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Replace ntohl with equivalent function #8

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Replace ntohl with equivalent function #8

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b513385
Replace ntohl with equivalent function
Sirplentifus Sep 18, 2016
dc4d94c
Added a verification to check if the architecture is little endian.
Sirplentifus Sep 18, 2016
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134 changes: 75 additions & 59 deletions lfpsplitter.c
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Original file line number Diff line number Diff line change
@@ -1,12 +1,12 @@
/* lfpsplitter - Splits the .lfp files generated by Lytro's desktop app into
* .jpg, .json, and .txt files in a hopefully platform independent way
*
*
* Copyright (c) 2011, Nirav Patel <[email protected]>
*
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
Expand All @@ -22,12 +22,8 @@
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifdef _WIN32
#include <winsock.h>
typedef unsigned int uint32_t;
#else
#include <arpa/inet.h>
#endif
#include <stdint.h>

#include "lfpsplitter.h"

#define SHA1_LENGTH 45
Expand All @@ -41,6 +37,26 @@ typedef unsigned int uint32_t;
#define snprintf _snprintf
#endif

int is_little_endian()
{
//This implementation was found in http://stackoverflow.com/a/14791372/1577940
uint32_t one = 0x00000001;
uint8_t is_little_endian = *(uint8_t *)&one;
return is_little_endian;
}

uint32_t uint32_from_big_endian(uint32_t dword)
{
//This implementation was found in http://stackoverflow.com/a/14791372/1577940
if (!is_little_endian()) return dword;

//Picking all bytes and putting them in reverse order
return (((dword >> 0) & 0xff) << 24)
| (((dword >> 8) & 0xff) << 16)
| (((dword >> 16) & 0xff) << 8)
| (((dword >> 24) & 0xff) << 0);
}

// TODO: read directly from the file instead of copying to a string
// since camera backup files can be in the hundreds of megabytes
static lfp_file_p lfp_create(const char *filename)
Expand All @@ -50,19 +66,19 @@ static lfp_file_p lfp_create(const char *filename)
if (!lfp) {
return NULL;
}

if (!(fp = fopen(filename, "rb"))) {
return NULL;
}

fseek(fp, 0, SEEK_END);
lfp->len = ftell(fp);
fseek(fp, 0, SEEK_SET);
lfp->data = (char*)malloc(lfp->len);

lfp->len = fread(lfp->data, 1, lfp->len, fp);
fclose(fp);

return lfp;
}

Expand All @@ -79,49 +95,49 @@ static lfp_section_p parse_section(char **lfp, int *in_len)
int len = *in_len;
lfp_section_p section = calloc(1,sizeof(lfp_section_t));
if (!section) return NULL;

// There may be some null region between sections
while (*ptr == '\0' && len) {
ptr++;
len--;
}

if (len <= MAGIC_LENGTH+sizeof(uint32_t)+SHA1_LENGTH+BLANK_LENGTH) {
free(section);
return NULL;
}

// Copy the magic type
memcpy(section->typecode, ptr, 4);
// Move past the magic and the first 4 bytes of 0s
ptr += MAGIC_LENGTH;
len -= MAGIC_LENGTH;

// the length is stored as a big endian unsigned 32 bit int
section->len = ntohl(*(uint32_t *)ptr);
section->len = uint32_from_big_endian(*(uint32_t *)ptr);
ptr += sizeof(uint32_t);
len -= sizeof(uint32_t);

// copy and move past the sha1 string and the 35 byte empty space
memcpy(section->sha1, ptr, SHA1_LENGTH);
ptr += SHA1_LENGTH+BLANK_LENGTH;
len -= SHA1_LENGTH+BLANK_LENGTH;

// make sure there exists as much data as the header claims
if (len < section->len) {
free(section);
return NULL;
}

// just directly reference the existing buffer
section->data = ptr;

ptr += section->len;
len -= section->len;

*lfp = ptr;
*in_len = len;

return section;
}

Expand All @@ -132,10 +148,10 @@ static char *depth_string(const char *data, int *datalen, int len)
char *depth = (char*)malloc(filelen);
char *start = depth;
int i = 0;

if (!depth) return NULL;
depth[0] = '\0';

for (i = 0; i < len/4; i++) {
char val[20];
int vallen = 0;
Expand All @@ -144,9 +160,9 @@ static char *depth_string(const char *data, int *datalen, int len)
strncpy(depth, val, vallen);
depth += vallen;
}

*datalen = depth-start;

return start;
}

Expand All @@ -156,38 +172,38 @@ static char *converted_image(const unsigned char *data, int *datalen, int len)
const unsigned char *ptr = data;
unsigned short *image = (unsigned short*)malloc(filelen*sizeof(short));
unsigned short *start = image;

if (!image) return NULL;
// Turn the 12 bits per pixel packed array into 16 bits per pixel
// to make it easier to import into other libraries
while (ptr < data+len) {
*image++ = (*ptr << 8) | (*(ptr+1) & 0xF0);
*image++ = ((*(ptr+1) & 0x0F) << 12) | (*(ptr+2) << 4);

ptr += 3;
}

*datalen = filelen;

return (char *)start;
}

static int save_data(const char *data, int len, const char *filename)
{
FILE *fp;

if (!(fp = fopen(filename, "wb"))) {
fprintf(stderr, "Failed to open %s for writing\n", filename);
return 0;
}

if (fwrite(data, 1, len, fp) != len) {
fprintf(stderr, "Failed to write %s\n", filename);
return 0;
}

fclose(fp);

return 1;
}

Expand All @@ -204,28 +220,28 @@ static void lfp_identify_section(lfp_file_p lfp, lfp_section_p section)
// Move backwards to the corresponding name
while (quotecount < 3 && (ptr-- > lfp->table->data))
if (*ptr == '"') quotecount++;

