diff options
Diffstat (limited to 'src/sum.c')
| -rw-r--r-- | src/sum.c | 214 |
1 files changed, 214 insertions, 0 deletions
diff --git a/src/sum.c b/src/sum.c new file mode 100644 index 0000000..cb5bc03 --- /dev/null +++ b/src/sum.c @@ -0,0 +1,214 @@ +/* sum -- checksum and count the blocks in a file + Copyright (C) 1986-2022 Free Software Foundation, Inc. + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. */ + +/* Like BSD sum or SysV sum -r, except like SysV sum if -s option is given. */ + +/* Written by Kayvan Aghaiepour and David MacKenzie. */ + +#include <config.h> + +#include <stdio.h> +#include <sys/types.h> +#include "system.h" +#include "human.h" +#include "sum.h" + +/* Calculate the checksum and the size in bytes of stream STREAM. + Return -1 on error, 0 on success. */ + +int +bsd_sum_stream (FILE *stream, void *resstream, uintmax_t *length) +{ + int ret = -1; + size_t sum, n; + int checksum = 0; /* The checksum mod 2^16. */ + uintmax_t total_bytes = 0; /* The number of bytes. */ + static const size_t buffer_length = 32768; + uint8_t *buffer = malloc (buffer_length); + + if (! buffer) + return -1; + + /* Process file */ + while (true) + { + sum = 0; + + /* Read block */ + while (true) + { + n = fread (buffer + sum, 1, buffer_length - sum, stream); + sum += n; + + if (buffer_length == sum) + break; + + if (n == 0) + { + if (ferror (stream)) + goto cleanup_buffer; + goto final_process; + } + + if (feof (stream)) + goto final_process; + } + + for (size_t i = 0; i < sum; i++) + { + checksum = (checksum >> 1) + ((checksum & 1) << 15); + checksum += buffer[i]; + checksum &= 0xffff; /* Keep it within bounds. */ + } + if (total_bytes + sum < total_bytes) + { + errno = EOVERFLOW; + goto cleanup_buffer; + } + total_bytes += sum; + } + +final_process:; + + for (size_t i = 0; i < sum; i++) + { + checksum = (checksum >> 1) + ((checksum & 1) << 15); + checksum += buffer[i]; + checksum &= 0xffff; /* Keep it within bounds. */ + } + if (total_bytes + sum < total_bytes) + { + errno = EOVERFLOW; + goto cleanup_buffer; + } + total_bytes += sum; + + memcpy (resstream, &checksum, sizeof checksum); + *length = total_bytes; + ret = 0; +cleanup_buffer: + free (buffer); + return ret; +} + +/* Calculate the checksum and the size in bytes of stream STREAM. + Return -1 on error, 0 on success. */ + +int +sysv_sum_stream (FILE *stream, void *resstream, uintmax_t *length) +{ + int ret = -1; + size_t sum, n; + uintmax_t total_bytes = 0; + static const size_t buffer_length = 32768; + uint8_t *buffer = malloc (buffer_length); + + if (! buffer) + return -1; + + /* The sum of all the input bytes, modulo (UINT_MAX + 1). */ + unsigned int s = 0; + + /* Process file */ + while (true) + { + sum = 0; + + /* Read block */ + while (true) + { + n = fread (buffer + sum, 1, buffer_length - sum, stream); + sum += n; + + if (buffer_length == sum) + break; + + if (n == 0) + { + if (ferror (stream)) + goto cleanup_buffer; + goto final_process; + } + + if (feof (stream)) + goto final_process; + } + + for (size_t i = 0; i < sum; i++) + s += buffer[i]; + if (total_bytes + sum < total_bytes) + { + errno = EOVERFLOW; + goto cleanup_buffer; + } + total_bytes += sum; + } + +final_process:; + + for (size_t i = 0; i < sum; i++) + s += buffer[i]; + if (total_bytes + sum < total_bytes) + { + errno = EOVERFLOW; + goto cleanup_buffer; + } + total_bytes += sum; + + int r = (s & 0xffff) + ((s & 0xffffffff) >> 16); + int checksum = (r & 0xffff) + (r >> 16); + + memcpy (resstream, &checksum, sizeof checksum); + *length = total_bytes; + ret = 0; +cleanup_buffer: + free (buffer); + return ret; +} + +/* Print the checksum and size (in 1024 byte blocks) to stdout. + If ARGS is true, also print the FILE name. */ + +void +output_bsd (char const *file, int binary_file, void const *digest, + bool tagged, unsigned char delim, bool args, + uintmax_t length) +{ + + char hbuf[LONGEST_HUMAN_READABLE + 1]; + printf ("%05d %5s", *(int *)digest, + human_readable (length, hbuf, human_ceiling, 1, 1024)); + if (args) + printf (" %s", file); + putchar (delim); +} + +/* Print the checksum and size (in 512 byte blocks) to stdout. + If ARGS is true, also print the FILE name. */ + +void +output_sysv (char const *file, int binary_file, void const *digest, + bool tagged, unsigned char delim, bool args, + uintmax_t length) +{ + + char hbuf[LONGEST_HUMAN_READABLE + 1]; + printf ("%d %s", *(int *)digest, + human_readable (length, hbuf, human_ceiling, 1, 512)); + if (args) + printf (" %s", file); + putchar (delim); +} |