mirror of
https://github.com/mickael-kerjean/filestash.git
synced 2025-10-31 10:07:15 +08:00
129 lines
4.4 KiB
C
129 lines
4.4 KiB
C
#include <stdio.h>
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#include <jpeglib.h>
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#include <setjmp.h>
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#include <stdlib.h>
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#include "utils.h"
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#define JPEG_QUALITY 50
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typedef struct filestash_jpeg_error_mgr {
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struct jpeg_error_mgr pub;
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jmp_buf jmp;
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} *filestash_jpeg_error_ptr;
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void filestash_jpeg_error_exit (j_common_ptr cinfo);
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int jpeg_to_jpeg(int inputDesc, int outputDesc, int targetSize) {
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#ifdef HAS_DEBUG
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clock_t t;
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t = clock();
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#endif
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int status = 0;
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FILE* input = fdopen(inputDesc, "rb");
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FILE* output = fdopen(outputDesc, "wb");
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if (!input || !output) {
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return 1;
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}
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struct jpeg_decompress_struct jpeg_config_input;
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struct jpeg_compress_struct jpeg_config_output;
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struct filestash_jpeg_error_mgr jerr;
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jpeg_config_input.err = jpeg_std_error(&jerr.pub);
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jpeg_config_output.err = jpeg_std_error(&jerr.pub);
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jpeg_config_input.dct_method = JDCT_IFAST;
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jpeg_config_input.do_fancy_upsampling = FALSE;
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jpeg_config_input.two_pass_quantize = FALSE;
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jpeg_config_input.dither_mode = JDITHER_ORDERED;
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jpeg_create_decompress(&jpeg_config_input);
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jpeg_create_compress(&jpeg_config_output);
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jpeg_stdio_src(&jpeg_config_input, input);
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jpeg_stdio_dest(&jpeg_config_output, output);
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jerr.pub.error_exit = filestash_jpeg_error_exit;
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if (setjmp(jerr.jmp)) {
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ERROR("exception");
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goto CLEANUP_AND_ABORT;
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}
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DEBUG("after constructor decompress");
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if(jpeg_read_header(&jpeg_config_input, TRUE) != JPEG_HEADER_OK) {
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status = 1;
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ERROR("not a jpeg");
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goto CLEANUP_AND_ABORT;
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}
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DEBUG("after header read");
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jpeg_config_input.dct_method = JDCT_IFAST;
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jpeg_config_input.do_fancy_upsampling = FALSE;
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jpeg_config_input.two_pass_quantize = FALSE;
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jpeg_config_input.dither_mode = JDITHER_ORDERED;
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jpeg_calc_output_dimensions(&jpeg_config_input);
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int image_min_size = min(jpeg_config_input.output_width, jpeg_config_input.output_height);
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jpeg_config_input.scale_num = 1;
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jpeg_config_input.scale_denom = 1;
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int targetSizeAbs = abs(targetSize);
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if (image_min_size / 8 >= targetSizeAbs) {
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jpeg_config_input.scale_num = 1;
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jpeg_config_input.scale_denom = 8;
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} else if (image_min_size * 2 / 8 >= targetSizeAbs) {
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jpeg_config_input.scale_num = 1;
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jpeg_config_input.scale_denom = 4;
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} else if (image_min_size * 3 / 8 >= targetSizeAbs) {
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jpeg_config_input.scale_num = 3;
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jpeg_config_input.scale_denom = 8;
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} else if (image_min_size * 4 / 8 >= targetSizeAbs) {
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jpeg_config_input.scale_num = 4;
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jpeg_config_input.scale_denom = 8;
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} else if (image_min_size * 5 / 8 >= targetSizeAbs) {
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jpeg_config_input.scale_num = 5;
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jpeg_config_input.scale_denom = 8;
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} else if (image_min_size * 6 / 8 >= targetSizeAbs) {
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jpeg_config_input.scale_num = 6;
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jpeg_config_input.scale_denom = 8;
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} else if (image_min_size * 7 / 8 >= targetSizeAbs) {
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jpeg_config_input.scale_num = 7;
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jpeg_config_input.scale_denom = 8;
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}
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DEBUG("start decompress");
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if(jpeg_start_decompress(&jpeg_config_input) == FALSE) {
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ERROR("jpeg_start_decompress");
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status = 1;
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goto CLEANUP_AND_ABORT;
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}
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DEBUG("processing image setup");
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int jpeg_row_stride = jpeg_config_input.output_width * jpeg_config_input.output_components;
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jpeg_config_output.image_width = jpeg_config_input.output_width;
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jpeg_config_output.image_height = jpeg_config_input.output_height;
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jpeg_config_output.input_components = jpeg_config_input.num_components;
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jpeg_config_output.in_color_space = jpeg_config_input.out_color_space;
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jpeg_set_defaults(&jpeg_config_output);
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jpeg_set_quality(&jpeg_config_output, JPEG_QUALITY, TRUE);
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jpeg_start_compress(&jpeg_config_output, TRUE);
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JSAMPARRAY buffer = jpeg_config_input.mem->alloc_sarray((j_common_ptr) &jpeg_config_input, JPOOL_IMAGE, jpeg_row_stride, 1);
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DEBUG("processing image");
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while (jpeg_config_output.next_scanline < jpeg_config_output.image_height) {
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jpeg_read_scanlines(&jpeg_config_input, buffer, 1);
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jpeg_write_scanlines(&jpeg_config_output, buffer, 1);
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}
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DEBUG("end decompress");
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jpeg_finish_decompress(&jpeg_config_input);
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DEBUG("finish decompress");
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jpeg_finish_compress(&jpeg_config_output);
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CLEANUP_AND_ABORT:
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jpeg_destroy_decompress(&jpeg_config_input);
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jpeg_destroy_compress(&jpeg_config_output);
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DEBUG("final");
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return status;
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}
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void filestash_jpeg_error_exit (j_common_ptr cinfo) {
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filestash_jpeg_error_ptr filestash_err = (filestash_jpeg_error_ptr) cinfo->err;
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longjmp(filestash_err->jmp, 1);
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}
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