// Read the name if we can
if ((!quotecount == 3) || (sscanf(ptr, "\"%255[^\"]\"", section->name) != 1))
strcpy(section->name, "unknown");
}

// Test for Lytro Version 1 depth map
if (section->len == LUT_DIM_V1 * LUT_DIM_V1 * 4) {
section->type = LFP_DEPTH_LUT;
strcpy(section->name, "depth");
return;
}

// Test for Lytro Version 2 LUT (depth or confidence) map
if (section->len == LUT_DIM_V2 * LUT_DIM_V2 * 4) {
section->type = LFP_LUT;
strcpy(section->name, "lut");
return;
}

// Check for the magic bytes to see if its a jpg
if ((section->len > sizeof(jpeg)) &&
if ((section->len > sizeof(jpeg)) &&
(memcmp(section->data, jpeg, sizeof(jpeg)) == 0)) {
section->type = LFP_JPEG;
strcpy(section->name, "image");
Expand All @@ -237,7 +253,7 @@ static void lfp_identify_section(lfp_file_p lfp, lfp_section_p section)
section->type = LFP_BLOCK_OF_IMAGES;
return;
}

// Assume anything else that isn't called imageRef is plain text json
if (strcmp(section->name, "imageRef"))
section->type = LFP_JSON;
Expand All @@ -247,23 +263,23 @@ static void lfp_parse_sections(lfp_file_p lfp)
{
char *ptr = lfp->data;
int len = lfp->len;

// Move past the first header
ptr += MAGIC_LENGTH+sizeof(uint32_t);
len -= MAGIC_LENGTH+sizeof(uint32_t);

// Assume the first section is always the table of contents
lfp->table = parse_section(&ptr, &len);
lfp->table->type = LFP_JSON;
lfp->table->name = "table";

lfp_section_p cur_section = NULL;
while (len > 0) {
lfp_section_p new_section = parse_section(&ptr, &len);
if (!new_section) break;

lfp_identify_section(lfp, new_section);

if (!lfp->sections) lfp->sections = new_section;
else if (cur_section) cur_section->next = new_section;
cur_section = new_section;
Expand All @@ -277,12 +293,12 @@ static void lfp_save_sections(lfp_file_p lfp)
int jpeg = 0, raw = 0, text = 0, image_block = 0, lut = 0;
char *buf;
int buflen = 0;

// Save the plaintext json metadata
snprintf(name, STRING_LENGTH, "%s_%s.json", lfp->filename, lfp->table->name);
if (save_data(lfp->table->data, lfp->table->len, name))
printf("Saved %s\n", name);

while (section != NULL) {
switch (section->type) {
case LFP_RAW_IMAGE:
Expand All @@ -294,13 +310,13 @@ static void lfp_save_sections(lfp_file_p lfp)
free(buf);
}
break;

case LFP_JSON:
snprintf(name, STRING_LENGTH, "%s_%s%d.json", lfp->filename, section->name, text++);
if (save_data(section->data, section->len, name))
printf("Saved %s\n", name);
break;

case LFP_DEPTH_LUT:
// Parse the depth lookup table and save as plaintext
buf = depth_string(section->data, &buflen, section->len);
Expand Down Expand Up @@ -328,7 +344,7 @@ static void lfp_save_sections(lfp_file_p lfp)
free(buf);
}
break;

case LFP_JPEG:
snprintf(name, STRING_LENGTH, "%s_%.2d.jpg", lfp->filename, jpeg++);
if (save_data(section->data, section->len, name))
Expand All @@ -342,7 +358,7 @@ static void lfp_save_sections(lfp_file_p lfp)
printf("Saved %s\n", name);
break;
}

section = section->next;
}
}
Expand All @@ -351,7 +367,7 @@ static void lfp_close(lfp_file_p lfp)
{
if (lfp) {
lfp_section_p section = lfp->sections;

if (lfp->data) free(lfp->data);
if (lfp->filename) free(lfp->filename);
while (section) {
Expand All @@ -373,19 +389,19 @@ int main(int argc, char *argv[])
fprintf(stderr, "Usage: lfpsplitter file.lfp\n");
return 1;
}

if (!(lfp = lfp_create(argv[1]))) {
fprintf(stderr, "Failed to open file %s\n", argv[1]);
lfp_close(lfp);
return 1;
}

if (!lfp_file_check(lfp)) {
fprintf(stderr, "File %s does not look like an lfp\n", argv[1]);
lfp_close(lfp);
return 1;
}

// save the first part of the filename to name the jpgs later
if (!(lfp->filename = strdup(argv[1]))) {
lfp_close(lfp);
Expand All @@ -395,9 +411,9 @@ int main(int argc, char *argv[])
if (period) *period = '\0';

lfp_parse_sections(lfp);

lfp_save_sections(lfp);

lfp_close(lfp);
return 0;
}