c - base64 decoding files of length greater than 8192? -

-

whenever try base64 decode files (using openssl's bio_f_base64()) larger 8192, seem wrong value.

what magic number 8192? educate me appreciated!

updated:

here part of code:

int dgst(char *alg)  {  evp_md_ctx ctx;  const evp_md *md;  unsigned char md_value[evp_max_md_size];  unsigned int md_len, i;  char *tob64val = null;  char *data = null;   openssl_add_all_digests();   md = evp_get_digestbyname(alg);   if(!md) {         printf("unknown message digest %s\n", alg);         exit(1);  }   data = readfilebuffer("file_out");  printf("strlen(data) %d\n", strlen(data));  evp_md_ctx_init(&ctx);  evp_digestinit_ex(&ctx, md, null);  evp_digestupdate(&ctx, data, strlen(data));   evp_digestfinal_ex(&ctx, md_value, &md_len); //retrieve digest ctx unto md_value , #bytes written copied   md_len  evp_md_ctx_cleanup(&ctx);  unsigned char *copy = malloc(md_len);  memcpy(copy, md_value, md_len);  char *buff = encbase64(copy, md_len);   printf("digest is:%s\n ", buff);   free(buff);  free(tob64val);  free(data);  return 0;  }   char *readfilebuffer(char *name) {     file *file;     char *buffer = null;     unsigned long filelen;     //open file     file = fopen(name, "rb");     if (!file)     {         fprintf(stderr, "unable open file %s", name);         return;     }     //get file length     fseek(file, 0, seek_end);     filelen=ftell(file);     printf("file length  = %ld\n", filelen);     fseek(file, 0, seek_set);      //printf("allocate memory\n");     buffer=(char *)malloc(filelen+1);     printf("length of write buffer = %d\n", strlen(buffer));     if (!buffer)     {         fprintf(stderr, "memory error!");      }      long int n = fread(buffer,1, filelen,file);     buffer[n] = '\0';     printf("read no. of bytes = %ld buffer \n", n);     printf("len of buffer  %d  \n", strlen(buffer));     if (!buffer)     {         fprintf(stderr, "memory error!");         fclose(file);     }     fclose(file);     return buffer;  }  char *encbase64( char *input, int length) { bio *bmem, *b64; buf_mem *bptr;  b64 = bio_new(bio_f_base64()); //bio_set_flags(b64,bio_flags_base64_no_nl); bmem = bio_new(bio_s_mem()); b64 = bio_push(b64, bmem);  bio_write(b64, input, length); bio_flush(b64); bio_get_mem_ptr(b64, &bptr);   char *buff = (char *)malloc(bptr->length); memcpy(buff, bptr->data, bptr->length-1); buff[bptr->length-1] = 0;   bio_free_all(b64);  return buff; }

it doesn't seem have problems 8k boundaries. show soucecode how call it?

update:

