banan-os/LibImage/Netbpm.cpp

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#include <BAN/Optional.h>
#include <LibImage/Netbpm.h>
#include <ctype.h>
#include <inttypes.h>
#include <stdio.h>
namespace LibImage
{
static BAN::Optional<uint64_t> parse_u64(BAN::ConstByteSpan& data)
{
size_t digit_count = 0;
while (digit_count < data.size() && isdigit(data[digit_count]))
digit_count++;
if (digit_count == 0)
return {};
uint64_t result = 0;
for (size_t i = 0; i < digit_count; i++)
{
if (BAN::Math::will_multiplication_overflow<uint64_t>(result, 10))
return {};
result *= 10;
if (BAN::Math::will_addition_overflow<uint64_t>(result, data[i] - '0'))
return {};
result += data[i] - '0';
}
data = data.slice(digit_count);
return result;
}
BAN::ErrorOr<BAN::UniqPtr<Image>> load_netbpm(BAN::ConstByteSpan image_data)
{
if (image_data.size() < 11)
{
fprintf(stddbg, "invalid Netbpm image (too small)\n");
return BAN::Error::from_errno(EINVAL);
}
if (image_data[0] != 'P')
{
fprintf(stddbg, "not Netbpm image\n");
return BAN::Error::from_errno(EINVAL);
}
if (image_data[1] != '6')
{
fprintf(stddbg, "unsupported Netbpm image\n");
return BAN::Error::from_errno(EINVAL);
}
if (image_data[2] != '\n')
{
fprintf(stddbg, "invalid Netbpm image (invalid header)\n");
return BAN::Error::from_errno(EINVAL);
}
image_data = image_data.slice(3);
auto opt_width = parse_u64(image_data);
if (!opt_width.has_value() || image_data[0] != ' ')
{
fprintf(stddbg, "invalid Netbpm image (invalid width)\n");
return BAN::Error::from_errno(EINVAL);
}
image_data = image_data.slice(1);
auto width = opt_width.value();
auto opt_height = parse_u64(image_data);
if (!opt_height.has_value() || image_data[0] != '\n')
{
fprintf(stddbg, "invalid Netbpm image (invalid height)\n");
return BAN::Error::from_errno(EINVAL);
}
image_data = image_data.slice(1);
auto height = opt_height.value();
if (!Image::validate_size(width, height))
{
fprintf(stddbg, "invalid Netbpm image size\n");
return BAN::Error::from_errno(EINVAL);
}
auto header_end = parse_u64(image_data);
if (!header_end.has_value() || *header_end != 255 || image_data[0] != '\n')
{
fprintf(stddbg, "invalid Netbpm image (invalid header end)\n");
return BAN::Error::from_errno(EINVAL);
}
image_data = image_data.slice(1);
if (image_data.size() < width * height * 3)
{
fprintf(stddbg, "invalid Netbpm image (too small file size)\n");
return BAN::Error::from_errno(EINVAL);
}
BAN::Vector<Image::Color> bitmap;
TRY(bitmap.resize(width * height));
// Fill bitmap
for (uint64_t y = 0; y < height; y++)
{
for (uint64_t x = 0; x < width; x++)
{
const uint64_t index = y * width + x;
auto& pixel = bitmap[index];
pixel.r = image_data[index * 3 + 0];
pixel.g = image_data[index * 3 + 1];
pixel.b = image_data[index * 3 + 2];
pixel.a = 0xFF;
}
}
return TRY(BAN::UniqPtr<Image>::create(width, height, BAN::move(bitmap)));
}
}