+               /* write the unary end bit and binary LSBs */
+               if(!FLAC__bitbuffer_write_raw_uint32(bb, pattern, parameter+1))
                        return false;
+       }
+       return true;
+}
+
+bool FLAC__bitbuffer_write_golomb_signed(FLAC__BitBuffer *bb, int val, unsigned parameter)
+{
+       unsigned bits, msbs, uval;
+       unsigned k;
+
+       assert(bb != 0);
+       assert(bb->buffer != 0);
+       assert(parameter > 0);
+
+       /* convert signed to unsigned */
+       if(val < 0)
+               /* equivalent to
+                *     (unsigned)(((--val) << 1) - 1);
+                * but without the overflow problem at -MAXINT
+                */
+               uval = (unsigned)(((-(++val)) << 1) + 1);
+       else
+               uval = (unsigned)(val << 1);
+
+       k = ilog2_(parameter);
+       if(parameter == 1u<<k) {
+               unsigned pattern;
+
+               assert(k <= 30);
+
+               msbs = uval >> k;
+               bits = 1 + k + msbs;
+               pattern = 1 << k; /* the unary end bit */
+               pattern |= (uval & ((1u<<k)-1)); /* the binary LSBs */
+
+               if(bits <= 32) {
+                       if(!FLAC__bitbuffer_write_raw_uint32(bb, pattern, bits))
+                               return false;
+               }
+               else {
+                       /* write the unary MSBs */
+                       if(!FLAC__bitbuffer_write_zeroes(bb, msbs))
+                               return false;
+                       /* write the unary end bit and binary LSBs */
+                       if(!FLAC__bitbuffer_write_raw_uint32(bb, pattern, k+1))
+                               return false;
+               }
+       }
+       else {
+               unsigned q, r, d;
+
+               d = (1 << (k+1)) - parameter;
+               q = uval / parameter;
+               r = uval - (q * parameter);
                /* write the unary MSBs */
-               if(!FLAC__bitbuffer_write_zeroes(bb, msbs))
+               if(!FLAC__bitbuffer_write_zeroes(bb, q))
                        return false;
-               /* write the end bit */
+               /* write the unary end bit */
                if(!FLAC__bitbuffer_write_raw_uint32(bb, 1, 1))
                        return false;
+               /* write the binary LSBs */
+               if(r >= d) {
+                       if(!FLAC__bitbuffer_write_raw_uint32(bb, r+d, k+1))
+                               return false;
+               }
+               else {
+                       if(!FLAC__bitbuffer_write_raw_uint32(bb, r, k))
+                               return false;
+               }
+       }
+       return true;
+}
+
+bool FLAC__bitbuffer_write_golomb_unsigned(FLAC__BitBuffer *bb, unsigned uval, unsigned parameter)
+{
+       unsigned bits, msbs;
+       unsigned k;
+
+       assert(bb != 0);
+       assert(bb->buffer != 0);
+       assert(parameter > 0);
+
+       k = ilog2_(parameter);
+       if(parameter == 1u<<k) {
+               unsigned pattern;
+
+               assert(k <= 30);
+
+               msbs = uval >> k;
+               bits = 1 + k + msbs;
+               pattern = 1 << k; /* the unary end bit */
+               pattern |= (uval & ((1u<<k)-1)); /* the binary LSBs */
+
+               if(bits <= 32) {
+                       if(!FLAC__bitbuffer_write_raw_uint32(bb, pattern, bits))
+                               return false;
+               }
+               else {
+                       /* write the unary MSBs */
+                       if(!FLAC__bitbuffer_write_zeroes(bb, msbs))
+                               return false;
+                       /* write the unary end bit and binary LSBs */
+                       if(!FLAC__bitbuffer_write_raw_uint32(bb, pattern, k+1))
+                               return false;
+               }
+       }
+       else {
+               unsigned q, r, d;
+
+               d = (1 << (k+1)) - parameter;
+               q = uval / parameter;
+               r = uval - (q * parameter);
+               /* write the unary MSBs */
+               if(!FLAC__bitbuffer_write_zeroes(bb, q))
+                       return false;
+               /* write the unary end bit */
+               if(!FLAC__bitbuffer_write_raw_uint32(bb, 1, 1))
+                       return false;
+               /* write the binary LSBs */
+               if(r >= d) {
+                       if(!FLAC__bitbuffer_write_raw_uint32(bb, r+d, k+1))
+                               return false;
+               }
+               else {
+                       if(!FLAC__bitbuffer_write_raw_uint32(bb, r, k))
+                               return false;
+               }
        }
        return true;
 }
@@ -791,18 +1005,94 @@ bool FLAC__bitbuffer_read_raw_int64(FLAC__BitBuffer *bb, int64 *val, unsigned bi
 
 bool FLAC__bitbuffer_read_rice_signed(FLAC__BitBuffer *bb, int *val, unsigned parameter, bool (*read_callback)(byte buffer[], unsigned *bytes, void *client_data), void *client_data)
 {
-       uint32 sign = 0, lsbs, msbs = 0;
-       unsigned bit;
+       uint32 lsbs, msbs = 0;
+       unsigned bit, uval;
 
        assert(bb != 0);
        assert(bb->buffer != 0);
+       assert(parameter <= 32);
 
