#include "bytesource.h"
#include "choice.h"
#include "dehuff.h"
+#include "driver.h"
#include "idct.h"
#include "input.h"
#include "zigzag.h"
-struct jpeg_image {
- unsigned precision;
- unsigned width, height;
- unsigned num_components;
- unsigned hsample[256], vsample[256], qtable[256];
- unsigned max_hsample, max_vsample;
- unsigned num_blocks_horizontal, num_blocks_vertical;
- uint32_t qvalues[256][DCTSIZE2];
- void* idct_data[256];
- uint8_t* pixel_data[256];
-};
-
ssize_t stdio_read(void* userdata, uint8_t* buf, size_t count)
{
return fread(buf, 1, count, (FILE*)userdata);
unsigned width = image->num_blocks_horizontal * image->hsample[c] * DCTSIZE;
unsigned height = image->num_blocks_vertical * image->vsample[c] * DCTSIZE;
+ image->stride[c] = width;
image->pixel_data[c] = (uint8_t*)malloc(width * height);
assert(image->pixel_data[c] != NULL);
+ image->pixel_write_pointer[c] = image->pixel_data[c];
fprintf(stderr, "Component %u: allocating %d x %d\n", c, width, height);
}
}
+void decode_ac_coefficients(const struct huffman_table* tbl, struct bit_source* bits, int16_t* coeff)
+{
+ possibly_refill(bits, DEHUF_AC_TABLE_BITS);
+ for (unsigned i = 0; i < DCTSIZE2 - 1; ) {
+ unsigned lookup = peek_bits(bits, DEHUF_AC_TABLE_BITS);
+ int code = tbl->ac_table_codes[lookup];
+ unsigned length = tbl->ac_table_length[lookup];
+ unsigned r = tbl->ac_table_skip[lookup];
+
+ if (code == AC_DEHUF_SLOW_PATH) {
+ unsigned rs = read_huffman_symbol_no_refill(tbl, bits);
+ if (rs == 0x00) {
+ /* end of block */
+ break;
+ }
+
+ unsigned r = rs >> 4;
+ unsigned s = rs & 0xf;
+ i += r + 1;
+ possibly_refill(bits, s);
+ coeff[unzigzag[i]] = extend(read_bits(bits, s), s);
+ possibly_refill(bits, DEHUF_AC_TABLE_BITS);
+ } else {
+ assert(bits->bits_available >= length);
+ read_bits(bits, length);
+ possibly_refill(bits, DEHUF_AC_TABLE_BITS);
+
+ assert(r >= 1);
+ i += r;
+ coeff[unzigzag[i]] = code;
+ }
+ }
+}
+
void read_scan(struct byte_source* source, struct jpeg_image* image, huffman_tables_t* tables)
{
unsigned len = read_uint16(byte_source_input_func, source);
while (!bits.source_eof) {
for (unsigned c = 0; c < num_components; ++c) {
unsigned cn = component_num[c];
- unsigned stride = image->num_blocks_horizontal * image->hsample[cn] * DCTSIZE;
assert(image->idct_data[image->qtable[cn]] != NULL);
-
- for (unsigned local_yb = 0; local_yb < image->vsample[cn]; ++local_yb) {
- for (unsigned local_xb = 0; local_xb < image->hsample[cn]; ++local_xb) {
+
+ uint8_t* pixel_write_pointer_y = image->pixel_write_pointer[cn];
+ for (unsigned local_yb = 0; local_yb < image->vsample[cn]; ++local_yb, pixel_write_pointer_y += image->stride[cn] * DCTSIZE) {
+ uint8_t* pixel_write_pointer = pixel_write_pointer_y;
+ for (unsigned local_xb = 0; local_xb < image->hsample[cn]; ++local_xb, pixel_write_pointer += DCTSIZE) {
const struct huffman_table* dc_table = &((*tables)[DC_CLASS][dc_huffman_table[c]]);
const struct huffman_table* ac_table = &((*tables)[AC_CLASS][ac_huffman_table[c]]);
int16_t coeff[DCTSIZE2] = { 0 };
