change: decode message, description and timestamp

laumann

Sep 1, 2022, 9:15 PM

Y26WT3ZFN7KSVXOZ26B5Y2OR4M4VQYQLPMAHPC4O5VIT3ENBISXAC

Dependencies

[2] WMFNGOYT change: reduce printed noise, rework some code
[3] Q7TKZCJP Add initial support for reading the offsets from a (fixed) change
[4] 3NA345CN Add zstd_seekable + many headers
[5] B3XLVPNC Add ani.c and initial Makefile
[6] FB67XX5E add argument parsing setup
[7] X36ICMJN Initial import for blake3
[8] VKLGQREY change: add base32 decode, initial deconstruction of hashed
[9] 3OHR6ZPH make: prettify output
[*] PEUS54XQ
[*] RIWSVVAS change: decompress the 'contents' with zstd_seekable
[*] OBKF6SII change: decompress the hashed section too

Change contents

file addition: scaffold.h (----------)

[11.1]

#ifndef SCAFFOLD_H
#define SCAFFOLD_H

/* Various scaffolding functions around stdlib functions */

void *xmalloc(size_t size);

#endif
file addition: scaffold.c (----------)

[11.1]

#include <stdio.h>
#include <stdlib.h>
#include "scaffold.h"

/**
* Expand to support varargs like a regular printf
*/
void die(const char *msg)
{
fprintf(stderr, msg);
exit(57);
}

void *
xmalloc(size_t size)
{
void *ret;

ret = malloc(size);
if (!ret)
die("Unable to allocate memory");

return ret;
}
replacement in change.h at line 39

[3.173]→[3.173:209](∅→∅)

void *authors; /* something... */

[3.173]

[3.209]

void *authors; /* a "key"="value" collection */
edit in change.c at line 10

[3.1192]

[12.39]

#include "scaffold.h"
edit in change.c at line 15

[3.711]

[13.0]

#include "bincode.h"
edit in change.c at line 165

[13.1172]

[3.872]

uint8_t *p;
edit in change.c at line 171

[2.362]

[12.2591]

uint64_t len;
replacement in change.c at line 197

[3.1399]→[2.792:832](∅→∅)

/* TODO Decode into 'struct hashed' */

[3.1399]

[3.1399]

p = buf;
dump_buf("hashed", p, hashed_len);

hashed.version = bincode_getu64(p);
printf("version = %lu\n", hashed.version);
p += sizeof(uint64_t);

len = bincode_getu64(p);
p += sizeof(uint64_t);

hashed.header.message = bincode_getstr(p, len);
p += len;
printf("message = '%s'\n", hashed.header.message);

/**
* Description! This is like the commit "body", and is optional, so we
* have a byte indicating its presence, '0' = None, '1' =
* Some(description)
*/
if (*p++) {
len = bincode_getu64(p);
p += sizeof(uint64_t);

hashed.header.description = bincode_getstr(p, len);
p += len;
printf("description = '%s'\n", hashed.header.description);
} else
printf("description = (none)\n");

len = bincode_getu64(p);
p += sizeof(uint64_t);
edit in change.c at line 230

[3.1400]

[13.1373]

if (len != 30)
printf("warning: timestamp field has unexpected length %lu (expected 30)\n", len);
hashed.header.timestamp = bincode_getstr(p, len);
p += len;

printf("timestamp = '%s'\n", hashed.header.timestamp);
file addition: bincode.h (----------)

[11.1]

#ifndef BINCODE_H
#define BINCODE_H

/** Requires: <stdint.h> */

/**
* Definitions for the bincode encode/decode routines.
*
* Generally, the idea here is that you open a file, get a file descriptor and
* use the encode/decode routines to get components read from the fd and and
* decoded as the type you want.
*/

/**
* Some notes regarding the bincode format:
*
* Enum types: The order of the variants matter, as the encoding indicates the
* variant with a u32.
*/
uint16_t bincode_getu16(uint8_t *);
uint32_t bincode_getu32(uint8_t *);
uint64_t bincode_getu64(uint8_t *);

/**
* Allocate and return a string of the given length.
*
* The memory allocated shall be the given length plus one, to hold the
* terminating zero.
*
* Returns the allocated string. The caller is responsible for deallocating.
*/
char *bincode_getstr(uint8_t *, size_t);

/* void bincode_putu16(uint8_t *, uint16_t); */
/* void bincode_putu32(uint8_t *, uint32_t); */
/* void bincode_putu64(uint8_t *, uint64_t); */

#endif
file addition: bincode.c (----------)

[11.1]

#include <stdint.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include "scaffold.h"
#include "bincode.h"

uint16_t
bincode_getu16(uint8_t *b)
{
return (uint16_t)b[1] << 8 | (uint16_t)b[0];
}

uint32_t
bincode_getu32(uint8_t *b)
{
return (uint32_t)b[3] << 24
| (uint32_t)b[2] << 16
| (uint32_t)b[1] << 8
| (uint32_t)b[0];
}

uint64_t
bincode_getu64(uint8_t *b)
{
return (uint64_t)b[7] << 56
| (uint64_t)b[6] << 48
| (uint64_t)b[5] << 40
| (uint64_t)b[4] << 32
| (uint64_t)b[3] << 24
| (uint64_t)b[2] << 16
| (uint64_t)b[1] << 8
| (uint64_t)b[0];
}

char *
bincode_getstr(uint8_t *b, size_t len)
{
char *str;

str = xmalloc(len + 1);
memcpy(str, b, len);
str[len] = '\0';

return str;
}
edit in Makefile at line 24

[3.3742]

[3.53469]

OBJS += bincode.o
OBJS += scaffold.o
replacement in Makefile at line 33

[3.634]→[3.95:118](∅→∅)

@printf "LD\t%s\n" $@

[3.634]

[3.53606]

@printf " LD\t%s\n" $@