-       /* read the sign bit */
-       if(!FLAC__bitbuffer_read_bit_to_uint32(bb, &sign, read_callback, client_data))
-               return false;
+       /* read the unary MSBs and end bit */
+       while(1) {
+               if(!FLAC__bitbuffer_read_bit(bb, &bit, read_callback, client_data))
+                       return false;
+               if(bit)
+                       break;
+               else
+                       msbs++;
+       }
        /* read the binary LSBs */
        if(!FLAC__bitbuffer_read_raw_uint32(bb, &lsbs, parameter, read_callback, client_data))
                return false;
+       /* compose the value */
+       uval = (msbs << parameter) | lsbs;
+       if(uval & 1)
+               *val = -((int)(uval >> 1)) - 1;
+       else
+               *val = (int)(uval >> 1);
+
+       return true;
+}
+
+bool FLAC__bitbuffer_read_golomb_signed(FLAC__BitBuffer *bb, int *val, unsigned parameter, bool (*read_callback)(byte buffer[], unsigned *bytes, void *client_data), void *client_data)
+{
+       uint32 lsbs, msbs = 0;
+       unsigned bit, uval, k;
+
+       assert(bb != 0);
+       assert(bb->buffer != 0);
+
+       k = ilog2_(parameter);
+
+       /* read the unary MSBs and end bit */
+       while(1) {
+               if(!FLAC__bitbuffer_read_bit(bb, &bit, read_callback, client_data))
+                       return false;
+               if(bit)
+                       break;
+               else
+                       msbs++;
+       }
+       /* read the binary LSBs */
+       if(!FLAC__bitbuffer_read_raw_uint32(bb, &lsbs, k, read_callback, client_data))
+               return false;
+
+       if(parameter == 1u<<k) {
+               /* compose the value */
+               uval = (msbs << k) | lsbs;
+       }
+       else {
+               unsigned d = (1 << (k+1)) - parameter;
+               if(lsbs >= d) {
+                       if(!FLAC__bitbuffer_read_bit(bb, &bit, read_callback, client_data))
+                               return false;
+                       lsbs <<= 1;
+                       lsbs |= bit;
+                       lsbs -= d;
+               }
+               /* compose the value */
+               uval = msbs * parameter + lsbs;
+       }
+
+       /* unfold unsigned to signed */
+       if(uval & 1)
+               *val = -((int)(uval >> 1)) - 1;
+       else
+               *val = (int)(uval >> 1);
+
+       return true;
+}
+
+bool FLAC__bitbuffer_read_golomb_unsigned(FLAC__BitBuffer *bb, unsigned *val, unsigned parameter, bool (*read_callback)(byte buffer[], unsigned *bytes, void *client_data), void *client_data)
+{
+       uint32 lsbs, msbs = 0;
+       unsigned bit, k;
+
+       assert(bb != 0);
+       assert(bb->buffer != 0);
+
+       k = ilog2_(parameter);
+
        /* read the unary MSBs and end bit */
        while(1) {
                if(!FLAC__bitbuffer_read_bit(bb, &bit, read_callback, client_data))
@@ -812,10 +1102,26 @@ bool FLAC__bitbuffer_read_rice_signed(FLAC__BitBuffer *bb, int *val, unsigned pa
                else
                        msbs++;
        }
-       /* compose the value */
-       *val = (msbs << parameter) | lsbs;
-       if(sign)
-               *val = -(*val);
+       /* read the binary LSBs */
+       if(!FLAC__bitbuffer_read_raw_uint32(bb, &lsbs, k, read_callback, client_data))
+               return false;
+
+       if(parameter == 1u<<k) {
+               /* compose the value */
+               *val = (msbs << k) | lsbs;
+       }
+       else {
+               unsigned d = (1 << (k+1)) - parameter;
+               if(lsbs >= d) {
+                       if(!FLAC__bitbuffer_read_bit(bb, &bit, read_callback, client_data))
+                               return false;
+                       lsbs <<= 1;
+                       lsbs |= bit;
+                       lsbs -= d;
+               }
+               /* compose the value */
+               *val = msbs * parameter + lsbs;
+       }
 
