#include <stdio.h>
+#include <string.h>
#include <stdlib.h>
#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];
-};
-
ssize_t stdio_read(void* userdata, uint8_t* buf, size_t count)
{
return fread(buf, 1, count, (FILE*)userdata);
}
+void read_dqt(struct byte_source* source, struct jpeg_image* image)
+{
+ unsigned len = read_uint16(byte_source_input_func, source);
+ assert(len >= 67);
+ uint8_t precision_table = read_uint8(byte_source_input_func, source);
+ int precision = precision_table >> 4; // 0 = 8 bits, otherwise 16 bits.
+ int table = precision_table & 0x0f;
+
+ if (image->idct_data[table] != NULL) {
+ idct_choice_free(image->idct_data[table]);
+ }
+
+ if (precision != 0) {
+ assert(len == 131);
+ fprintf(stderr, "Quantization table %u: 16 bits/entry\n", table);
+ } else {
+ assert(len == 67);
+ fprintf(stderr, "Quantization table %u: 8 bits/entry\n", table);
+ }
+
+ for (unsigned i = 0; i < 64; ++i) {
+ if (precision != 0) {
+ image->qvalues[table][unzigzag[i]] =
+ read_uint16(byte_source_input_func, source);
+ } else {
+ image->qvalues[table][unzigzag[i]] =
+ read_uint8(byte_source_input_func, source);
+ }
+ }
+
+ image->idct_data[table] = idct_choice_alloc(image->qvalues[table]);
+}
+
void read_sof(struct byte_source* source, struct jpeg_image* image)
{
unsigned len = read_uint16(byte_source_input_func, source);
assert(len >= 8);
image->precision = read_uint8(byte_source_input_func, source);
assert(image->precision == 8);
- image->width = read_uint16(byte_source_input_func, source);
image->height = read_uint16(byte_source_input_func, source);
+ image->width = read_uint16(byte_source_input_func, source);
image->num_components = read_uint8(byte_source_input_func, source);
len -= 8;
image->qtable[c] = read_uint8(byte_source_input_func, source);
len -= 3;
+ if (image->hsample[c] > image->max_hsample) {
+ image->max_hsample = image->hsample[c];
+ }
+ if (image->vsample[c] > image->max_vsample) {
+ image->max_vsample = image->vsample[c];
+ }
+
fprintf(stderr, "Component %u: sampling factors %u x %x, quantization table %u\n",
c, image->hsample[c], image->vsample[c], image->qtable[c]);
}
+
+ image->num_blocks_horizontal = (image->width + image->max_hsample * DCTSIZE - 1) / (image->max_hsample * DCTSIZE);
+ image->num_blocks_vertical = (image->height + image->max_vsample * DCTSIZE - 1) / (image->max_vsample * DCTSIZE);
+
+ for (unsigned c = 0; c < 256; ++c) {
+ if (image->hsample[c] == 0) {
+ continue;
+ }
+
+ 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)
}
struct bit_source bits;
- init_bit_source(&bits, byte_source_input_func, source);
+ init_bit_source(&bits, byte_source_input_func, 8, source);
+
+ unsigned mcu_x = 0, mcu_y = 0;
- for ( ;; ) {
+ while (!bits.source_eof) {
for (unsigned c = 0; c < num_components; ++c) {
unsigned cn = component_num[c];
- unsigned nc = image->vsample[cn] * image->hsample[cn];
- for (unsigned n = 0; n < nc; ++n) {
- 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]]);
-
- // decode DC component
- unsigned dc_category = read_huffman_symbol(dc_table, &bits);
- possibly_refill(&bits, dc_category);
- last_dc[c] += extend(read_bits(&bits, dc_category), dc_category);
-
- // printf("dc=%d ac=", last_dc[c]);
- putchar(last_dc[c]);
-
- // decode AC components
- int zz[63] = { 0 };
- for (unsigned i = 0; i < 63; ++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;
- }
+ assert(image->idct_data[image->qtable[cn]] != NULL);
- possibly_refill(&bits, s);
+ 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]]);
- i += r;
- zz[unzigzag[i]] = extend(read_bits(&bits, s), s);
- }
-
- for (unsigned i = 0; i < 63; ++i) {
- putchar(zz[i]);
- //printf("%d ", zz[i]);
+ // decode DC component
+ unsigned dc_category = read_huffman_symbol(dc_table, &bits);
+ possibly_refill(&bits, dc_category);
+ last_dc[c] += extend(read_bits(&bits, dc_category), dc_category);
+
+ int16_t coeff[DCTSIZE2] = { 0 };
+ coeff[0] = last_dc[c];
+ decode_ac_coefficients(ac_table, &bits, coeff);
+
+ uint8_t pixdata[DCTSIZE2];
+ idct_choice(coeff, image->idct_data[image->qtable[cn]], pixdata);
+
+ 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);
+ }
}
- //printf("\n");
+ }
+ image->pixel_write_pointer[cn] += DCTSIZE * image->hsample[cn];
+ }
+
+ if (++mcu_x == image->num_blocks_horizontal) {
+ ++mcu_y;
+ mcu_x = 0;
+
+ 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) {
+ return;
}
}
}
}
}
-int main(void)
+void read_jpeg(struct jpeg_image* jpeg, FILE *input)
{
- struct jpeg_image 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;
/* comment */
case 0xff:
/* ignore */
+ skip_segment(&source);
+ break;
case 0xdb:
/* DQT */
- skip_segment(&source);
+ 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 */
+ 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