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65 lines
1.5 KiB
65 lines
1.5 KiB
5 years ago
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#include <png.h>
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#include <stdio.h>
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#include <string.h>
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#define FAIL(format, args...) do { fprintf(stderr, format "\n", ## args); \
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goto done; } while (0)
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static int apng = 0;
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static int read_chunk(png_structp png_ptr, png_unknown_chunkp chunk) {
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(void) png_ptr;
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if (strncmp((const char *) chunk, "acTL", 4) == 0)
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apng = 1;
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return 0;
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}
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int main(int argc, char *argv[]) {
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FILE *fp;
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const char *filename;
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unsigned char header[8];
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png_structp png_ptr = NULL;
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png_infop info_ptr = NULL;
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int result = 1;
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if (argc != 2) {
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fprintf(stderr, "Usage: %s <png>\n", argv[0]);
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return -1;
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}
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filename = argv[1];
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fp = fopen(filename, "rb");
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if (!fp) {
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perror(filename);
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return -1;
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}
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if (fread(header, 8, 1, fp) != 1)
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FAIL("%s: Couldn't read header.", filename);
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if (png_sig_cmp(header, 0, 8))
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FAIL("%s: Not a PNG.", filename);
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png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,
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NULL, NULL, NULL);
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if (!png_ptr)
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FAIL("Couldn't set up PNG reader.");
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info_ptr = png_create_info_struct(png_ptr);
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if (!info_ptr)
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FAIL("Couldn't set up PNG info reader.");
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if (setjmp(png_jmpbuf(png_ptr)))
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goto done;
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png_init_io(png_ptr, fp);
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png_set_sig_bytes(png_ptr, 8);
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png_set_read_user_chunk_fn(png_ptr, NULL, &read_chunk);
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png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_NEVER, NULL, 0);
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png_read_info(png_ptr, info_ptr);
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puts(apng ? "APNG" : "PNG");
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result = 0;
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done:
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if (png_ptr)
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png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
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fclose(fp);
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return result;
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}
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