diff options
Diffstat (limited to 'src/jpeg-6/jcdctmgr.c')
-rw-r--r-- | src/jpeg-6/jcdctmgr.c | 89 |
1 files changed, 0 insertions, 89 deletions
diff --git a/src/jpeg-6/jcdctmgr.c b/src/jpeg-6/jcdctmgr.c index f31a96f2..debba72b 100644 --- a/src/jpeg-6/jcdctmgr.c +++ b/src/jpeg-6/jcdctmgr.c @@ -179,95 +179,6 @@ start_pass_fdctmgr (j_compress_ptr cinfo) * blocks. The quantized coefficients are returned in coef_blocks[]. */ -#if 0 // bk001204 -METHODDEF void -forward_DCT (j_compress_ptr cinfo, jpeg_component_info * compptr, - JSAMPARRAY sample_data, JBLOCKROW coef_blocks, - JDIMENSION start_row, JDIMENSION start_col, - JDIMENSION num_blocks) -/* This version is used for integer DCT implementations. */ -{ - /* This routine is heavily used, so it's worth coding it tightly. */ - my_fdct_ptr fdct = (my_fdct_ptr) cinfo->fdct; - forward_DCT_method_ptr do_dct = fdct->do_dct; - DCTELEM * divisors = fdct->divisors[compptr->quant_tbl_no]; - DCTELEM workspace[DCTSIZE2]; /* work area for FDCT subroutine */ - JDIMENSION bi; - - sample_data += start_row; /* fold in the vertical offset once */ - - for (bi = 0; bi < num_blocks; bi++, start_col += DCTSIZE) { - /* Load data into workspace, applying unsigned->signed conversion */ - { register DCTELEM *workspaceptr; - register JSAMPROW elemptr; - register int elemr; - - workspaceptr = workspace; - for (elemr = 0; elemr < DCTSIZE; elemr++) { - elemptr = sample_data[elemr] + start_col; -#if DCTSIZE == 8 /* unroll the inner loop */ - *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; - *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; - *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; - *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; - *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; - *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; - *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; - *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; -#else - { register int elemc; - for (elemc = DCTSIZE; elemc > 0; elemc--) { - *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; - } - } -#endif - } - } - - /* Perform the DCT */ - (*do_dct) (workspace); - - /* Quantize/descale the coefficients, and store into coef_blocks[] */ - { register DCTELEM temp, qval; - register int i; - register JCOEFPTR output_ptr = coef_blocks[bi]; - - for (i = 0; i < DCTSIZE2; i++) { - qval = divisors[i]; - temp = workspace[i]; - /* Divide the coefficient value by qval, ensuring proper rounding. - * Since C does not specify the direction of rounding for negative - * quotients, we have to force the dividend positive for portability. - * - * In most files, at least half of the output values will be zero - * (at default quantization settings, more like three-quarters...) - * so we should ensure that this case is fast. On many machines, - * a comparison is enough cheaper than a divide to make a special test - * a win. Since both inputs will be nonnegative, we need only test - * for a < b to discover whether a/b is 0. - * If your machine's division is fast enough, define FAST_DIVIDE. - */ -#ifdef FAST_DIVIDE -#define DIVIDE_BY(a,b) a /= b -#else -#define DIVIDE_BY(a,b) if (a >= b) a /= b; else a = 0 -#endif - if (temp < 0) { - temp = -temp; - temp += qval>>1; /* for rounding */ - DIVIDE_BY(temp, qval); - temp = -temp; - } else { - temp += qval>>1; /* for rounding */ - DIVIDE_BY(temp, qval); - } - output_ptr[i] = (JCOEF) temp; - } - } - } -} -#endif // 0 - #ifdef DCT_FLOAT_SUPPORTED METHODDEF void |