coeff[0] = last_dc[c];
+ decode_ac_coefficients(ac_table, &bits, coeff);
- // decode AC components
- for (unsigned i = 1; i < DCTSIZE2; ++i) {
- unsigned rs = read_huffman_symbol(ac_table, &bits);
- unsigned r = rs >> 4;
- unsigned s = rs & 0xf;
-
- if (rs == 0x00) {
- /* end of block */
- break;
- }
- if (rs == 0xf0) {
- /* 16 zero coefficients */
- i += 15;
- continue;
- }
- i += r;
-
- possibly_refill(&bits, s);
- coeff[unzigzag[i]] = extend(read_bits(&bits, s), s);
- }
-
uint8_t pixdata[DCTSIZE2];
idct_choice(coeff, image->idct_data[image->qtable[cn]], pixdata);
- for (unsigned y = 0; y < DCTSIZE; ++y) {
- unsigned real_x = (mcu_x * image->hsample[cn] + local_xb) * DCTSIZE;
- unsigned real_y = (mcu_y * image->vsample[cn] + local_yb) * DCTSIZE + y;
-
- memcpy(image->pixel_data[cn] + real_y * stride + real_x,
- pixdata + y * DCTSIZE,
- DCTSIZE);
+ uint8_t* dest_pixdata = pixel_write_pointer;
+ for (unsigned y = 0; y < DCTSIZE; ++y, dest_pixdata += image->stride[cn]) {
+ memcpy(dest_pixdata, pixdata + y * DCTSIZE, DCTSIZE);
}
}
}
+ image->pixel_write_pointer[cn] += DCTSIZE * image->hsample[cn];
}
-
+
if (++mcu_x == image->num_blocks_horizontal) {
++mcu_y;
mcu_x = 0;
-
- // Some debug code.
- const int c = 1;
+
+ for (unsigned c = 0; c < num_components; ++c) {
+ unsigned cn = component_num[c];
+ image->pixel_write_pointer[cn] += (image->vsample[cn] * DCTSIZE - 1) * image->stride[cn];
+ }
if (mcu_y == image->num_blocks_vertical) {
- unsigned stride = image->num_blocks_horizontal * image->hsample[c] * DCTSIZE;
- printf("P5\n%u %u\n255\n", stride, image->height);
- fwrite(image->pixel_data[c], stride * image->height, 1, stdout);
+ return;
}
}
}
}
}
-int main(void)
+void read_jpeg(struct jpeg_image* jpeg, FILE *input)
{
- struct jpeg_image jpeg;
- memset(&jpeg, 0, sizeof(jpeg));
- init_choices();
-
+ memset(jpeg, 0, sizeof(*jpeg));
+
struct byte_source source;
- init_byte_source(&source, stdio_read, stdin);
+ init_byte_source(&source, stdio_read, input);
huffman_tables_t tables;
break;
case 0xdb:
/* DQT */
- read_dqt(&source, &jpeg);
+ read_dqt(&source, jpeg);
break;
case 0xc0:
/* SOF0 (baseline DCT, Huffman encoded) */
- read_sof(&source, &jpeg);
+ read_sof(&source, jpeg);
break;
case 0xd8:
/* SOI */
break;
case 0xd9:
/* EOI */
- exit(0);
+ return;
case 0xc4:
/* DHT (define Huffman tables) */
read_huffman_tables(&tables, byte_source_input_func, &source);
break;
case 0xda:
/* SOS (start of scan) */
- read_scan(&source, &jpeg, &tables);
+ read_scan(&source, jpeg, &tables);
break;
default:
fprintf(stderr, "Error: Unknown marker 0x%02x\n", m2);
}
}
}
+
+int main(void)
+{
+ init_choices();
+
+ struct jpeg_image jpeg;
+ read_jpeg(&jpeg, stdin);
+
+ // Some debug code.
+ const int c = 1;
+ unsigned stride = jpeg.num_blocks_horizontal * jpeg.hsample[c] * DCTSIZE;
+ unsigned height = jpeg.num_blocks_vertical * jpeg.vsample[c] * DCTSIZE;
+ printf("P5\n%u %u\n255\n", stride, height);
+ fwrite(jpeg.pixel_data[c], stride * height, 1, stdout);
+}
projects / fjl / blobdiff