104 lines
2.4 KiB
C
104 lines
2.4 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/stat.h>
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#define CHUNK 4096
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int match_at(const unsigned char *buf, size_t len, const char *pat) {
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size_t p = strlen(pat);
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if (len < p) return 0;
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return memcmp(buf, pat, p) == 0;
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}
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size_t find_in_buffer(const unsigned char *buf, size_t len, const char *pat) {
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size_t p = strlen(pat);
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for (size_t i = 0; i + p <= len; i++) {
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if (memcmp(buf + i, pat, p) == 0)
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return i;
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}
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return (size_t)-1;
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}
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void write_pdf(const unsigned char *data, size_t len, int idx, const char *outdir) {
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char path[512];
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snprintf(path, sizeof(path), "%s/pdf_%04d.pdf", outdir, idx);
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FILE *f = fopen(path, "wb");
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if (!f) return;
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fwrite(data, 1, len, f);
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fclose(f);
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}
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int main(int argc, char **argv) {
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if (argc != 3) {
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fprintf(stderr, "Usage: %s <image_file> <output_dir>\n", argv[0]);
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return 1;
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}
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const char *infile = argv[1];
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const char *outdir = argv[2];
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mkdir(outdir, 0755);
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FILE *f = fopen(infile, "rb");
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if (!f) {
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perror("open input");
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return 1;
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}
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unsigned char *buf = malloc(CHUNK * 2);
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size_t buf_len = 0;
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int pdf_count = 0;
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unsigned char *file_data = NULL;
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size_t file_size = 0;
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int collecting = 0;
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while (!feof(f)) {
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size_t r = fread(buf + buf_len, 1, CHUNK, f);
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buf_len += r;
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size_t i = 0;
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while (i < buf_len) {
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if (!collecting) {
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if (i + 5 < buf_len && memcmp(buf + i, "%PDF-", 5) == 0) {
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collecting = 1;
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file_data = malloc(1024);
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file_size = 0;
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}
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}
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if (collecting) {
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if (file_size % 1024 == 0) {
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file_data = realloc(file_data, file_size + 1024);
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}
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file_data[file_size++] = buf[i];
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if (file_size > 6) {
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if (memmem(file_data, file_size, "%%EOF", 5)) {
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write_pdf(file_data, file_size, pdf_count++, outdir);
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free(file_data);
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file_data = NULL;
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file_size = 0;
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collecting = 0;
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}
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}
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}
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i++;
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}
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buf_len = 0;
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}
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free(buf);
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fclose(f);
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return 0;
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}
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