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authorKostya Shishkov <kostya.shishkov@gmail.com>2020-04-11 09:57:33 +0200
committerKostya Shishkov <kostya.shishkov@gmail.com>2020-04-11 10:21:44 +0200
commitd23f332792cbfeec125033b84d386a112da71c48 (patch)
treeecad2a5e1df0885586f22b5e30f6b185fc1435d7
parentcd18e9d6925d272f5259e1beabc337b9bc6fd8f6 (diff)
downloadnihav-d23f332792cbfeec125033b84d386a112da71c48.tar.gz
core/io: check for non-unique codes while generating codebook LUT
-rw-r--r--nihav-core/src/io/codebook.rs26
1 files changed, 16 insertions, 10 deletions
diff --git a/nihav-core/src/io/codebook.rs b/nihav-core/src/io/codebook.rs
index 9882610..9355deb 100644
--- a/nihav-core/src/io/codebook.rs
+++ b/nihav-core/src/io/codebook.rs
@@ -144,7 +144,7 @@ const TABLE_FILL_VALUE: u32 = 0x7F;
const MAX_LUT_BITS: u8 = 10;
fn fill_lut_msb(table: &mut Vec<u32>, off: usize,
- code: u32, bits: u8, lut_bits: u8, symidx: u32, esc: bool) {
+ code: u32, bits: u8, lut_bits: u8, symidx: u32, esc: bool) -> CodebookResult<()> {
if !esc {
let fill_len = lut_bits - bits;
let fill_size = 1 << fill_len;
@@ -152,16 +152,19 @@ fn fill_lut_msb(table: &mut Vec<u32>, off: usize,
let lut_value = (symidx << 8) | u32::from(bits);
for j in 0..fill_size {
let idx = (fill_code + j) as usize;
+ if table[idx + off] != TABLE_FILL_VALUE { return Err(CodebookError::InvalidCodebook); }
table[idx + off] = lut_value;
}
} else {
let idx = (code as usize) + off;
+ if table[idx] != TABLE_FILL_VALUE { return Err(CodebookError::InvalidCodebook); }
table[idx] = (symidx << 8) | 0x80 | u32::from(bits);
}
+ Ok(())
}
fn fill_lut_lsb(table: &mut Vec<u32>, off: usize,
- code: u32, bits: u8, lut_bits: u8, symidx: u32, esc: bool) {
+ code: u32, bits: u8, lut_bits: u8, symidx: u32, esc: bool) -> CodebookResult<()> {
if !esc {
let fill_len = lut_bits - bits;
let fill_size = 1 << fill_len;
@@ -169,21 +172,24 @@ fn fill_lut_lsb(table: &mut Vec<u32>, off: usize,
let step = lut_bits - fill_len;
for j in 0..fill_size {
let idx = (fill_code + (j << step)) as usize;
+ if table[idx + off] != TABLE_FILL_VALUE { return Err(CodebookError::InvalidCodebook); }
table[idx + off] = (symidx << 8) | u32::from(bits);
}
} else {
let idx = (code as usize) + off;
+ if table[idx] != TABLE_FILL_VALUE { return Err(CodebookError::InvalidCodebook); }
table[idx] = (symidx << 8) | 0x80 | u32::from(bits);
}
+ Ok(())
}
fn fill_lut(table: &mut Vec<u32>, mode: CodebookMode,
- off: usize, code: u32, bits: u8, lut_bits: u8, symidx: u32, esc: bool) -> bool {
+ off: usize, code: u32, bits: u8, lut_bits: u8, symidx: u32, esc: bool) -> CodebookResult<bool> {
match mode {
- CodebookMode::MSB => fill_lut_msb(table, off, code, bits, lut_bits, symidx, esc),
- CodebookMode::LSB => fill_lut_lsb(table, off, code, bits, lut_bits, symidx, esc),
+ CodebookMode::MSB => fill_lut_msb(table, off, code, bits, lut_bits, symidx, esc)?,
+ CodebookMode::LSB => fill_lut_lsb(table, off, code, bits, lut_bits, symidx, esc)?,
};
- bits > lut_bits
+ Ok(bits > lut_bits)
}
fn resize_table(table: &mut Vec<u32>, bits: u8) -> CodebookResult<u32> {
@@ -254,7 +260,7 @@ fn build_esc_lut(table: &mut Vec<u32>,
let bits = code.bits;
if code.bits <= MAX_LUT_BITS {
fill_lut(table, mode, bucket.offset, code.code, bits,
- maxlen, code.idx as u32, false);
+ maxlen, code.idx as u32, false)?;
} else {
let ckey = extract_lut_part(code.code, bits, MAX_LUT_BITS, mode);
let cval = extract_esc_part(code.code, bits, MAX_LUT_BITS, mode);
@@ -268,7 +274,7 @@ fn build_esc_lut(table: &mut Vec<u32>,
let maxlen = min(sec_bucket.maxlen, MAX_LUT_BITS);
let new_off = resize_table(table, maxlen)?;
fill_lut(table, mode, cur_offset, key, maxlen,
- MAX_LUT_BITS, new_off, true);
+ MAX_LUT_BITS, new_off, true)?;
sec_bucket.offset = new_off as usize;
}
@@ -322,7 +328,7 @@ impl<S: Copy> Codebook<S> {
let code = cb.code(i);
if bits == 0 { continue; }
if bits <= MAX_LUT_BITS {
- fill_lut(&mut table, mode, 0, code, bits, maxbits, symidx, false);
+ fill_lut(&mut table, mode, 0, code, bits, maxbits, symidx, false)?;
} else {
let ckey = extract_lut_part(code, bits, MAX_LUT_BITS, mode) as usize;
if table[ckey] == TABLE_FILL_VALUE {
@@ -330,7 +336,7 @@ impl<S: Copy> Codebook<S> {
if let Some(bucket) = escape_list.get_mut(&key) {
let maxlen = min(bucket.maxlen, MAX_LUT_BITS);
let new_off = resize_table(&mut table, maxlen)?;
- fill_lut(&mut table, mode, 0, key, maxlen, MAX_LUT_BITS, new_off, true);
+ fill_lut(&mut table, mode, 0, key, maxlen, MAX_LUT_BITS, new_off, true)?;
bucket.offset = new_off as usize;
}
}