Save one refill from inner coefficient-reading loop.

[fjl] / driver.c

diff --git a/driver.c b/driver.c
index 04e236912ca45d56bc4f1a34f16b3c04185112d9..6db737ff7d585033109f1ba58253c71e500cd83d 100644 (file)
--- a/driver.c
+++ b/driver.c
@@ -164,7 +164,7 @@ void read_scan(struct byte_source* source, struct jpeg_image* image, huffman_tab
 
                                        // decode DC component
                                        unsigned dc_category = read_huffman_symbol(dc_table, &bits);
 
                                        // decode DC component
                                        unsigned dc_category = read_huffman_symbol(dc_table, &bits);

-                                       possibly_refill(&bits, dc_category);
+                                       possibly_refill(&bits, dc_category + DEHUF_TABLE_BITS);

                                        last_dc[c] += extend(read_bits(&bits, dc_category), dc_category);
                                        
                                        int16_t coeff[DCTSIZE2] = { 0 };
                                        last_dc[c] += extend(read_bits(&bits, dc_category), dc_category);
                                        
                                        int16_t coeff[DCTSIZE2] = { 0 };


@@ -172,7 +172,7 @@ void read_scan(struct byte_source* source, struct jpeg_image* image, huffman_tab
 
                                        // decode AC components
                                        for (unsigned i = 1; i < DCTSIZE2; ++i) {
 
                                        // decode AC components
                                        for (unsigned i = 1; i < DCTSIZE2; ++i) {

-                                               unsigned rs = read_huffman_symbol(ac_table, &bits);
+                                               unsigned rs = read_huffman_symbol_no_refill(ac_table, &bits);

                                                unsigned r = rs >> 4;
                                                unsigned s = rs & 0xf;
 
                                                unsigned r = rs >> 4;
                                                unsigned s = rs & 0xf;
 


@@ -182,12 +182,13 @@ void read_scan(struct byte_source* source, struct jpeg_image* image, huffman_tab
                                                }
                                                if (rs == 0xf0) {
                                                        /* 16 zero coefficients */
                                                }
                                                if (rs == 0xf0) {
                                                        /* 16 zero coefficients */

+                                                       possibly_refill(&bits, DEHUF_TABLE_BITS);

                                                        i += 15;
                                                        continue;
                                                }
                                                i += r;
 
                                                        i += 15;
                                                        continue;
                                                }
                                                i += r;
 

-                                               possibly_refill(&bits, s);
+                                               possibly_refill(&bits, s + DEHUF_TABLE_BITS);

                                                coeff[unzigzag[i]] = extend(read_bits(&bits, s), s);
                                        }
                        
                                                coeff[unzigzag[i]] = extend(read_bits(&bits, s), s);
                                        }