static void bastardized_rice_decompress(ALACContext *alac, int32_t *output_buffer, int output_size, int readsamplesize, /* arg_10 */ int rice_initialhistory, /* arg424->b */ int rice_kmodifier, /* arg424->d */ int rice_historymult, /* arg424->c */ int rice_kmodifier_mask /* arg424->e */ ) { int output_count; unsigned int history = rice_initialhistory; int sign_modifier = 0; for (output_count = 0; output_count < output_size; output_count++) { int32_t x; int32_t x_modified; int32_t final_val; /* read x - number of 1s before 0 represent the rice */ x = get_unary_0_9(&alac->gb); if (x > 8) { /* RICE THRESHOLD */ /* use alternative encoding */ x = get_bits(&alac->gb, readsamplesize); } else { /* standard rice encoding */ int extrabits; int k; /* size of extra bits */ /* read k, that is bits as is */ k = 31 - count_leading_zeros((history >> 9) + 3); if (k >= rice_kmodifier) k = rice_kmodifier; if (k != 1) { extrabits = show_bits(&alac->gb, k); /* multiply x by 2^k - 1, as part of their strange algorithm */ x = (x << k) - x; if (extrabits > 1) { x += extrabits - 1; skip_bits(&alac->gb, k); } else skip_bits(&alac->gb, k - 1); } } x_modified = sign_modifier + x; final_val = (x_modified + 1) / 2; if (x_modified & 1) final_val *= -1; output_buffer[output_count] = final_val; sign_modifier = 0; /* now update the history */ history += x_modified * rice_historymult - ((history * rice_historymult) >> 9); if (x_modified > 0xffff) history = 0xffff; /* special case: there may be compressed blocks of 0 */ if ((history < 128) && (output_count+1 < output_size)) { int block_size; sign_modifier = 1; x = get_unary_0_9(&alac->gb); if (x > 8) { block_size = get_bits(&alac->gb, 16); } else { int k; int extrabits; k = count_leading_zeros(history) + ((history + 16) >> 6 /* / 64 */) - 24; extrabits = show_bits(&alac->gb, k); block_size = (((1 << k) - 1) & rice_kmodifier_mask) * x + extrabits - 1; if (extrabits < 2) { x = 1 - extrabits; block_size += x; skip_bits(&alac->gb, k - 1); } else { skip_bits(&alac->gb, k); } } if (block_size > 0) { memset(&output_buffer[output_count+1], 0, block_size * 4); output_count += block_size; } if (block_size > 0xffff) sign_modifier = 0; history = 0; } } }