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Handle integer overflow

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This commit is contained in:
Johan Walles 2023-07-08 17:09:06 +02:00
parent bf9edda02d
commit afcb45ab9d
1 changed files with 14 additions and 1 deletions
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15
m/reader.go
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@ -5,6 +5,7 @@ import (
"bytes"
"fmt"
"io"
"math"
"os"
"os/exec"
"path"
@ -517,6 +518,18 @@ func (r *Reader) GetLines(firstLineOneBased int, wantedLineCount int) (*InputLin
return r.getLinesUnlocked(firstLineOneBased, wantedLineCount)
}
func nonWrappingAdd(a int, b int) int {
if b < 0 {
panic(fmt.Sprintf("b must be >= 0, was: %d", b))
}
if a > math.MaxInt-b {
return math.MaxInt
}
return a + b
}
func (r *Reader) getLinesUnlocked(firstLineOneBased int, wantedLineCount int) (*InputLines, overflowState) {
if firstLineOneBased < 1 {
firstLineOneBased = 1
@ -535,7 +548,7 @@ func (r *Reader) getLinesUnlocked(firstLineOneBased int, wantedLineCount int) (*
}
firstLineZeroBased := firstLineOneBased - 1
lastLineZeroBased := firstLineZeroBased + wantedLineCount - 1
lastLineZeroBased := nonWrappingAdd(firstLineZeroBased, wantedLineCount-1)
if lastLineZeroBased >= len(r.lines) {
lastLineZeroBased = len(r.lines) - 1