int dgst(char *alg)  {  evp_md_ctx ctx;  const evp_md *md;  unsigned char md_value[evp_max_md_size];  unsigned int md_len, i;  char *tob64val = null;  char *data = null;   openssl_add_all_digests();   md = evp_get_digestbyname(alg);   if(!md) {         printf("unknown message digest %s\n", alg);         exit(1);  }   data = readfilebuffer("file_out");  //printf("strlen(data) %d\n", strlen(data)); <- don't use strlen on binary data  evp_md_ctx_init(&ctx);  evp_digestinit_ex(&ctx, md, null);  evp_digestupdate(&ctx, data, strlen(data));   evp_digestfinal_ex(&ctx, md_value, &md_len); //retrieve digest ctx unto md_value , #bytes written copied   md_len  evp_md_ctx_cleanup(&ctx);  unsigned char *copy = malloc(md_len);  memcpy(copy, md_value, md_len);  char *buff = encbase64(copy, md_len);   printf("digest is:%s\n ", buff);   free(buff);  free(tob64val);  free(data);  return 0;  }   char *readfilebuffer(char *name) {     file *file;     char *buffer = null;     unsigned long filelen;     //open file     file = fopen(name, "rb");     if (!file)     {         fprintf(stderr, "unable open file %s", name);         return;     }     //get file length     fseek(file, 0, seek_end);     filelen=ftell(file);     printf("file length  = %ld\n", filelen);     fseek(file, 0, seek_set);      //printf("allocate memory\n");     buffer=(char *)malloc(filelen/*+1*/); // <- not string - no need +1     //printf("length of write buffer = %d\n", strlen(buffer)); <- again strlen on binary data (you allocated it, contains random bytes)     if (!buffer)     {         fprintf(stderr, "memory error!");      }      long int n = fread(buffer,1, filelen,file);     //buffer[n] = '\0';                  // not string - no need end     printf("read no. of bytes = %ld buffer \n", n);     //printf("len of buffer  %d  \n", strlen(buffer));  <- buffer length in 'n'     if (!buffer)     {         fprintf(stderr, "memory error!");         fclose(file);     }     fclose(file);     return buffer;  }  char *encbase64( char *input, int length) { bio *bmem, *b64; buf_mem *bptr;  b64 = bio_new(bio_f_base64()); //bio_set_flags(b64,bio_flags_base64_no_nl); bmem = bio_new(bio_s_mem()); b64 = bio_push(b64, bmem);  bio_write(b64, input, length); bio_flush(b64); bio_get_mem_ptr(b64, &bptr);   char *buff = (char *)malloc(bptr->length); memcpy(buff, bptr->data, bptr->length/*-1*/); // removed '+1' //buff[bptr->length-1] = 0;       // not string   bio_free_all(b64);  return buff; }

Comments

Post a Comment

Popular posts from this blog

c# - How to set Z index when using WPF DrawingContext? -

-
how set z-index drawing object when using drawingcontext.drawxxx() methods? the object drawn last have higher z index. can't change index of drawn objects. way draw in order. if using wpf (as placed tag), can use, example, canvas control. create shapes need like polyline obj = new polyline(); //... // ... set properties of obj and add them canvas uielementcollection: yourcanvasname.children.add(obj); //or yourcanvasname.children.insert(i, obj); first items of collection have higher z index. advantages in way: no need redraw on window changes, can anytime move objects , change order.
Read more

razor - Is this a bug in WebMatrix PageData? -

-
i think may have found bug in webmatrix's pagedata, not sure. concerns how pass data partial page calling page. in webmatrix documentation (tutorials, e.g. " 3 - creating consistent look ", , example code), pagedata recommended mechanism pass data between pages (e.g. content page layout page, or partial page). however have found not work other way, pass data partial page calling page. modifying or adding entries in pagedata in partial page, not seem calling page. cutting right down simplest possible example, in test page may have this: @{ pagedata["test"] = "initial entry"; } <p>before calling partial page, test value @pagedata["test"]</p> @renderpage("_testpartial.cshtml") <p>after returning calling page, test value @pagedata["test"]</p> and in _testpartial.cshtml page might have this: @{ pagedata["test"] = "modified entry"; } <p>in partial page...
Read more

visual c++ - Using relative values in array sorting ( asm ) -

-
i need sort through array , sort each individual row in array in ascending order. doesn't seem going (surprise!) keep getting hit 2 errors: a2101: cannot add 2 relocatable labels , a2026: constant expected here's sort, makes sense me, think i'm still trying implement high-lvl language techniqes assembly. there way around not being able use relative values? (the array 7 rows 9 columns, btw). mov cx, 7; cx = number of rows outer: ; outer loop walk through rows push cx mov cx, 9 mov row, cx ;rows middle: ; middle-loop walk through columns push cx sub cx, 1 ;cx = cx-1 mov column, cx ;columns inner: ;inner loop - compare , exchange column values cmp marray[row*9 + column], marray[row*9 + column+1] xchg marray[row*9 + column+1], marray[row*9 + column] ; compare , exchange values marray table inc column loop inner pop cx loop mid...
Read more