        return true;
 }

diff --git a/src/libFLAC/include/private/bitbuffer.h b/src/libFLAC/include/private/bitbuffer.h
index 192b6c9..4e902d9 100644 (file)
--- a/src/libFLAC/include/private/bitbuffer.h
+++ b/src/libFLAC/include/private/bitbuffer.h
@@ -43,8 +43,15 @@ bool FLAC__bitbuffer_write_raw_uint32(FLAC__BitBuffer *bb, uint32 val, unsigned
 bool FLAC__bitbuffer_write_raw_int32(FLAC__BitBuffer *bb, int32 val, unsigned bits);
 bool FLAC__bitbuffer_write_raw_uint64(FLAC__BitBuffer *bb, uint64 val, unsigned bits);
 bool FLAC__bitbuffer_write_raw_int64(FLAC__BitBuffer *bb, int64 val, unsigned bits);
+unsigned FLAC__bitbuffer_rice_bits(int val, unsigned parameter);
+unsigned FLAC__bitbuffer_golomb_bits_signed(int val, unsigned parameter);
+unsigned FLAC__bitbuffer_golomb_bits_unsigned(unsigned val, unsigned parameter);
 bool FLAC__bitbuffer_write_rice_signed(FLAC__BitBuffer *bb, int val, unsigned parameter);
 bool FLAC__bitbuffer_write_rice_signed_guarded(FLAC__BitBuffer *bb, int val, unsigned parameter, unsigned max_bits, bool *overflow);
+bool FLAC__bitbuffer_write_golomb_signed(FLAC__BitBuffer *bb, int val, unsigned parameter);
+bool FLAC__bitbuffer_write_golomb_signed_guarded(FLAC__BitBuffer *bb, int val, unsigned parameter, unsigned max_bits, bool *overflow);
+bool FLAC__bitbuffer_write_golomb_unsigned(FLAC__BitBuffer *bb, unsigned val, unsigned parameter);
+bool FLAC__bitbuffer_write_golomb_unsigned_guarded(FLAC__BitBuffer *bb, unsigned val, unsigned parameter, unsigned max_bits, bool *overflow);
 bool FLAC__bitbuffer_write_utf8_uint32(FLAC__BitBuffer *bb, uint32 val);
 bool FLAC__bitbuffer_write_utf8_uint64(FLAC__BitBuffer *bb, uint64 val);
 bool FLAC__bitbuffer_zero_pad_to_byte_boundary(FLAC__BitBuffer *bb);
@@ -57,6 +64,8 @@ bool FLAC__bitbuffer_read_raw_int32(FLAC__BitBuffer *bb, int32 *val, unsigned bi
 bool FLAC__bitbuffer_read_raw_uint64(FLAC__BitBuffer *bb, uint64 *val, unsigned bits, bool (*read_callback)(byte buffer[], unsigned *bytes, void *client_data), void *client_data);
 bool FLAC__bitbuffer_read_raw_int64(FLAC__BitBuffer *bb, int64 *val, unsigned bits, bool (*read_callback)(byte buffer[], unsigned *bytes, void *client_data), void *client_data);
 bool FLAC__bitbuffer_read_rice_signed(FLAC__BitBuffer *bb, int *val, unsigned parameter, bool (*read_callback)(byte buffer[], unsigned *bytes, void *client_data), void *client_data);
+bool FLAC__bitbuffer_read_golomb_signed(FLAC__BitBuffer *bb, int *val, unsigned parameter, bool (*read_callback)(byte buffer[], unsigned *bytes, void *client_data), void *client_data);
+bool FLAC__bitbuffer_read_golomb_unsigned(FLAC__BitBuffer *bb, unsigned *val, unsigned parameter, bool (*read_callback)(byte buffer[], unsigned *bytes, void *client_data), void *client_data);
 bool FLAC__bitbuffer_read_utf8_uint32(FLAC__BitBuffer *bb, uint32 *val, bool (*read_callback)(byte buffer[], unsigned *bytes, void *client_data), void *client_data, byte *raw, unsigned *rawlen);
 bool FLAC__bitbuffer_read_utf8_uint64(FLAC__BitBuffer *bb, uint64 *val, bool (*read_callback)(byte buffer[], unsigned *bytes, void *client_data), void *client_data, byte *raw, unsigned *rawlen);
 void FLAC__bitbuffer_dump(const FLAC__BitBuffer *bb, FILE *out);